最新刊期
卷 38 ， 期 12 ， 2010
- 摘要：The data-rates of transit ports and access ports in the homogeneous Mesh network consisting of low earth orbit (LEO) satellites were deduced based on the symmetrical characteristic of the network topology.According to the traffic,the capacities of the ports were optimized by the Lagrange multiplier method to minimize the packet lost ratio.In the network constituted by m orbit-planes with n satellites each,the capacities of intra-orbit ports should be inversely proportion to the orbit number m,approximately n/8 times of accessing data rates.The capacities of inter-orbit ports should be inversely proportion to the satellite number n in each orbit,approximately m/8 times of accessing date rates.Before optimization,the packet lost ratio was minimum when m=n.After optimization,the packet lost ratio is reduced and keeps decreasing as the total number of satellites increases.关键词：optical satellite networks;Mesh networks;capacity dimensioning;Lagrange function;network simulation4|1551|1更新时间：2025-07-16
- 摘要：This paper has researched on the problem of track correlation with systematic errors in radar network,analyzed that how do the general and big systematic errors affect the detected tracks of target theoretically;On the basis,prior to registration,a target track alignment-correlation algorithm based on phasecorrelation has been presented.Based on the characteristics of Radon transform and Fourier transform,the algorithm estimates the rotation and the mass motion using 1D and 2D phase correlation respectively.Thus,the target tracks provided by different radars in common coordinates could be aligned and associated accurately without estimation and registration of radar systematic errors in advanced.Finally,the Monte-Carlo simulation result illustrates that the algorithm has excellent alignment-correlation performance in different systematic error and target environments,and shows that the algorithm can provide reliable associated tracks for the later registration.关键词：phase correlation;Radon transform;Fourier transform;systematic errors;track correlation;radar network2|1512|16更新时间：2025-07-16
- 摘要：For an even integer n not less than 4,a sufficient and necessary condition was established for constructing a Bent function in n+2 variables from 4 Bent functions in n variables.An iterative construction of Bent functions was proposed to construct (n+2)-variable Bent functions from n-variable Bent functions.The algebraic degree of some Bent functions constructed by the proposed method was also analyzed.The iterative method unifies and generalizes two previous constructions of Bent functions.关键词：Bent function;Walsh spectrum;nonlinearity;algebraic degree2|1723|3更新时间：2025-07-16
- 摘要：Aiming at the deficiency of the H-Alpha based classification,a new scheme of unsupervised terrain classification is proposed based on target scattering similarities.This new scheme divides terrain scattering into three classes with target scattering randomness firstly;and then subdivides these three classes with target scattering similarities ulteriorly.As terrain scattering class is determined by target scattering similarities automatically,the deficiency of the arbitrarily fixed linear decision boundaries of Alpha angle is overcomed.As an application,a new method of unsupervised terrain classification is also presented under the frame of the new scheme.After the partition of terrain scattering with target entropy which is a measure of target scattering randomness,the new method subdivides three classes into ten classes with surface scattering similarity,double scattering similarity and volume scattering similarity ulteriorly.As surface scattering,double scattering and volume scattering are the inherent characteristics of terrain physical scattering mechanisms,the classification result of the new method is consistent with the real terrain scattering.With the real polarimetric data of San Francisco,the feasibility of the new scheme and the validity of the new method are validated.关键词：scattering similarity;terrain classification;H-Alpha based classification2|1204|3更新时间：2025-07-16
- 摘要：In analysis of waveguide discontinuities by the traditional mode matching (MM) method,the phase constant and the analytical expression of mode function must be required.This limitation makes the application of the method only suitable for waveguide discontinuities with simple boundary shapes.In order to determine the mode spectrum of complex shaped waveguide,an eigen equation is established using four-component two-dimension finite-difference frequency-domain (2-D FDFD) method.Phase constants and mode functions could be easily solved as eigen values and eigen vectors,respectively.Once the eigen problem was solved,the generalized scattering parameters can be calculated by the MM technique.Finally,demonstrations of a single-ridged iris and a cross-shaped iris are analyzed.The results show this hybrid method is correct and efficient.关键词：mode matching;two-dimension finite-difference frequency-domain;generalized scattering parameters;single-ridged iris;cross-shaped iris2|1246|0更新时间：2025-07-16
