最新刊期
卷 39 ， 期 12 ， 2011
- 摘要：Waters proposed an identity-based encryption and signature scheme in standard model.Then Paterson and Schuldt proposed an identity-based signature scheme based on Waters' IBE.Zhang and Xu proposed an identity-based multi-signcryption scheme that using the above schemes.However,we show that Zhang-Xu's scheme is insecure under randomizing private key attack.Furthermore,we propose an improved identity-based multi-signcryption scheme in standard model.In our scheme,we divide the private keys into two parts,one is for decryption,the other is for signature,and the private key used for signature cannot be randomized.Moreover,our scheme can resist insider leak attack.关键词：identity-based cryptography;multi-signcryption;randomize private key;bilinear pairings2|1246|6更新时间：2025-07-16
- 摘要：The effect of co-channel interference of multiple tiers of cells on both average ergodic capacity and optimal antenna location is analyzed in a multicell environment with distributed transmit antennas,and the relationship between the optimal antenna location and the average ergodic capacity is also studied.Numerical analysis and simulation results show that the optimal distributed antenna location is determined by the interference energy of the first tier of peripheral co-channel interfering cells.For example,In a cell with a typical radius of 1000 meters,the average ergodic capacity of the cell reaches the peak when all antennas are located at about 450 meters from the center.关键词：wireless communication;distributed antennas systems;antenna location optimization;multicell interference;average ergodic capacity3|1019|2更新时间：2025-07-16
- 摘要：The characteristic of the Code Division Multiple Access (CDMA) signal is analyzed in this paper.And the CDMA system is modeled as the blind source separation pattern,with the received signal is divided into two-spreading-period-length temporal vectors overlapped by one spreading period.The model is applicable for both the synchronous and asynchronous systems.In the new method,the blind source separation algorithm is used to estimate the spreading sequences and information sequences blindly in synchronous and asynchronous systems,no matter the desynchronization time is known or not,and with the users' power are equally or not.At last,mathematical analysis and simulation results demonstrate the validity of the new method.关键词：short-code CDMA;blind estimation of the spreading sequence;blind estimation of the information sequence;blind source separation(BSS);independent component analysis(ICA)2|1125|4更新时间：2025-07-16
- 摘要：The problem of direction-of-arrival (DOA) estimation and subspace tracking of coherent signals is researched based on acoustic vector sensor array.According to the shift invariance property of the steering matrix of the linear array with the centre of symmetry,we propose a new "particle-velocity-field smoothing" algorithm (PVFSIA),with improved effective array aperture,which is based on single snapshot smoothing and available for the fast estimates of DOA in multi-path environment.Then a subspace tracking algorithm of coherent sources based on iteration is presented,which has higher tracking speed,and requires neither the eigen-decomposition into signal/noise subspace nor the inverse operation of matrix.Finally,the perturbation analysis of PVFSIA is introduced and the theoretical covariance formulas of fast DOA estimates are given.Simulation results are shown to verify the efficacy of the proposed algorithm.关键词：acoustic vector sensor array;coherent signals;direction of arrival;shift invariance property;spatial smoothing;subspace tracking2|1973|1更新时间：2025-07-16
- 摘要：The alert correlation,choquet fuzzy integral and fuzzy cognitive maps was analyzed,the correlation of IDS alerts based choquet fuzzy integral was proposed and the correlation engine of intrusion detection system was designed.Though experiences of the DRDOS attack and LLDOS attack,it is proved that the alert correlation in the paper could correlate the alerts with high feasibility.关键词：intrusion detection;fuzzy integral;fuzzy measure;alert correlation;alarm correlation2|957|1更新时间：2025-07-16
- 摘要：Memory race recording is a key technology in deterministic multi-core replay.High hardware consumption,large log size and slow replay speed limited the application of previous memory race recording algorithms.This paper proposes a new efficient hardware memory race recording algorithm,which is implemented in chunks and logs the outcomes of memory races in a point-to-point approach.In this recording mechanism,memory race is presented in a new stricter indirect dependency,a chunk-based transitive reduction algorithm is introduced to reduce the number of memory races logged,a maximum timestamp approximation method is proposed to deal with those races evicted from cache.This new memory race recording algorithm can replay a program at production run speed,and log a smaller memory race log using smaller hardware than previous point-to-point approaches.关键词：multi-core program;deterministic replay;memory race recording2|1639|2更新时间：2025-07-16
