最新刊期
卷 47 ， 期 6 ， 2019
- 摘要：Visualization technology is conducive to the evaluation and analysis of the solution sets obtained by solving many-objective optimization problem,but the existing many-objective visualization technology cannot effectively preserve Pareto dominance relation,maintain frontier distribution and retain shape.To solve the above problems,this paper presents quasi-circular mapping visualization.Many-objective are uniformly distributed in order on a unit arc according to their correlation.Based on the fitness function value,the solution sets are mapped into a polygon in quasi-circular space.So 3 dimensional visualization of the solution set is achieved through the geometric center and area of polygons.On the basis of this,the quasi-circular domination and equilibrium are defined.The dominance relation and mapping occlusion under quasi-circular mapping are theoretically analyzed and proved.Compared with parallel coordinates,principal component analysis and radial visualization,this method can preserve the Pareto dominance.In addition,it can also reflect frontier distribution and shape in the original space and effectively avoid data blocking.It helps decision makers to evaluate and select many-objective solution sets visually.关键词：many-objective optimization problem;visualization technology;many-objective visualization;quasi-circular mapping;Pareto domination;shape of Pareto front2|2|2更新时间：2025-07-02
- 摘要：The root cause of cache-based side-channel attacks is that the application will access different cache memory depending on different values of sensitive information.This paper proposes a symbolic-execution-based vulnerability detection technology to identify the code in an application that can be exploited in cache attacks.It analyzes program's data propagation of symbolized sensitive information to locate candidate vulnerabilities,and determines the exploitability through comparison of different possible accessed cache addresses.A prototype system called CSCVulDiscover is developed and tested against 12 kinds of implementation of 3 popular cryptographic algorithms including RSA,and the result shows that 125 vulnerabilities are detected.关键词：cache-based side-channel attack;vulnerability detection;symbolic execution;differential cache access;taint analysis;data propagation;vulnerabilities;exploitability2|2|1更新时间：2025-07-02
- 摘要：The suppression of mainlobe jamming (MLJ) is a hard task and an open problem in the radar field,and it brings a big challenge for radar target detection,tracking,and identification.Hence,we propose a "same dimension" sparse estimation method for radar target parameter in MLJ.The proposed method can effectively suppress the MLJ and simultaneously estimate the target range and angle.Precisely,the block matrix preprocessing (BMP) algorithm is adopted to suppress the MLJ,and the target angle information can be hold on.Then the target range is estimated effectively through the beamforming and pulse compression.According to the target range estimation result,the preprocessed data should be intercepted as training samples for the target angle estimation.The proposed method can be applied for linear array and planar array.It is worth pointing out that the proposed method can effectively estimate the target azimuth and elevation simultaneously when the target azimuth (or elevation) equals to the jamming azimuth (or elevation).关键词：mainlobe jamming (MLJ);jamming cancellation;radar target detection;sparse recovery;direction of arrive (DOA) estimation2|2|7更新时间：2025-07-02
- 摘要：Aiming at the technical challenges brought about by the fast time-varying characteristics of the channel in high-speed scenes to precoding in multiple input multiple output (MIMO) system,this paper proposes an improved Tomlinson-Harashima precoding (THP) algorithm for MIMO systems based on the dynamic channel state information (CSI) model.Channel statistical information and correlations are exploited to compensate instantaneous CSI,which could reflect current real-time channel status exactly.Further,aimed at maximizing the signal to interference plus noise ratio,a multi-user scheduling algorithm based on loop traversal search is proposed.And the multi-user scheduling algorithm is applied to THP,which could improve the precoding accuracy of the traditional THP.Simulation results show that the proposed scheme can be efficiently applied to high-speed mobile scenario,and improve bit error ratio performance as well as channel capacity.关键词：high-speed mobility;MIMO system;dynamic channel state information;Tomlinson-Harashima precoding;user scheduling;signal to noise ratio6|2|3更新时间：2025-07-02