- 摘要：In additive non-Gaussian clutter modeled as a spherically invariant random vector (SIRV),a novel detector is designed for range-spread target.Moreover,the parameters for this detector are derived simply.The formulas relating the false alarm probability to the detection thresholds are also deduced,which show the constant false alarm rate (CFAR) properties.The experimental results show that,with proper parameters,the proposed detector performs much better than two existing range-spread target detectors.It is shown that as the number of sensors,the number of target scatterers or the clutter spikiness increases,its performance improves.In addition,the dirived detector is robust to the third thresholds and correlations of clutter.关键词：spherically invariant random vector;non-Gaussian clutter;radar target detection;clutter correlation;constant false alarm rate2|1199|8更新时间：2025-07-16
- 摘要：Traditional ideal model of skylight polarization pattern can’t be extended to actual situations without analysis of scattering process.In this paper,electric field intensity vector is used to describe light waves.Then the celestial coordinate system and the north-east-up coordinate system are established respectively to analyze the scattering process.Utilizing the transformational relation of the two coordinate systems,the analytical method of Rayleigh scattering can be applied to every measured point over the celestial hemisphere.Degree of polarization and polarization direction vector are used to express skylight polarization information which can be calculated by electric vector of scattered light.Simulation results show that the new modeling method has certain expansibility and applicability because it can not only provide an accurate description of ideal skylight polarization pattern,but also offer the reference data for actual models.关键词：atmospheric optics;skylight polarization pattern;electric vector;coordinate system transformation2|1587|5更新时间：2025-07-16
- 摘要：We brought forward a hyperspectral imagery unmixing methods based on the posterior probability of relevance vector machine.In the hyperspectral imagery unmixing methods based on the posterior probability of support vector machine,the posterior probability have to be got by sigmoid function approximately,and the model need to set regularization coefficient by cross-validation.Relevance vector machine is a sparse model in the Bayesian framework,its mathematics model doesn’t have regularization coefficient and its kernel functions don’t need to satisfy Mercer's condition.In this paper,we firstly analyzed the disadvantages of the support vector machine for hyperspectral imagery unmixing,introduced the sparse Bayesian model and the model parameters inference,and selected the fast sequential sparse Bayesian learning algorithm.Through the unmixing experiments of PHI imagery,the advantages of the relevance machine for hyperspectral imagery unmixing were given out.关键词：hyperspectral imagery;mixed-pixel unmixing;sparse Bayesian model;relevance vector machine2|1847|13更新时间：2025-07-16
- 摘要：A novel algorithm is presented to solve the ambiguity problem of across-track velocity estimation for moving targets in airborne sidelooking SAR system.In this method,the across-track velocity can be unambiguously estimated according to the slope calculated by Radon transform of the profile extracted from the echo’s range walk trajectory.In order to solve the problem the along-track velocity estimation is influenced by the across-track acceleration,we propose a new along-track velocity estimation approach.The along-track velocity can be obtained by the real synthetic aperture time (synthetic aperture length) of target.Proposed methods can be applied to both single- and multi-channel SAR systems.The validity and practicability are verified by the simulated and real measured data.关键词：synthetic aperture radar (SAR);ground moving target indication (GMTI);Radon transform;velocity ambiguity;parameter estimation2|1352|2更新时间：2025-07-16
- 摘要：In multi-carrier-frequency Multiple-Input Multiple-Output (MIMO) radar,the separated echoes of a target with high speed locate in neither the same range bin nor the same Doppler bin.As a result,the parameters (including range,azimuth and elevation) of the target can’t be estimated using the traditional supper-resolution algorithms.A method based on cascaded Keystone transformation is presented to estimate the parameters of the targets moving at a high speed.Keystone transformation is used to correct range migration in the fast-time dimension,and then the Doppler migration is corrected in the slow-time dimension.Finally the Multiple Signal Classification (MUSIC) algorithm is applied on the corrected data to obtain the range,azimuth and elevation of targets.The simulation results indicate the feasibility and validity of the methods presented.关键词：multi-frequency MIMO radar;Keystone transformation;MUSIC;multiple parameters estimation2|1614|6更新时间：2025-07-16
