最新刊期
卷 45 ， 期 10 ， 2017
- 摘要：Named Data Networking (NDN) is a new content-centric architecture.Its original Leave Copy Everywhere (LCE) strategy has many shortcomings,for instance,massive cache redundancy and poor utilization of neighbors' cache,which waste cache space and lower cache efficiency.We proposed a routing scheme named K-Medoids Hash Routing (KMHR) combining on-path non-cooperation and off-path cooperation schemes.K-medoids algorithm is used to select some content routers as medoids in hierarchical clusters.And for different popularity of contents,we choose Hash routing or the shortest path routing separately.KMHR locates and insures the uniqueness of contents with high popularity in the cluster,which significantly reduces cache redundancy and improves cache efficiency.Based on the real world network topology,simulation results show that KMHR has the shortest request time,optimal routing gain and fewer cached contents.关键词：named data networking;hierarchical cluster;K-medoids algorithm;Hash routing159|382|0更新时间：2025-07-16
- 摘要：In reality,the diversification and complexity of the multi-objective optimization problems (MOPs) require the development of some novel multi-objective optimization algorithms.Inspired by the hybrid multi-objective evolutionary algorithms (MOEAs) and new evolutionary instances,an enhanced multi-objective fireworks explosion optimization algorithm (eMOFEOA for short) is proposed to solve the hard MOPs efficiently in the paper.Firstly,the proposed approach uses the approach of combining uniformization and randomization to generate an initial population that are scattered uniformly over the feasible search space,so that the algorithm can acquire a good beginning for the subsequent iterations.Secondly,a fine control strategy of explosion radius is adopted in the eMOFEOA,that is to say,different generation of population has different radius,and the different firework in the same generation have different radius based on its strength of Pareto dominace,so as to save the computation resource to the maximum extent.Thirdly,a simplified k-nearest neighbor approach is employed to maintain the diversity of external archive in the eMOFEOA.The proposed eMOFEOA is compared with the other five peer comparison algorithms in the performance of convergence and diversity based on 12 benchmark multi-objective test functions,and the experimental results show that our eMOFEOA has the overall performance advantages in convergence,diversity and stability.关键词：fireworks explosion optimization;multi-objective evolutionary algorithm;radius fine-controlled304|457|3更新时间：2025-07-16
- 摘要：The new concept of Passive Synthetic Aperture Antenna Array (PSAAA) is introduced into this paper.The same receiver carried by small aircraft is virtually taken as PSAAA element at different flight track position at multiple different moments.Using the characteristics of aircraft space movement and radar antenna circular rotation,an effective method to estimate the passive localization information Virtual Time Differences of Arrival (VTDOAs) is proposed.Based on VTDOAs estimation,they are proposed that the construction method for a binary quadratic localization equation group and a closed-form solution algorithm for radar position estimation.Simulations corroborate the performance of the proposed methods and it's proved that the proposed passive radar source localization method based on PSAAA is applicable for search alert radars in practical applications.关键词：passive localization;synthetic aperture antenna array;radar source;virtual time differences of arrival167|279|3更新时间：2025-07-16
- 摘要：Due to the target appearance changes and occlusion during tracking,the KCF algorithm using a single iterative update filter will accumulate much more noise information in the process of learning,which leads to the loss of the target.To solve this problem,we propose a correlation filtering target tracking algorithm based on multi-lifespan learning.We establish complementary relationship among global stage filter model,consistency stage filter model and initial stage filter model to parallel track the target.The experimental results achieved on the 51 video databases on benchmark show that our algorithm is superior to most existing methods in both overall accuracy and overall success rate with the scores of 77.6% and 68.9%,respectively.关键词：target tracking;multi-lifespan learning;filter update;consistency196|478|7更新时间：2025-07-16
- 摘要：Most of the evolutionary algorithm researches related to diversity maintenance scheme are dedicated to the diversity of objective space and ignore the diversity of decision space.This arrangement could lead to excessive diversity in the objective space but poor diversity in the decision space.To address this issue,this paper proposes a two-space-density based multi-objective evolutionary algorithm.Two-space-density is defined to reflect the diversity in both the objective space and the decision space.Based on two-space-density,TSD-mating selection is presented to balance the convergence and the diversity of population;TSD-selection is designed to fully explore the objective space and the decision space.The experimental results show that our algorithm performs competitively against the chosen state-of-the-art designs.关键词：artificial intelligence;evolutionary algorithm;space density;decision space;objective space137|288|1更新时间：2025-07-16
