最新刊期
卷 35 ， 期 12 ， 2007
- 摘要：Based on the clonal selection optimization with quantum crossover,a novel Quantum Clonal Optimization Algorithm is proposed for solving SAR image classification problems,theoretical analysis based on the theory of Markov has proved that the new algorithm could converage to the global optimum.The new algorithm can carry out searching in many directions around the same antibody simultaneously.The proposed quantum crossover operator realizes the information interactions among the sub-population so as to prevent premature convergence effectively.The experimental results on X-band and Ku-band SAR images indicate that compared with the Fuzzy C-means algorithm,the K-Nearest Neighbor algorithm,and the Clonal Selection Algorithm,the average correct rate of the new algorithm is improved by 13.57%,11.79% and 5.79%,and the robust of the new algorithm also outperforms the other three methods.关键词：clonal selection;quantum computing;SAR image;image classification3|808|5更新时间：2025-07-16
- 摘要：This paper presents an algorithm of sensor management based on reweighted interacting multiple models kalman filtering(RIMMKF).In this algorithm,discrimination via,information gain is obtained by measurement update and Markov transform update of joint multi-target probability using RIMM,and then the sensor resource is distributed by maximizing information gain.In this algorithm,the deficiency of interacting multiple models (IMM) is improved by RIMM.Simulation results show that compared with the method of IMMKF discrimination,this algorithm is reasonable and the sensor resource is effectively distributed under the circumstance of dynamic multiple models.关键词：sensor management;discrimination;information gain;reweighted interacting multiple models kalman filtering(RIMMKF)2|752|3更新时间：2025-07-16
- 摘要：Antenna subset selection is an effective method to reduce the number of radio frequency chains and improve the spatial correlation properties.However,the space for the installation of the antenna array is usually limited in practical applications,thus the performance of antenna selection will be limited.Based on the polarization reconfigurable antenna,a low complexity selection scheme is proposed.This proposed scheme possesses compact structure,and can be implemented in small terminals.Significant performance improvement can be shown through theory analysis and Monte Carlo simulations.关键词：reconfigurable antenna;antenna selection;polarization diversity;MIMO system;correlation matrix4|1130|6更新时间：2025-07-16
- 摘要：CPT is a data hiding scheme for binary images.In this paper,we prove that there are 2mn-r equivalent keys for CPT.Moreover,by viewing the CPT as a block cipher,we propose a fast key searching algorithm with difference analysis,which can succeed in output a equivalent key given mn pairs of plain and cipher data with negligible time complexity O(2r).关键词：cryptanalysis;steganalysis;CPT scheme;difference analysis2|638|1更新时间：2025-07-16
- 摘要：A method based on the 4-port S parameters of the unit cell and the Bloch theory is proposed to analyze planar 2-D Left-handed structures.The Left/Right-handed frequency bands are identified by the Bloch wave number and the Bloch impedance.Compared to the previous unit cell analysis methods,the new method is suitable for analysis of more flexible structures,can give better consideration to the distributed elements’ dispersion,can determine the Left/Right-handed frequency bands more easily and accurately,and can be used to analyze anisotropic and lossy structures.As an example,a capacitance-enhanced Left-handed structure is designed and analyzed with the new method.FDTD simulation is also performed to illustrate the backward wave propagation in the periodic structure with infinite arrays in Left-handed frequency band.This demonstrates the effectiveness of the new method.关键词：planar 2-D left-handed structures;S parameters;Bloch wave number;Bloch impedance;backward wave2|1035|0更新时间：2025-07-16
- 摘要：A stochastic simulator prototype DWSS on precipitation,temperature and solar radiation in JAVA was developed.This paper describes the designing considerations,functions,and features of it.DWSS can be used on desktop or network environment,and a running example with the help of some figures and table on desktop is presented.This simulator can provide more selections to users than other popular weather generators.关键词：weather;stochastic modeling;Java;Web4|1892|2更新时间：2025-07-16
