最新刊期
卷 33 ， 期 10 ， 2005
- 摘要：According to the analysis of meteor burst channel,the mechanism of variable rate data transmission for Meteor Burst Communication (MBC) is developed and a receiver based on coefficients-mapped decision feedback equalization (DFE) via channel acquisition is proposed,which agrees with the structure of MBC data frame.With the channel impulse response being obtained by fast correlation operation,the relationship between channel parameters and equalizer coefficients is derived so that DFE coefficients can be directly calculated from the estimated channel parameters.It is shown that,the presented algorithm provide more significantly robust against channel variation than a traditional DFE employing adaptive coefficient tracking,and therefore makes data receiving stable for variable rate data transmission of MBC system.Computer simulation results are also included to support our development.0|2|7更新时间：2025-07-02
- 摘要：This paper defines a Q-matrix,based on which a new ensemble of LDPC code is created.Furthermore,it presents the algorithm of constructing the sparse parity-check matrix and designing encoder by studying the character of Q-matrix,and gives the quick searching algorithm of Q-matrix.Studying shows that the complication of the algorithm to encode a Q-matrix LDPC code is O(N),if Q-matrix is searched off-line,and stored on-line by means of Q-vector.The Q-matrix LDPC code has high flexibility concerning design of code length and rate,which makes it compatible with the existed standard.关键词：LDPC(low-density parity-check) code;encoder;parity-check matrix0|2|9更新时间：2025-07-02
- 摘要：Pseudo noise (PN) sequence has been applied widely because of its optimum property of the autocorrelation function.However,it has been seriously limited in practice by many side peaks and regular sequence length.In this paper,a novel method to design a new PN sequence named low or zero autocorrelation (LZA) sequence through Barker code or quaternary Barker code or super Barker code and PN sequence is proposed.Simulations show that LZA sequence has four merits when compared with the conventional PN sequences.First,the length of LZA sequence is optional.Second,the autocorrelation values of the LZA sequence are small or zero except at the point of time delay of zero.Third,the memory cell and circuit cell to construct the LZA sequence are very small even though the length of LZA sequence is as long as what you expect.Finally,the LZA sequence has great capability of security.Obviously,compared with the famous PN sequence,LZA sequence has supplied a gap of PN sequence with better performance,thus it will be useful in practice and theory.关键词：low or zero auto-correlation (LZA) sequence;pseudo noise (PN) sequence;Barker code;quaternary Barker code;super Barker code0|2|2更新时间：2025-07-02
- 摘要：Based on the system feature of softswitch-based heterogeneous clustered media server,this paper proposed a limited resource vector load-balancing algorithm.Harmonious usage of system resources was considered and violent shaking of the system performance was avoided in the algorithm.A lot of simulations on the Petri net model of balance system had been conducted and the algorithm had been compared with some traditional algorithms on balancing ability for heterogeneity,system throughput,request response time,and performance stability.Results of simulation experiments show that the algorithm can make system get higher performance and it has excellent ability to deal with the heterogeneity of clustered media server.关键词：load-balancing algorithm;heterogeneous cluster;media server;softswitch;stochastic Petri net0|2|3更新时间：2025-07-02
- 摘要：To solve the problem of Quality-of-Service (QoS) routing in next generation high speed network,firstly a novel precomputation algorithm MKPPA for QoSR with accurate link-state information based on the K-optimal paths is proposed.Secondly a modified MKPPA,M-MKPPA,is presented to adapt the inaccurate link-state information of the network by introducing an "alert point".Finally the theoretical analysis indicates that the MKPPA is not only fit to the QoSR in which all constraint parameters are additive but also the QoSR in which some constraint parameters are additive and the others are non-additive,the M-MKPPA can adapt the dynamical character of link-state information of the network.The extensive simulation results show that the proposed algorithms have the higher routing computation success ratio with either accurate link-state information or inaccurate link-state information of the network.关键词：quality of service (QoS);multiple constraints;QoS routing;K-optimal paths;precomputation0|2|1更新时间：2025-07-02
- 摘要：Present call model can not satisfy all complex controlling requirements required by multimedia services and mobile services for transport bearer.This paper proposed a novel universal layered and Signalling and Bearer Separated Control State Model (SBS-CSM) without increasing complexity compared to current call model.SBS-CSM provides protocol independent call control function in session control module by separating signalling control and bearer control into two unrelated state machines and opens those two control capabilities to service control independently.Protocol access module accomplishes the specific media link processing for each supported protocol.The performance data gathered from softswitch system implementing SBS-CSM illustrates the availability and efficiency of SBS-CSM.关键词：softswitch;multimedia call;call control model;signalling control;bearer control0|2|0更新时间：2025-07-02
