最新刊期
卷 37 ， 期 6 ， 2009
- 摘要：The generalization of reinforcement learning methods to large-scale or continuous spaces has become a major focus in the research field of reinforcement learning.Unlike the present reinforcement learning methods for continuous spaces based on a value-function approximation method,the reinforcement learning is constructed as a simple binary-class problem.A kind of reinforcement learning method for continuous state and action spaces based on a Gaussian process classifier is proposed using a classification algorithm to obtain a control policy.At first,a continuous action space is discretized into discrete actions with definite number,and the Gaussian process classifier is used to predict the probability of class for a continuous-state-discrete-action pair.Then a continuous action is generated based on a weighted operation of the positive actions with their probability values.Computer simulations involving a boat problem illustrate the validity of the proposed reinforcement learning method.关键词：gaussian process;classifier;continuous space;reinforcement learning;boat problem3|2887|9更新时间：2025-07-16
- 摘要：Frequency Modulated Continuous Wave (FMCW) Synthetic Aperture Radar (SAR) is a new conceptual SAR system.This paper analyses the effect of the platform’s continuous motion in squint FMCW SAR,i.e.generating Doppler frequency shift,and its effect on image focusing.Considering the deficiency of the present FS algorithm in the case of high squint angle,this paper proposes an equivalent side-looking method for squint FMCW SAR.After pre-processing for the squint SAR data,we can use the imaging algorithm for side-looking mode to process the squint SAR data;for the azimuth focusing depth induced by the pre-processing,this paper utilizes the azimuth non-linear chirp scaling algorithm to overcome this phenomenon.At last,imaging results of the simulated data have proved the validity of the proposed algorithm.关键词：squint FMCW SAR;equivalent side-looking method;azimuth focusing depth;non-linear chirp scaling2|1272|13更新时间：2025-07-16
- 摘要：The forward projection of cone-beam CT image reconstruction algorithms requires both excessive computation and time consuming.A novel CT forward projection method based on graphics processing unit is proposed for accelerating the forward projection calculation.The method achieves the forward projection calculation in circular cone-beam scanning mode by using texture mapping techniques in GPU programmable pipeline.Because projections are calculated slice by slice in parallel,this method has the advantages of higher computational efficiency and calculation at full floating point precision.Three optimization methods are also presented for further improving the execution efficiency of the method.The advantages of this method are verified by the experiments of the projection calculation of Shepp-logan phantom and 3D image reconstruction with iterative image reconstruction algorithm.关键词：computerized tomography;graphics processing unit;image reconstruction;forward projection2|1892|7更新时间：2025-07-16
- 摘要：The Loffeld’s Bistatic Formula (LBF) is the first solution for general bistatic SAR point target reference spectrum. Unfortunately,the original LBF shows limitation when applied to the bistatic system which consists of different type of platforms. By using a Doppler contribution weight in the phase history division,the weighted LBF can be used to focus the bistatic SAR data collected by heterogeneous platforms. A WLBF-based range Doppler algorithm is presented to focus the whole SAR scene.关键词：bistatic SAR;weighted LBF;heterogeneous platform;RD algorithm2|1095|4更新时间：2025-07-16
- 摘要：The Spaceborne ATI-GMTI system is made up of several satellites equipped with Synthetic Aperture Radar.The space between satellites must be big enough to acquire high sensitivity and avoid collision.However,the long baseline brings on blind velocity and worsens the GMTI performance.It is an important problem to determinate the length of the along track baseline for an ATI-GMTI system.Basing on splitting the whole aperture into multiple sub-apertures,this paper investigates the design method of optimum velocity response.Firstly,the output signal-to-clutter-plus-noise ratio expression of the system is derived,and then the way of designing optimum velocity response is presented.Finally,computer simulation results validate its effectiveness.关键词：along track interferometric;ground moving target indication;output SCNR2|876|0更新时间：2025-07-16