- 摘要：Air-or vehicle-borne Ultra-Wide Band Synthetic Aperture Radar (UWB SAR) has the capability to detect landmines and landmine fields over large area from a standoff distance quickly,which is the trend of landmine detection.In order to reduce the false alarms in landmine detection,it is needed to extract efficient landmine feature to classify landmine and clutter.In this paper,a High-Dimensional Time-Frequency Distribution (HDTFD) based method to extract the aspect invariance feature of landmine scattering is proposed,where the realization can be performed with High-Dimensional Wigner-Ville Distribution (HDWVD) and High-Dimensional Choi-Williams Distribution (HDCWD).The proposed HDTFD based feature extraction method can extract the frequency and aspect angle dependent information in scattering function efficiently while maintains high spatial resolutions.The HDWVD and HDCWD based feature extraction methods have been compared using the real data collected by the Rail-GPSAR system in terms in resolution,cross-terms suppression and aspect invariance feature extraction.Field data processing results have shown that the HDCWD based feature extraction method is more suitable for real data processing.关键词：ultra-wide band;synthetic aperture radar;feature extraction;high-dimensional time-frequency distribution;landmine2|605|1更新时间：2025-07-16
- 摘要：Based on the principle of high frequency ground wave radar in realization and the basic principle of the target’s angular glint,the target’s angular glint in the echo signals of radar are suppressed by dummy frequency agility.Experiments show that the method can suppress the angular glint of the complex backward scatter target effectively without affecting the echo signals of the point target.Moreover,the method can be put into use in practical projects for its low computation cost.关键词：angular glint;dummy frequency agility;high frequency ground wave radar2|782|1更新时间：2025-07-16
- 摘要：This paper discusses SAR Internal Calibration (SIC) Technique in TWT transmitter SAR system.Firstly,the SIC algorithm is presented.The following section focuses on the SIC signal processing and precision analysis.Finally,a SAR image data is corrected by the algorithm mentioned above.The next paper will discuss the internal calibration scheme based on transmogrification electrical bridge principle.关键词：SAR Internal calibration;relative gain shift;internal calibration precision;image gray calibration5|772|4更新时间：2025-07-16
- 摘要：Clutter suppressing is the prime problem for ground moving target indication(GMTI).We focus on clutter inner undulating which influences the performance of moving target detection.Exploring correlation between along-track synthetic aperture radar (SAR) images,a clutter suppressing algorithm based on joint noise eigen-subspace projection is presented.The robustness for clutter inner undulating and images registration error is proved by subspace analysis and extensive simulation.关键词：ground moving target indication;synthetic aperture radar;distributed constellation;subspace2|950|3更新时间：2025-07-16
- 摘要：A novel method is proposed for segmenting multi-look fully polarimetric SAR images.The Wishart distribution of the covariance matrix is integrated with the Markov random field model,and then the iterative conditional modes (ICM) algorithm is taken to implement the maximum a posteriori estimation of pixel labels.The initial segmentation map for ICM is obtained using the Wishart-based ML.Using multi-look fully polarimetric SAR images,acquired by the NASA/JPL AIRSAR sensor,the new approach is compared with several other common ones,higher accuracy are observed,as well as less isolated pixels and better connectivity.关键词：polarimetry;synthetic aperture radar;image segmentation;Wishart distribution;Markov random field2|1451|10更新时间：2025-07-16
- 摘要：UTD method with the radiant source on convex surface is widely used in analyzing and designing of antennas mounted on electrically large targets and a creeping ray tracing algorithm of UTD method is given when the radiant point is on arbitrary convex surface.The creeping rays in shadow region were traced by numerical differential geometry measures.The Non-Uniform Rational B-splines surfaces were introduced to model the targets,which makes the UTD method able to be applied to arbitrary surfaces.The algorithm given can be applied to arbitrary surfaces,the validity and usefulness can be seen from numerical results.关键词：UTD;NURBS;source on surface;ray tracing2|534|1更新时间：2025-07-16