- 摘要：As a basic characteristic of radar target in high frequency domain,scattering centers can characterize its elaborate physical structure.Using the weak coupling property between the type and position parameters of a scattering center,the three-dimensional (3D) position parameters were estimated via an ESPRIT method based on the foundation of 3D Coherent Polarimetric GTD (CP-GTD) model.Then the types of scattering centers were estimated on the orthogonality between the signal subspace and noise subspace,while the least square method was used to calculate the coherent polarimetric scattering matrices.Compared to existing estimation methods based on the mono-polarization model,the proposed method provides better estimation performance and stronger noise resistance,and can estimate the coherent scattering matrices of scattering centers directly.Simulation results show its effectiveness and robustness.关键词：coherent polarimetric GTD model;3D scattering center;parameter estimation;coherent scattering matrix2|1334|4更新时间：2025-07-16
- 摘要：Considering the uncertainty of message bit width,the Cramer-Rao Bounds (CRBs) for the estimation of message bit width,frequency of arrival (FOA) and time of arrival (TOA) from Galileo search and rescue (SAR) signal were researched.General formula for calculating the elements of Fisher information matrix was derived first.Then the calculation expressions for the Fisher matrix elements of Galileo SAR signal were acquired.When calculating the sum of the square of Dirac delta function,the properties of Dirac delta function and Parseval's theorem were used to transform the computation from time-domain to frequency-domain.Then the closed-form analytical solutions of the CRBs for the estimation of message bit width,FOA and TOA were derived.Numerical calculation and Monte Carlo simulation results validate the effectiveness of the CRBs above which can be used to evaluate the performance of message bit width,FOA and TOA estimation algorithm.关键词：Cramer-Rao Bound (CRB);message bit width;FOA and TOA;Galileo SAR signal2|1394|1更新时间：2025-07-16
- 摘要：The existing service migration methods bring the server cluster heavy burden,and their time spending is so high that seriously affects the service continuity.In order to enhance the survivability of IP network services,the paper puts forward an intent-perceptible service migration model (ISM).In this model,we design a novel trigger mechanism and object selecting method for service migration,and make the service migration intention perceptible for the client with the cooperation of the server.The evaluation results show that ISM model can not only ensure the service invulnerability by maintaining a high randomness of service migration,but also improve the service continuity by reducing the service gap time spending on service migration to the maximum extent.Therefore,ISM model can enhance IP network survivability efficiently.关键词：IP network survivability;service migration;pseudo-random sequence;invulnerability;gap time2|1623|2更新时间：2025-07-16
- 摘要：This paper derives the motion errors model of small size airborne low frequency ultra-wideband synthetic aperture radar (UWB SAR),and analyze the difference of the motion errors between the low frequency UWB SAR and the high frequency narrow band SAR as well as the reason of the traditional motion compensation (MoCo) method failure.To resolve this problem,a three-stage MoCo method is proposed.The procedure of the proposed MoCo method is as follows:At the first stage,removing the echo envelope error completely and the phase error partly by the MoCo based on the sensor data.Then,compensating the second-order phase error by the MoCo based on the Doppler chirp rate estimation at the second stage.At last,the residual high-order phase error is compensated by applying the autofocus algorithm in the image domain at the third stage,and the focused UWB SAR image is obtained.Experiment results on real data prove the validity of the proposed MoCo method.关键词：ultra-wideband;synthetic aperture radar;motion compensation2|1156|2更新时间：2025-07-16