- 摘要：Compared with the traditional airborne phased-array radar,the ability for clutter suppression and moving target detection of space-time adaptive processing in the airborne multiple-input multiple-output radar (MIMO-STAP) can be greatly improved.However,the huge computational cost and training sample requirement limit its practical application.In order to solve this problem,we proposed the post-Doppler adaptive processing method based on the multi-stage spatial decomposition in airborne MIMO radar.This method decomposed the post-Doppler adaptive weight vector into the Kronecker product of several short weight vectors.Then the cyclic iteration was applied to solve the desired weight vector.The simulation experiments showed that this method had the advantage of fast convergence.Its performance is evidently superior to the traditional post-Doppler processing method especially in large-scale antenna array radar.关键词：space-time adaptive processing (STAP);airborne MIMO radar;clutter suppression;cyclic iteration201|299|4更新时间：2025-07-16
- 摘要：Sparse representation is one of effective methods in dealing with the moving object detection.However,the quickness and robustness of object detection are far from being solved in the existing methods.In this paper,a fast and robust moving object detection model based on the maximum posteriori probability is proposed,and a two-stage detection algorithms is designed.At the first stage,sparse coefficient is quickly solved by using coding transfer; At the second stage,based on spatial continuity structure,moving object detection is achieved by using graph cut.The experimental results on several challenging image sequences show that the proposed method has better performance than the existing classical moving object detection algorithms in rapidity and robustness.关键词：moving object detection;sparse representation;coding transfer;graph cut141|309|1更新时间：2025-07-16
- 摘要：To address the dilemma of trade-off between efficiency and accuracy for object detection,based on the mechanism of object perception and recognition in visual attention theory,the two sides derived from gradient feature as magnitude and direction have been revisited to manifest their complementary characteristics.The new rapid object detection model based on two-layer cascade with gradients is motivated,making two types of category-independent and category-dependent detectors efficiently described.On the one hand,gradient magnitude can be used to generate the efficient object proposal in clutter from sliding window samples which guarantees the significant decrease on the number of windows for candidate and speeds up detection.On the other hand,the cascade-architecture in form of multiple sub-detectors can well adapt to the varying scales of different objects resulting in boost of accuracy.Experimental performance in PASCAL presents the effectiveness of cascade structure for gradient features,and demonstrates that our model can dramatically speed up the detection with the advantages of comparable accuracy against the state-of-the-art.关键词：object detection;category-independent and category-dependent;gradient feature;cascade structure;complementarity114|228|0更新时间：2025-07-16
- 摘要：With the development of hyperspectral imaging technology,the raising spectral resolution improves the ability of target detection and classification.But its great data size and high data dimension also bring challenge to analysis and processing.As a dimensionality reduction technology,band selection (BS) plays an important role in the pre-processing of hyperspectral imagery (HSI).However,few BS algorithms are specially designed for target detection.In this paper,based on analyzing the character of constrained energy minimization (CEM) algorithm,a sparse representation based band selection method (TD-SRBBS) is proposed for HSI target detection.The symmetric Kullback-Leibler divergence is defined for subspatial partition,which makes the original HSI dataset some subset.Sparse reconstruct the detection result in each subset,and then band selection can be implemented based on the one-to-one correspondence between selected bands and nonzero elements of sparse vector.The experiments on real hyperspectral data demonstrate the effectiveness of TD-SRBBS.关键词：band selection;hyperspectral imagery;sparse representation;Target Detection;subspatial partition126|278|4更新时间：2025-07-16
- 摘要：Since it is extremely time-consuming for the traditional total focusing method (TFM) to process ultrasonic full matrix data, a novel total focusing method based on drawing elliptical arcs (DEA), called DEA-TFM, is proposed in this paper. Unlike the reversed computing process of the traditional TFM, DEA-TFM reinterprets the new total focusing method in the forward direction to improve its performance. Combined with the generation of elliptic arcs in computer raster graphics, DEA-TFM converts the generation of the result image to scan-conversion operations of multiple elliptical arcs. Besides, based on Bresenham ellipse algorithm, a rendering algorithm applicable to arbitrary elliptic arcs is put forward, making the novel total focusing method suitable for phased array probes in any shapes. The simulation experiments show that the result images generated by the novel total focusing method, DEA-TFM, are identical to those obtained by the traditional method, but the new total focusing method speeds up the imaging process by one order of magnitude.关键词：ultrasonic phased array;non-destructive testing;total focusing method;ellipse rendering algorithm;forward explanation178|326|0更新时间：2025-07-16
