最新刊期
卷 29 ， 期 7 ， 2001
- 摘要：This paper is devoted to the choice of chaotic spreading sequence for asynchronous DS-CDMA communication.Aiming at the characteristic of asynchronous DS-CDMA system,some criteria on optimizing spreading sequences are proposed.The method of choosing is also presented.According to the method,chaotic spreading sequences with better performance are obtained.Calculation shows that these optimized chaotic spreading sequences are much better than Gold sequences.At last,5 kinds of chaotic sequences' performance are compared.关键词：asynchronous DS-CDMA;chaotic spreading sequences;criteria2|1317|15更新时间：2025-07-16
- 摘要：In this paper,we design a chaos-based frequency hopping (FH) sequence generator with multidimensional chaotic systems because the sequences generated by unimodal maps are easy to attack.Some modifications are introduced to n-dimensional nonlinear digital filters in order to improve the period and distribution properties of the resulted sequences.Moreover,the generator is realized in FPGAs (field programmable gate arrays) and then tested.The generator produces sequences with uniform distribution,large complexity and Hamming correlation of Gaussian distribution with mean L/q.Test results suggest that the design of generator is successful.关键词：frequency hopping;chaos;nonlinear digital filters;FPGA3|1394|12更新时间：2025-07-16
- 摘要：A novel adaptive clustering protocol,called the mobile clustering protocol,is presented firstly.It acquires network control architecture rapidly and adapts to topological changes with less control overhead than those proposed so far.It also supports node mobility and maintains the stability and robustness of the network architecture.The new method to adopt overlapping clusters for cluster size optimization is proposed secondly.The area with high node density is divided into clusters with a small number of nodes,so that the maximum throughput of each node can be increased.The intelligent control protocol is proposed finally to prevent gateways from becoming communication bottlenecks among clusters with different channels and avoid missing packets on their non-sensing channels.Simulation and numerical results are shown in the paper.关键词：wireless ad hoc network;mobile clustering protocol;mobility support;multihop network architecture;cluster size optimization;intelligent gateway control3|980|2更新时间：2025-07-16
- 摘要：The concept of setupless and stateless QoS routing was proposed in this paper.The key idea in implementation of stateless QoS routing lies in:(1)how to insert application's QoS requirements into IP packet header;(2)how to efficiently design forwarding strategy of a router.Combined with certain QoS-based routing heuristics,several novel solutions were proposed.The proposed stateless QoS routing schemes maximize the utilization of best-effort routing entries and are scalable,robust,simple and efficient.关键词：QoS routing;stateless;setupless2|835|0更新时间：2025-07-16
- 摘要：This paper proposes a novel method for objective assessment of speech quality based on one-step strategy.Using the theory of multi-dimension non-linear mapping of the feedfoward neutral network,the method combines the traditional two steps of average distortion computing and mapping from the average distortion value to the Mean Opinion Score (MOS) into one step.It can embody adequately the perception properties of the human auditory system with simple computing and also is a unanimous estimate for MOS in statistical sense.Experimental results show that the correlation coefficient between the subjective test score and objective MOS estimate of one-step method can reach up to about 0.95,which is obviously better than that of the conventional two-step methods.关键词：speech quality objective assessment;neural network2|1018|2更新时间：2025-07-16
- 摘要：Generalized Fuzzy Operator(GFO)has attracted more and more researchers who are studying edge-detection operator characterized by its fine detection.accurate location and unique responses.But,its extension and application are limited because of factitious parameters.In this paper,we present a method which can calculate the key parameters of GFO.The experimental result shows that the method is practical and effective.关键词：generalized fuzzy operator(GFO);linear transform;edge detection2|885|2更新时间：2025-07-16
- 摘要：In this paper,we proposed an improved 3D object representation first,which computes the local signatures of a given basic polygon on the surface mesh,and converts the signatures to a 2D array called the distance-angle(DA) images.This representation is adaptive to free-form objects,resistant to occlusion and clutter.Furthermore,it has distinct meaning,and adaptation to different resolution and irregular triangle mesh.Secondly,based on the representation,a novel 3D object recognition algorithm is presented,which is a multi-resolution mesh based,coarse-to-fine recognition.By matching the DA image of a polygon in the scene surface mesh with the DA images of models in low resolution,a model candidate set is obtained.The set is filtered in the neighborhood of the matched polygons in high-resolution mesh and verified by the model candidate sets of other polygons.Experiments show that this algorithm needs less computation,and is very accurate and robust.关键词：computer vision;3D object recognition;multi-resolution mesh;range image2|1839|3更新时间：2025-07-16
