最新刊期
卷 47 ， 期 3 ， 2019
- 摘要：The shipborne high frequency sky-surface wave radar is a further extension of the sky-surface wave radar system under the traditional fixed platform.However,due to the influence of the shipborne platform motion and the ionosphere in the propagation channel,the first-order sea clutter spectrum exhibits more features.Based on the first-order electric field equation in the Walsh model,the analytic expression of the first-order ocean surface cross-section for the sky-ship propagation mode is derived.Then,according to the expression,the effects of different factors on the first-order spectrum are simulated and analyzed.Simulation results demonstrate that the radar operating frequency,the motion of the platform and the horizontal motion of the ionosphere are the main reasons of the first-order sea clutter Doppler spectrum broadening.The wind direction mainly affects the morphological changes of the first-order sea clutter spectrum,and this feature provides the possibility of ocean remote sensing according to the first-order sea clutter spectrum.关键词：shipborne high frequency sky-surface wave radar;ionosphere;sea clutter spectrum;ocean surface cross section142|515|1更新时间：2025-07-02
- 摘要：This paper proposes several sensor control strategies via Gaussian mixture multi-target filter (GM-MTF) with random finite set.First,on the basis of the cubature Kalman Gaussian mixture multi-target nonlinear filter,the global information gain of the GM-MTF is deduced through the Bhattacharyya distance between the two Gaussian distributions.Then,taking advantage of this information distance,this paper proposes a corresponding sensor control strategy.Furthermore,a joint sampling method of Gaussian particle is designed to sample the predicted Gaussian component of multi-target filter.Subsequently,a set of weighted particles are used to approximate the multi-target statistical characteristic,and their weights are updated with the ideal measurement set.Next,a Rényi divergence based sensor control strategy which has better adaptability is proposed.Finally,a detailed Gaussian mixture implementation of the posterior expected number of targets (PENT) is given.Simulation results verify the effectiveness of these algorithms.关键词：sensor control;multi-target tracking;Gaussian mixture;finite set statistics;partially observable Markov decision process112|468|2更新时间：2025-07-02
- 摘要：An energy harvesting method based on power splitting-based relay is adopted,where the relay converts part of the received radio frequency signals into energy and amplifies and forwards the remaining signal using the collected energy.By using maximum-ratio combining/maximum-radio transmission receiving and precoding technology at the relay node,the corresponding lower bound expressions for the ergodic rate of each user are derived and the optimal relay power allocation ratio which maximizes the sum rate of all users is calculated.The simulation results show that the maximum sum rate can be obtained under the optimal relay power allocation ratio,and the relationship between the sum rate with the number of relay antennas and the number of users is given.What's more,the performance of the relay system based on energy harvesting outperforms that without energy harvesting.关键词：two-way relay system;multipair users;energy harvesting;power splitting based relay;maximum-ratio combining/maximum-radio transmission;sum rate74|366|3更新时间：2025-07-02
- 摘要：In the target tracking of Doppler radar,how to effectively solve the nonlinear relationship between the measurement of the system and the target's state and achieve maneuvering target tracking on this basis is an urgent problem.A measurement conversion based interactive multiple model (IMM) target tracking algorithm is proposed.The algorithm uses the IMM as a framework,and combines the structure of static fusion filter to solve the maneuvering target tracking in Doppler radar.The simulation results demonstrate the effectiveness of the proposed algorithm.关键词：converted measurements;Doppler radar;maneuvering target tracking;nonlinear filtering90|362|1更新时间：2025-07-02
- 摘要：This work is motivated by the increasing demand on anti-jamming techniques in radar systems.The current challenging issues on the anti-jamming task in conventional radar frameworks are outlined. Focused on deceptive jamming countermeasure issue,a novel framework,referred to as waveform diverse array (WDA) radar,is proposed to address the anti-jamming problem.Utilizing the additional degrees-of-freedom (DOFs) in transmit spatial frequency in frequency diverse array (FDA) multiple-input multiple-output (MIMO) radar,the true target and repeated false target can be isolated in the transmit spatial frequency domain.Moreover,this paper investigates the feasibility by using the suggested FDA-MIMO radar to suppress the deceptive jamming signals,even those from the mainlobe direction,with help of some information on true target obtained in earlier detection stage.In consideration of the random distribution of repeated false target in time domain,a jamming signal sample selection approach based on multi-hypothesis test is proposed,which evidently improves the estimation accuracy of jamming covariance matrix.Further analysis and simulation results are provided to confirm the effectiveness of the proposed waveform diverse array technique.关键词：waveform diverse array;radar anti-jamming;mainlobe deceptive jamming;anti-jamming principle;transmit degrees-of-freedom452|528|16更新时间：2025-07-02