- 摘要：Subspace method is classical pattern recognition method,that uses global information mainly to denote an image.Recently,with the introduction of deep learning,the feature extraction model based on local self-learning has attracted more and more attention.By using the theory of deep learning,this paper presents a new feature extraction model based on multi-layered deep local subspace sparse optimization to solve the problem of object recognition.Firstly,we calculate the PCA mapping matrix on the first layer by minimizing the reconstruction error on the training sample set,then we optimize the feature mapping results through L1 norm to enhance the robustness of algorithm.Secondly,we use the output of the first layer as the input of second layer,then we implement same actions of feature learning.In this way we can map the image to deep PCA subspace.Finally we merge these feature extraction results from different layers with weighting and encode the merged feature with binary hash code and histogram segment code.After that,we obtain the multi-layered deep local subspace sparse feature.The experimental results on face database of FERET、AR、Yale and target database of MNIST、CIFAR-10 show that this feature extraction model can achieve high recognition rate and robustness for illumination,expression and pose.At the same time,compared with the convolutional neural networks,our algorithm owns the advantages of simple structure and fast convergent rate.关键词：deep learning;multi-layered fusion;subspace;sparse optimization342|515|4更新时间：2025-07-16
- 摘要：Coarse-grained pooled features obtained from convolutional autoencoder (CAE) achieve scale and shift invariances and have been widely used recently.However,in most previous works coarse-grained pooled features are obtained by empirically modulating parameters in CAE.In this paper,we see the CAE as a whole,find the probabilistic factors affecting the performance of it,and formulate a general framework to regulate parameters in it to obtain better coarse-grained representation.Firstly,the discrimination-invariance tradeoff of coarse-grained features is probabilistically evaluated in the pooled feature maps.Furthermore,the proper convolved filter scales and appropriate whitening parameters are suggested in a CAE.Secondly,pooling approaches are combined with the sparsity degree in pooling regions,and we propose the preferable pooling approach in different cases.Experimental results on two independent benchmark datasets (STL-10 and CIFAR-10) demonstrate that our framework can guide CAEs to extract better coarse-grained pooled features and performs better in multi-class classification task.关键词：coarse-grained features;pooling;convolutional autoencoder;unsupervised learning;deep learning439|389|3更新时间：2025-07-16
- 摘要：In this paper a modified dislocated grids scheme combined with the FFT-based method is proposed to reduce the burden of the near correction matrix.The scheme first adopts two sets of dislocated Cartesian grids that are respectively applied to projections of the field points and the source points.Then parts of Green's function values are modified for further improving the accuracy of fitting.When the proposed scheme is applied to the Real coefficients Fitting Green's function Fast Fourier Transformation,the number of near correction elements is reduced.Compared with the traditional uniform grid scheme,the new scheme has lower total memory requirement and higher calculation speed.关键词：the FFT-based method;RFG-FFT (the Real coefficients Fitting Green's function Fast Fourier Transformation method);dislocated grids;near correction matrix;Green's function135|172|0更新时间：2025-07-16
- 摘要：With the fast development of testing instruments,the application of high frequency signal is becoming more and more,the testing system performance requirements are also getting higher and higher.Based the high-performance low-frequency and narrow-band synthesizer,an ultra-high performance and wide-band frequency synthesizer scheme is introduced.The scheme uses dual-loop PLL which contain fractional-N PLL and frequency-mixed PLL.The fast phase-locked which use the fractional-N PLL,achieves the large amplitude switching in the wideband.In the frequency-mixed PLL,it obtains ultra-high performance and wide-band frequency synthesizer through mixing narrowband signals in different frequency bands and the feedback signal of VCO.The stability and wide-band high frequency signal is realized finally.关键词：ultra-high performance;wide-band;synthesizer;dual-loop78|210|0更新时间：2025-07-16