- 摘要：Effective motion compensation for MMW seeker helps to improve the performance of 1-D range profile formation and target recognition.This paper focuses on the motion compensation for the Costas frequency coded pulse seeker,and exploits multi-frame data to propose a high-precision velocity estimation method using subspace decomposition.The computational efficiency of the proposed method is then further improved by taking the special structure of the subspace.Numerical simulations are carried out to verify the satisfying performance of the proposed methods.关键词：MMW seeker;motion compensation;sub-space decomposition;1-D range profile2|1019|0更新时间：2025-07-16
- 摘要：Global QoS optimal Web services selection is a NP complete problem.In order to overcome slow convergence of existing schemes,an improved discrete particle swarm optimization,called Discrete Particle Swarm Optimization with Non-Uniform Mutation Algorithm (short for DPSONUMA),is proposed.In DPSONUMA,we firstly redefine the particle position,velocity and update operations to make the algorithm more suitable for this problem.Then the best particle is introduced a mutation ability,and a mutation probability function is also designed.And weight factors of velocity will adaptively change according to the fitness values,which can improve convergence.In addition,a local fit first strategy is introduced,which lead to both quicker converge and better results.Experimental results show DPSONUMA costs less time but higher quality components are obtained for composite web services.关键词：Web services selection;QoS global optimal;non-uniform mutation;adaptive weight adjustment;local fit first2|1479|15更新时间：2025-07-16
- 摘要：In order to solve the blind source separation (BSS) problems,a fast joint diagonalization (FJD) algorithm based on the diagonalization of a set of output auto-correlation matrices at different delays is proposed.The algorithm adopts a multiplicative update scheme to minimize the Frobenius-norm formulation of the approximate joint diagonalization problem.The special approximation of the cost function and the skilful denotation of concerning variables contribute to the highly computational efficiency of the algorithm.In each of multiplicative iterations,a strictly diagonally-dominant updated matrix is obtained,ensuring the invertibility of the diagonalizer and preventing the convergence to trivial values.The algorithm discards pre-whitening procedure,relaxes the positive-definiteness assumption on target matrices and can be used in complex-valued space,thus has more general utilizations.Computational complexity analysis shows the efficiency and easy implementation of FJD.Extensive numerical simulations illustrate the high convergent speed and good performance of FJD.Thus it can be used to solve the BSS problems efficiently.关键词：blind source separation (BSS);fast joint diagonalization (FJD);multiplicative update;strictly diagonally-dominant matrix2|1052|1更新时间：2025-07-16
- 摘要：In ensuring the content of digital vector maps lossless,a high-capacity digital watermarking algorithm is proposed based on encoding scheme.According to the structure of TAB file for digital vector maps,the watermark is hidden into the attribute blocks.As each vector object definition reserves redundant space,these information bits cannot be edited and displayed by any map editing tool,the watermark has good concealment.Experimental results show that the algorithm maintaining high capacity and good invisibility,it also can strongly resist various geometric transformations such as cropping,rotation,projection,etc.关键词：information hiding;digital watermarking;vector map;lossless2|1498|3更新时间：2025-07-16
- 摘要：Spaceborne-airborne hybrid bistatic SAR is translational variant bistatic SAR.So the traditional algorithms are no longer suitable any more.An imaging algorithm is proposed in this paper,which suitable for Spaceborne-airborne hybrid bistatic SAR.The main idea of this method is that:decomposing the imaging space into several linearity regions,and expanding the range history in space domain in every region;find the differences of ehco sinals between reference point and other points in the regions,which can be used to reduce the computational cost.Then SIFFT is used to correcting the RM,after that the phenomenon of non-uniformly-spaced is analyzed and corrected.At last the final imaging is finished using range-dividing,and the validity of this algorithm is prooved.关键词：spaceborne-airborne bistatic SAR;scaled IFFT(SIFFT);truncation error;nonuniformly-spaced correction(NUSC)2|1016|1更新时间：2025-07-16
- 摘要：To deal with the problem of emitter identification caused by the vector neural network (VNN),which is incapable of processing the linguistic information and considering the reliability of the training samples in training phases,this paper proposes a new identification method based on cloud model and vector neural network (CMVNN). The new method,which utilizes the cloud model to realize the transformation from qualitative concepts to their quantitative interval expressions,can make use of the improved vector neural network to come true the nonlinear mapping between the interval-value input data and the interval-value output emitter types. A number of simulations are presented to demonstrate the performance of the CMVNN algorithm,including processing 3-type emitter identification problem. Simulation results show that the CMVNN algorithm not only processes the linguistic and numerical input data,but also has higher identification rate in environment with measure errors.关键词：radar;emitter identification;cloud model;vector neural network;interval value;identification rate2|1265|10更新时间：2025-07-16