- 摘要：Illumination change is of great importance in affecting the performance of some existing face recognition algorithms.Though edge-based methods are robust to illumination variation and are easy to implement,they do not work perfectly in the cases with expression variation.In order to improve both the lighting robustness and expression robustness,a novel face recognition method based on the fusion of binary edge and grayscale features was proposed.Also the second-order mutual information was used for the similarity metric of grayscale face image for the first time.AR dataset and Yale dataset with various illumination and expression variation were tested to evaluate the effect of the proposed method.Results showed that the overall face recognition rate of the proposed method was better than that of other methods.And these results indicate that our method is more effective for practical use.关键词：face recognition;illumination change;expression change;feature fusion;binary edge feature;grayscale feature2|1181|3更新时间：2025-07-16
- 摘要：An automatic identification system based on the public wireless mobile IP network—MIP-AIS is put forward,to give a solution of the navigation and collisions of non-IMO Convention ships in the coastal and inland waterways,which will compensate the AIS based on VHF communications for the application limitations.Based on the research of the foundation principle and search algorithm in MIP-AIS,some key technologies are resolved about finding the "adjacent" ships by the public wireless communications,achieving the real time information transmission among the "adjacent" ships and minimizing the burdens on the wireless communications.The efficiency of the search algorithm and the bandwidth demand of data transmission are analyzed.The experiments show that the MIP-AIS is capable to realize the ship identification in coastal and inland waterways,the function and performance of MIP-AIS can satisfy the requirements of IMO international standards.关键词：automatic identification system (AIS);GPRS/CDMA;mobile IP AIS (MIP-AIS)2|820|1更新时间：2025-07-16
- 摘要：The biggest challenge in the development of spaceborne/airborne hybrid bistatic synthetic aperture radar,abbreviated as SA-BSAR in the text,is the beam synchronization of the antenna footprints.A method by performing beam steering on both sides has been reported in some published literature.There are,however,in the existing method,some assumptions that significantly limit its practicability.Two methods are given and validated.In the discussion of the first method,a modified mathematical model is presented to cancel those assumptions.The second method transmits a very wide beam in azimuth making use of the characteristic of the receiving distance in SA-BSAR is much shorter than the one in spaceborne SAR systems.The second approach provides,with the same azimuth resolution,a longer scene extension than the length achieved by the first approach.Advantages and disadvantages of each method are discussed and the applicable ranges for each method are also analyzed.关键词：spaceborne/airborne hybrid bi-static SAR;beam synchronization;beam steering;wide-beam illumination2|1151|2更新时间：2025-07-16
- 摘要：The observation model plays a key role in performance improvement of the super resolution algorithms.The author proposed a weight-matrix based blind super resolution algorithm:a new observation model based on a motion compensate matrix and a weight-matrix is defined first,then the high resolution image and the weight matrix were joint estimated by alter minimization method under the framework of Maximum A Prior(MAP).Evaluated by both still and active image sequences,the algorithm can descript the degrading process of the observed low resolution images more accurately.It shows obvious performance improvement compared with the traditional super resolution algorithm.For several cases,it has even exceeded the results when the observation model is known.关键词：blind super resolution restoration;observation model;maximum a prior;weight matrix2|1091|3更新时间：2025-07-16
- 摘要：A precise algorithm of determining theoretical locations of sunglints in remote sensing images from geostationary satellites was described.An application of the algorithm in FY-2C Images for different hours in each day of year 2006 was presented,and with help of sea-land distribution information,temporal and spatial characteristics of sunglint happenings could be inferred.Theoretical calculation results of selected samples were compared with manual results.Errors were analyzed and two adjustments were made,which led to satisfying consistent results.The emerging mechanism of sunglint areas was discussed then,and the theoretical calculation results of their shapes and sizes were shown in a visualized way.关键词：satellite remote sensing;geostationary satellites;sunglints;locating of sunglints2|1028|0更新时间：2025-07-16
- 摘要：An INS/dual-antenna integrated missile positioning method is presented to overcome the problem of lacking of positioning information in SAR scene matching application.While imaging ground objects,it is capable of measuring the height of the missile via an additional antenna system with downward beam.The positioning principle is introduced firstly and then the positioning model using relative range,Doppler frequency and the missile altitude is derived.The effects of the missile altitude measurement error on the positioning error are also given.In the next part,the method for reduction of errors resulting from the terrain elevation exactly below the missile is presented based on iteration and terrain matching,respectively,for varied hypsography.The radar system requirements of dual-antenna positioning are analyzed in the end.The simulation results show that the positioning error of the above techniques is remarkably smaller than that of using INS and barometric altimeter.关键词：missile-borne SAR;missile positioning;terrain navigation2|1131|9更新时间：2025-07-16