- 摘要：The next generation network will provide voice,data and multimedia services,which are with different performance requirements.To research the impact of these services' performances between each other and to assure these performances is significant to implement the next generation network successfully.The paper designs a softswitch multi-service control framework with multi-queue,and a dynamic MSN(maximum session number) method to allocate system resources is proposed and analyzed to effectively utilize system resources to insure service's performances,which are based on the control framework.The simulation results prove that the dynamic MSN can ensure the system's stability and satisfy each softswitch service's performance requirement in the softswitch multi-service environment.关键词：softswitch;multi-service;dynamic MSN;service performance0|2|1更新时间：2025-07-02
- 摘要：In order to ensure that the interference-limited multimedia CDMA mobile communication systems operate stably and reliably,a call admission control mechanism is implemented,with the goal to effectively,fleetly,and accurately control the number of users in the systems.In this study a fast adaptive call admission control (FACAC) method for WCDMA air interface is going to be introduced making able fast,accurate,adaptive threshold,simple and feasible decision about incoming calls.Simulation results verify the correctness of theoretic derivations and show that the drop probability and the grade of service (GoS) for FACAC is lower by above 60% and lower by about 23% than those for conventional CAC schemes respectively (when traffic load is higher in the systems).关键词：adaptation;call admission control;power control;WCDMA;mobile communications0|2|0更新时间：2025-07-02
- 摘要：An orthogonal rotation constellation for Differential Unitary Space-Time Modulation (DUSTM) with traditional cyclic constellation as a searching subset,is proposed for any transmit antennas to larger the diversity product,which is the key property to the performance of the DUSTM.Using this constellation,the symbol error rate performance is improved about 2dB coding gain over traditional cyclic constellation which is a diagonal unitary matrix consisting of Fourier coefficients.关键词：DUSTM;diversity product;constellation;orthogonal rotation0|2|1更新时间：2025-07-02
- 摘要：This paper proposes a formal model of feature interactions based on the semantic of message lists in runtime between the object of service logical programming instance and the network entities.First,feature interaction manager views the instances of services logics and network entities as sub-lists of their interacting messages sets,with viewpoint of syntax and semantic of messages between the instance of service logic and external entity,it presents formal models for detecting non-deterministic,livelock and properties-inconsistency in runtime.Additionally,this paper addresses that it is only a necessary condition using the message lists to detect anti-property type service interaction without additional processing.Finally,the simple complementary approach to detecting the anti-property feature interaction is given.关键词：next generation network;feature interactions;runtime detection;formal model;message semantic0|2|0更新时间：2025-07-02
- 摘要：In this paper,we investigate non data-aided channel estimation for orthogonal frequency division multiplexing (OFDM) systems without cyclic prefix.By exploiting channel diversity using only two receive antennas,a blind deterministic algorithm is proposed. Identifiability conditions are derived that guarantee the channel to be identified up to a scalar ambiguity.This diversity-based algorithm is computationally efficient and does not have any restriction on the input symbols with regard to their constellation or their statistical properties.Simulation results illustrate the performance of the proposed algorithm.关键词：blind channel estimation;Orthogonal Frequency Division Multiplexing(OFDM);receiver diversity0|2|0更新时间：2025-07-02
- 摘要：Through simultaneous diagonalization of the overall covariance matrices of clean speech and noise signal observed by microphone array,an improved speech enhancement algorithm based on signal subspace is presented.It estimates clean speech signal subspace without any preassumption on the stochastic property of noise signal.The proposed method does not rely on any signal model and efficiently attains the optimal estimation of speech corrupted by colored noise,which overcomes the disadvantage of original method only suitable for white noise.Simulation results demonstrate that the algorithm possesses good performance both in objective and subjective tests.关键词：speech enhancement;signal subspace;array signal0|2|4更新时间：2025-07-02