- 摘要：A fault diagnosis and degradation failure prediction method for the electromagnetic valves which are used in hydraulic supports electro-hydraulic control system of the underground combined mining face is proposed.Through analyzing the mechanical kinetic characteristic of electromagnetic valves,the parametric relationship among the driving voltage,length of magnetic circuit working air gap and driving current is determined and the steady state and transient performance of driving end current is also obtained.According to the transient performance,the energy feature and K-L transforming feature based on template matching is extracted in the movement interval of valve spool,and according to the steady state performance,the inductive reactance feature of the drive coil is also obtained in the static interval of valve spool.24,000 sets of data are gained by 2.4 million switching experiments in 143 days.The five stages of electromagnetic valves which are normal operation,beginning of failure,a little of failure,some failure and damage is accurately identified between two types of electromagnetic valve by using the neural network analytical approach,and the rates of identification are respectively 98.1% and 99%.The study provides basis for the fault prediction and maintenance of electromagnetic valves,and the productive efficiency of coals and the productive safety are improved.This prediction method can be widely applied to the degradation failure detection of many other types of electromagnetic valves.关键词：hydraulic;electromagnetic valve;fault prediction;driving end current;degradation failure;K-L transform2|1100|3更新时间：2025-07-16
- 摘要：Through defining the new potential functions,a SAR image segmentation method is proposed based on Bayes belief propagation and regional MRF model.Considering the rich texture information of SAR images,texture features are extracted from the watershed over-segmented regions,and then an MRF model is defined over the region adjacency graph of the initially segmented regions.Features of each small region are denoted by the texture features,the average and variance of the gray level of all the pixels in each region.The associated potential function is defined by the initial segmentation obtained from FCM clustering with the region.The features of the small regions are introduced to the interaction potential function.The new interaction potential function can effectively protect edge and promote regional consistency at the same time.In the experiments,the proposed algorithm is compared with other MRF image segmentation algorithms using real SAR images.The experimental results show that the proposed method is more effective for SAR image segmentation.关键词：SAR image;Markov random field;Bayes belief propagation;interaction potential function2|1827|13更新时间：2025-07-16
- 摘要：Considering the uncertain time-delay characteristic of network congestion control,a novel Active Queue Management (AQM) algorithm based on Dynamic Output Feedback Control (DOFC) is proposed.The model of TCP/AQM is converted into a linear system with bounded time-delay,sufficient condition to judge the stability of the closed-loop system is deduced,and approach to design the parameter of DOFC based on linear matrix inequality is recommended.Simulation results show that the proposed algorithm is able to stabilize the queue length to the target value quickly in condition that network configuration parameters are large delay,and is more robust in dynamic network environment with uncertain characteristic parameters.关键词：network congestion control;active queue management;time-delay systems;dynamic output feedback2|1027|1更新时间：2025-07-16
- 摘要：A discriminator algorithm and a loop filter structure critically affect the performance of a GPS carrier tracking loop and a receiver.Firstly,from the analysis of the traditional PLL (phase-locked loop) and FLL (frequency-locked loop) discriminators,a new discriminator algorithm is put forward based on a shared four-quadrant arctangent function between PLL and FLL.Secondly,a loop filter design is given based on the boxcar digital integrator by comparison with a digital bilinear transform integrator.Finally,a low complexity design scheme for GPS carrier tracking loop is represented,which is composed of the proposed discriminator and the loop filtering algorithms.The theoretical analysis and simulation results confirm that this novel design has low complexity,less resources and achieves good tracking performance.关键词：carrier tracking loop;PLL(phase-locked loop);FLL(frequency-locked loop);loop filter;low complexity2|1815|8更新时间：2025-07-16