- 摘要：A improved secure communication method based on chaotic masking is proposed to overcome weakness of low dimensional chaotic map.In the scheme the chaotic time series with dynamic parameters for encryption based on hierarchical two-level key management is designed .The performance of the encryption speed and transmission speed is not lowered while the security of ciphertext is obtained.The results showed that low dimensional chaotic map has great potential of secure communication.关键词：chaotic map;key;attack;secure communication2|1098|7更新时间：2025-07-16
- 摘要：On base of detailed analysis of the decomposed coefficients of BOR multiwavelet,the "layer" concept of an image in MWD (multiwavelet domain) was proposed.For this unique character,data can be hidden in different layer subimages,the selection of hiding layer undoubtedly gives another secret key.An adaptive blind watermarking algorithm is put forward to embed a binary image into the first layer subimage and four layers respectively according to above trait.Experimental results show that the two given methods have good imperceptibility and high robustness.关键词：BOR multiwavelet;layer character;digital watermarking;robustness2|949|1更新时间：2025-07-16
- 摘要：With a comparison on a few of rate estimation algorithms,an improved methods resided in the decoder is proposed in this paper.The proposed method estimates the rate of each bitplane with the side information and the Laplacian distribution of difference between the source and the side information.Then,the result is transmitted to the encoder via a feedback channel.The experimental results show that the mean error of estimated rate is within(0.02 for each bit,as compared to that of the ideal rate estimation algorithm.With an efficient improvement on the precision of rate,the proposed method declines the computational complexity of the decoder.关键词：distributed video coding;laplacian distribution;rate estimation2|1092|4更新时间：2025-07-16
- 摘要：Based on the orthogonal feature,a mathematic model is established in frequency domain for MIMO OSTBC-OFDM systems.Then we present a subspace blind channel estimation method which subjects to the constrained optimization.This method has less computational complexity.Finally,we use precoding to resolve the ambiguities which are inherent to any second-order statistics(SOS) based method.The results show that the presented estimation method has faster convergence,and it has no constraint for input symbols or additional bandwidth consumption.关键词：blind channel estimation;orthogonal space-time block codes(OSTBCs);multiple-input-multiple-output(MIMO);orthogonal frequency division multiplexing(OFDM)2|1298|5更新时间：2025-07-16
- 摘要：Radar imaging must obtain an extent of target spatial spectral-domain sampling,and the filling of spatial spectral domain is in direct connection with the quality of imaging result.Firstly,this paper proves the effect of spatial convolution that exists in MIMO(Multiple-Input Multiple-Output)radar signal model.Based on the electromagnetic inverse scattering theory,an imaging method is derived and the relation between imaging performance and spatial spectral-domain filling is presented.The influence of transmitting and receiving array on the spatial spectral-domain filling is discussed.Some principles of array distribution are achieved.Finally,simulations are performed in order to validate the effectiveness of the imaging method.The simulation results show the effectiveness of the imaging method and the theoretical results.关键词：radar imaging;MIMO radar;spatial spectral-domain2|1330|9更新时间：2025-07-16
- 摘要：An algorithm is proposed for the non-consistent judgment matrix in AHP.A primary judgment matrix is generated firstly through pre-ordering the targeted factor set,and a compared matrix is built through the top integral function.Then a relative error matrix is created by comparing the compared matrix with the primary judgment matrix which is regulated under the control of the relative error matrix and the dissimilar degree of the matrix step by step.Finally,the targeted judgment matrix is generated to satisfy the requirement of consistence and the least dissimilar degree.The feasibility and validity of the proposed method are verified by simulation results.关键词：analytical hierarchy process;judgment matrix;consistency;pre-ordering;top integral function2|1028|2更新时间：2025-07-16