- 摘要：When a single-phase full-bridge inverter works in the hard-switching state,the switching loss will increase significantly with the increasing of switching frequency,so that it will affect the efficiency of the inverter.In order to solve this problem,an energy-saving single-phase full-bridge resonant pole inverter is proposed.When the inverter is in the dead state,the voltage across the resonant capacitor in parallel with the main switch can decrease to zero via the resonance of the auxiliary circuit.The main switch can achieve zero-voltage switching,and the bidirectional auxiliary switch can realize zero-current switching.The operation process of the circuit in a switching cycle is analyzed.The experimental results show that the main switch and auxiliary switch can realize soft-switching.Therefore,the single-phase full-bridge soft-switching inverter can be applied at high switching frequency.关键词：inverter;dead zone;bidirectional switch;zero-voltage switching;zero-current switching2|2|1更新时间：2025-07-02
- 摘要：Peak power is a critical factor on the power consumption of a data center.This paper proposes a peak power estimation method to predict the peak power to join operations in DBMS.The challenge of non-runtime peak power estimation lies in that there is no runtime system information to use for model construction.To overcome this issue,this paper uses CPU-boundedness as the proxy of CPU power consumption and analyzes the characteristics of the peak power occurring stage of join algorithms with async I/O in theory.By simulating the behavior of this stage,we estimate the maximal CPU-boundedness of join algorithms.By examining the relationship between the CPU-boundedness and CPU power,the peak power models of join algorithms under different CPU execution frequency are hence constructed.Experiments validate the effectiveness of the proposed models on three typical join algorithms in DBMS with async I/O techniques.Results showed that our proposed methods had good accuracy with the average relative error less than 7%.关键词：peak power;power modeling;CPU-boundedness;DBMS energy efficiency2|2|0更新时间：2025-07-02
- 摘要：Taking into account the probabilistic uncertainty on the target radar cross section parameter,a robust power allocation scheme is presented for multiple target localization.The aim of this scheme is to minimize the total power consumption of the colocated MIMO radar,while meeting a specified multi-target localization accuracy requirement with high probability.Firstly,the Cramer Rao Lower Bound (CRLB) is derived.Then,the chance constrained model is built with the objective of minimizing the total transmit power of the colocated MIMO radar,while the joint CRLB outage probability is enforced to be greater than a specified probability.By formulating the Karush-Kuhn-Tuckers conditions,we transform the resulting chance constrained problem into a nonlinear equation solving problem,and then obtain its optimal solution in an analytical form.Finally,the effectiveness and robustness of the proposed algorithm are verified by the simulation results.关键词：MIMO radar;multi-target localization;power allocation;chance constrained programming2|2|6更新时间：2025-07-02
- 摘要：In actual dada collection,the sensitivity of different sensitive information is different so that the concrete privacy need is different,too.However,the existing local privacy preservation model based on randomized response (RR),which is called conventional randomized response (CRR) for convenience,focuses on a universal approach that exerts the same amount of preservation for all sensitivity values,without catering for their concrete privacy needs.As a result,it may be offering insufficient protection to a subset of people with relatively higher privacy needs,while applying excessive privacy control to another subset with relatively lower privacy needs.Based on this,a new framework which is called personalized randomized response (PRR) is proposed based on the concept of CRR for multiple sensitive values-oriented personalized privacy preservation.The PRR technique considers personalized privacy needs,introduces sensitive value weights for different sensitive values,and then introduces the weights into the decision of RR for satisfying all sensitivity values' privacy needs,and thus,attains personalized privacy preservation.Both theoretical derivation and simulation experiment reveal that the estimate error of statistics of PRR mechanism is smaller than that of the CRR mechanism for a certain subjective degree of privacy leakage,that is,the quality of statistics obtained by PRR mechanism is higher than that of the CRR model while guaranteeing personalized privacy protection for a given subjective degree privacy preservation.关键词：randomized response;sensitive value weight;subjective degree of privacy leakage;data quality;personalized privacy preservation3|2|0更新时间：2025-07-02