- 摘要：Most of works in modeling the spectrum sharing of Cognitive Radio Ad Hoc Networks (CRAHNs) ignored the relationships between processes of using primary channels and that of using secondary channels.Some works considered the relationship and set up simplified queue-based model.However,they are not accurate in analysing the performance of CRAHNs.The main challenge may come from the complexity of setting up states transfer graph and that of computation in the multiple-dimensions Markov model.This paper copes with the challenge by a novel method.We decompose the complex original model into multiple 2-D models which are much easier to analyse,and then compose them all into a structured 3-D Markov model,which is arbitrary order extendable and programmable computation of the stable probability.By the new model,the performance of CRAHNs with an arbitrary number of primary channels and secondary channels can be evaluated .Extensive experimental results testify the validity of the proposed model.关键词：cognitive radio ad hoc networks;spectrum sharing;Markov model;performance analysis2|1020|0更新时间：2025-07-16
- 摘要：This paper proposes the concept of rational trusted party.Any rational party can be the TTP to distribute the shares in the secret sharing such that it is to be more suitable for use.As far as we know,that is firstly to analyze distribution of shares with game theory in secret sharing scheme.It is formalized as n tow-person games.It is proven that rational dealer always selects cheating all players to get more payoffs in these games.Simultaneously a rational secret distribution mechanism is proposed to solve this problem.Moreover,we construct a mechanism of reconstruction of secret based on oblivious transfer protocol,which solve the problem of players' non-cooperation in reconstruction phase.关键词：game theory;NASH equilibrium;secret sharing;rational third party2|1894|15更新时间：2025-07-16
- 摘要：Most existing compressed sensing reconstruction algorithms are based on single measurement vector.When processing image signal,the efficiency of these algorithms is low because the image is treated as one-dimension signal and the quality of the reconstructed image needs to be improved.A reconstruction algorithm based on multiple measurement vectors and sparse Bayesian learning is proposed in this paper.The image is reconstructed quickly because the weighting coefficient matrix can be got directly by processing each column of the measurement matrix simultaneously.The proposed algorithm has better reconstructed image and the efficiency has been improved significantly under the same sample rate.The validity of the proposed algorithm is proved by the experiments to the standard test images.关键词：image reconstruction;compressed sensing;sparse Bayesian learning;multiple measurement vectors2|2789|11更新时间：2025-07-16
- 摘要：Magnetic induction tomography (MIT) is an imaging method for reconstructing the electrical conductivity of biological tissues.Gauss-Newton method aims at nonlinear reconstruction by iterating continuously and re-calculating sensitivity matrix,which has a high precision but is time-consuming.Gauss-Newton one-step dynamic algorithm in combination with regularization technique was proposed and used to experiment for obtaining optimized solutions of relative parameters.MIT measurement model based on forward mathematical model is set up and solved by the finite element method.The obtained sensitivity matrix and magnetic vector potential are applied in the inverse problem and the method presented in the paper realized the reconstruction of the absolute conductivity.Uncorrelated Gaussian noise with different signal-noise-ratio (SNR) is added in the measurement voltage to simulate the real measurement value and the simulated results are compared.The results prove that the algorithm in the paper gets better effect in precision and speed than others.关键词：magnetic induction tomography (MIT);image reconstruction;finite element;sensitivity;inverse problem2|1101|4更新时间：2025-07-16
- 摘要：Due to the intensity inhomogeneous in brain MR image,it is difficult for the traditional methods to obtain accurate segmentation results.In this paper,by using the bias fitting field with Legendre basis,a new parameterize mutual information metric is firstly proposed,and a unified variational model is proposed for the optimizing of segmentation and bias correction.Finally,we present a fast algorithm based on split Bregman iteration methods.Comparative results demonstrate that our method can obtain more accurate segmentation and bias correction results with a faster convergence rate.关键词：brain MR image;segmentation;bias correction;split Bregman iteration2|1252|2更新时间：2025-07-16