- 摘要：RF Analog Front-end (RFAF) is one technique-bottleneck to realize the large dynamic range and broadband Digital Intermediate Frequency Receivers (DIFR),and could restrict the bandwidth,dynamic range and some other key parameters of the DIFR.It has been researched that the constraint condition for the broadband and large dynamic range of the DIFR.Based on the ADC parameters,the correlation expression for the following characters is given:the noise figure,bandwidth,"processing gain" of the under-sampling,and the sensitivity of the DIFR.The relational expression for the gain and noise figure of the RFAF and the dynamic range of the DIFR is also performed.It is reduced and simulated that the relationship between the gain of the RFAF,the signal-to-noise ratio of the ADC and the instantaneous dynamic range,and the step and adjust-range of the RF-DAGC and the extended dynamic range of DIFR.It is discussed the optimization design of RFAF,and provided a practical design example.关键词：RF analog front-end;broadband;instantaneous dynamic range;extend dynamic range2|1711|3更新时间：2025-07-16
- 摘要：Federated dual estimation model and algorithm for parameters and state estimation which based on federated filter thought is proposed in this paper,and also the distribution principle for it is discussed.The use scope of dual estimation and federation kalman filtering is effectively expanded.Based on the actually observation data from BEIDOU/LORAN_C,dual estimation and federal dual estimation methods are used to carry on the experimental comparison.The result of experiment shows that the precision of parameters and the state estimation is improved.关键词：federation dual estimation;parameters and state estimation;information distribution4|706|0更新时间：2025-07-16
- 摘要：Conformal mapping-based method and partial capacitance method are given to accurately calculate inter-digital capacitance and the inter-digital high impedance ground plane (HIGP) design formulas are revised.The models are useful for a wide range of dielectric constants and layer thickness.Every finger length and spacing may be different;moreover,the derived formulas can easily extend to multi-layer dielectric including cover layer.Three samples of the inter-digital high impedance ground plane are manufactured and the surface wave propagating property of the inter-digital HIGP are simulated and tested to demonstrate the potential of the models.关键词：high impedance ground plane;conformal mapping technique;inter-digital capacitance;surface wave property2|1424|2更新时间：2025-07-16
- 摘要：To improve the interframe prediction capability of motion estimation and motion complement (ME+MC) in video coding,a motion pattern recognition (MPR) algorithm based on self-organizing feature maps (SOM) was proposed,and it was tested in object-based conference video coding.The frequency sensitive self-organizing feature maps (FSOM) algorithm was also proposed to overcome the disadvantages of SOM algorithm.Experimental results show that FSOM-MPR algorithm has better coding performances than ME+MC algorithm.When the compression ratio is 170:1,the improvement of PSNR is about 2.7dB using Claire conference video sequence.关键词：motion pattern recognition;object-based video coding;self-organizing feature maps2|1165|1更新时间：2025-07-16
- 摘要：In this paper,a test set optimization method based on the genetic reordering is presented,which optimizes the row vectors’ order of the test set’s vector-fault matrix by genetic algorithm and adopts the row-column elimination as the evaluation method in the genetic process.Experiment results show that the method effectively reduces the number of the test vectors and ensures that no redundant test vector left in the optimal test set obtained.关键词：test set optimization;genetic algorithm;row-column elimination2|809|3更新时间：2025-07-16
- 摘要：Optimum multiuser detection (OMD) is an NP-complete combinatorial optimization problem in DS-CDMA wireless communication systems and heuristics are efficient methods for solving such problems.By analyzing the fitness landscape of the OMD problem,a series of multiuser detection algorithms are presented,which have lower computational complexity and good performance.The evolution strategy (ES) algorithm can achieve the performance of the OMD bound,and the fast iterated local search (FILS) method can obtain much better solution than that of other correlative algorithms with lower computational complexity.关键词：CDMA;multiuser detection;fitness landscape;combinatorial optimization2|666|0更新时间：2025-07-16