- 摘要：Proximity operator is used to solve the rapid magnetic resonance image reconstruction model based on compressed sensing theory and an efficient iterative algorithm is proposed.Experiments show that the proposed algorithm is not sensitive to noises,and that the algorithm does not depend on the choice of initial iterative values,and that faithful MR images can be reconstructed efficiently through the algorithm.关键词：magnetic resonance imaging;image;reconstruction;proximity operator;compressed sensing2|1233|2更新时间：2025-07-16
- 摘要：To resolve the problem of motion estimation of high speed moving targets about the stepped-frequency Chirp Signal,a acceleration and velocity estimation method based on polynomial phase transform is proposed,with a negative-positive stepped-frequency Chirp Signal. This method can achieve the real-time acceleration and accurate velocity estimation;then a method to resolve velocity ambiguity based on the image contrast is also presented;in the end,simulation results prove the well anti-noise,efficient and real-time performance of proposed methods.关键词：stepped-frequency chirp signal;high speed moving target;motion estimation;velocity ambiguity2|1419|3更新时间：2025-07-16
- 摘要：The wavenumber domain (WD) algorithm has the ability to handle the range-azimuth coupling correctly,which is suitable for processing the wide-beam low frequency ultra-wideband synthetic aperture radar (UWB SAR) data.But the traditional WD algorithm is difficult to integrate with motion compensation method,which limits its application.Especially,in the case of no navigational instrument data available,it is difficult to achieve high quality low frequency UWB SAR image.In this paper,a modified WD (MWD) algorithm is proposed.Based on the MWD algorithm,the parameters estimation from the raw data and the accurately motion compensation could be implemented.Moreover,some modifications were made on the traditional motion compensation method according to the characteristics of MWD,and the focusing performance of MWD algorithm on low frequency UWB SAR raw data is improved.At last,some simulation experiments and the raw data processing results demonstrated the effectiveness of the proposed algorithms.关键词：synthetic aperture radar;low frequency ultra-wdieband;modified wavenumber domain algorithm;motion compensation2|1310|3更新时间：2025-07-16
- 摘要：The power-law-integral is a commonly formula used to estimate the subpicosecond level jitter of clocks,while the results are determined by the integral-limits,in particular,by the lower limits.The transform formulas from phase noise to jitter are introduced firstly.Then we deduced quantitative relationship between the lower limits,the frequency of sampling clock,the maximum frequency of analog input signals and the effective resolution of analog-to-digital converters,as a result,we provide a formula to estimate the lower limits.Finally,provides a typical application example of the formula.关键词：jitter;phase noise;power spectral density;power-law-integration;IF sampling2|1091|0更新时间：2025-07-16
-
Seeker Measurement Error Suppressing Using Precision Speed Information of Inertial Navigation System
摘要：A novel extended Kalman filter (EKF) aided by precision inertial navigation system (PINS) velocity information is proposed for the application of terminal seeker random measurement error suppression.Missile motion was modeled by PINS velocity solution,while target maneuver by first-order Markov process.The dynamic model describing missile-to-target motion using the relative state vector was given,seeker random measurement error was then suppressed by using the novel EKF.The proposed filter could overcome the shortcoming of conventional filter in relative motion modeling,in which the factor of missile guidance and control might be involved.The validity of proposed filter in missile terminal guidance was then tested by simulation.关键词：extended Kalman filters;missile-to-target information;precision inertial navigation system;speed information of inertial navigation system2|1120|0更新时间：2025-07-16 - 摘要：A new radar detection method based on some obtained decision information is proposed in this paper.The decision information,which can be roughly considered as a priori knowledge about the target,can be utilized to modify the current decision rules of the system.Such modification can improve the detection performance of the system.Additionally,we make an analysis on the expression of the likelihood ratio,present the approach to determine the decision threshold,and evaluate the detection performance of the system.The computer simulation experiments verify the feasibility of the proposed detection method.关键词：detection method;decision information;Neyman-Pearson criterion2|1139|4更新时间：2025-07-16
- 摘要：In order to minimize the potential interferences between the ultra-wideband systems and the narrowband communication systems effectively,a compact slot ultra-wideband antenna with assembled band notched structure is presented.A polygon slot on a printed circuit board is taken as the radiating element and is fed by a T-shaped stub.The overall size of the antenna is as small as 16mm×25mm×0.8mm.The assembled band-notch structure formed by a C-shaped slit in the T-shaped stub and a rectangular slit embedded in the ground plane is implemented to shape a much sharper,wider,and deeper notch-band.Simulated and measured results indicate that the proposed antenna yields an voltage standing wave ratio (VSWR) of less than 2 in the impedance bandwidth range of 3.1 to 10.6 GHz,except the bandwidth of 5.0~6.0 GHz for band notch.Thus,the negative effect of WLAN on ultra-wideband system is eliminated effetively.Omnidirectional radiation pattern and stable gain are obtained in the whole bandwidth range.关键词：ultra-wideband antenna;notched characteristics;slot antenna;small antenna2|1471|12更新时间：2025-07-16