- 摘要：The existing methods need to know a priori dual word of a convolutional code to reconstruct the feedback polynomial of a synchronous scrambler placed after a convolutional encoder.To overcome this limitation,a novel reconstruction method is proposed based on the triple correlation property of m-sequences.First,the scrambled bit sequence is divided into multiple blocks.The length of each block equals the constraint length of the convolutional encoder,and the interval between two start points of adjacent blocks is the codeword length.Then,it is proved that the generated sequence by the dot product of scrambled bit blocks with a dual word is also an m-sequence,having the same period as the synchronous scrambler.With this result,a dual word of the convolutional encoder can be estimated based on the triple correlation property of m-sequences.Finally,the feedback polynomial is reconstructed by using two locations of triple correlation peaks.For the case that there are bit errors in the received sequence,the probability distributions of the peak and non-peak values of triple correlation are derived.Therefore,the threshold for detecting triple correlation peaks is obtained,and the confidence level of the correct reconstruction is analyzed.Simulation results show the effectiveness of the proposed method.Compared with the existing methods,the proposed method does not require the prior knowledge of a dual word and eliminates the uncertainty in the reconstruction results.Moreover,the proposed method is more robust to bit errors.关键词：synchronous scrambler;convolutional code;m-sequence;triple correlation property;dual word84|370|3更新时间：2025-07-02
- 摘要：Aiming at the maneuvering target tracking problem,a novel square-root cubature Kalman filter (SCKF) is proposed by the integration of the adaptive constant acceleration (CA) model and the waveform scheduling.On the basis of the CA model,the approximation relationship between the Jerk and the velocity as well as the acceleration is established in order to make the connection of the state process noise with the state error covariance matrix.As such,the adaptive adjustment of the proposed model is realized.Additionally,the fractional Fourier transform (FrFT) is utilized to rotate the ambiguity function of the transmitted waveform to maintain the orthogonality between the measurement error ellipse and the state prediction error ellipse.Thereby,the optimal transmitting waveform can be obtained and the tracking performance is systematically improved in both of the data processing and the signal processing.The simulation results show that the proposed algorithm possess a simpler structure and higher accuracy than the unscented Kalman filter based on the modified current statistical (CS) model,the SCKF based on the CS model,the SCKF based on the CA model and the interactive multiple model SCKF (IMM-SCKF).关键词：maneuvering target tracking;constant acceleration model;waveform scheduling;square-root cubature Kalman filter103|369|3更新时间：2025-07-02
- 摘要：This paper solves the problem of optimization of energy transmission efficiency in the two dimensional omnidirectional charging cyber physical system (2DOWC-CPS) with two phase alternating current (AC) power supply,the frequency bifurcation and energy transmission mechanism are found,and a formal model of the system is established by using hybrid automata theory.An optimal transmission control strategy adopting different power supply modes when the load is in different intervals determined by the characteristic parameters of the physical coils is put forward,and a reactive algorithm based on the optimal control strategy is also developed to carry out the frequency optimization of energy transmission efficiency.It simulates the frequency bifurcation phenomenon under resonant condition,and verifies the optimal transmission theory model under two-phase AC power supply.So,it provides an application reference for mobile charging including electric vehicles and smart phones.关键词：two dimensional omnidirectional;wireless charging;energy transfer;cyber-physical systems;frequency bifurcation;two phase alternating current power supply;hybrid automata;power supply mode221|367|1更新时间：2025-07-02
- 摘要：In the existing two-dimensional direction-of-arrival (DOA) estimation algorithms based on spectral peak search,the complexity is high and the accuracy is greatly influenced by the search interval.To overcome these problems,this paper examines a two-dimensional DOA estimation with coprime rectangular array using bi-directional propagator method,which realizes a low complexity,high accuracy,unambiguous for 2-D estimation.Firstly,this algorithm introduces coprime array into 2-D DOA estimation,and constructs a coprime rectangular array model.The two rotation factor matrices along the different directions for propagator method can be got,the elevation angle and azimuth angle for the sources can be obtained from the rotation factor matrices.Further more,the multi values of sparse array are eliminated by using coprime theory,and the proof of unambiguous for two-dimensional DOA estimation under the coprime array model is provided.This paper also analyzes the complexity and gives the Cramer Rao lower bounds (CRB) of coprime rectangular array.Theoretical analysis and simulation results show that this algorithm does not need to angle matching and spectrum peak search,under the same conditions,the root mean square error (RMSE) performance is better than the multiple signal classification (MUSIC) algorithm of uniform rectangular array.At the same time,the proposed algorithm can reach the same accuracy of high dimensional grid search with low complexity and without ambiguity.关键词：coprime rectangular array;propagator method;direction-of-arrival (DOA);Cramer Rao lower bounds (CRB)73|384|4更新时间：2025-07-02