- 摘要：How to simplify a large scale tetrahedral dataset in order to use in the real time rendering is of more importance.A novel technique based on triangle decimation for tetrahedral simplification is described here.A triangle area ratio is defined as cost function for every triangular in the model.Through this ratio,a list of priority sequences is obtained in the per-compute period .The triangle which of high priority will be deleted firstly.Compared to the published paper,this method can be used to delete at least 8 tetrahedral in one triangle decimation cycle.In the test model,we can delete at most 13 tetrahedral one time.The results of this technique are of high practical use especially in the real time compression transformation of tetrahedral,finite element computation and rendering.2|656|1更新时间：2025-07-16
- 摘要：The status,function and limitation of current navigation techniques are analyzed,the current technologic condition and understandings to celestial navigation techniques are summarized,the advantages of celestial navigation techniques are pointed out.Based on this,the emphasis of this paper is to discuss some key techniques in improving celestial navigation,such as the radio signal measurement of both natural and artificial celestial bodies,some new celestial navigation methods which are free from horizontal benchmark or visible light observation.关键词：celestial navigation;status and function;key techniques;navigation system2|5020|23更新时间：2025-07-16
- 摘要：A method to achieve the sparsification of the impedance matrix is proposed when the higher order hierarchical vector basis functions and the maximally orthogonalized higher order vector basis functions are applied to electromagnetic integral equations.Both the theory analysis and the numerical experiment demonstrate that this method will decrease the memory requirement for storing the impedance matrix and the CPU time consumed in solving the matrix equation when using an iterative method.Moreover,some numerical results have been given to study the different effects on the requirements for the memory and CPU time caused by different thresholds.关键词：electromagnetic integral equations;higher order vector basis functions;maximally orthogonalization;sparse impedance matrix3|1239|3更新时间：2025-07-16
- 摘要：The inter-satellite baseline determination of a certain precision and data rate is a key factor for the realization of formation flying satellites technology.The optimal basis function approximation method was applied to process the measurement data with low sampling rate.The precision-keeping and high-rate interpolation technique for inter-satellite baseline determination was studied by means of measurement data processing.We focused on the analysis of the influences of the sampling rate and the random disturbance on the baseline parameter determination precision.Theoretical derivation illustrates that the precision of high-rate baseline parameters depends on the combined influences of the function approximation error and the measurement error.Simulations were performed based on the analysis of the variation characteristics of the inter-satellite baseline.The results show that the white noise level of the measurement produces more remarkable influence on the baseline determination than the function approximation error based on the currently available sampling rate.关键词：formation flying;baseline determination;data rate;function approximation;precision analysis2|684|0更新时间：2025-07-16
- 摘要：This paper focuses on a fast subspace tracking algorithm-approximated power iterations (API) algorithm,and its application to direction-of-arrival(DOA) estimation and blind multiuser detection (MUD) in CDMA system.The algorithm is derived by exerting an approximation on the power iterations method,which guarantees the orthonormality of the estimated subspace at each iteration,and satisfies a global convergence property.Its performance outperforms many subspace tracking algorithms,such as the projection approximation subspace tracking (PAST) method,the novel information criterion (NIC) method,and the Orthonormal PAST (OPAST) method,while keeping the same computational complexity as the above mentioned algorithms.The effectiveness is validated through some numerical simulations of DOA estimation in a narrowband source scenario and blind MUD in a synchronous DS-CDMA system,respectively.关键词：subspace tracking;power iterations method;direction-of-arrival(DOA) estimation;multiuser detection2|1157|3更新时间：2025-07-16