- 摘要：This paper introduces the measurements of ocean wave directional spectra from a space-borne radar.It also presents the radar spectrometer instruments.Then an End-to-End simulation method is adopted to analyze the performances of the system,taking into account data processing parameters and ocean surface conditions.The simulations show that the proposed radar can measure spectra of fully developed waves with significant wave heights (SWH) over approximately 2.0m and spectra of swell surface under low wind conditions (SWH>0.8m),in high precision.The minimum detectable wavelength in this study is about 40m.The wavelength resolution for a wavelength of 200m is better than 20m,and the directional resolution after averaging is better than 20°.Finally,it is proved that a beam configured with an incidence of 10° performs better on spectra retrieval than the one with an incidence of 6°.关键词：real aperture radar;spectrometer;directional spectrum;modulation spectrum;correlation coefficient4|2124|7更新时间：2025-07-16
- 摘要：The Markov chain model for the shuffled frog leaping algorithm (SFLA) was established.It was shown that the frog memeplex state sequence containing both the frog states and the current local and the global optimal frog states constructs a homogeneous Markov chain.The transition process of the frog memeplex state sequence was analyzed,and the conclusion that sequence will eventually converges to the optimal state set was drawn.Furthermore,it was proved that the shuffled frog leaping algorithm ensures global convergence as it meets the global convergence criterions of random search algorithms.关键词：intelligent optimization;shuffled frog leaping algorithm;Markov chain;global convergence2|1932|29更新时间：2025-07-16
- 摘要：This paper presents a discovery that Metaphysics Electricity Bridge (MEB) Principle(MEBP) can be applied to the auto gain control (AGC) of the radio frequency (RF) channels,including active and passive circuits.In this paper,the basic theory of MEBP AGC is discussed,which consists of the transfer function,AGC transfer voltage,the limit gain precision of the MEBP AGC model,and the MEB balance model (MEBM).Further,the design of the MEBP AGC is provided,and the corresponding principle,AGC transfer voltage formed,is also delivered.Finally,the effectiveness of the MEBP AGC was demonstrated through S band RF channel,and the output power curve was plotted out of the temperature experiment data.The result indicates that the gain error of MEBP AGC is less than 0.2 dB.关键词：metaphysics electricity bridge principle;MEBP AGC;RF channel;MEB model;gain controlled error2|1180|0更新时间：2025-07-16
- 摘要：Based on the analysis of relationship between the geometric dilution of precision (GDOP) and the geometry layout of constellation,a new fast satellite selection method,which is called geometry satellite selection approach (GSSA),is proposed for multi-constellation satellite navigation system.The operation of satellite selection of the proposed method is operated on the premise that the positioning requirement must be met and on the principle of uniform distribution of satellites.Simulation results show that the decrease in computation load of GSSA is more than 99% in contrast with the traditional optimal GDOP method,and the constellation GDOP obtained by GSSA can meet the demand of navigation and positioning.At the same time,the number of selecting satellites also is little,and the satellite selection is simple and rapid.And it is satisfied to the real-time capability and accuracy demand of satellite selection of satellite navigation system.关键词：satellite navigation system;satellite selection;geometry layout;geometric dilution of precision (GDOP);simulation3|1899|8更新时间：2025-07-16
- 摘要：A robust feature based image registration method is proposed for multi-source remote-sensing images.Firstly,phase congruency transform is used to compute phase information images for removing the influence of the great differences in gray-level or contrast and to extract the control points.Then,the cross correlation function is reconstructed by Zernike moment and maximized to match the control-point pairs under rotation condition.Simultaneously,the initial feature point pairs are gained with the matching strategy of the bidirectional greatest cross correlation coefficient.Lastly,an iterative refined parameters method is used to improve the accuracy of registration.Experimental results demonstrate that this novel method can efficiently offer a reliable,robust and accurate image registration for the multi-source remote-sensing images.关键词：multi-source remote-sensing image registration;phase congruency;cross correlation reconstruction;Zernike moment;iterative method2|1943|13更新时间：2025-07-16