- 摘要：Through analyzing samples distribution in high dimensional space,a novel algorithm for speaker-independent continuous figure speech recognition is presented based on high-dimensional space covering,biomimetic pattern recognition and dynamic scanning in this paper.Without endpoints detection and segmenting the continuous speech is dynamic scanned,then distance curves from the continuous speech to every kind of covering area in high dimensional space are obtained.The continuous speech is recognized by detecting the minimum values in the curves.关键词：continuous speech recognition;high-dimensional space covering;speaker independent1|3|4更新时间：2025-07-02
- 摘要：A method for separating the overlap signals is proposed in this paper.It sets up a multi-signals separating model using the polynomial phase fitting to estimate the signal phase.This method changes multi-signals separation into the sequence and channel parameters estimation.Then,the method for joint estimating the sequence and channel parameters is took to estimate the each signal amplitude and phase of multi-signals and separate the multi-signals.The method can separate signals entirely overlapped in time and frequency using single channel reception.Simulation and the practical experiment results indicate that the method has the excellent performance.关键词：multi-signals separation;overlapped signal;separation model;joint estimation;single channel reception0|2|2更新时间：2025-07-02
- 摘要：A single-channel mono-pulse tracking receiver is given in this paper,it use broadband data transferred signal (such as modulation mode is BPSK or QPSK,data rate is 100kbps to 300Mbps) as angel-measured source,and two modes (sum mode is TE11 and difference mode is TM01) as tracking antenna feed.The tracking receiver can detect angel error signal when IF band is one part of signal main band (such as 1/5 or 1/10).This paper analyze angel tracking theory from three aspects:first is mathematic theory;second is physical explanation,third is experimentation demonstration.According to this theory,Ka band angel tracking system was successfully developed,its performance was very fine.关键词：mono-pulse tracking;broadband data transferred signal;acquisition and tracking0|2|2更新时间：2025-07-02
- 摘要：In this paper,by the introduction of martingale and the study of immune operators,the martingale characteristic of the population related to the Immune Genetic Algorithm (IGA) was analyzed.Then the strong convergence (a.s.) of IGA is deduced with lemmas.Next,the convergence rate of IGA was studied and the quantitative expression that relates to many parameters in IGA is presented.The discussion about the effect of different parameters on the convergence rate was carried out,which will be helpful to improve the performance of the algorithm.关键词：immune genetic algorithm;strong convergence (a.s.);martingale;convergence rate0|2|7更新时间：2025-07-02
- 摘要：The two-dimensional(2-D) harmonics parameters estimation in multiplicative and additive noise is studied from the viewpoint of cyclostationary processes.Using the property of cyclic cumulants,the statistical properties of the single record estimator of 2-D third-order cyclic-moments are obtained.A new method for 2-D harmonics parameters estimation based on special slice of the third-order cyclic-cumulants is presented.The strong compatibility and convergence rate of the estimators are obtained.Simulation examples illustrate the algorithm.关键词：two-dimensional harmonic;multiplicative noise;third-order cyclic-moments;convergence rate0|2|1更新时间：2025-07-02
- 摘要：For the SINR(signal-to-interference-and-noise-ratio) equation based on the polarization ellipse parameters,an optimal polarization scheme called Zero Differential Orthogonal Searching (ZDOS) is suggested and discussed in detail.There are three key points in ZDOS:the global optimal point of SINR is approached to by the first optimization along a special line,then the searching processes are designed along two orthogonal lines to search minimal differential in each direction,and used only the previous local optimal solutions simply.Many experiments are made,and the range of the parameters is given.These experiment results show that ZDOS scheme takes generally several steps to reach the global optimum.关键词：polarization ellipse;optimal polarization;orthogonal searching0|2|3更新时间：2025-07-02
- 摘要：This paper proposes a new periodic correlation signal,which is almost perfect binary array pair (APBAP).We present the definitions of APBAP and its transformation properties.To reduce the searching range and improve the searching efficiency of almost perfect binary array pair,limited conditions of APBAP are discussed.Based on these limited conditions,we search out many almost perfect binary array pairs with small length no more than 20.The searching results show that almost perfect binary array pairs have such high energy efficiency that they are feasible for engineering applications as synchronization codes and multi-user codes.关键词：perfect signal;array pair;correlation;information theory0|2|10更新时间：2025-07-02