- 摘要：In cloud computing,tasks in a job often need to run on different datacenters due to the input data locality or special preference for resources,that is,the job runs across geo-distributed sites.The different tasks in a job have to be scheduled in different domain (data center) to execute for their personalization requirements,so the job completion time depends on the slowest task,which is called "barrel effect".As geo-distributed scheduling strategy without regard to heterogeneous resources leads too long execution time span,this dissertation proposes an optimization strategy for geo-distributed scheduling named MIN-Max-Min.The strategy gives priority to select the expectation shortest completion job to execute by heuristic rule.Experiments show that compared with first come first service strategy,the strategy can reduce cross domain average execution time span to less than 40% under the simulation load.关键词：cloud computing;geo-distributed data centers;jobs across geo-distributed data centers241|301|0更新时间：2025-07-16
- 摘要：In the view of the high complexity about similarity calculation and the indifference about individual nodes,a social network recommendation scheme based on bipartite graph and node role division is presented in this study.Firstly,the native social network structure is simplified by dividing overlapping groups.Furthermore,the bipartite graph model of group and individual is given.Secondly,the role division model is proposed by combining topological features of bipartite graph with node attributes.Finally,in order to resolve high computational complexity,the individual bipartite graph model is constructed based on user role difference.The model implements a hierarchical and personalized recommendation.Experiments show that the scheme can effectively recommend among social users who have different interests.In addition,the complexity of individual similarity computation is reduced because the target individual recommendation list is generated based on small scale bipartite graph.关键词：social network;bipartite graph;role division;individual recommendation2|2|1更新时间：2025-07-16
- 摘要：Quotient space theory is one of the most important models of granular computing.The structure in the existing quotient space model is usually a topology.If the domain structure is an algebraic structure,the equivalence relation in topological structure is no longer applicable.So the congruence relation in use is stricter than the equivalence relation.When a given relation is a non congruent equivalence relation,it introduces the concept of congruence closure and congruence interior to approximate the relation.The method,the properties and the conclusions are systematically demonstrated in the paper.On this basis,the algebraic quotient space model is systematically studied.The paper provides theoretical basis for solving complicated problems with the algebraic structure using quotient space theory.关键词：granular computing;quotient space;algebraic quotient space;congruence closure;congruence interior2|2|1更新时间：2025-07-16
- 摘要：Families of pseudorandom sequences derived from Fermat quotients possess good cryptographic properties.In this paper,based on the theory of trace function in the finite field and cosets,we firstly determine the discrete Fourier transform (DFT) of the r-ary sequences derived from Fermat quotients.Then from which we obtain the sequences' trace representation.The trace representation we determined plays an important role in the engineering realization of the sequences,and also provides a new tool for analyzing the pseudorandom properties of the sequences.关键词：r-ary sequences;Fermat quotients;discrete Fourier transform;trace representation2|2|2更新时间：2025-07-16
- 摘要：Chain graphs(CGs) including both Bayesian networks(BNs) and Markov networks(MNs) as special cases,can express more independence models compared to the basic probabilistic graphical models.Today there exist several researches on structure learning of chain graphs.In this paper,we propose an algorithm for learning the equivalence classes of a chain graph based on the Grow-Shrink(GS) algorithm for structure learning of Bayesian networks.The algorithm works by first learning the adjacent nodes of each node in a chain graph for recovering its skeleton,and then discovering its complexes using the conditional independence tests and the property of the complexes.Theoretical analysis and experimental results demonstrate the effectiveness and correctness of the proposed algorithm.关键词：chain graph;structure learning;conditional independence test;Markov property2|2|2更新时间：2025-07-16
- 摘要：This paper proposed an efficient approach for predicting electromagnetic interference emission of motor and its drive system under field-circuit and transmission line(TL) coupling.As the common mode interference circuit is the main source of electromagnetic emission,its propagation path is analyzed.On this basis,the key components' models in common mode interference conduction path are established,such as AC induction motor's equivalent circuit modell,drive system's inputs' and outputs' harness model of shielded cable and so on.Then,each part circuit model is connected according to the system's actual combination and the system's EMI prediction model is obtained.Finally,CST MWS and CST CS studio joint simulation method is used to analyze the proposed prediction model and the results are in good agreement with experiment measurement,which validate the accuracy of our proposed approach.关键词：motor;drive system;electromagnetic interference emission;prediction approach;common mode interference4|2|6更新时间：2025-07-16