- 摘要：It is difficult to design an effective image super-resolution model and algorithm that can preserve the geometric structures and texture.Two incoherent geometry and texture sub-dictionaries are constructed,which can provide sparse representations of geometry and texture structures respectively.Thus,a multi-morphology sparse representation model is established.Furthermore,a convex variational model is proposed for multi-frame image super-resolution with multi-morphology sparsity regularization.The regularization term constrains the underlying image to have a sparse representation in a multi-component dictionary.The fidelity term restricts the consistency with the measured image in terms of the data degradation model.An alternate minimization iteration algorithm is proposed to solve it numerically and proximal forward-backward operator splitting method is adopted for each sub-problem.Numerical experiments for optics and infrared images are presented and the experimental results demonstrate that our super-resolution model and numerical algorithm are both effective.关键词：super-resolution;sparse representation;multi-component dictionary;morphological diversity;forward-backward operator splitting2|2222|18更新时间：2025-07-16
- 摘要：To meet the requirements of large system capacity and miniaturized terminal of mobile satellite communication,Muti-beam array antenna is adopted to realize the high gain and wide coverage by LEO satellite.This paper presents a planar transmitter array antenna with equal flux density coverage according to CDMA standard utilized by LEO satellite.The phased array antenna consists of an array antenna with 61 micro-strip elements,61 RF front ends,and digital beam forming network (BFN).Orthogonal transform and phase-amplitude adjustment are completed in digital BFN.The 61-channel IF signals outputted by digital BFN are up-converted and amplified by RF front ends,finally transmitted by array antenna to realize the desired shaped-beam coverage.The design methodology and measured results of DBF phased array antenna is discussed in the paper.The measurements demonstrate that all the parameters of array antenna are consistent with the predefined requirements,which validates the rationality of system design and project implementation.关键词：phased array antenna;digital beam forming;genetic algorithm;multi-beam3|3623|3更新时间：2025-07-16
- 摘要：The dynamics model of electronic (active) decoys in exo-atmospheric flight is derived and the corresponding mathematical characteristic is analyzed in detail.It is found that the orbit of decoys is determined both by the radar position and the delay parameter of jammer.The decoy at every time instant still follows the law of elliptical orbit,with the semi-major and semi-minor axes in accordance with the physical targets,but the instantaneous elliptical center precesses around the Earth center.The delay parameter of the jammer determines the maximum radius of the precession while the radar position determines the varying angle of precession.This analysis can provide both countermeasure sides with theoretical basis when selecting a suitable countermeasure method.关键词：ballistic missile;electronic decoy;trajectory characteristic;range deception;precession2|1414|3更新时间：2025-07-16
- 摘要：To solve the confliction between auto-correlation and cross-correlation of waveforms transmitted by instantaneous polarization radar,the receiver filter is optimized in this paper.The optimal filter is designed to decrease the interference between the range gates and channels,improve the estimation accuracy of polarization scattering matrix (PSM) and the detection performance of radar.Firstly,the target echo is modeled.The estimation error of PSM is analyzed.Secondly,the filter for each polarization channel is optimized via convex optimization,which is based on the minimum the sum of estimation error.Finally,the performance of the filter is analyzed in a variety of typical scenarios,e.g.,single stationary target,motional targets,multiple targets,etc.It is demonstrated that this method is effective by numerical examples using both simulation and experiment data.The research is valuable for the receiver design and implement of instantaneous polarization radar.关键词：polarization scattering matrix;instantaneous polarization radar;convex optimization;optimal filter2|1373|1更新时间：2025-07-16
- 摘要：Speech perception of human is bimodal because of the simultaneous audible and visible influence.This paper investigates how to fuse speech and visual speech features.From research on articulatory mechanism,the apparently observed audio-visual asynchrony is represented by asynchronous articulatory feature streams.An audio-visual model composed of speech and lip-moving is proposed based on Dynamic Bayesian Network,and then the multi-level fusion is implemented to improve the robustness of speaker recognition system.The experiment for audio-visual bimodal corpus shows that the multi-level fusion can improve the performance at all levels of acoustic signal-to-noise ratio (SNR) from 0 to 30dB.关键词：articulatory feature;audio-visual;speaker recognition;dynamic Bayesian network2|1633|3更新时间：2025-07-16