- 摘要：Though the weighted least squares algorithm for mobile location performs well in case of line-of-sight propagation,the conventional approach may be improved further in case of asymmetrically distributed measurement errors due to non-line-of-sight (NLOS) effect because high-order moment information should not be ignored.In this paper,a high-order moment approach is proposed to mitigate the NLOS error.The ordinary range location algorithm coincides with a special case of this method.Numerical examples show that it improves the location performance significantly in serious NLOS environment.关键词：range location;non-line of sight;asymmetric distribution;high-order moment0|2|1更新时间：2025-07-02
- 摘要：The problem of designing an optimal filter for unstable linear discrete-time systems is firstly investigated.By use of state-observer and coprim-factorization,the problem of the optimal filter design for unstable system is converted to a solvable model matching problem,which can be solved by point to point optimization approach.A simulation example shows the effectiveness and feasibility of the proposed results.Thus the point-to-point optimization approach is extended to unstable systems.Furthermore,this paper considers the optimality of linear filter for linear discrete-time systems.It is shown that for linear discrete-time systems using nonlinear filter instead of linear filter does not improve the optimality of filter.关键词：unstable linear system;unknown but bounded noise;linear filter;nonlinear filter;optimal filter0|2|0更新时间：2025-07-02
- 摘要：Depending on the general protocol model,this paper analyzed the possibility of blocking Instant Messaging (IM) at TCP layer and IM protocol layer respectively.At TCP layer,packets of FIN or RST were inserted to close a TCP connection;at IM protocol layer,certain commands with special flag were inserted to enforce a client to be idle.To implement these blocking policies effectively,a message-driven algorithm was offered,too.Some experiments to block Yahoo! Messenger and their statistical analyses were also presented in this paper. The results showed that all the policies implemented through the message-driven algorithm block IM effectively,their performances are independent of the back traffic,and thus,they don't impose much burden on the whole Internet.The works done in this paper provided practicable and effective solutions to block IM.关键词：block;instant messaging(IM);peer-to-peer(P2P);protocol;threat0|2|4更新时间：2025-07-02
- 摘要：Two threshold cryptosystems secure against chosen ciphertext attacks are proposed.The ciphertext in the first system is the resulting of applying the Canetti-Halevi-Kazt approach to the Boneh-Boyen Identity-Based Encryption scheme.While,in the second system,the ciphertext is essentially the same as that in the Waters IBE scheme except that the"identity"here is the hash of the first two parts of the ciphertext.Since the servers can publicly verify the ciphertext validity before providing the decryption shares and the shares can be publicly verified by the combiner,both the schemes achieve the non interactivity.The security in both the proposals is proved under the standard Decisional Bilinear Diffie-Hellman assumption.关键词：encryption;chosen ciphertext security;Decisional Bilinear Diffie-Hellman assumption0|2|0更新时间：2025-07-02
- 摘要：A quadratic unsharp masking (QUM) operator is presented,which extracts edge and detail information from an image with equal weights.QUM which is the mean of QUM values for all pixels in an image,TEM which is the mean of TEM (Laws' texture energy measure) values for all pixels in the image,and standard deviation (σ) of the image are combined to form a three-dimensional feature vector (QUM ,TEM ,σ),for performing classification on side-scan sonar seafloor images.150 sidescan sonar images for mud,sand and rock seafloors are classified using the presented three-dimensional feature vector,and recognition rates of maximum 96.7% and minimum 90.7% are achieved.These same 150 seafloor images are also classified using the conventional gray level co-occurence matrix features,and a recognition rate of 87.3% is achieved,which shows that the presented seafloor classification method has better classification performance.关键词：quadratic unsharp masking (QUM);texture energy measure (TEM);seafloor sediment classification;and side-scan sonar imagery0|2|3更新时间：2025-07-02
- 摘要：A novel idea of using Fast Transversal Filter (FTF) adaptive algorithm in Ultra WideBand (UWB) RAKE receiver is proposed for the first time.By using forgetting factor diagonal matrix,we derive the recursion formula of FTF algorithm with forgetting factor lambda.The receiver with FTF adaptive filters can track the amplitude of received signal to form a real-time amplitude estimation.The simulation results show that FTF algorithm has a better performance than RLS algorithm in convergence speed,bit error rate and computational complexity,and the special point is that the convergence speed is insensitive to the relativity of the data in FTF algorithm.关键词：ultra wideband;RAKE receiver;fast transversal filter0|2|2更新时间：2025-07-02