- 摘要：The discrete Hartley transform has been proposed as an alternative tool suitable for DFT referring real data and has been used in many signal and image processing applications.Because the existed algorithms for three-dimension discrete Hartley transform(3-D DHT)only can compute sequences whose lengths are the m th power of 2(m is an integer),this paper proposes a novel split-radix-2/4 algorithm for the fast computation of 3-D DHT,which provides more flexibility in selecting the sequence length.Moreover,it achieves a large reduction in computational complexity compared to computing by zero padding.关键词：3-D DHT;split-radix;fast algorithm2|983|0更新时间：2025-07-16
- 摘要：A variational super-resolution reconstruction method is proposed.First of all,a kind of structure-adaptive anisotropic filter is designed based on the recently reported bilateral filtering.It is not only edge-preserving but also corner-preserving.Then,an anisotropic Markov random field(MRF)model is deduced,which is the improvement of both the classical MRF and bilateral total variation image models.Driven by the anisotropic MRF model,an edge-enhancing super-resolution algorithm is subsequently proposed,simultaneously estimating the high resolution image and the sub-pixel motion among low-resolution frames.The half-quadratic regularization approach and steepest descent are exploited to solve the corresponding minimization functional.Experiment results demonstrate the effectiveness of the proposed approach,both in the visual effect and the peak signal to noise ratio(PSNR)value.关键词：super-resolution;image restoration;anisotropic MRF model;bilateral filter;motion estimation2|2409|9更新时间：2025-07-16
- 摘要：Current concurrency control protocols can not eliminate all covert channels in multi-level secure database management systems(MLS/DBMS).Existence of covert channels leads penetrated malicious transactions leak and interpolate confidential information.To improve database survivability,covert channels in MLS/DBMS are firstly analyzed.Then Conspired and malicious noise transactions can be detected based on malicious transaction characteristics and abnormal varieties of covert channel capacities by simulated parameters and experiments according to real systems.Further,transitive property of multi-conspiracies along with the influence of malicious noise transaction is analyzed.关键词：multi-level secure model;covert channel;malicious transaction;conspiracy2|925|4更新时间：2025-07-16
- 摘要：We propose a two-dimensional piecewise linear spiking neuron model that combines the dynamical property of Hodgkin-Huxley neuron model and the analytical property of integrate-and-fire neuron model.We show that this framework allows a qualitative description of excitable systems through bifurcation theory but also a quantitative analysis of neuronal behavior through an explicit analytical representation of the state variables.A detailed analytical study of the model is presented.The model gives rise to new neuro-computational properties not present in one-dimensional integrate-and-fire neuron models.In experiments,using this model we simulated the spiking and bursting behavior of known types of cortical neurons.关键词：piecewise linear dynamical system;integrate-and-fire neuron;bifurcation analysis;bursting;cortical neuron2|1202|5更新时间：2025-07-16
- 摘要：Make a uniformly orthogonal testing for 20 kHz signal PCB of radar,and use the testing data to analysis the testing results.Conclude the general rule of performance degradation of electronic equipment in the environment of temperature and humidity;Aiming at the electronic equipment reliability prediction problem,which play an important role in fault prediction,present an new method about electronic equipment reliability prediction based on Combine Environmental ALT.This method extends the performance degradation theory to accelerated performance degradation theory.The no failure data problem in ALT was resolved combining the theory and traditional reliability prediction.In the end,validity of this method was proved by an example.关键词：temperature and humidity testing;metal cauterization;accelerated performance degradation testing(APDT);fault prediction;reliability prediction2|1454|6更新时间：2025-07-16
- 摘要：In view of the variable curvature radius of the platform and different orientations of elements,array manifold model for arbitrary 3D conformal array is established.The equivalence of the array mutual coupling and angularly dependent gain and phase uncertainties is developed.With the help of some carry-on instrumental sensors and some time-disjoint pilot sources in unknown directions,Instrumental Sensors Method(ISM)is proposed for the mutual coupling calibration of conformal array antenna.ISM is able to achieve a favorable mutual coupling auto-calibration just using a one-dimensional search and solution of linear system of equations,with no high-dimensional nonlinear search and convergence burden involved.Simulation results are provided to demonstrate the effectiveness and behavior of the proposed ISM.关键词：conformal array antenna;array calibration;mutual coupling;instrumental sensors method2|1198|8更新时间：2025-07-16