- 摘要：Strapped relativistic magnetron (strapped RM) was proposed and its PIC simulation study was carried out.By comparing the strapped RM with the traditional A6 model,we observe that the use of straps can significantly change the distribution of field in the interaction region and reduce the harmful effect of the intense RF field to the beam wave interaction.It can also lower the anode current and reduce the energy loss of the electron beam on the surface of the anode.All these help to increase the efficiency of RM.By PIC simulation,the efficiency of strapped RM can be more than 70%.It effectively get rid of low efficiency which is the first shortcoming of RM.关键词：strapped RM;PIC simulation;high efficiency2|959|0更新时间：2025-07-16
- 摘要：Estimation of distribution algorithm in continuous domains is generally based on assumption that variables subject to Gaussian distribution and that the probability model is single-peaked one,which is not capable of describing the solutions distribution effectively for complex optimization problems.Aiming to improve such drawback,an estimation of distribution algorithm depending upon sequential importance sampling particle filters is presented.In this algorithm,the variables are not required to subject to Gaussian distribution.Instead,the distribution of samples is represented by weighted particles and the used probability model is multi-peaked.The next generation of population is produced from the above distribution.The simulation results indicate the validity of the algorithm.关键词：estimation of distribution algorithm;sequential importance sampling;particle filters2|1270|1更新时间：2025-07-16
- 摘要：A novel Retinex algorithm based on IIR low-pass filter is presented,this method can preserve sharp edges in images,so it doesn’t produce halo.And it is combined with a real-coded Genetic Algorithm.Thus images with different characteristic can be enhanced with parameters choosed automatically.Compared to MSR and MSRCR,results on a series of low-light condition and foggy images show the efficiency of the proposal approach in both clarity and color.关键词：image enhancement;retinex;IIR low-pass filter;genetic algorithm;CIELab color space2|2592|18更新时间：2025-07-16
- 摘要：Transportation network can be well described and analyzed through graph data.The analyzing methods include mine,query,and classification,etc.The improvement on the efficiency of scalable algorithms on large graph dataset is important in graph analyzing.Given a graph dataset and query graph,graph containment query retrieves graphs from the dataset which are subgraphs of query graph.In this paper,a frequent closed subgraph (CFG) based graph containment query algorithm is proposed.The algorithm selects discriminative-redundancy-aware CFG to build a tree structure index,which satisfies such query.Theoretical analysis and experimental evaluation are presented at the end.The results show that this algorithm is not only filtering out correlated indexed features efficiently,but also reducing subgraph isomorphism tests between query graph and indexed features effectively.关键词：transportation network;graph database;graph index;containment query;frequent subgraph2|1237|1更新时间：2025-07-16
- 摘要：For the applications’ needs of the future large-scale multimedia multicast system,consulting the service class of IEEE 802.16,proposal a novel service class with some restrict rules,then develop an energy efficient scheduling algorithm called VARTUL based on OFDMA,make best efforts to help mobile station prolong the time in sleep mode and reduce the times of mode switch.In this algorithm,unicast traffic coexist with multicast traffic,following the restrict rules and then users can subscribe the services freely,so VARTUL can support the system which merge broadcast services and data services into one platform to provide video,audio,data and other programs.Numerical results show that VARTUL is adaptive to meet the instance of uplink and downlink traffic ratio variety and random distributing of service traffic,and it can save energy significantly and guarantee the service combinations and service experience of every user.关键词：energy efficient scheme;VARTUL service class;integrated scheduling2|986|0更新时间：2025-07-16
- 摘要：In order to overcome the problem of step by step searching method in the two-dimensional Fractional Fourier domain,a hybrid algorithm combines chaos optimization method and multi-step Quasi-Newton method is proposed by deriving the first derivative and its fast computation algorithm.And the global convergence of the algorithm is proved and tested.The simulation result indicates that the presented method is preferable than that of direct searching method,chaos optimization algorithm and multi-step quasi-Newton method mixed with direct searching method considering computation efficiency and accuracy.关键词：fractional Fourier transform;chaos optimization;multi-step Quasi-Newton method;LFM signal2|1546|2更新时间：2025-07-16
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0