- 摘要：While nonnegative matrix factorization based speech enhancing methods can improve signal to noise ratio (SNR) of recovered speech signal,these methods lead to the speech distortion,and thus degrade the performance of speaker verification system under noisy environment.This paper proposes a nonnegative matrix factorization with partial constrains (PCNMF),with objective of enhancing the robustness of speaker verification system in presence of unknown and unstable noises.PCNMF constructs the speech and noise dictionaries while satisfying partition conditions.Considering that the speech dictionary generated by traditional speech training contains a little noise element,PCNMF generates speech dictionary using the spectra of pitch and their harmonics via mathematical model,and accordingly imitates the formant structure of human voice.The purpose is to guarantee the purity of speech dictionary.In addition,in order to alleviate the problem about the loss of the information of the noise sample,PCNMF performs framing operation and Short-Time Fourier Transform against the noise samples separated online,and then generates noise dictionary by means of linear combination of the spectrum frames of the noise samples.Our experiment takes unknown and unstable noises into account,demonstrating that the proposed PCNMF achieves significant improvement of robustness under various noise conditions.Particularly,the equal error rate of PCNMF is reduced by an average of 5.2% in comparison with the base-line (Multi-Condition system).关键词：speech processing;speaker verification;nonnegative matrix factorization;additive noise2|2|1更新时间：2025-07-02
- 摘要：In order to realize emergency decision-making and situation assessment,and to satisfy the requirement of reliable and energy-saving long-distance transmission of panoramic or spatial stereoscopic information in key areas,this paper takes UAV as space-based sensing platform to study the long-distance communication of UAV formation under energy-constrained conditions in emergency mobile Internet of Things applications.A cooperative task planning method for nonholonomic constrained ground mobile relays is analyzed.For this emergent mobile Internet of Things,first,its model is derived.Second,according to UAV air base platform scattering in the key airspace,area-division algorithm and location update algorithm for ground mobile relays are studied.The algorithms ensure a reliable and energy-efficient communication by deciding the ground mobile relay coverage area and optimal deployment scheme.Third,joint motion strategy for multiple ground mobile relays is researched to improve the expansibility of ground mobile relays for covering the UAV clusters,which is causing by nonholonomic constraints.It is useful to deal with the ground mobile relays failure or costs reduce.Finally,the effectiveness of the proposed method is verified through experiments.关键词：emergency mobile internet of things (EMIoT);ground mobile relay (GMR);UAV;air-ground coordination2|2|5更新时间：2025-07-02
- 摘要：Traditional scheduling algorithms in the phased array radar cannot be utilized to fully release multi-function potential of digital array radar.Aiming at this problem,an online interleaving scheduling algorithm is proposed on the basis of the task internal structure.By decomposing the interleaving scheduling analysis into the time resource constraint analysis and the energy resource constraint analysis,the algorithm is able to interleave all kinds of tasks as far as they meet the resource constraints.Thereby not only the waiting duration is utilized to execute other task's transmitting duration or receiving duration,but also receiving durations of different tasks are able to be overlapped.The simulation results show that,due to the efficient usage of the waiting duration and the receiving duration,the proposed algorithm effectively improves the successful scheduling ratio,the high value ratio and the time utilization ratio compared with the three existing algorithms.关键词：digital array radar;task scheduling;online interleaving;time constraint3|2|3更新时间：2025-07-02
- 摘要：web-offset press is a kind of coupling nonlinear dynamic system.We use the lumped mass method,Newton's second law,the differential equations and series theory and method to establish the gear system nonlinear dynamic modeling of web-offset printing machine wherein the time-varying meshing stiffness,backlash,dynamic transmission error and other nonlinear factors were considered.the concept of general time-state space comprising of state variables,control variable and time t is established.Then the model of web-offset printing machine can be transformed into a state equation of nonlinear system.In order to solve the state equation of nonlinear control systems,at the operation point of general time-state space,the right side of the state equation can be expanded as Taylor series about time.Then the series solution of the nonlinear control state equation,for which the solution is expression in time series,can be obtained by using direct-integrating approach.Then we use Matlab to simulate the equation of the web-offset printing machine's gear system.We obtain the curves of the relationship of gear's angular velocity and time and the relationship of angular acceleration and time.we contrast these curves and the facts.the contrast result verifies the validity of the dynamic model and the analytic solution of the system equation.关键词：gear system;dynamic model;nonlinear systems;state equation;direct-integrating2|2|0更新时间：2025-07-02