- 摘要：The robustness of broadband adaptive beamformer decreases in practice and the detection ability of weak signal is limited by signal noise ratio (SNR).To solve those problems,a broadband robust diagonal reducing adaptive beamforming based on subarray subspace is proposed.Firstly,the subarray subspace projection method is used to correct signal steering vector,and a spherical uncertainty set is designed to get subarray robust capon beamformer (RCB) weight vector.On the other hand,the least eigenvalue of subarray cross spectral density matrix is proposed as the estimation of non-correlated noise power,and the main diagonal of subarray cross spectral density matrix is subtracted from the noise power and processed by the proposed beamformer.The above process is repeated for each sub-band and all outputs are incoherently summed to obtain the final result of the proposed method.Theoretical and experimental analysis shows that the proposed algorithm can improve the robustness and the output SNR of the adaptive beamformer.关键词：signal and information processing;broadband robust adaptive beamforming;subarray subspace;diagonal reducing82|335|0更新时间：2025-07-02
- 摘要：To eliminate the selective harmonics of radio frequency pulse width modulation (RF-PWM) signals,a novel multi-level RF-PWM method for all-digital transmitters (ADTx) is proposed.This method compares the adaptive thresholds in real-time with the phase modulated signal,and controls the pulsewidth of the corresponding subpulses to make the selected harmonics cancel each other out and keep the weighted superposition of fundamental frequency components proportional to input envelope.Compared with the existing techniques,the proposed method can significantly relax the filtering requirements and improve the wideband performance of the ADTx.For the third harmonic elimination,the corresponding 5-level RF-PWM scheme is presented in this paper.Finally,the proposed scheme is verified by extensive simulations and offline measurements.关键词：all-digital transmitter;pulse-width modulation;multi-level;adaptive thresholding;selective harmonic elimination93|322|1更新时间：2025-07-02
- 摘要：Elevated duct can be measured through direct or indirect ways.Nevertheless,both of these traditional methods are inadequate because direct measurement can only obtain single-point information,while indirect measurement can not obtain multidimensional information with high temporal and spatial resolution.Geostationary meteorological satellite can be used to monitor ocean atmospheric environment because of its ability to capture four-dimensional information with high temporal and spatial resolution.This paper presents a foreign inversion method of elevated duct based on geostationary meteorological satellite data,and the applicability of this method was verified with cloud classification and cloud top temperature productions from FY-2G,ground-based meteorological observation and radiosonde data in Chinese regional seas.Several key research aspects are needed to be solved for setting up the method in Chinese regional seas as,which include: Using high-precision cloud-top temperature data,selecting appropriate standard pressure level from 850hPa or 700hPa,obtaining values of empirical parameters according to local-area radiosonde data,and setting up a local parameterization schemes.The verification of applicability for the method in Chinese regional seas will be carried out,positive result of which can potentially see as an effective new means used in monitoring elevated duct in Chinese regional seas.关键词：monitoring of elevated duct;meteorological satellite data;cloud top temperature;inversion method80|365|4更新时间：2025-07-02
- 摘要：The current research of network security based on game theory fails to analyze the real-time,continuous,and random network attack and defense process.For the randomness of security states and the real-time character of network defense decision-making,we analyzed the network attack and defense behaviors from the view of dynamic and real-time confrontation.Then we combined and extended the differential game model and Markov decision-making method.On these basis,a Markov attack-defense differential game model is constructed,which can be adopted to analyze the multi-stage attack and defense process with short duration in each stage.Besides,a multi-stage game equilibrium solution is proposed,and an optimal defense strategy selection algorithm is designed.Finally,the experiments demonstrate that the model and method proposed in this paper are valid.关键词：network security;network attack and defense;game theory;differential game;Markov decision-making;network defense;attack-defense analysis;optimal defense strategies123|357|5更新时间：2025-07-02