- 摘要：A traffic control model in multi-service systems is proposed based on mobile intelligent network SCP systems.An overload control algorithm,which implement to distribute system resources to each service by its priority,and to dynamically control traffic,is designed.In addition,it is appropriate for the algorithm to be applied in application server of the next generation network.The theoretic analysis and the simulation results demonstrate the algorithm's effectiveness and fairness in multi-service environment.关键词：overload control;mobile intelligent network;SCP(service control point);next generation network0|2|1更新时间：2025-07-02
- 摘要：This paper presents an uplink power control algorithm using hybrid neural network techniques.Based on the FER target criteria and CRC detection of wireless channel in real time,the Adaline out-loop controller adjusts the target SIR according to the FER need.The Hopfield inner-loop controller adjusts the mobile transmit power in order to keep the received uplink signal to interference ratio at the SIR target.Comparing with the conventional fixed-step approaches,this algorithm enhances control accuracy,improves the control system stability,and provides better QoS criteria.Simulations show the effectiveness of the algorithm.关键词：power control;neural networks;WCDMA;quality of service(QoS);frame error ratio(FER)0|2|1更新时间：2025-07-02
- 摘要：In complex situations,the ordinary mobile station (MS) often suffers from ubiquitous non-line of sight (NLOS) propagation.Unlike the approaches that depend on the effort of the individual MS,a novel method is proposed,which first exploits the training data collected from the advanced MS to extract the knowledge of environment,then conveys it through a nonlinear filter to the ordinary MS,and finally improves the latter's location performance.Simulation results show that it improves the location performance significantly in serious NLOS environment.关键词：range-difference location;non-line of sight;adaptive nonlinear filter;knowledge of environment1|2|1更新时间：2025-07-02
- 摘要：A novel multiuser detector with pretreater is presented in this paper,which pretreater is obtained from global optimality conditions for quadratic optimization with binary constraints.The pretreater mentioned in this paper can calculate most user information sequences by low computational complexity and assure that the results obtained from pretreater are the same as that of optimum multiuser detection.Since the user information sequences obtained from pretreater have been global optimization,we can reject them from original multiuser detector and then a relative small scale multiuser detector can be obtained.Compared with the original one,the multi-access interference of small scale multiuser detector is reduced.As a result,we can solve this small scale multiuser detection by some common multiuser detector.关键词：multiuser detection;multi-access interference;near-far problem;Code-division multiple access0|2|1更新时间：2025-07-02
- 摘要：An adaptive rate control algorithm based on significant priority is presented for embedded block coding with optimized truncation.The coding passes of all coding block are evaluated by different significant priority according to the bit-planes the pass located in and the coding type,which are encoded by T1 encoder in the significant priority order.T2 encoder sends feedback to control the coding depth by the accumulated bit rate and complete the rate-distortion optimization truncation.The experimental results show that the proposed scheme can efficiently reduce the cost of computation and memory usage,which is suitable for hardware implementation.关键词：image compression;embedded block coding;significant priority;rate distortion optimization0|2|4更新时间：2025-07-02
- 摘要：In order to get how the proportion of customers are satisfied with the business processing time,we model a business processes with a workflow model,then get the instances' staying-time distribution at the workflow by three steps:firstly we work out the distribution function at each activity;Secondly we work out the distribution function at each basic structure;thirdly we work out the distribution function at the whole workflow model.Finally according to the given instances staying-time limit,we can know the proportion of customers that are satisfied.关键词：workflow;staying-time;distribution;resources constraints0|2|9更新时间：2025-07-02
- 摘要：Closed-form expressions for the spectral regrowth of code division multiple access (CDMA) signal passed through a nonlinear amplifier by a digitally modulated carrier are derived using the power series and statistical methods of high order cumulant.The technique yields an analytical expression for the autocorrelation function of the output signal as a function of the statistics of the input signal transformed by a behavioral model of the amplifier.The third-order nonlinearity is expressed in terms of IP3 to include the memory effects of the circuit in-band and out-of-band reactance.The analysis is based on a time-domain model of the signal and the model is used to derive the power spectrum density and other statistical properties of the CDMA signal.Such analytical results are useful in finding optimal operating conditions of the power Amplifier.关键词：spectral regrowth;CDMA;power spectrum density;auto-relation function;high order cumulant0|2|0更新时间：2025-07-02