- 摘要：As a wide spread technology in radar systems,pulse compression is used to improve the radar resolution.With the development of wide band radar systems,the points of pulse compression become larger and larger.A method of fast implementation of ultra-long points pulse compression in frequency domain based on 2-D FFT algorithm is proposed.TMS320C6678 EVM board is used to test the new method.The experiment result shows that the efficiency of the proposed method is improved by more than 20% compared with the traditional methods.128K points pulse compression can be finished in about 0.81ms by only one 1GHz TMS320C6678 chip.关键词：pulse compression;ultra long FFT;2D FFT;TMS320C66782|2|0更新时间：2025-07-02
- 摘要：A cognitive radar target tracking algorithm is proposed for the tracking problem in complex battlefield environment.Based on the theory of human "perception-action" cycle,first,the Cramer-Rao lower bound (CRLB) of target radial distance,radial velocity and azimuth is approximated to the measurement error covariance.Then,the information entropy is used to describe the uncertainty of target tracking,and the connection between data processing in radar receiver and signal processing in radar transmitter is established with the criterion of minimum entropy.Furthermore,inspired by the three stage memory mechanism of human brain,"memory" is nested in Interacting Multiple Model (IMM) algorithm to overcome the tracking precision degradation problem when the model transition probability is set improperly.Thus,the transition probability can be adaptively adjusted to enhance the dominant model and weaken the bad competition of the mismatched model.The simulation results verify the effectiveness of the proposed algorithm.关键词：cognitive radar;information entropy;maneuvering target tracking;waveform selection5|2|9更新时间：2025-07-02
- 摘要：For the remaining useful life (RUL) prediction method based on relevance vector machine (RVM),kernel function is the important item of RVM model for the final prediction result.The current RVM prediction models are dominated by single kernel,and the selection of RVM kernel is a little bit subjective.So,the prediction performance of the constructed RVM model is limited.To address this problem,a multi kernel RVM model is proposed for the RUL estimation,using the fruit fly optimization algorithm (FOA) to find the best corresponding coefficients of multi kernel in the linear combination of multi kernel functions,and to improve the prediction performance of RVM model applied in the RUL estimation of lithium-ion battery.The battery test data sets of the national aeronautics and space administration (NASA) and the center of advanced life cycle engineering (CACLE) in the university of Maryland are used respectively.Experiments have been carried out to test the performance of the proposed method.The results show that the mean absolute error (MAE) and root mean square error (RMSE) of multi kernel RVM method are both less than the single kernel RVM algorithm.关键词：multi kernel relevence vector machine;fly optimization algorithm;lithium-ion battery;remaining useful life prediction4|3|24更新时间：2025-07-02
- 摘要：In multi-mode mode,pattern characteristics,frequency characteristics and distance characteristics of the ionosphere side scatter response signals are simulated.Comparing with the obatained experimental data,ionospheric side scatter characteristics and the relationship between the ionosphere characteristicson of the two links based on point-to-point are verified.The mode of ionospheric side-scattering is a combination of two link modes of side-scattering.The minimum available frequency of each combination mode corresponds to the larger value of the minimum frequency of the two modes.The maximum available frequency of the combination mode corresponds to the smaller value of the maximum frequency of the two modes.The group distance of each combination mode is the sum of the group distances of the two combination modes.It is of great significance,for the study of subsequent ionospheric characteristics ionospheric side scattering for target detection,multi-base positioning,operating parameter selection,etc.关键词：ionosphere;ray tracing;side scatter;response signal4|2|0更新时间：2025-07-02