- 摘要：The frequency conversion sinusoidal chaotic neural network (FCSCNN) cannot consider search accuracy and convergence speed simultaneously.In order to solve the mentioned problem,a novel self-adaptive simulated annealing (SSA) strategy is proposed by analyzing the optimization mechanism of the transiently chaotic neural network (TCNN) and the existing annealing strategy.It can give appropriate self-feedback connection weights based on the characteristics of Lyapunov exponent.The reversed bifurcation,Lyapunov exponent and annealing function evolution diagram of the chaotic neuron are given and the dynamic characteristic is analyzed.It shows that the SSA strategy can choose appropriate annealing speed in different stages,which can not only make full use of chaotic global searching ability but also accelerate convergence speed.Based on the neuron model,a novel FCSCNN with SSA strategy (FCSCNN-SSA) is proposed and applied to nonlinear function optimization and combinational optimization problems.The simulation results show that:(1) The SSA strategy can targeted choose the appropriate annealing speed,which is superior to other several existing simulated annealing methods for pertinence and adaptability and can be expanded to other similar models with same optimization mechanism; (2)FCSCNN-SSA can converge with a fast speed and search accuracy simultaneously than TCNN,TCNN-SEA,I-TCNN,NCNN,BFS-TCNN,FCSCNN.关键词：frequency conversion sinusoidal chaotic neural network;Lyapunov exponent;self-adaptive simulated annealing;optimal computation92|342|2更新时间：2025-07-02
- 摘要：A detection algorithm based on energy feature extraction is proposed for the detection of frequency-hopping signals in complex environments.The algorithm can accurately determine the existence of frequency hopping signal in the channel.Firstly,the receiving data is projected into the energy domain to be whitened,and the color noise in the receiving signal is suppressed.Then,the time-domain continuous signal in the channel is extracted through the energy distribution feature to remove the short-term burst signal in the receiving signal.Finally,the channel processing is used to decompose the receiving signal into each subchannel and detect the existence of frequency-hopping signal by means of short-term energy cancellation.The statistical properties of the algorithm,the false alarm probability and the detection probability are theoretically derived,and the experimental simulation is carried out to verify the effectiveness of the algorithm.关键词：frequency-hopping signal detection;complex channel;principal component analysis77|402|6更新时间：2025-07-02
- 摘要：Symbolic execution is of vital importance for software engineering activities,such as path exploration,debugging and verification.However,symbolic execution techniques do not scale well for complicated realistic programs,because the number of feasible executions paths increases exponentially.Path condition expression extracting and constraint solving are the bottlenecks of symbolic execution.State merging is a common method to tackle the problem of state explosion,but this abstract procedure would be prone to incorrect path information.According to different searching strategy of symbolic engine,symbolic execution tools could generate unsolved path conditions during the process of symbolic variable state combination.A symbol value analysis based on dependent condition reconstruction method is proposed,which analysize the logic path conditions and extracts the common variable symbols to enhance the combination efficiency.Meanwhile,the backward analysis method is used to generate dependent condition set to improve the accuracy of path analysis.The experimental results demonstrate that it has better execution efficiency and accuracy compare to the tradition state combination methods.关键词：program analysis;symbolic execution;related dependency;constrain solving71|322|0更新时间：2025-07-02
- 摘要：At present,facial beauty prediction is facing the problems,in which data is insufficient,the face image is hard to classify,and the deep feature lacks research.To solve these problems,a solution to facial beauty prediction research based on double activation layer depth convolution feature is proposed.Firstly,we use the method of data augmentation and face alignment to increase the number of samples in training set and improve the data quality of database.Secondly,we propose a double activation layer (DAL) to design a CNN model that is more suitable for facial beauty prediction.Experimental results based on 2000 test set show that the method proposed is superior to the traditional method of facial beauty prediction both in classification and regression.In addition,the proposed method achieves better results and real time performance than the state-of-art CNN model,in which rank-1 recognition rate is 61.1% and the Pearson correlation coefficient is 0.8546.Consequently,the DAL method plays an important role in deep facial prediction learning,which can be widely used in face recognition and image processing.关键词：facial beauty prediction;convolutional neural network (CNN);double activation layer;data augmenta-tion116|393|6更新时间：2025-07-02