- 摘要：A new algorithm for Conforming Delaunay triangulation in 2-D is presented.The algorithm inserts points along constraint edges in order to maintain the global Delaunay criterion,while at the same time preserves the constraint edges.Compared with other strategies,our algorithm makes better use of the empty circle property in Delaunay triangulation,so that the number of extra points is greatly reduced.Corroborating experimental results are also given.关键词：Delaunay triangulation;constraint;global delaunay criterion;criterion2|1429|4更新时间：2025-07-16
- 摘要：Based on the property of P( u ,c),we can conclude that the performance of P( u ,c) and Vpc( u ,c) as cluster validity function is alike.At the same time,FP( u ,c) is not suitable for cluster validity function according to theoretical analysis and experiments.关键词：fuzzy clustering;partition coefficient;cluster validity function2|1059|2更新时间：2025-07-16
- 摘要：IGA (Improved Genetic Algorithm), a new genetic algorithm, is proposed in this paper. With five additional steps which are hybrid selection operator,competition among brothers , greedy operation, filter operation, and dynamic supply new individuals, IGA can improve global convergence property and convergence speed. The experimental results show IGA has great advantage over many existing genetic algorithms.关键词：genetic algorithm;convergence speed;filter operation;competition among brothers2|2698|10更新时间：2025-07-16
- 摘要：In this paper,a variable structure adaptive robust control algorithm is presented for a class of uncertain nonlinear systems with unknown control gain parameters of the system and unknown bound of uncertainty.An example illustrating the method described is included for ship roll stabilization by fin control system.It is shown that it makes the designed system guarantees the performance of robustness with respect to the perturbations and uncertainties.关键词：nonlinear system;variable structure control;robust control;adaptive control;ship roll stabilization2|1113|5更新时间：2025-07-16
- 摘要：In this paper,An adaptive L-filtering algorithm and its deterministic properties are discussed.Differentiating from the several proposed adaptive L-filtering algorithms based on the signal to noise ratio,the new algorithm adjusts parameters of the L-filter adaptively according to properties of time-varying signals.Theoretical analysis and simulation show that the algorithm is very efficient for edge preservation.关键词：adaptive;L-filter;non-stationary signal;complicated distribution2|1143|3更新时间：2025-07-16
- 摘要：As an important mechanism to provide guaranteed QoS in packet-switched networks,queuing scheduling algorithms have been widely researched in recent years.We present an Enhanced Rate-Proportional Server (ERPS),which gives the method and condition of designing system virtual-time function and compute their fairness index.We also give an example of packet-level queuing scheduling algorithm based on ERPS.关键词：weighted fairness queuing;rate-proportional server;Quality of Service;packet-switched networks2|830|1更新时间：2025-07-16
- 摘要：Optimal FIR transmit filterbanks and non-linear DFE receivers are derived for block-based transmissions over frequency-selective channel.The joint optimization of precoders and equalizers is based on the maximum mutual information criteria subject to fixed transmission power constraint.We get a new result from which the precoder can be interpreted as converting the frequency fading channel into a set of independent flat fading subchannels,and the feedback filter is equivalent to a direct subchannel,thus the SNR of each subchannel is increased and the system has better overall BER performance while maintains all the advantages of Scaglione's optimization.Simulations illustrate the merits of our design.关键词：filterbank;precoding;decision-feedback equalization;dispersive channel2|751|1更新时间：2025-07-16
- 摘要：An integrated error resilience technology for video communication is proposed in this paper.At beginning,a control strategy of subjective video quality is presented.Then,an unequal forward error-correction (FEC) based on H.263+ video coder is suggested to protect the different video information.However,if there are still error bits in the reconstructed images,temporal/spatial error concealment is used in the video decode according to the various coding types.Simulation results show that the subjective and objective video quality is obviously improved using proposed integrated error resilience technology with control of subjective quality.These technologies have been used in practice.关键词：video communication;control strategy of subjective video quality;unequal FEC;temporal/spatial error concealment2|988|0更新时间：2025-07-16
- 摘要：Turbo codes are preferred for high rate data services in the third generation mobile communication system IMT-2000.Thus low decoding delay and low complexity iterative decoding are of paramount importance.The modiffied soft output Viterbi algorithm(SOVA)and the Max-Log-MAP algorithm are such decoding techniques.The equivalence of the modified SOVA and Max-Log-MAP algorithm has been proven under the condition of no a priori information and infinite decoding depth.Since the a priori information has to be updated in iterative decoding,we prove their equivalence when there exists a priori information in the paper.We also discuss the relationship between the sliding window Max-Log-MAP algorithm and the modified SOVA for finite decoding depth.关键词：SOVA;MAP decoding;Max-Log-MAP decoding2|927|2更新时间：2025-07-16