- 摘要：A new algorithm for constrained multi-objective optimization is presented.The algorithm treats the constraints as an objective and the immune clone and immune memory mechanism are introduced.Therefore,the new algorithm could find the Pareto-optimal solutions from the feasible region and the edge of the infeasible region,which assures both the convergence and diversity of the obtained solutions.Simulation results show that the new algorithm has much better performance in finding a much better spread of solutions,in maintaining a better uniformity of the solutions and in obtaining a better convergence.关键词：artificial immune system;constrained multi-objective optimization;immune memory;Pareto-optimal2|1707|12更新时间：2025-07-16
- 摘要：The optimal cut angle in passive triangulation system is studied in the case of bearing-nly (1D) and two dimensional (2D) passive sensor system.In the sense of minimum RMSE,the optimum cut angle is obtained under the consideration that the two sensors have different measure accuracy.The influence on the optimal cut angle caused by elevation and measure accuracy is discussed.The obtained results are helpful for the optimal deployment of passive sensors.关键词：triangulation;optimal cut angle;optimal deployment of passive sensors2|1049|4更新时间：2025-07-16
- 摘要：Currently the design data in a programmable chip is widely protected by block cipher,and the ciphertext is deciphered by a keyed circuit before the use of the data.Typically,the size of such a circuit is from 30 to 65 thousand gates,and the processing rate of it is from 3.0 to 3.7 Gigabits per second(Gbps).This paper proposes a 2-round multivariate cryptosystem.The algorithm of its decryption does not compose the constituent polynomial maps but only concatenates them.And with the processing rate from 7.76 to 13.6 Gbps,the decryption can be implemented by only about several or ten thousand gates.Because the decryption polynomials are encapsulated and disguised,most attacks against multivariate cryptosystems become inapplicable.And the new cryptosystem also resists the attacks that do not need to know the decryption polynomials,including the interpolation,linearization attack,side-channel attack,etc.关键词：intellectual property protection;chip design protection;cryptographic chip;information security2|945|0更新时间：2025-07-16
- 摘要：In order to enlarge the array aperture in the case of having determinate number of sensors,this paper utilizes a sparse symmetric array which allows the inter-element spacing to exceed the quarter-wavelength upper limit.To avoid the direction-of-arrival (DOA) ambiguity and complicated 2-D search,a method based on rank reduction(RARE) has been presented for estimating the DOA and range of near-field sources without ambiguity.And the ambiguity of DOA estimation is analyzed.The algorithm utilizes second-order statistics and only requires 1-D search,and all parameters are automatically matched.Therefore the computational burden is reduced and the spatial resolution is enhanced when the number of sensors is limited.Simulations are included to show the validity of this proposed method.关键词：signal processing;near field source localization;rank reduction;sparse symmetric array;DOA estimate;range estimate;DOA ambiguity2|1594|13更新时间：2025-07-16
- 摘要：A fit setting of the scale factor F can usually improve greatly the performance of differential evolution,however,how to set is nuisance.Two differential evolutions without scale factor F are presented in the paper.The algorithms look upon each individuals as a charged particle and utilize the attraction-repulsion mechanism of the particles to decide on the step length of the motion of the individual in the direction of the difference for the purpose of avoiding the setting of the scale factor F.The comparisons of numerical experiments among the proposed algorithms,two PSO algorithms and four other algorithms with the different setting strategies are done, which show that the performance of the proposed algorithms outperform other compared algorithms.关键词：electromagnetism-like mechanism;global optimization;particle swarm optimization;differential evolution12|1353|11更新时间：2025-07-16
- 摘要：The rotational phase component (RPC) of target’s prominent scattering centers may affect the performance of Doppler centroid tracking (DCT) seriously in the inverse synthetic aperture radar (ISAR) autofocusing.Based on a unified ISAR scattering signal model,this paper introduces the concept of induced angle to evaluate the effect of RPC,and the factors affecting the induced angle are also analyzed.It is proved that the performance of DCT may be improved with the increase of radar pulse repetition frequency,and it is also shown that two improved DCT methods,i.e.circular shifting based DCT (CS-DCT) and image equilibrium based DCT (IE-DCT) are equivalent in principle.At last,numerical experiments are also provided to verify the effectiveness of the above performance analysis.关键词：inverse synthetic aperture radar (ISAR);autofocusing;Doppler centroid tracking (DCT);pulse repetition frequency (PRF)2|1696|2更新时间：2025-07-16