- 摘要：Surface non-uniformity including temperature,work and geometric profile affect intrinsic emittance of thermionic cathode of vacuum electronics and accelerators.In order to understand how intrinsic emittance is manipulated by work function variation,a general intrinsic emittance model consisting of contributions from surface non-uniformity was developed.Finite-difference time-domain particle-in-cell (FDTD-PIC) simulation verified numerical calculation result of cathodes with work function radical variation and 1D cosine periodic variation.Furthermore,theoretical results and simulation for cathodes with work function of 2D cosine periodic variance and 2D random distribution showed that emittance increase coefficient approaches to 1 and variance of emittance increase coefficient decreased quickly when spatial frequency increased.This paper shows that work non-uniformity hardly affects intrinsic emittance if cathode diameter is much larger than the average size of micro work region;in contrast,intrinsic emittance may differ from uniform case notably if micro size is comparable to cathode diameter.Moreover,theoretical model and simulation method are useful to assess influence of work or temperature non-uniformity on intrinsic emittance of kinds of cathode.关键词：cathode electronics;thermionic cathode;FDTD;PIC;intrinsic emittance;work function variation140|353|1更新时间：2025-07-02
- 摘要：In many practical applications of evolutionary optimization,the fitness evaluation is subject to noise.In this paper,the effect of normal random noise on fitness evaluation is studied,and the performance of different fitness evaluation methods is compared and analyzed.A dynamic fitness evaluation method is proposed.In the process of population regeneration,the method evaluates all surviving individuals again,reduces the survival period of the pseudo-superior individuals (the inferior individuals),and restrains the interference with noise on the survival of the fittest.Experimental results show that the proposed method has better performance than the method of one evaluate and one sampling or one evaluate and multiple sampling at the same total number of sampling.关键词：genetic algorithm;noisy environment;fitness evaluation70|465|1更新时间：2025-07-02
- 摘要：Using the piecewise logistic map(PLM) as a local chaotic map for the 2D coupled map lattices (CML),this paper proposes a chaotic model with complex dynamic behavior.The influence of some parameters to the model features,such as the Lyapunov exponent(LE),bifurcation,ergodicity,and probability density distribution,is analyzed from the view of cryptographic applications.The analysis results provide the theoretic evidence for the model to configure parameters in the secure communication.Moreover,an offset is introduced to adjust the status value of lattices,which improve the ununiformity of probability density of status value.The research results show that the proposed model has good performance,and provide good foundation and conditions for the research of designing secure communication scheme based on this model.关键词：spatiotemporal chaos;coupled map lattices;Lyapunov exponent;chaos-based cryptography;secure com-munication174|349|6更新时间：2025-07-02
- 摘要：With the rapid development of internet and cloud computing technology,the existing dynamic random access memory (DRAM) have been unable to meet the requirements of performance and energy consumption of some real time systems.The emergence of non-volatile memory (NVM) have shown great potential for the development of the computer storage architecture.This paper proposes a kind of efficient memory page management mechanism based on the hybrid NVM and DRAM memory architecture.The main idea of this mechanism is to save the data pages with different access characteristics in the appropriate memory space according to the characteristics of different memory media,to reduce the number of system migration operations and improve the system performance.At the same time,the mechanism uses an efficient wear-leveling algorithm to improve NVM's lifetime.Finally,the experimental results show that the proposed method is effective.关键词：non-volatile memory;wear leveling;memory computing;hybrid memory72|391|2更新时间：2025-07-02
- 摘要：The absorption performance is going to decline when the composite absorbing metamaterial is in conformity with a cylindrical carrier.A non-uniform structure for conformal composite absorbing metamaterial and its optimization design is proposed to improve the wideband absorbing property.The periodic boundary conditions are established based on the periodicity in the direction of no curvature change.The number of sub-blocks parted by the characteristic basis function method is compressed by the periodical boundary conditions,and the dimension of the inverse of impedance matrix is also reduced to accelerate the optimization.A prototype is fabricated and measured with the optimized parameters given by genetic algorithm.The simulated and measured results show the proposed conformal absorbing material improves the influence of the cylindrical conformal and reduces the radar cross section in 2.8~8.0GHz for different polarized incidence.关键词：characteristic basis function method (CBFM);composite absorbing metamaterial;hexagonal loops;ultra-wideband;periodic boundary condition157|326|1更新时间：2025-07-02