- 摘要：Different from most the past routing algorithms only considering the shortest path first,or evaluating the trust level solely on the forwarding behavior,or depending on recommendation-based trust mechanism,we propose a novel subjective trust routing model under consideration to both communication reliability and path length.We introduce the concept of attribute similarity to inherently bind neighbor selection,trust evaluation,packet forwarding,and other routing processes.Based on the similarity degree,we put forward a new forwarding behavior.We give a recommended method to calculate the similarity degree between attributes.Simulations show that the routing scheme behaves better than Dynamic Source Routing (DSR) protocol and previous trust-based routing protocols on standing against the blackhole attack and the on-off attack,and meanwhile is not affected by the slander attack.关键词：mobile ad hoc networks;attribute similarity;malicious nodes;trusted routing;dynamic source routing2|1265|2更新时间：2025-07-16
- 摘要：From the principle of signal synthesis,a new outfield calibration method is presented based on phase interferometric,and phase difference formula is derived with the combination of overdetermined equations solution.Special state shift is realized with phase shifter,and phase difference is obtained by multiple channel power synthesis.The mechanism analysis and the outfield experiments show that this method is efficient and correct.关键词：phased array antenna;calibration;power-measurement;phase interferometric4|1933|2更新时间：2025-07-16
- 摘要：To register the images which are simultaneously distorted by blur degradation and geometric transformation,we propose a new registration method based on the mixture of blurring and geometric invariant and of the orthogonal Legendre moment.It constructs a new set of combined blur and geometric invariants of Legendre moment as feature descriptor to establish the correspondence of feature points between images which are extracted by Harris-Laplace detector.Then,with the help of the correspondence above,transformation parameters are estimated and finally the distorted images can be aligned through interpolation.The experimental results show that our method can efficiently register the distorted images with better performance than the other methods in the literature.关键词：image registration;Harris-Laplace detector;orthogonal Legendre moment;mixture of invariants2|1093|1更新时间：2025-07-16
- 摘要：Fully polarimetric microwave radiometer is a new type of passive microwave sensor for measuring ocean wind vector.Digital correlation technology is used inside it to get all the four Stokes parameters of ocean emission in this paper.Digital correlator is the main part of the fully polarimetric radiometer.In the paper,design of a novel digital correlator is presented.Two high-speed,dual A/D converters are used to sample four signals,and the sampling results are operated in FPGA-Vertex5 to make both self- and cross-correlation calculations.The testing results of the correlator are given.The sampling rate is 360 MHz with effective number of bits more than 7.2 bits in 8 bits resolution.For both 100 MHz and 150 MHz input,the correlation coefficient between the measurements and their theoretical results is more than 0.9999999.The whole power of digital correlator is 11.3 W.关键词：fully polarimetric microwave radiometer;digital correlator;FPGA;ADC2|1325|4更新时间：2025-07-16
- 摘要：In this paper,the clutter characteristics of airborne bistatic radar with range ambiguity are analyzed,and a novel clutter suppression method based on maximum likelihood estimation is proposed.Firstly,the amplitude of various training samples including ambiguous ranges are estimated using maximum likelihood estimation.Secondly,clutter of cell under test (CUT) and the corresponding ambiguous ranges are rebuilt by non-uniform frequency sampling.Thirdly,the clutter covariance matrix of CUT is obtained from the rebuilt clutter data.Finally,clutter suppression is achieved by space-time adaptive processing weight from clutter covariance matrix.The simulation results show that the proposed method is more effective than the traditional method for clutter suppression of airborne bistatic radar with range ambiguity.关键词：airborne bistatic radar;range ambiguity;clutter suppression;maximum likelihood estimation;space-time adaptive processing3|1231|5更新时间：2025-07-16
- 摘要：A Petri net based optimal control policy is proposed for the check of behavioral incompatibility in web services composition.According to a real case of multiple services interaction,this paper presents a formalized definition of controlled service composition,and the reduced state reachability graph of service composition net is given according to the reduce rules,thus the deadlock states and the deadlock-free states are identified.With the maximally permissive feedback control strategy developed,the appropriate control place and arc are appended in the key transition which can lead to deadlock states.Thus the appropriate optimal controller is developed,the proposed approach is verified.In addition,for the behavioral incompatibility case,a policy of appending optimal controller is presented.It is proved that our policy can be a good solution.Finally,the proposed controller is transformed as the activity of BPEL.关键词：web services composition;compatibility;optimal controller;deadlock prevention2|1137|4更新时间：2025-07-16