- 摘要：In this paper,SLDA-TC,a novel text categorization model based on supervised topic model is proposed.The new parameter represents the probability distribution of topic-category is introduced.The SLDA-TC-Gibbs sampling algorithm is presented.At each iteration,a word's latent topic sampling only utilizes the other training documents having the same category with the document the word occurred,meanwhile,the theoretical proof is given.In the SLDA-TC model,the number of topics is only slightly larger than the number of categories.The experimental results demonstrate that the SLDA-TC model promotes the accuracy and speed for text classification compared with the LDA-TC and SVM algorithms.关键词：text categorization;topic model;latent Dirichlet allocation;Gibbs sampling2|2|10更新时间：2025-07-02
- 摘要：To solve the contradiction of the scheduling success rate (SSR),the time shifting rate (TSR) and the algorithm timeliness in the task scheduling of phased array radar,this paper proposes a scheduling algorithm based on the branch and bound method (BBM).Firstly,this algorithm acquires all executable tasks from available scheduling results,i.e.,obtaining several "nodes" on multiple "layers",and forms several optional "branches" with these nodes through multistep recursion.In this way,the range of solution space is extended,and the algorithm performance is improved.Then,this algorithm "discards" branches with low yield and keeps the solution space to a certain range,which improves the accuracy of the algorithm and reduces the calculation amount.The simulation experiment indicated that compared with the algorithm based on integrated priority The simulation experiment suggested that the proposed algorithm enjoyed a 52% increase in scheduling success rate(SSR) over the traditional integrated priority algorithm,experienced a 61% reduction in the time shifting rate(TSR) compared with the time pointer algorithm,and took only 1~2% of the time consumed by the genetic algorithm.关键词：phased array radar;task scheduling;branch and bound method(BBM);scheduling success rate(SSR);time shifting rate(TSR);integrated priority;time pointer;genetic algorithm2|2|3更新时间：2025-07-02
- 摘要：Optical flow field is an important basis for many computer vision tasks such as target detection and unmanned aerial vehicle positioning.In order to develop the accuracy and robustness of optical flow estimation suffered from the difficult motion such as non-rigid movement and large displacement motion,this paper proposes a large displacement optical flow estimation approach based on non-rigid dense patch matching.Firstly,we utilize the non-rigid dense patch matching to compute the initial nearest neighbor field between the consecutive frames,and eliminate the inconsistent regions of the computed nearest neighbor field according to the consistency of the neighboring patches in the image to obtain an accurate image nearest neighbor field.Secondly,we merge the nearest neighbor field into the TV-L1(Total Variational with L1 norm,TV-L1) optical flow model,and employ the nearest neighbor field to compensate the large displacement optical flow of TV-L1 model by using the quadratic pseudo-Boolean optimization (QPBO) fusion algorithm during the coarse-to-fine computation scheme.Finally,we employ the standard test image sequences to evaluate the performance of our approach and some state-of-the-art methods including LDOF(Large Displacement Optical Flow,LDOF),Classic+NL,NNF(Nearest Neighbor Fields,NNF) and FlowNet2.0.The experimental results demonstrate that the proposed method has the higher accuracy and better robustness of optical flow estimation for difficult motion such as non-rigid movement,large displacement motion and motion occlusion.关键词：optical flow field;Target Detection;unmanned aerial vehicle;computer vision;non-rigid patch matching;large displacement motion;nearest-neighbor filed;deep learning2|2|5更新时间：2025-07-02
- 摘要：In order to enhance the real-time performance and stability of industrial-level machine vision systems,this paper proposes a fast template matching method with rotation invariance based on equal-area ring projection and Zernike moments.The method uses a coarse-to-fine matching strategy.The coarse matching stage uses the equal-area ring projection vector as the feature to obtain the candidates,and then use Zenrike moments to accurately match in candidates.The main contributions of this paper are proposing the equal-are ring projection vector feature with low complexity,noise insensitive and rotation invariance,and further reducing the computational cost of Zernike moments based on the octant circle method using circular symmetry.Theoretical analysis and experimental results show that the proposed method is faster than the state-of-the-art algorithm under high matching accuracy,and it is robust to Gaussian noise and linear brightness variations.关键词：photoelectric inspection;machine vision;template matching;rotation invariant;equal-area ring projection;Zernike moments254|148|1更新时间：2025-07-02