- 摘要：In order to improve the drawback of brightness preserving bi-histogram equalization (BHE) algorithms,a dynamic range optimization method based on maximum entropy model is proposed to extend the application range of BHE algorithms,which makes it not only suitable for normal brightness image,but also can get good effect on low illumination and high brightness image.Firstly,the segmentation point decided by Otsu divides the original histogram into two sub-histograms.And then,a hybrid adjustable method is proposed to pre-process the initial histogram.After that,based on the proposed maximum entropy model,the best dynamic range segmentation point is determined by an ergodic optimization method.Finally,the BHE procedure outputs the final contrast enhanced image.Multiple image databases are selected for testing and compared with BBHE (Brightness preserving Bi-Histogram Equalization),BPCLBHE (Brightness Preserving and Contrast Limited Bi-Histogram Equalization),ESIHE (Exposure based Sub Image Histogram Equalization) and DRSHE (Dynamic Range Separate Histogram Equalization),and we use the entropy,contrast and NIQE (Natural Image Quality Evaluator) as objective evaluation indexes.The experimental results demonstrate that the proposed algorithm outperforms other state-of-the-art BHE algorithms on almost all types of images,with better subjective visual effective and better objective score of quality evaluation,and it takes the enhancement of contrast into account while preserving details.关键词：maximum entropy model;dynamic range segmentation;ergodic optimization;bi-histogram equalization;contrast enhancement;image enhancement279|493|11更新时间：2025-07-02
- 摘要：The backdoor instruction of chip is one of the typical ways to activate hardware Trojan,which has high security risk and a wide range of impact besides being difficult to be detected.In this paper,we propose a detection method of the backdoor instruction based on power analysis technology.By utilizing the segmented exhausting process and some power traces,the backdoor instruction can be distinguished from the conventional instruction effectively.The experiments show that the backdoor instruction can be analyzed successfully from the power traces by simple power analysis (SPA).Moreover,we also present an automatic detection method for the backdoor instruction based on correlation power analysis (CPA).By comparing the correlation coefficient with the mean value of the coefficient,backdoor instruction can be analyzed efficiently and automatically.关键词：chip;SPA;differential power analysis(DPA);CPA;backdoor;smart card316|433|4更新时间：2025-07-02
- 摘要：When transfer learning attempts to leverage the decision knowledge effectively from multiple source domains to predict the labels of instances accurately in target domain,it should consider how to well balance source and target domains,and their instances in both domains.In this paper,a novel multi-source transfer learning method called mlti-source transfer learning by balancing both domains and instances (MTL-BDI) is proposed to achieve the above goal.The basic idea of the proposed method is to embed the doubly weighted domain-level and instance-level balance term into the original objective function of transfer learning and then solve the proposed objective function effectively by using the alternating optimization technique.Extensive experiments on text and image datasets indicate that the proposed method indeed outperforms several existing multi-source transfer learning methods MCC-SVM (Multiple Convex Combination of SVM),A-SVM (Adaptive SVM),Multi-KMM (Multiple Kernel Mean Matching) and DAM (Domain Adaptation Machine) in the sense of classification accuracy on target domain.关键词：transfer learning;multi-source domain adaptation;fuzzy C-means clustering;instance weighting;universum learning;support vector regression;alternative optimization407|470|9更新时间：2025-07-02
- 摘要：The final carbon content is the key factor in determining the quality of steel,and is one of the core variables to be controlled in the process of converter steel-making.Based on the Levy whale optimization algorithm (LWOA) and least squares support vector machine (LSSVM),a comprehensive prediction model of carbon content at the end of the steel-making process is established.When the random selection of the parameters of the traditional whale optimization algorithm (WOA) is replaced with the Levy flight algorithm,the ability to jump out of the local optimum is optimized.Changing the method of coefficient vector convergence results in improvements to the generalization ability,prediction precision and convergence speed of the WOA.Data simulation results show that the proposed LWOA-LSSVM forecasting model not only overcomes the local optimization to obtain the global optimal solution,but also achieves faster convergence speed and higher prediction accuracy.Prediction results of the model,concerning root mean square error,mean absolute error,and mean absolute percentage error,show noticeable improvements when compared to those of the genetic algorithm and back propagation (BP) neural network,the genetic algorithm and LSSVM,and the traditional WOA and LSSVM.At the same time,through adjustments of the target hit ratio and the number of training sample entries,the prediction model is proven to be more robust than the aforementioned algorithms.关键词：steel-making;carbon content;whale optimization algorithm (WOA);least squares method;support vector machine;Levy flight353|667|12更新时间：2025-07-02