- 摘要：Fine-grained data integrity checking methods could isolate a portion of corrupted data segments and assure the integrity of other data at the same time.They could mitigate the disastrous effect that all the data become invalid caused by accidental errors or intentional forging modification.The issues of integrity checking for fine-grained data are summarized at first.Based on the finite projective geometry theory,a novel data integrity checking method (integrity indication code) is proposed to improve the error indication efficiency.The basic idea of the method is mapping the relationship of points and lines in finite projective geometry to the check relationship of hashes and data objects,and achieving uniform crossover of all the hashes.The performances analysis and experimental results show that this code is effective with higher compression ratio.关键词：computer forensics;hash;data integrity;finite projective geometry2|1079|1更新时间：2025-07-16
- 摘要：We present a time-domain inverse scattering approach using functional analysis and variational method,which is applied to reconstruct dispersive dielectric properties of stratified lossy media.This approach firstly formulates a cost functional,according to least squares criterion,to turn the inverse problem into a constrained minimization problem.The resulting constrained minimization problem is then transformed into an unconstrained minimization problem by a penalty function technique.And then,the closed Fréchet derivatives of the Lagrange function with respect to the properties are derived based on the calculus of variations.Thus,the unconstrained minimization problem can be solved by using any gradient-based algorithm and the finite-difference time-domain (FDTD) method.Also,the first-order Tikhonov's regularization is adopted to cope with noise and the ill-posedness of the problem.In numerical examples,the presented algorithm is applied to a one-dimensional (1-D) breast model in several cases with the help of a set of nonlinear conjugate gradient (CG) methods,and the simulated results demonstrate its robustness and validity in the lesions identification.关键词：inverse scattering;frequency-dependent media;regularization method;finite-difference time-domain (FDTD) method2|1169|10更新时间：2025-07-16
- 摘要：The number of debris is continuously increasing,so it is necessary to develop the space surveillance radar and collect the information of the space debris.The selection of the radar system is a very important issue and it affects the performance of the General survey radar.The comparison of the single radar fence,double radar fence,Graves,phased array is presented;as a result,the single radar fence is a better choice for the space surveillance radar.关键词：space object surveillance;space debris;fence;orbit determination2|1696|5更新时间：2025-07-16
- 摘要：Vehicle ad hoc networks(VANETs) which depend on special application scenarios are different from mobile ad hoc networks(MANETs).The existing routing protocols of MANETs cannot be applied to VANETs effectively.Many new routing protocols are presented for VANETs.Firstly,we describe the characteristic features of VANETs,then introduce the conceptions of unicast routing,broadcast routing and geocast routing.Moreover,we classify and characterize the existing representative routing protocols for VANETs,and also discuss their advantages and disadvantages.We give a qualitative comparison of these routing protocols with respect to application scenarios,classification methodology,characteristic features and assumptions involved.Finally,the important features that ideal routing protocols possess are summarized,and open research issues and possible directions of future research related to VANETs routing are proposed.关键词：vehicle ad hoc networks;routing protocols;unicast routing;broadcast routing;geocast routing2|3348|6更新时间：2025-07-16