- 摘要：Since the signals we have collected always don't meet the normal distribution,the signal processing method based on the high-order statistics becomes more popular.For the feature of the handwritten Chinese characters,its decentralization characteristic can not be described as the normal distribution.So a new method based on the high-order statistic is proposed to describe it.Three different calculational methods of high-order statistics are given in the paper,and the performance of the template matching based on these three methods are compared according to the experiments on HCL2004 handwritten Chinese characters database.At the same time,the validity of the high-order statistics based recognition method is approved.关键词：Chinese characters recognition;high-order statistics;template matching;distance metric0|2|1更新时间：2025-07-02
- 摘要：Because handwritten characters in practical bank check are always interfered by background image and seals,the accuracy rate of OCR is very low.To obtain required precision,most samples have to be rejected,by which the auto-processing rate is confined.In this paper,a new confidence evaluation method based on support vector machines is proposed.In this method,special SVMs are constructed for every character class to evaluate confidence and recognize similar character.This method makes full use of SVM's studying ability in the condition of few training samples,and can accurately estimate the confidence.By this method we can reject fewer samples to obtain required precision.关键词：Chinese character recognition;support vector machine;similar character;confidence;bank check OCR0|2|1更新时间：2025-07-02
- 摘要：The single figure syllable modeling based on neural network for continuous speech recognition is discussed.A new feature extraction method is used which mainly includes compressing single figure frames according to a certain inter-frame angle,extracting representative information comparing to standard single figure of fixed length.2640 single figure syllables made from continuous speech are used to construct each kind of high dimensional space covering area.By biomimetic pattern recognition theory 7308 single figure syllables made from continuous speech are used to confirm this model in CASSANN-II neural computer and get a quite good result.Experiments show the recognition rate is higher than SVM when the training samples are small.关键词：continuous speech;high-dimensional space covering;single syllable;neural network modeling0|2|1更新时间：2025-07-02
- 摘要：Palmprint recognition is one of the most reliable and new technique of biometrics.This paper presents a new approach based on 2D PCA algorithm,which extracts the statistical feature of palmprint images.Experimental results illustrate its performance and generalization ability over PCA.Furthermore,we propose improved 2D PCA method,and prove that the algorithm can hold the global scatter of the training images while decorrelates rows as well as columns of them.In this way,we obtain high accuracy (99.72%) while reducing the feature dimension efficiently,the responding time of recognition is only 0.03s,which enhances the practicability of the system.关键词：palmprint recognition;2D PCA;improved 2D PCA;PCA0|2|22更新时间：2025-07-02
- 摘要：It introduces a two-dimensional matched-phase transform.For multicomponent polynominal phase signals (mc-PPS) whose phase order is beyond five,their instantaneous frequency rate (IFR) will be local maxima in the transform.However their crossterms seldom emerge as local maxima.IFR of signal component is continuous function of time,but local maxima produced by crossterms have not this property.So one can realize the estimation of IFR of each component at all time instant by this transform.Accuracy is theoretically analyzed and compared with simulation result.关键词：polynominal phase signal;instantaneous frequency rate;parameter estimation;matched-phase transform0|2|4更新时间：2025-07-02
- 摘要：A new subspace method based on Cumulant is presented for joint estimation of ranges directions-of-arrival (DOA's) and frequencies of multiple near-field sources impinging on an array of sensors.The parameters of sources are directly given by the eigenvalues of certain constructed matrices.Compared with several existing methods,the loss of array aperture is effectively avoided and hence the performance improvement of parameter estimation is achieved.Simulation results show that the proposed method outperform an ESPRIT-like method.关键词：near-field source;DOA estimate;range estimate;frequency estimate;cumulant0|2|14更新时间：2025-07-02
- 摘要：The block-based DCT compression methods often cause blocking artifacts due to low bit rates.In order to not only reduce blocking artifacts,but also preserve edges and textures adequately,a new blocking artifacts reduction algorithm is proposed in this paper.The algorithm introduces the definition of homogeneous blocks and the measurement with an alterable threshold for judging whether a shifted block is homogeneous.For each row (or column) of the homogeneous blocks,an adaptive Sigmoid function is used to replace the step function to reduce blocking artifacts.For the inhomogeneous blocks,Sigma filter is used to smooth the blocks.Simulation results show that the proposed algorithm can outperform the algorithms proposed by Liu (2002) and Luo (2003).关键词：blocking artifacts;adaptive processing;Sigmoid function;Sigma filter0|2|5更新时间：2025-07-02