- 摘要：Because the optical flow field contains both the motion information of the object and the three-dimensional structure information of the scene,optical flow calculation technology is one of the important tasks in the field of computer vision and machine vision.But,for the existing optical flow methods,there is over-smoothing problem in image boundary preserving.This paper proposes a global TV-L1(Total Variational with L1 norm,TV-L1) variational optical flow computation method based on the mutual-structure guided filtering.By extracting the mutual-structural regions of the image with higher confidence,we construct the global mutual-structure guided filtering objective function,and optimize the algorithm via combining the pyramid layering strategy with the alternating iteration scheme.This method can better preserve the image boundary information.Finally,we compare the proposed method with the existing representative variational methods LDOF(Large Displacement Optical Flow,LDOF),CLG-TV(Combined Local-Global Total Variation,CLG-TV),Classic++,NNF(Nearest Neighbor Fields,NNF) and deep learning method FlowNet2.0 by using standard test image datasets.The experimental results demonstrate that the presented method has more accuracy and better robustness than the other evaluated methods,especially has the significant effect of boundary preserving in the areas,and it has application prospects in moving target detection,robot obstacle avoidance,and so on.关键词：optical flow calculation;computer vision;machine vision;image boundary preserving;image mutual-structure;deep learning;moving target detection;robot obstacle avoidance395|430|3更新时间：2025-07-02
- 摘要：The construction of two-weight codes over finite fields is an important research topic in graph,coding and cryptography fields.We obtain two new series of two-weight codes over finite fields and they are both optimal,which arrive at Griesmer bound.These codes are defined as p-ary images of trace codes over the extended fields.They have the algebraic structure of abelian codes.Their weight distributions are evaluated explicitly by using character sums,Gauss sums in particular.We also calculate the minimum distance of the dual codes of the image codes.Finally,an application of the Gray images of trace codes over the extended fields to secret sharing schemes is described.关键词：two-weight codes;trace codes;cyclic codes;Gauss sums;secret sharing schemes;Griesmer bound192|388|1更新时间：2025-07-02
- 摘要：At present,many researchers usually directly add the label confidence matrix as a priori knowledge to the classification model,and do not consider the influence of non-equilibrium prior knowledge on the quality of the label set.Based on this,the method of non-equilibrium parameters is introduced,and the basis confidence matrix obtained from the prior knowledge is non-equilibrium.Therefore,a multi-label learning algorithm is proposed,which uses kernel extreme learning machine with non-equilibrium label completion (KELM-NeLC).Firstly,information entropy is used to measure the correlation between labels which gets the basic label confidence matrix.Secondly,the basic label confidence matrix is improved to construct non-equilibrium label completion matrix by the non-equilibrium parameter.Finally,in order to learn to obtain a more accurate label confidence matrix,the non-equilibrium label completion matrix is introduced with the kernel extreme learning machine to solve the multi-label classification problem.The experimental results of the proposed algorithm in the opening benchmark multi-label datasets show that the KELM-NeLC algorithm has some advantages over other comparative multi-label learning algorithms and the statistical hypothesis test further illustrates the effectiveness of the proposed algorithm.关键词：machine learning;multi-label learning;label correlations;information entropy;label completion;extreme learning machine398|487|4更新时间：2025-07-02
- 摘要：The failure models of SiC JFET and SiC MOSFET have been developed.Based on the conventional circuit models of SiC JFET and SiC MOSFET,the additional leakage currents between the electrodes are introduced.For SiC JFET,the leakage current between the drain and the source is considered.For SiC MOSFET,two leakage currents are considered,one is the current between the drain and the source,another is the additional leakage current of the gate.Furthermore,the mobility dependent on the temperature and the electric-field strength replaces the constant mobility in conventional circuit models.The results from other experimental works and TCAD simulations verify the failure models of SiC JFET and SiC MOSFET.The developed failure models can be used to compare the short-circuit performances of SiC JFET and SiC MOSFET.关键词：SiC JFET;SiC MOSFET;failure;mobility;leakage current;short-circuit120|384|1更新时间：2025-07-02