- 摘要：To improve the performance and energy-efficiency of in-order processors,this paper proposes a novel hardware mechanism,pre-execution based on value prediction and instruction reuse(PVPIR).If a load instruction incurs a long-latency cache miss,PVPIR predicts its data value and uses the predicted value to pre-execute the following dependent instructions,including loads that incur long-latency misses,thus improving the performance.To reduce the energy consumption,PVPIR reuses the valid pre-executed results and thus avoids the re-execution of completed instructions.PVPIR also implements a hybrid value predictor which is a combination of stride prediction and address-value delta(AVD) prediction.The predictor only records history value for loads that have incurred long-latency misses,thus gaining good prediction results with little overhead.Experimental results demonstrate that PVPIR improves the performance by 7.5% and 9.2% while decreases the energy consumption by 11.3% and 4.9%,thus improving the energy-efficiency by 17.5% and 12.9%,as compared to Runahead-AVD and iEA,respectively.关键词：pre-execution;value prediction;instruction reuse;load latency tolerance2|984|1更新时间：2025-07-16
- 摘要：The process of experimental study of a broadband output circuit of rectangular π-TM310 mode double-gap cavity loaded by coaxial line filter is introduced.Meliorative structure and some improved measures aiming at the main technical difficulties are taken to obtain reliable experimental results.The tested data show that the rectangular π-TM310 mode double-gap cavity couples with the output coaxial line moderately,the external quality factor is about 30,and the characteristic impedances along different beam holes remain uniform.The broadband output circuit of rectangular π-TM310 mode double-gap cavity loaded by coaxial line filter has a relatively wide band,the bandwidth in X band reaches 800MHz,and the phase delay is linear with frequency.These tested data are consistent with simulation result and confirm the conclusions of theoretical researches.The results of this experimental study demonstrate that the broadband output circuit of rectangular π-TM310 mode double-gap cavity loaded by coaxial line filter will be favorable to upgrading efficiency and bandwidth of X band high-power multi-beam klystrons,and the application to the practical development engineering is feasible.关键词：multi-beam klystron;high order mode;double-gap cavity;the external quality factor;the characteristic impedance;the gap impedance;broadband output circuit;coaxial line filter2|1135|3更新时间：2025-07-16
- 摘要：It is one of the development directions of passive radar to expand the number of illuminators and increase the available signal power to improve the system performance.Aimed at the FM broadcasting passive radar,this paper researched the coherent processing technique based on multi-frequency signals.Starting from signal model,it deduced the expression of each matching-filter output,and analyzed the phase relationship of each signal and various factors infecting coherent integration of multi-signals.The differentia phase item of each signal was compensated during signal processing to realize coherent integration.At last,the performance improvements of range distinguishing,clutter restraint and detection SNR were discussed.Simulation results proved the valid of the theory analysis,and it was important to improve the system performance of passive radar.关键词：passive radar;multi-frequency signals;coherent integration;FM broadcasting2|1460|9更新时间：2025-07-16
- 摘要：Some new properties,such as structural characterizations of open and closed sets,of the Stone space of all maximally consistent theories in the formal deductive system L* are investigated.A new three-valued topology on the set of all maximally consistent theories is introduced and it is proved that such three-valued topological space is zero-dimensional,covering-compact and Hausdorff.Lastly,the relationship between the three-valued topology and the Stone topology is clarified.All these results lay a foundation for the theory of reasoning about knowledge based on L*.关键词：formal system L*;maximally consistent theory;Cantor space;three-valued topology2|1062|4更新时间：2025-07-16
- 摘要：This paper describes a new non-homogeneous clutter and interference mitigation method for forward-looking airborne early warning radar with arbitrary linear array configuration.The approach is performed in three stages,i.e.the minimal mean square space-time spectral estimation with iterative processing which using only a single range bin data,the clutter and jammer ridge reconstruction based on image feature extraction,moving target detection with subspace projection.An important feature of the proposed method is its ability to extract requisite implementation information from the data itself without sacrificing space-time aperture.A preliminary result against an airborne simulation data demonstrates the effectiveness of the proposed method.关键词：airborne early warning radar;ground moving target indication;space-time adaptive processing;non-homogeneous clutter cancellation2|1354|5更新时间：2025-07-16