- 摘要：With the development of digital tehnology,video broadcast has come into digital age.In DTV,it needs zero-knowledge identity authentication between the smart card and the digital Set-Top-Box because of the scurity requirement.This paper presents a new authentication scheme that will not leak the signature based on ECDSA,and applies it in DTV,and at the same time we analyze its security and efficiency.关键词：digital set-top-box;identity authentication;ECDSA;Smart cards2|934|2更新时间：2025-07-16
- 摘要：This paper investigates the effect of side-information,obtained by the opponent through an initial reconciliation step,on the size of the secret-key that can be distilled safely by subsequent privacy amplification in uncoditionally-secure secret-key agreement protocol based on smooth entropy,and obtains the size of the secret-key with some probability.关键词：smooth entroy;secret-key agreement;information reconciliation;privacy amplification2|1242|3更新时间：2025-07-16
- 摘要：HDTV has attracted worldwide attentions these years with the impact of increasing demand as well as technological maturity.This paper describes the realization of ATSC 8-VSB Modulator of the VSB-based HDTV terrestrial broadcasting system by using almost all digital methods.It gives an overview of the system requirements and analyses the mathematical equations of our method.Finally,the hardware design method and realization are presented.关键词：8-VSB;modulator;interpolation;polyphase structure;shaping filter;FPGA2|1044|0更新时间：2025-07-16
- 摘要：In order to solve the problem of sampling remote UWB radar signals,a real-time sampling design plan based on 1Gsps ultra-speed sequences has been proposed,which uses a new method for reducing the frequencies in all databases with the input of 1ns in a dual-memory system structure.When demanding for improvement factor on an A-D dynamic range has come out,the principle of random sampling with combination of pS timing on the time axis is exposed to increase the realization of technology in 12 units of 5Gsps design methods for sampling systems.This method gives a very high practical value to the UWB radar signals processing,digital oscilloscopes,frequency spectrum analyzers,etc.,that exist among the theory and applications of high-speed digital oscilloscopes system designs.关键词：equivalence sampling;random sampling;trigger phase difference;time axis explanation;UWB radar2|1133|5更新时间：2025-07-16
- 摘要：In this paper,a new transmit signal for mm-wave automotive collision warning radar applications is proposed.This signal,named Coded Stepped-FMCW,providing high range resolution and good anti-interference capability.A trial and error approach algorithm for multi-target detection is also suggested and its usefulness in eliminating the false target is confirmed by computer simulation.The optimization of waveform design is investigated and the simulation results is presented in the end.关键词：automotive collision warning radar;coded stepped-FMCW;multi-target detection;waveform optimization3|2109|6更新时间：2025-07-16
- 摘要：In this paper,the effects from mutual coupling and imbalance between channels on the interferometric correlation are analyzed.It is shown that the correlation error is mainly introduced by the phase imbalance.The phase balance of the central frequency can ensure the accuracy of the correlation phase,and the residual phase error will only reduce the coherency.Coherent/Incoherent noise calibration can correct the channel imbalance related interferometric correlation errors.关键词：microwave radiometer;interferometry;synthetic aperture;mutual coupling;imbalance2|1062|8更新时间：2025-07-16
- 摘要：The latest progress and the research direction on reducing spectrum leakage in periodic signal measurement and analysis are simply introduced firstly,and a synchronization method of re-locating the second sampling coordinate is presented.Then,a formula for locating the second sampling coordinate,and a synchronization algorithm (1st order linear,2nd order parabolic,and 4th order interpolation etc.),and their theoretial truncation errors are also discussed in this paper.By computer simulation lastly,through the synchronization calculation and the error analysis of various harmonic signals,the theoretical and practical error characteristics of the linear synchronization algorithm,and the practical error characteristics of the 2nd order parabolic and 4th order interpolation synchronization algorithm are obtained.Simulation results show that the algorithm could be used not only in steady state signal analysis,but also in periodical non-steady state process signal analysis.关键词：asynchronous sampling;synchronization algorithm;error characteristics2|982|7更新时间：2025-07-16