- 摘要：This paper analyzes the rank of clutter with arbitrary beamwidth,observed by a sidelooking radar with arbitrary element spacing under the far field condition.The rank of spatial clutter with arbitrary beamwidth and element spacing is first analyzed in the range-wavenumber domain.Utilizing the space-time equivalence,the space-time clutter observed by an array is equivalent to the spatial clutter observed by another array with larger size.Thus,the rank of space-time clutter with arbitrary beamwidth and element spacing can be derived in a similar way and a formula for computating the space-time clutter rank is given.Simulation results are given to verify the validity of the analysis.关键词：sidelooking radar;radar clutter;clutter rank;space-time adaptive processing(STAP)2|853|1更新时间：2025-07-16
- 摘要：This paper proposes a novel conformal tri-polarization antenna,which has three independent ports and is capable of receiving up to three independent components of electric field at single location.To verify the design,a prototype antenna was manufactured and measurde.The measured result agrees well with the simulations .The measured VSWR 3:1 banwidth covers 150MHz.The antenna consists of three stacked layers with a total height of 10mm.关键词：polarization;conformal antenna3|2246|5更新时间：2025-07-16
- 摘要：The quadrature demodulation errors in broadband phased array radar will influence the performance of the broadband beamforming.Based on the broadband signal model and demodulation error model the covariance matrices of the time-domain and frequency-domain broadband beamforming in error case are derived.Through the analysis of the covariance matrix,it is found that the degrees of freedom of the interference will increase and the performance of beamforming will become worse.Consider the demodulation errors,more degrees of freedom should be provided to a real radar system.关键词：broadband phased array radar;broadband beamforming;quadrature demodulation errors2|1016|0更新时间：2025-07-16
- 摘要：Based on the analysis of advantages and disadvantages of present single station passive location methods,and contrapossing the characteristics of fast locating immobile targets with mobile platforms,a fast passive location method has been put forward in this paper via resolving the relations of angle and its changing rate between observation station and the target.According to the GDOP (Geometric Dilution of Precision) of location error,the simulation of location precision with single or multiple times validates its high precision and quickness.关键词：single station location;passive ranging;location precision3|1838|7更新时间：2025-07-16
- 摘要：The multipath propagation of skywave over-the-horizon radar (OTHR) in target tracking makes the tracking filter in radar coordinate inevitably produce several tracks for a single target,and the propagation modes of the tracks are not determinate.The target state in ground coordinate can be obtained by the association of tracks,propagation modes and targets,and track fusion.Other problems of OTHR are low detection probabilities,low measurement accuracy and low data-sampling rate,which usually results in track absence in some radar dwells or the case that tracks of some modes may be never initialized.An adaptive OTHR multipath track fusion algorithm is proposed,which decides the optimal association of tracks,propagation modes and targets by the information of present time and the historical information.The mode association hypothesis of each step is modified with new data cumulating.The simulation results show that the algorithm of this paper can greatly decrease the state estimation error,compared with the multihypothesis fusion of multipath OTHR tracks algorithm.关键词：skywave over-the-horizon radar;track fusion;track absence;target tracking2|1178|7更新时间：2025-07-16
- 摘要：Abstract:Since the effect of nonlinear phase factor and aberration which result in image blurring and resolution reducing in Millimeter wave synthetic aperture radiometer (MMW-SAR) near sensing imaging,the fractional Fourier transform (FRFT) and Radon-Wigner transform (RWT) using in diffraction imaging are introduced based on analyses the comparability between MMW-SAR passive imaging and the optical diffraction patterns. Through correlation and coordinate rotation on the time-frequency plane,the introduced algorithms reduce the impact of nonlinear phase and improve image quality. And mutual coherence function propagation equation (MCFPE) is also raised into MMW-SAR near sensing imaging,which can eliminate the fuzzy problem of imaging through twice Fourier transform and improve the imaging quality.关键词：millimeter wave radiometer;aperture synthesis;near imaging;MCFPE;FRFT;RWT2|986|6更新时间：2025-07-16
- 摘要：The effect of PN code synchronization and BER together on transmission ranges in DS/CDMA Moble Ad hoc networks(MANET)is studied.The expected forward progress per slot that is a product of local throughput and link distance is put forward.The optimum transmission ranges can be obtained by maximizing expected forward progress.The results show that the probability of PN synchronization decreases the expected forward progress per slot compared with previous results.The results also show that the optimum probability p of each terminal transmitting a packet is different from previous results.关键词：ad hoc;DS/CDMA;PN code synchronization;expected progress per hop2|828|2更新时间：2025-07-16