- 摘要：In this paper,a novel method based on spectral clustering ensemble using nonnegative matrix factorization (NMF) is proposed for the segmentation of SAR image.Firstly,diversity segmentation components are obtained due to the spectral clustering method is sensitive to the scaling parameter.Secondly,these components are combined by using NMF,NMF is a method that can obtain a representation of data full of intuitive meaning and physical interpretation.Finally,segmentation result is obtained according to the combined result.To show the effectiveness of the novel method,experiments with three texture images and four SAR images are considered.The segmentation results are evaluated by comparing with K-means method,spectral clustering method based on Nystrom approximation and Meta-clustering method.According to the qualitative and quantitative analysis,the proposed method is effective and has some practical value.关键词：synthetic aperture radar (SAR);image segmentation;clustering ensemble;spectral clustering;nonnegative matrix factorization (NMF)2|1404|11更新时间：2025-07-16
- 摘要：Sparse dictionary learning means that learning for a dictionary which has sparse representation on a known base dictionary.In the paper,with block-relaxation,the sparse dictionary learning can be translated into respective optimization of dictionary and coefficients.It means that the target function can be optimized respectively with fixed dictionary or fixed coefficients by optimization method of surrogate function.Through above process,the update algorithm of coefficients with fixed dictionary and update algorithm of dictionary with fixed coefficients can be obtained.Then the sparse dictionary learning algorithm is obtained.The convergence of the algorithm is illuminated theoretically.Comparison in simulation indicates that the algorithm put forward in this paper is superior to sparse K-SVD algorithm in convergence and operating efficiency.关键词：sparse representation;sparse dictionary;block-relaxation;surrogate function;K-SVD2|1222|1更新时间：2025-07-16
- 摘要：The k-error linear complexity is one of the important measures for assessing the pseudorandom properties of sequences.For binary sequences with period a power of 2,of which the first decreasing point of the linear complexity is 4,the possible values of the 4-error linear complexity and the number of sequences with given 4-error linear complexity are established based on the Games-Chan algorithm.Moreover,the expected value of the 4-error linear complexity is also provided.The results show that the 4-error linear complexity is close to the linear complexity.关键词：stream cipher;periodic sequences;linear complexity;k-error linear complexity2|1011|3更新时间：2025-07-16
- 摘要：To estimate the parameters of unknown frequency-hopping (FH) signals,a blind parameters estimation method for FH signals based on time-frequency distribution maxima is proposed.Due to the transient frequencies of FH signals,the hop period can be estimated accurately via the wavelet transform of the time-frequency distribution maxima of a FH signal.The switching time instants and the hopping frequencies can be estimated accordingly.The theoretical analysis and simulation result show that the method can accurately estimate the parameters of FH signals with a low computational complexity.The performance of this method is superior to the current existing method.关键词：frequency-hopping signals;time-frequency distribution maxima;wavelet transform3|1578|10更新时间：2025-07-16
- 摘要：Electrocardiography(EKG) and electro-oculogram (EOG) are the most common interference in electroencephalogram(EEG),and this paper presents an algorithm to filter artifacts in EEG based on blind source separation of maximum signal noise ratio.The algorithm takes separation matrix as a variable to establish the objective function of original signal to noise ratio,looking for the separation matrix which makes the objective function reach a maximum (or minimum ) value.Then the estimated signal can be obtained through the separation matrix.The algorithm has the following steps in the implementation process.Firstly,part noise in the original EEG is removed through wavelet transform.Then the denoised EEG which still contains EKG and EOG is separated by the algorithm to filter artifacts based on blind source separation of maximum signal noise ratio.And correlation coefficient is introduced to verify the consistency between the outputs of blind source separation and the original signals.The experimental results indicate that the cross-correlation coefficient between the output signals of blind separation dropped significantly compared with the original signals.Thus the algorithm is effective for removing EKG and EOG in EEG.关键词：electroencephalogram;wavelet transform;maximum signal noise ratio;blind signal separation;cross-correlation coefficient2|2059|5更新时间：2025-07-16
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