- 摘要：According to the characteristics of block cipher algorithm,the parallelism of block cipher algorithm can be divided into Four Dimensions Parallelism(FDP),which consists of same operational parallelism in a block,different operational parallelism in a block,same operational parallelism among multiple blocks and different operational parallelism among multiple blocks.Four Dimensions Parallel Processing Model (FDPM) for block cipher based on Amdahl's law was proposed,which can guide the design of block cipher processing architecture and provide the overall suggestions for resource allocation and parallelism development.And then Reconfigurable block Cipher Stream Architecture (RCSA) based on FDPM was proposed,which can effectively develop parallelism of block cipher and improve processing performance and the utilization rate of resources.The experimental results prove the veracity of FDPM and efficiency of RCSA.关键词：block cipher;Amdahl's law;four dimensions parallel processing;stream architecture;speedup3|3|0更新时间：2025-07-16
- 摘要：Optimal selection of tests is an important problem that arises in design for testability for complex electronic systems.Firstly,from the perspective of test tolerance,the reason of how tests produce miss detection and false alarm is analyzed.Then,a new mathematic model for the problem of test selection in the presence of imperfect tests is developed.It consists of minimizing the sum of test cost,miss detection cost and false alarm cost,subject to lower bound constraints on fault detection rate and fault isolation rate.To optimize the model,an improved quantum-inspired evolutionary algorithm is proposed.It is formed by making some improvements to an extant algorithm that has been used for optimal selection of perfect tests,including population initialization,fitness calculation and the strategy of population evolution.Finally,two simulation examples are used to validate the effectiveness and superiority of the solution method and the model.关键词：design for testability;test selection;imperfect tests;quantum-inspired evolutionary algorithm2|2|7更新时间：2025-07-16
- 摘要：A test data generation method named multi-neighborhood Kalman filter PSO(MNKFPSO) was proposed to reduce the evolution number and to improve the success rate of path coverage.Particles except the global best one update themselves' positions using Kalman filter.One of them is allotted to a fixed neighborhood.A designated particle learns from the global best particle,others learn from the best in one neighborhood.And the global best particle's position changes by a simple PSO which discards the particle velocity.The experimental results show that it can generate test data covering the specified path in the less evolutionary using MNKFPSO and has high success rate of path coverage even though the paths difficult to cover.The algorithm also exhibits a stable performance.关键词：test data generation;particle swarm optimization (PSO);Kalman filter;neighborhood topology2|2|2更新时间：2025-07-16
- 摘要：In this paper,we propose an approach to verify the trustworthiness of big data including the trustworthiness of data source and data content.The trustworthiness of data source is achieved by verifying the identity of data owner based on public key certificate.We design an interactive challenge-response protocol to verify the trustworthiness of data content on the basis of simple random sampling test and aggregated signature-based broadcast encrypting scheme.The protocol can make the users who know the public parameters of the data owner validate the verification result with high probability by sampling only a small amount of data.Formal security analysis and experimental evaluations are also conducted,showing that the proposed scheme is practical to achieve the design goal for big data.关键词：big data security;trustworthiness verification;verification tag;security protocol3|2|2更新时间：2025-07-16
- 摘要：To improve the accuracy of the transformer fault diagnosis based on dissolved gas analysis in oil(DGA),a transformer on-line fault diagnosis based on spectral clustering ensemble (TOFD-SCE) was proposed in this paper.The weighted double sampling algorithm create the samples set of the basic spectral clustering,which learned the local knowledge of the problems.The accuracy was improved by integrating the results of ensemble members,which were picked up form the basic spectral clustering in terms of the accuracy and variety.The conventional models are only trained by the historical data,and can't learn on-line.TOFD-SCE is trained and modified by both historical and new online data,and the accuracy is improved.The TOFD-SCE was validated by diagnosing the fault of SSP300000/500 transformers.Comparing with IEC three ratio,BP-neural networks and support vector machine,TOFD-SCE is more outstanding.关键词：fault diagnosis;power transformer;spectral clustering ensemble;dissolved gas analysis in oil;signal processing2|2|2更新时间：2025-07-16