- 摘要：An algorithm of extended Radon-Wigner transformation (ERWT) is proposed.Mapping the delay and the Doppler frequency of radar echo to a parameter space of ERWT,the echo signal,with waveform of non-linear frequency modulated (NLFM),can be detected based on the parameter space and the parameter of the echo can be estimated simultaneously.The proposed method is insensitive to the interference terms and has high precision of delay estimation.Validity of the method is verified by simulation results.关键词：ERWT(Extended Radon-Wigner Transformation);NLFM(Non-Linear Frequency Modulated);signal detection;parameter estimation2|1350|3更新时间：2025-07-16
- 摘要：The NC-2q-MUSIC(Multiple Signal Classification)algorithm,which is an extension of the 2q-MUSIC algorithm to noncircular(NC)applications,is proposed.The performance of NC-2q-MUSIC algorithm for noncircular signals is better than 2q-MUSIC algorithm due to the utilization of noncircular information of signals.The resolution and robustness to modeling errors of NC-2q-MUSIC algorithm become better with the increase of q.The computational complexity of the NC-2q-MUSIC algorithm is analyzed and the NC-2q-MUSIC algorithm for uniform linear array(ULA),needs much less computation is also proposed.Simulation results show the better performance of NC-2q-MUSIC algorithm over 2q-MUSIC and validate other conclusions about NC-2q-MUSIC.关键词：array signal processing;direction finding;aperture extension;cumulants;MUSIC(Multiple Signal Classification)2|636|2更新时间：2025-07-16
- 摘要：A hybrid method for the computation of electromagnetic scattering problems is introduced in this paper.This method is based on the high order Moment Method (MoM) and the Physical Optics (PO) method.Curvilinear and parametric description is used to model the scatters,which eliminates the model discretization error.When the MoM regions and PO regions are chosen properly,the computations are then restricted on the MoM regions and the efficiency is increased.The high order property provides extra accuracy controls.The interpolation vector basis functions simplify the implementation phase.The high order moment method and the hybrization with PO method are useful and efficient for electromagnetic computations.关键词：electromagnetic scattering;high order moment method;hybrid method;vector basis function2|938|0更新时间：2025-07-16
- 摘要：A novel scheme based on mobile node handovers frequently between PAR and NAR for predictive fast handovers for mobile IPv6 was proposed to solve the problems of long latency,high lost packets and excessive signaling redundancy in existing schemes.A new Hop-by-Hop option header named TM,PCoA table and tunneling table were defined in this paper.TM is put in the acknowledgement of the last data packets between NAR and PAR,telling PAR that MN will be back to the domain of PAR in the near future,and hoping that the previous bidirectional tunneling between PAR and NAR is available.Theory analysis shows that this scheme would be viewed as an effective method to solve the above problems and can improve the Quality of Service for mobile users.关键词：Mobile IPv6;fast handoff;FMIPv6;predictive FMIPv62|1092|1更新时间：2025-07-16
- 摘要：This paper studies a wireless data communication system based on OFDM technology which could greatly increase the frequency efficiency of VHF/UHF frequency band.The paper gives a detailed discussion to the synchronization which is the key technology of the system,including frame synchronization,symbol synchronization,fraction frequency offset and integral frequency offset synchronization.Compared with the known solutions of synchronization,this system needs less calculation and lower realization complexity but also has a good performance.关键词：synchronization;algorithm improvement;VHF/UHF frequency band;high frequency efficiency2|948|1更新时间：2025-07-16
- 摘要：Due to the imprecision for solving the permutation ambiguity problem,the frequency domain methods for convolutive blind separation have their fundamental limitations in separation quality.Without additional priori information,a post-processing approach is proposed to further attenuate spatial interference from competing sources and noise.Firstly,an M×N multiple-input multiple-output (MIMO) system is converted into N single-input multiple-output (SIMO) systems by splitting spectrogram technique,and then the transfer functions ratios and generalized sidelobe canceller are employed to reconstruct source signals from the N SIMO systems respectively.The performance of the proposed algorithm is demonstrated by computer simutation results.关键词：blind source separation;convolutive mixtures;speech enhancement;transfer functions ratios;generalized sidelobe canceller3|682|1更新时间：2025-07-16