- 摘要：This paper proposes a new hybrid optical CDMA coding scheme of frequency hopping/time spreading together with the structure of its coder and decoder.This new coding scheme uses (L,ω,1)-OOC as frequency hopping pattern,prime code as time spreading pattern,and we call it as Prime/OOC code.This new coding scheme has good performance in autocorrelation,crosscorrelation and code's capacity.More important,the coder and decoder of the hybrid code can be implemented by multiple-bragg grating fiber.Compared with coder and decoder of time spread CDMA system,the coder and decoder are simpler,easier in selecting address and in integration.关键词：hybrid optical CDMA of frequency hopping/time spreading;OOC;prime code;prime/OOC code;multiple-bragg fiber grating3|1048|4更新时间：2025-07-16
- 摘要：Surface integral equation formulations have been widely used for the analysis of electromagnetic scattering problems,however,the wrong calculated results will be given using the method of moments at the discrete resonant frequencies.In this paper,based on the electric field integral equation,the singular value decomposition technique is used for finding out the current of the resonant mode,and the current distribution of the non-resonant mode can be obtained by filtering out the resonant mode current using the orthogonalized method.The scattering cross section is calculated for an infinitely long,perfectly conducting circular cylinder at the interior resonance,and the obtained results are in good agreement with the analytical results.The forward scattering cross section of an infinite isosceles triangular cylinder is also calculated.It is shown that the present method is valid and accurate.关键词：singular value decomposition;method of moments;interior resonance;scattering cross section2|1074|6更新时间：2025-07-16
- 摘要：In this paper,a statistical method is proposed to modify the routing and wavelength assignment (RWA) algorithms whose optimum object is the minimum number of wavelength required (MNWR) in wavelength division multiplexing all optical network.With this statistical method,a smaller NWR can be acquired through numerical simulation.And,it is the first time that the statistical method is proposed to compare the performance of different RWA algorithms.Two RWA algorithms can be compared by contrasting the distribution of the NWRs obtained by each RWA algorithm.关键词：WDM all optical network;routing and wavelength assignment algorithm;minimum number of wavelength required;statistical method2|965|2更新时间：2025-07-16
- 摘要：In this paper,according to the theory of microwave network and the concept of mesh wave impedance,the wave reflection of non-uniform mesh for FDTD technique is analyzed,and the concept of analysis and synthesis of mesh network is presented.The reflecting characteristic of mesh network is analyzed first.Then the procedure of synthesising a mesh network is deduced.On the basis of the above theory,network characteristics of non-uniform mesh,which can be used to match non-uniform mesh or improve the transmitted characteristic for a mesh wave to travel along the non-uniform mesh etc.,are realized in 1-D (TEM wave),3-D microstrip structures and waveguide.关键词：mesh network characteristic;non-uniform meshes;FDTD algorithm;mesh wave impedance2|1378|2更新时间：2025-07-16
- 摘要：The theoretic method used for calculating evaporation duct height is described based on similarity theory with pseudo-refractivity Np(h) as similarity variable.With the approximation of refractivity gradient independent of air pressure in the vicinity of sea surface,a parameter,the pseudo-refractivity Np(h) as we call,is defined.The M profile of evaporation duct,which is always not available in references,is given explicitly.The modeling results of evaporation duct height and the calculated results of evaporation duct parameters from the measured weather data are in agreement.关键词：evaporation duct;refractivity profile;similarity theory2|2197|53更新时间：2025-07-16
- 摘要：DNA computing is a new method of simulating molecular biology structure of DNA by means of molecular biology technological computation.This method suggests a new way of solving a NP-complete problem,and has been widely used in many respects.This article first introduces the basic idea of DNA computing,and then presents a review of the most important advances in the last few years.The relation of DNA computing and GAs is analyzed.Finally,the state of DNA computing is surveyed and future research directions are pointed out.关键词：DNA computing;molecular computing;DNA computer;genetic algorithm2|3946|11更新时间：2025-07-16
- 摘要：In this paper,we analyze the property of loss in a packet-voice multiplexer with limited buffer based on flow-fluid model.From the simulation,we find that,in the multiplexing of such bursty voice sources,the flow-fluid model can dope out the trend of loss with a bit more gap.A more accurate solution of loss could be obtained with our fitting analysis of modified formula from flow-fluid model.关键词：flow-fluid;buffer;voice;fitting2|926|0更新时间：2025-07-16
- 摘要：This paper presents the performance analysis of recursive least square algorithm with error-saturation in mixture noise.The algorithm is referred to nonlinear RLS (NRLS).Generalized clipping function is considered for the error-saturation nonlinearity.An improved mean square behavior of NRLS is carried out.It is shown that the theoretical analysis and the simulation result are close to each other.From the analysis,we can relate the convergence and the mean square error in terms of the slope and the clipping level of the nonlinear function.Based on the normalized mean square error,an instrumental variable is derived for yielding a variable clipping function to provide fast convergence and small mean square error.关键词：recursive least square;RLS;nonlinear;mean square analysis;mixture noise2|729|2更新时间：2025-07-16