- 摘要：Automatic program repair based on code enumeration exploits mutation operators to fix buggy programs by mutating the faulty statements.Its effectiveness is hindered by lack of grammar-directed mutation and limited number of mutation operators.This paper proposes a new automatic program repair method based on version space algebra,which uses inductive learning techniques to automatically produce repair solution for the faulty statement of buggy program.Specifically,the proposed method has the following features:(1) automatic derivation of version spaces from grammars,(2) defining consistency of version space according to its type,and (3) combining static and type checking with version space algebra.Experimental results show the proposed method outperforms other existing automatic program repair approaches in terms of repair success rate,and static and type-checking mechanism can prune the hypothesis space efficiently.关键词：automatic program repair;version-space algebra;inductive learning;context-free grammar;derivative tree2|2|0更新时间：2025-07-16
- 摘要：In this paper,a spectrum co-prime rearrangement based sampling scheme at very low rate is presented.This scheme extends SFT from discrete time domain to continuous time domain.Firstly,the spectrum of sparse signal at the frequency domain is rearranged and compressed by co-prime Fourier sampling expansion.Then it is reconstructed by sub-linear algorithm on Chinese Remainder Theorem.The simulation results show that the proposed sampling scheme can further reduce the sampling rate of spectral sparse signal.关键词：spectral sparse signal;Sub-Nyquist sampling;sparse Fourier transform;Chinese Remainder Theorem;sub-linear algorithm3|2|1更新时间：2025-07-16
- 摘要：The principal purpose of this paper is to investigate and probe the theories and methods of analytical solution and valid numerical solution for the zero-poles of the classical regular RC fractal fractance approximation circuits considering both the circuit structure specialities and mathematic representation characteristics.A brief survey and review on fractal fractance approximation circuits is given and new concepts of iterating circuit,iterating function,and iterating matrix etc are introduced.Finding the iterating matrix power by means of eigenvalue decomposition method or Hamilton-Cayley expansion,a simple expression of the analytical solution is derived for the normalized impedance function of some classical (such as the Oldham fractal chain,the Carlson fractal lattice,H-type,2h-type etc) fractal fractance approximation circuits.An analytical solution and a valid numerical solution for the zeros and poles of some classical fractal fractance approximation circuit are presented.The solutions are tested in both theory and simulation experiments.关键词：fractional-order circuits and systems;fractance;iterating circuit;iterating matrix;polynomial roots2|2|8更新时间：2025-07-16
- 摘要：We present,so called,Magpie which is a new high-security lightweight block cipher.The block size of Magpie is 64 bits and the key size is 96 bits.It employs a SPN structure and consists of 32 rounds.Magpie encryption algorithm includes two parts:operation part and control part.Each operational round includes five basic modules:AddConstants,SubCells,ShiftRows,MixColumns,AddRoundKey.The control part is the key of 65 to 96 bits.65 to 80 bits of key control the SubCells.81 to 96 bits of key control the MixColumns and the ShiftRows.The control signal can control the order of the module operation.The Xilinx Virtex-5 FPGA hardware area of Magpie requires about 10679 slices and the throughout rate is 6.4869Gb/s.关键词：lightweight cryptography;block cipher;FPGA implementation4|2|5更新时间：2025-07-16
- 摘要：Differential cryptanalysis is a powerful attack on block ciphers and to evaluate the security against differential cryptanalysis is an important part for the security evaluation of block ciphers.Based on practical application background,the concept of four-block CLEFIA-like transform cluster is put forward.Using the relation between differential correspondences of two special block cipher structures,security evaluation against differential cryptanalysis for all block cipher structures of the cluster is given.关键词：block ciphers;four-block CLEFIA-like transform cluster;differential cryptanalysis;active round function3|3|5更新时间：2025-07-16
- 摘要：Semantic roles labeling is a kind of shallow semantic analysis.Existing Chinese semantic analysis methods and semantic roles labeling systems do not effectively characterize Chinese essential features,and it causes the currently larger difference between Chinese SRL systems and English SRL systems.Valence structures can better characterize syntactic structures and semantic constitution relations of Chinese sentences,so we appropriately modified the semantic roles labeling systems and incorporated the valence information of predicates into semantic roles labeling.Experimental results show that proper use of valence information significantly improves the performance of semantic roles labeling system:the verbal SRL approach achieves the performance of 93.69% in F1-measure and the nominal SRL approach achieves the performance of 79.23% in F1-measure on golden parse trees and golden predicates,and all outperform the state-of-the-art SRL systems.关键词：valence structure;verbal predicates;nominal predicates;semantic role labeling2|2|3更新时间：2025-07-16