- 摘要：This paper propose a novel method of Reconstruction of Vessel Axis on matching of multi-resolution projections and analyzing of corresponding points.The 3-D space is divided to several cubes.The cubes are projected to the actual projection directions separately.If a cube-projection includes vessel axes points,it is believed that the cube include 3D vessel.Then we divide the cube to several smaller cubes and repeats above process until the needed precision is reached.An approximate 3D model of vessel axes is constituted according to projections of the cubs.The corresponding relation of vessel axes between different direction projections is analyzed according to the approximate 3D axes model.Then we can constitute the accurate continuous 3D vessel axes by interpolation method.We use an actual DSA sequence as the experimental data and the result is satisfactory.关键词：multi-resolution projection;corresponding point;vessel axes;matching;3D reconstruction0|2|0更新时间：2025-07-02
- 摘要：The multi-directional and low-redundant wavelet with receptive fields properties of simple cells was constructed in 2D discrete Hilbert space.The multi-directional wavelet is named fanlet since its frequency spectrum support is fan-shaped.The fanlet transform can be implemented by circular symmetric multi-resolution decomposition and directional filter bank,it decomposes image into multi-resolution and multi-directional subbands.The circular symmetric filter banks in the fanlet transform,which satisfies reconstruction conditions,was designed by genetic algorithm.Compared to the contourlet,the fanlet is smoother,moreover,it doesn't have frequency aliasing phenomenon.Experiment on image denoising shows that fanlet outperforms contourlet in terms of both peak signal-to-noise ratio and visual quality.关键词：multi-directional wavelet;contourlet;receptive fields;genetic algorithm0|2|5更新时间：2025-07-02
- 摘要：High-quality and real-time processing are two important requirements for the compression of large radar video data set.However,the existed high-quality compression algorithms are too complex and time-consuming for the real-time processing.Some algorithms implemented by hardware can meet the real-time processing requirement,but their compression quality is low and the compression ratio can't be adjusted.In this paper,the characteristic that radar video data has strong correlation and short correlation length is obtained by analyzing actual radar data.Then a low-complex and high-quality compression algorithm is proposed based on lifting wavelet transform with length 5-3 and Golomb-Rice coder.The computational complexity of the algorithm is analyzed in detail.Experiment shows that the software implementation of the algorithm can meet the requirements of real-time radar video data compression.Finally,the algorithm has been successfully utilized in a record system of coastal surveillance radar.关键词：lifting wavelet transform;golomb-rice coder;radar video data compression0|2|1更新时间：2025-07-02
- 摘要：A new model and algorithm to realize adaptive adjustment of the weights of NN and to make global fusion information optimal were presented.The method utilizes Unscented Kalman filter (UKF) for nonlinear optimal estimation to solve the problem that weights of neural networks are not be on-line trained in data fusion.Applies the above project to a multi-sensors vessel integrated navigation system,obtains actual data from the integrated navigation system of DGPS/GPS/RLC/compass.First,using UKF methods estimates and filters the location information,then,NNKF and NNUKF are used to fuse them.The results of experiment and simulation show that the proposed approach is very useful for improving the accuracy and calculation speed of the system.关键词：data fusion;unscented Kalman filter;neural networks;integrated navigation;information allotment0|2|10更新时间：2025-07-02
- 摘要：Based on the importance of P transform and coherence in encryption-decryption in the S-P networks,we put forward the definition of involution-typed mixcolumn transform.Algebraic structure,branch and enumeration of involution-typed mixcolumn transform are researched deeply in this paper.It is shown that the maximum of branch and property of involution are restricted each other using algebraic structure of mixcolumn transform.Enumeration of involution-typed mixcolumn transform is solved and the relation between the weight of polynomial c(x) and the branch is given.In conclusion,some discussion of the design of block cipher are given and this provides a significant basis for the design and analysis of block cipher.关键词：involution-typed mixcolumn transform;algebraic structure;branch;enumeration0|2|7更新时间：2025-07-02
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