- 摘要：In this paper, we propose a non-decision-aided feedforward carrier frequency offset estimator for rotationally symmetric constellation. It is derived from the maximum likelihood (ML) principle. In order to solve the problem of phase wrapping and extend the estimation range, a new phase unwrapping algorithm is proposed. For 2π/M rotation symmetric constellation, the estimation range can be extended to ±1/(2MT). Computer simulation results demonstrate the estimation range, estimation precision and complexity of the estimator.关键词：carrier recovery;offset estimation;maximum likelihood;phase unwrapping2|1133|7更新时间：2025-07-16
- 摘要：Aimed at the limitation of two current kinds of Phase Difference Correction on discrete spectrum,a new global method is presented.That is to construct a new sequence by shifting the former N/2 points of original time-domain sequence at the scale of N/4 points,set both the former and latter N/4 points to zero,and then perform FFT analysis on the original sequence and new one.The spectrum can be corrected by taking advantage of the phase difference of two corresponding peak lines.Compared with the original two kinds of Phase-Difference Correction,only one sequence of time-domain signal is sampled and FFT analysis of same points is performed twice in this method.Simulated result demonstrates that this method is easily carried out with high precision,suits for all kinds of symmetrical window function and has high ability of anti-noise.关键词：spectrum analysis;correction;signal processing;phase difference2|2|9更新时间：2025-07-16
- 摘要：For every individual images I we define a distortion-rate function d(R/I) which is shown to be an asymptotically attainable lower bound on the distortion that can be achieved for I by any finite-state encoder operating at a fixed output rate R.This is done by means of a coding theorem and its converse.No probabilistic characterization of I is assumed.关键词：image compression;image complexity;finite-state encoder;finite-state decoder;distortion-rate function2|725|0更新时间：2025-07-16
- 摘要：A general expression of instant output signal-to-noise for orthogonal space-time block code over fading channel at the receiver is shown.An estimate of the symbol error rate for orthogonal space-time block is shown and a minimum distance sphere bound of the symbol error rate is given,from which one can easily obtain the "floor effect" of the transmitting antenna number.关键词：channel codes;space-time block codes;diversity technology1|1006|4更新时间：2025-07-16
- 摘要：In this paper,the 4-state Markov model is made as the long-bursting error possibility model of mobile channels,and punctured convolutional codes (PCC) are applied to image transmission system over mobile fast-fading channels.We propose a new scheme of unequal error protection (UEP) in image transmission by means of adjusting different code rates,constraint lengths of mother codes and interleaving degrees.Simulation results show the superiority of UEP directy.关键词：mobile channels;image transmission;punctured convolutional codes;unequal error protection2|743|2更新时间：2025-07-16
- 摘要：In this paper,the electromagnetic field and energy distribution of Gaussion beam existing in 3mm quasioptical resonator are simulated by using "Matlab" software package.Its results can be used as references to design resonator and in its measurement.And the paper also reveals that whatever mode the resonator applies its tangential electrical field is always zero at z=0.2|1041|3更新时间：2025-07-16
- 摘要：In this paper,the errors of planar near field scanning technique are analyzed for ultra-low-side-lobe antennas,and the concept of the total planar near-field amplitude and phase measured error is proposed.The relationship between the total errors and the far field pattern is then presented for the ultra-low-side-lobe antennas under test in planar near field measurement,and the related computer simulations are carried out.Finally,a "self-correction" method for reducing the multiple-reflection errors and the measurement environment errors is presented,which can improve efficiently the measurement precision in planar near-field measurement.关键词：planar near-field measurement;multiple reflection error;ultra-low side-lobe antennas;correction method2|943|3更新时间：2025-07-16
- 摘要：In this paper,the quantitative analysis method of the effects of airborne radome on the sidelobe of antenna enclosed is presented,by means of vector aperture-integration and surface-integration(AI-SI).When the radome dimension in elevation is around λ and the wall curvature varies significantly,it is more accurate to use the AI-SI method than 3 dimension ray tracking method.The calculated simulation results show good agreement with the scaled experimental data and the validity of the algorithm has been proven.3|1081|7更新时间：2025-07-16
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