- 摘要：Text similarity measures play a vital role in text related applications in tasks such as social networks,text mining,natural language processing,and others.The typical characteristics of short texts demonstrate severe sparseness and high dimension while the traditional short texts similarity calculation always ignores category information.A coupled distance discrimination and strong classification features based approach for short text similarity calculation,CDDCF,is presented.On the one hand,co-occurrence distance between terms are considered in each text to determine the co-occurrence distance correlation,based on which the weight for each term can be determined and the intra and inter relations between words are established.The similarity of coupling distance discrimination on short text can be captured.On the other hand,strong classification features are extracted via labeled texts.The similarity between two short texts is measured by using the common number of strong discrimination features with the same context.Finally,the distance discrimination and strong classification features are unified into a joint framework to measure the similarity of short texts.Experimental results show that CDDCF performs better compared to baseline algorithms in term of its performance and efficiency of similarity computation.关键词：text mining;natural language processing;text clustering;social network;coupling relation;feature extraction;word sense disambiguation;similarity computation123|286|3更新时间：2025-07-02
- 摘要：The energy level stabilization process of the multi-scale quantum harmonic oscillator algorithm (MQHOA) is the core part of the algorithm,which plays an important role in avoiding the algorithm falling into local optimum and improving the accuracy of the algorithm.In the studying of the energy level stabilization process of the algorithm,it is found that different energy level stabilization criteria will result in different performance of the algorithm at the same energy level.The relatively loose criterion makes the iteration of the algorithm inadequate in the process of energy level stabilization and easy to fall into premature.The more stringent criterion can make the wave function reach a stable state at the same energy level,improve the global search ability of the algorithm,but meanwhile the computing cost will also rise.Experiments show that loose energy level stability criterion of the algorithm has good effect on solving unimodal simple functions,and strict energy level stability criterion of it is suitable for solving multimodal complex functions.The algorithm has been effectively applied in resource optimization,adaptive control and energy consumption optimization management.关键词：optimization algorithm;multi-scale quantum harmonic oscillator algorithm;energy level stability;quantum computation;quantum harmonic oscillator;wave function;quantum annealing195|290|2更新时间：2025-07-02
- 摘要：The gate insulator material with high dielectric constant has some polarization and coupling effect,which makes ZnO-TFTs have high interface Fermi level pinning effect,large capacitive coupling effect and low carrier mobility.To solve these problems,in this paper,a kind of ZnO-TFTs structure using SiO2 modification of Bi1.5Zn1.0Nb1.5O7 as gate insulator was proposed.The effect of SiO2 modification on the performance of gate insulator and ZnO-TFTs was systematically investigated.The results showed that the properties of gate insulators and ZnO-TFTs were significantly improved after SiO2 modification,which makes ZnO-TFTs have a very wide application prospect in the next generation display field.The leakage current density and roughness of gate insulators decreased from 4.5×10-5A/cm2 to 7.7×10-7A/cm2 and from 4.52nm to 3.74nm,respectively.The sub-threshold swing and interface state density of ZnO-TFTs decreased from 10V/dec.to 2.81V/dec.and from 8×1013cm-2 to 9×1012cm-2,respectively.The mobility of ZnO-TFTs increased from 0.001cm2/(V·s) to 0.159cm2/(V·s).关键词：SiO2 thin films;ZnO-TFTs;modification layer;Bi1.5Zn1.0Nb1.5O7 thin films;RF magnetic sputtering2|2|0更新时间：2025-07-02
- 摘要：Co-saliency detection is a new branch with the rapid development in the field of visual attention,which concerns the detection of the common salient objects from multiple relevant scene images,and can be widely used in various computer vision tasks.Considering the key point of current research is the design of feature extraction strategy,the existing co-saliency detection methods are firstly summarized and qualitatively analyzed according to the different feature extraction strategies in this paper.Subsequently,based on the subjective and quantitative comparisons in the five open datasets,the performance of the state-of-the-art algorithms is evaluated,the influence of the feature extraction strategy on the performance of algorithms and the complexity of the datasets is analyzed,and the difference of co-saliency detection and saliency detection is also verified.Finally,the conclusion of this paper are presented,the problems of current research and the future development are also discussed.关键词：visual attention;co-saliency;feature extraction strategy;hand-designed features;shallow learning features;deep learning feature465|462|8更新时间：2025-07-02