- 摘要：The monostatic equivalent geometry model of bistatic synthetic aperture radar (SAR) is discussed and an extended ETF imaging algorithm for bistatic SAR is proposed.Compared with the conventional monostatic ETF algorithm,the azimuth focusing phase functions,calculated with the parameters of bistatic imaging geometry,are adopted in this algorithm.The procedures and efficiency of this approach are the same as the ETF algorithm for the monostatic SAR and without any interpolations.The limitation of the proposed approach is also discussed.The algorithm was validated through point target simulations.关键词：bistatic;synthetic aperture radar;imaging algorithm4|664|3更新时间：2025-07-16
- 摘要：The frequency selective characteristics of lossy dielectric periodic structure composed of left-handed materials are carefully studied by a method which combines the multimode network theory with the rigorous mode matching method;and some explanations for the new phenomena are made.Comparisons between left-handed and right-handed gratings for the effects of dielectric loss on frequency selective characteristics are given.Guidelines for accurate design of the new millimeter wave frequency selective surface are presented.关键词：LHM(left-handed materials);dielectric periodic structure;frequency selective characteristics;multimode network;dielectric loss2|716|2更新时间：2025-07-16
- 摘要：Two kinds of transform——exponential matched-phase transform and complex-lag matched-phase transform are defined,in order to estimate the instantaneous frequency rate(IFR) of a polynomial phase signal with arbitrary order.The principle and realization procedure with details of the two transforms are given.Then,three aspects application of IFR are studied,the first is the parameter estimation of PPS,the second is the estimation of instantaneous frequency of PPS,and the third is constructing a new time frequency distribution,this distribution concentrates along the instantaneous frequency of a PPS with order more than two.The results of computer simulation demonstrate the validity of the method proposed.关键词：exponential matched-phase transform(EMPT);complex-lag matched-phase transform(CLMPT);polynomial phase signal(PPS);instantaneous frequency rate(IFR)2|1124|4更新时间：2025-07-16
- 摘要：A combined moment method (MM)-physical optics (PO) approach is systematically developed to analyze the scattering properties of anisotropic impedance wedges.A PO model of a plane wave incident on an anisotropically loaded surface is analyzed to evaluate the electric currents and the magnetic currents on the surface.A novel technique is presented to solve the infinite integral for so-called weak-oscillating function.On use of the modified diffracted current basis function published by the authors in 2006,the improved MM-PO technique is presented.The current technique is validated by comparison with exact solutions and the uniform geometrical theory of diffraction (UTD) results.关键词：impedance wedge;PO equivalent electric and magnetic surface current;diffracted current basis function;infinite integral for weak-oscillating function2|525|0更新时间：2025-07-16
- 摘要：A SRMF-CLEAN algorithm for space debris is proposed.The proposed algorithm can successfully incorporate prior information of space debris movement into imaging process.Together with single-range matching filtering (SRMF) fast algorithm,it can improve the resolution and imaging speed effectively.For point spread function parameterization model is used in the algorithm,the effect of point spread function disturbance can be inhibited by correcting CLEAN algorithm.Combination of the two algorithms can realize high resolution imaging for space debris effectively.Theoretic derivation and simulation result verify validness of this algorithm.关键词：radar imaging;space debris;SRMF-CLEAN2|1239|3更新时间：2025-07-16
- 摘要：A switched parasitic yagi-uda diversity antenna for MIMO base station is presented.This diversity antenna system is composed of switched parasitic yagi-uda antennas and makes full use of the base station space.It contains antenna array along Z-direction to achieve array gain while uses the reconfigurable radiation pattern to get pattern diversity in the azimuth plane.Using it in the experimental MIMO system shows that this diversity antenna system can increase channel capacity and decrease BER of the communication system.关键词：MIMO wireless communication;antenna diversity;Yagi-uda antenna;radiation pattern reconfigurable6|630|1更新时间：2025-07-16