- 摘要：All the substrate integrated waveguide(SIW) resonant cavities with six different boundary conditions are summarized and analyzed totally.Based on the mirror image principle and Helmholtz equations,the closed form solutions of the guided mode field of the SIW resonant cavities under different boundary conditions are given.The field distributions of the resonant cavities under all the boundary conditions are analyzed,and the results are consistent with the results given by the full wave simulation analysis,transmission line model method and empty cavity model method.The formulas for calculating the resonant frequencies of the resonant cavities under various boundary conditions are presented.Based on the proposed theory that the transmission line added extra two boundary conditions is equivalent to the resonant cavity,the coexistence mechanism of TE mode,TM mode and TEM mode is analyzed.This paper describes the evolution of the SIW resonant cavities under different boundary conditions as well.Finally,a dual-mode SIW bandpass filter and a SIW equalizer,based on different boundary conditions are designed,fabricated and measured to demonstrate the proposed method.Two modes of the filter,TE100(or TEM mode) and TE102 can be tuned independent and the measured results are in agreement with the simulation results.The relevant research results provide ways for the miniaturization design of microwave devices.关键词：SIW resonator;field distribution;boundary condition;dual mode;BSF;equalizer3|3|3更新时间：2025-07-16
- 摘要：The system matrices generated by the moment methods are ill-conditioned matrices,which make the iterative methods hardly converge,even accelerated by the existing preconditioning techniques.This paper applies the concept of regularization methods of ill-posed problems,and introduces the so-called regularization matrix as a preconditioner.This preconditioner can shift the eigenvalues of the system matrix directly.And it needs no additional memory to store the preconditioner.Furthermore,this paper proposes to determine the optimized regularization parameter by finding the maximum value of the second derivative of the L-curve of the regularized matrix.Numerical experiments show that the proposed method can converge relatively fast for some matrix equation generated by the electric field integral equation (EFIE) or the magnetic field integral equation (MFIE) solved with the higher order moment method,while iterative methods with the existing preconditioners may converge slowly.关键词：moment methods;ill-conditioned matrix;iterative methods;regularization methods2|3|1更新时间：2025-07-16
- 摘要：Two-way satellite time and frequency transfer (TWSTFT) is general used in high-precision time and frequency transfer,the key equipment of TWSTT system is the modem.Nowadays,a new time transfer modem for TWSTFT has been developed at BIRMM.The direct sequence spread spectrum(DSSS)and binary phase shift keying (BPSK) modulation techniques are used to generate a pseudo-random noise (PRN) signal.A fast Fourier transform (FFT) parallel algorithm is applied to achieve fast acquisition of the PRN modulated receiving signal.A 2ndorder frequency lock loop (FLL) assisted 3rd order phase lock loop (PLL) is designed to keep both of the performance of loop dynamic stress and carrier phase tracking accuracy,and a 2nd order delay lock loop DLL is used to track and measure the code phase.A short baseline TWSTFT experiment was done with two 1.2m very small aperture terminal (VSAT) earth stations and a commercial geosynchronous orbit communication satellite to evaluate the modem's performance.The result shows very low noise with the standard deviation (1σ) equal to 0.13ns at a 2.5MChip/s code rate.关键词：two-way satellite time and frequency transfer (TWSTFT);modem;acquisition;phase lock loop;delay lock loop2|2|3更新时间：2025-07-16
- 摘要：A novel blind equalization approach called l0-norm constraint recursive least square constant module algorithm is proposed for MPSK signal in sparse multipath channel.Firstly,motivated by the traditional recursive least square constant module algorithm and sparse adaptive filter theory,a new exponential weighting based least mean square error cost function with the l0-norm penalty on the equalizer tap coefficients is constructed.Then,the iterative updating formula of the equalizer is derived according to the recursive least square algorithm.The algorithm takes the advantages of the recursive least square algorithm,as well as attracting the inactive taps to zero,to realize fast convergence of various tap coefficients.Theoretical analysis and simulation results show that the proposed algorithm outperforms the existing algorithms in increasing the convergence rate at the same residual inter-symbol interference level.关键词：sparse multipath channel;fast convergence blind equalization;l0-norm penalty;recursive least square constant module algorithm2|2|1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