- 摘要：Ground penetrating radar (GPR),as an important non-destructive detection technology,can image the shallow subsurface accurately and quickly to obtain the spatial and geometric information of the buried targets.This paper describes and summarizes seven detection methods of hyperbolic signatures in GPR images,i.e.,based on hyperbolic properties,based on the time domain signal analysis,based on the digital image analysis,based on the machine learning,based on the mathematical model,based on the comprehensive and deep learning methods.Finally,we discuss the application potential of the deep learning method for the recognition of hyperbolic signatures.关键词：geophysical technology;non-destructive detection;GPR;object recognition;hyperbola signature;deep learning195|381|11更新时间：2025-07-02
- 摘要：To improve the conversion efficiency of the three-phase inverter,a novel topology of three-phase resonant pole soft-switching inverter is proposed.By adding a simple auxiliary circuit on each phase of the bridge arm,the main switches realize zero-voltage turn-on and zero-current turn-off.Metal Oxide Semiconductor Field Effect Transistor (MOSFET) or Insulated Gate Bipolar Transistor (IGBT) which is used as the main switch of the inverter could realize the lossless switching,so as to solve the problem of capacitive turn-on loss caused by the MOSFET internal junction capacitance and the turn-off loss caused by the IGBT trailing current.This paper analyzes the working process of the circuit.The experimental results show that the switching devices achieve soft-switching.Therefore,the topology is of great importance to improve the performance of the inverter.关键词：inverter;resonant pole;soft-switching;zero-voltage turn-on;zero-current turn-off58|238|2更新时间：2025-07-02
- 摘要：A 45-degree linearly polarized microstrip antenna array with reflection-canceling unit is proposed at W band.The single-row series-fed antenna array with sidelobe suppression of 25dB is designed by the Taylor-weighted,combined with reflection-canceling unit.Meanwhile the cross polarization is improved in the main lobe by adding the rectangular welt groove.The power divider with first order and ten ways replaces quarter wavelength transmission lines with the T-shaped structure junction,which achieves the power division ratio of 4.5 times.The simulation and measure results show that the antenna works from 75.7GHz to 77.6GHz by arraying.The horizontal and vertical azimuth for 3dB beam width can cover from-5 degrees to 5 degrees,where the cross polarization ratio is all higer 18dB.The gain of the antenna is 24dB and the sidelobe suppression is up to 20dB.The antenna can be used in the vehicle anti-collision radar and further improve whose anti-jamming capability.65|346|2更新时间：2025-07-02
- 摘要：Mingantu Spectral Radioheliograph (MUSER) is a solar dedicated interferometric array using synthetic aperture imaging technology.There aren't redundant baselines in MUSER in order to make full use of these antennas,which requires an external signal source to carry out system calibration.This paper describes phase calibration of MUSER by using the geostationary satellite as calibrator.Some observations and results are introduced as well.We analyzed the advantages and disadvantages of the satellite as a calibrator,as well as the effect on image quality.关键词：synthesis aperture;phase calibration;satellite48|219|1更新时间：2025-07-02
- 摘要：Conventional beamforming technology is widely used in passive sonar engineering practice,in view of its simple principle and good robustness,while false alarms due to multilevel sidelobes and low bearing accuracy defect still exist.The method using different split-beam configurations is proposed,considering serial rough and accurate measurement employed in phase interferometer together with energy selection used in phase binning process,to achieve high precision and low false alarm detection.The experimental results show that the proposed method is practical to reduce the sidelobe interference,and the noise background level is reduced by at least 5dB compared to the conventional method.The algorithm is suitable for passive uniform line array,and also has certain reference significance for radar and active sonar in spatial spectrum construction.关键词：passive sonar;uniform linear array;sidelobe reduction;split-beam configuration;phase binning process;high bearing accuracy;low false alarm rate149|270|0更新时间：2025-07-02
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