- 摘要：This paper presents a method-Parallel Joint Probability Track Initiation Logic,and it is used for track initiation of maneuver- and non-maneuver targets in the airborne pulse Doppler fire radar based on the research of current track initiation methods.The idea of this method establishes track initiation logic by combining two track initiation methods with different performance (M of N and Bayesian track initiation) during engineering implementation.This method takes account of maneuver- and non-maneuver target track initiation.The results of Monte Carlo trials demonstrate that this method not only remains the advantage of M of N and Bayesian track initiation,but also overcomes its shortcomings.The proposed algorithm,on the one hand,decreases the track initiation average time,and on the other hand,the probabilistic correctness of track initiation is also improved.关键词：multi-target tracking;track initiation;data association2|698|2更新时间：2025-07-16
- 摘要：The exponential growth of the Internet coupled with the increasing popularity of dynamically generated content on the World Wide Web,has created the need for more and faster Web servers capable of serving the over 100 million Internet users.Server clustering has emerged as a promising technique to solve the problem.In this paper,.the defects of the existing Web Server Clustering technologies are summarized firstly.To attain the goal of keeping the balance of the server cluster,an syncretic strategy is advanced for hybrid heterogeneous parameters,through which a load-assignment algorithm is presented.A testbed is implemented by modeling the Web Server clustering.The simulation result shows that the presented scheme can guarantee the load balance and thus can provide better QoS guarantees.关键词：Web;QoS;clustering;load balance2|909|0更新时间：2025-07-16
- 摘要：This paper proposes a method for multi-polarimetric synthetic aperture radar (SAR) image compression based on three-dimensional matrix transform according to the correlation between the polarimetric channels.The multi-polarimetric SAR images (HH,HV,VV) are considered as a three dimensional unit,and then are processed by three dimensional matrix transform including.One-Dimensional DCT transform among the polarimetric channels and Two-dimensional DWT transform in the polarimetric SAR image.The three mixed coefficient planes are allocated different bits according to the Rate-Distortion(R-D) criteria and encoded by SPIHT algorithm.This method doesn’t process every channel image separately,so it removes the correlation of the image inside and the correlation between the polarimetric channels.Both the theory and the experimental results show that the method in this paper is efficient for multi-polarimetric SAR image compression.关键词：three-dimensional matrix;multi-polarimetric SAR image;set partitioning in hierachical trees(SPHIT);bit allocation;image compression;peak signal to noise ratio(PSNR)2|1060|0更新时间：2025-07-16
- 摘要：A Quasi-Orthogonal Group Layered Space-Frequency-Time Block Coded (QO-GLSFTBC)-OFDM scheme with full-rate and full-diversity is presented for improving the performance of quasi-orthogonal codes.Compared to the constellation-rotated quasi-orthogonal codes (the improved QO scheme),the newly proposed code has the advantage of not expanding the signal constellation at each transmit antenna.The proposed method can obtain full rate and full diversity.Furthermore,the encoding and decoding process of the proposed method is made of linear processing and requires simple operation.Simulation results show the validity of the proposed method.关键词：quasi-orthogonal design;group layered space-frequency-time block code (GLSFTBC);OFDM(Orthogonal Frequency Division Multiplexing);full diversity;full rate2|750|1更新时间：2025-07-16
- 摘要：For quaternion model of two-dimensional harmonics,the inner relationship between real model,complex model and quaternion model was discussed at first.We presented the singular values decomposition method of quaternion matrix to estimate frequency pairs of two-dimensional harmonics.This method can estimate the number of signals with singular values.Then,left and right singular vectors can be used to estimate frequency pairs.This method needs less data and its data matrix is very simple.It can also estimate frequencies at the same time.From simulations,our method can decrease computation burden effectively than those of other methods.关键词：quaternion;singular value;two-dimension;harmonic2|699|5更新时间：2025-07-16
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