- 摘要：Data structure is one of the key technologies for real-time information-hiding communication system.Therefore,the system design should be a related problem between source statistics and channel state as well as transmission rates.To satisfy some requirements with side-information at decoder,the paper presents a new method to approach information-hiding communication performances with asymmetric data structure.By means of variances distribution of image coefficients and channel states under various WNR,the proposed method can reduce system complex.Comparing the theoretical results by experimentation considered SCS and QIM(DC-DM)as well as SS techniques,the communication system possess the good trade-off performances.关键词：data-hiding communication;side information;codec;asymmetric data structure;transmission rates2|871|0更新时间：2025-07-16
- 摘要：In order to accurately model and quickly analyze the irregular microstrip patch antenna,the hybrid MPSTD-FDTD method is proposed based on the combination of multidomain pseudospectral time-domain (MPSTD) and finite difference time domain (FDTD),as thus,the hybrid method possesses the advantages of two time domain methods of MPSTD and FDTD.Firstly,detailed process of the hybrid method is presented,and matching condition for the subdomains interfaces corresponding with the hybrid method is derived.Secondly,the computation precision of the hybrid method and the primary factors affecting the computation precision are analyzed.Finally,an inclined microstrip patch antenna is analyzed using the hybrid method,numerical results indicate that the hybrid method is valid and accurate.关键词：MPSTD-FDTD algorithm;microstrip patch antenna;characteristic variables-physical boundary (CV-PB) matching condition2|920|3更新时间：2025-07-16
- 摘要：The seasurface scattering theroy was focused on microwave band.The multipath echo model at sea under the VHF band is analyzed.The complex dielectric constant is computed firstly.By simulating the correlative reflection coefficient and Rayleigh criterion,the conclusion is obtained that the specular reflection occupies the main in the scattering signals,the sea surface can be assumed smooth surface,the multipath model based on the specular reflection model is correct under the sea state six and the grazing angle less than five degrees.关键词：shipboard radar;the coarse sea surface;sea state;echo model2|2123|5更新时间：2025-07-16
- 摘要：A co-occurrence feature space is constructed,which can effectively reflect the changes of higher-order statistical characteristics caused by JPEG steganographic techniques.Supported by this feature space,a new scheme for designing steganalytic algorithms is presented based on multivariate regression model.With only JPEG stego images and no embedding details needed,this designing scheme is able to provide a good generality.Experimental results indicate that,our designing scheme can also produce remarkable steganalytic algorithm even for MB1 embedding mechanism,which has reached high performance of security.关键词：multivariate regression;JPEG;steganalysis;co-occurrence feature;MB(model based)2|767|2更新时间：2025-07-16
- 摘要：By analysis the factors which affect of UHF RFID reader's digital receiver,make it clear between signal noise first time,DC offset and receiver performance.A novel design of Base-band digital signal process method for Zero-IF receiver is presented,such as oversample filtering,DC offset adjust and correlation decode to solve this problem.The methods are implemented on Altera's FPGA and got better performance than other methods.关键词：RFID reader;Zero-IF;DC offset;base-band digital signal process3|1509|1更新时间：2025-07-16
- 摘要：For the robust loading sample matrix inversion (LSMI) beamforming algorithm,a solution is given,therein the precise formula for loading level is obtained,and it deduces that the optimal loading level is negative,and bears no relation to the constraint parameter.In order to improve the jammer resisting performance of LSMI,the linear jammer parameter constraint (LJC) is proposed,via modeling and solving the LSMI beamforming algorithm with LJC,the expression of the optimal weighting vector is obtained,and the solving method is given particularly.Numerical examples attest the correctness and the validity of the proposed algorithm,and indicate that LJC-LSMI has stronger capability for resisting the jammer than LSMI,and has more robust pointing performance than linear constraint minimum power (LCMP) beamforming algorithm.关键词：adaptive beamforming;loading sample matrix inversion;steering vector mismatch;linear jammer parameter constraint;negative diagonal loading2|1658|3更新时间：2025-07-16
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