- 摘要：The finite element analysis model of BGA (Ball Grid Array) solder joints is established.The height of solder joints,the maximum radial dimension of solder joints,the diameter of upper and lower solder joints are selected as design variables,and the stress of solder joints is taken as target value.29 groups of solder joints with different levels are designed and simulated by response surface methodology.The regression equation of solder joint stress and structural parameters is established.The structural parameters of solder joint are optimized based on the regression equation and genetic algorithm,and the optimal level combination of structural parameters with minimum solder joint stress is obtained.The results show that for lead-free solder SAC387,the solder joint stress decreases with the increase of solder joint height,and decreases with the decrease of maximum radial dimension;the combination of solder joint level with minimum stress is:solder joint height 0.38mm,maximum radial dimension 0.42mm,upper pad diameter 0.34mm and lower pad diameter 0.35mm.The results show that the maximum stress of the solder joint decreases by 4.66MPa after optimization,and the structure optimization of BGA solder joint is realized.关键词：BGA solder joint;thermal stress;regression analysis;genetic algorithm;power load93|342|7更新时间：2025-07-02
- 摘要：DDM (Domain Decomposition Method) is one of the most quickly developed methods in recent years.We investigate the fast solving techniques of adaptive refinement and discrete frequency sweep based on DDM.Besides,an in-house developed infrastructure is used to implement the proposed algorithms,which is able to scale to tens of thousands of CPU cores.We demonstrate the architecture and main features of the program.Then,the DDM,p-adaptive strategy and fast frequency sweep techniques are discussed as well to show how to solve the finite element linear systems quickly.Several numerical examples are presented to demonstrate its accuracy,parallel efficiency and capability in electromagnetic applications.关键词：electromagnetic field;finite element method;domain decomposition;multi-grid;adaptive calculation;dis-crete frequency sweep;parallel computing237|165|3更新时间：2025-07-02
- 摘要：Compared with conventional space-time adaptive processing (STAP) technique,sparse recovery (SR) STAP technique can significantly improve the clutter suppression performance in the case of limited training samples,and hence is well suited for practical non-homogeneous clutter environment.Firstly,the paper describes the principle of SR STAP,and analyzes the clutter sparsity in space-time plane for airborne radar.Then the development and current status of SR STAP is summarized.On this basis,some key issues about the technique are discussed which include space-time spectrum estimation or clutter suppression,single or multiple measurements,clutter whitening or nulling,parameter dependence or independence for recovery algorithms,whether applicable for non-stationary clutter environment,and whether feasible under the condition of jamming.Finally,key problems confronted in the real-world applications for sparse recovery STAP technique are presented,which include off-grid effect,influence of spatial errors,and huge computational cost.Meanwhile,effective ways including gridless compressive sensing and self-calibration of overcomplete dictionary are respectively discussed to solve above problems.关键词：space-time adaptive processing;airborne radar;clutter suppression;sparse recovery;non-homogeneous clutter environment;gridless compressive sensing427|455|15更新时间：2025-07-02
- 摘要：This paper proposes a novel memory reference reduction method for vector-radix 2D DCT pruning.This method aims to reduce the memory reference owing to weighting factors and signal input.The proposed method merges the butterflies at every neighboring two stages in the computation diagram,and then computes them with fewer weighting factors.Hardware platform based on general purpose processor is used to verify the effectiveness of the proposed method for vector-radix 2-D FCT pruning implementation.Experimental results validate the benefits of the proposed method with less clock cycle,less memory reference, and fewer memory space compared with the conventional implementation.关键词：digital signal processor(DSP);discrete cosine transform(DCT);butterflies;memory access81|294|0更新时间：2025-07-02
- 摘要：In order to improve performance of the inverter,a single-phase full bridge energy-saving inverter with auxiliary circuits in parallel with main switches is proposed.Limited monopole SPWM(Sinusoidal Pulse Width Modulation) is applied in the inverter.Only one main switch and one auxiliary switch need be controlled in every switching period.The duty cycle of the auxiliary switch is constant.Setting threshold of resonant current need not be designed to control the auxiliary switch.During the process of commutation in every switching period,the voltage across the resonant capacitor in parallel with the main switch decreases to zero and zero-voltage turning-on of the main switch can be achieved.All the components in the auxiliary circuit are not in series with DC(Direct current) bus,which can effectively reduce the conduction loss of auxiliary circuit.The working principle is analyzed in detail,and the experimental results show that the main switch and auxiliary switch can realize soft-switching.Therefore,the topology can effectively reduce the switching losses and improve efficiency of the inverter.关键词：inverter;resonant;switching loss;zero-voltage switching;zero-current turning-on79|348|5更新时间：2025-07-02
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