最新刊期
卷 ， 期 4 ， 1999
- 摘要：This paper first compares Leaky bucket,Callgap and Percent algorithms.The conclusion that Leaky bucket has strong robustness suitable for SSP’s limiting call is attained.Then the framework of overload control is described.Based on dynamic adjustment,an iterative algorithm suitable for SCP’s overload control is given.At last the algorithm is extended to satisfy different fair definitions and executed in multi service environment.The results of simulation prove this algorithm’s effectiveness and fairness.关键词：IN;overload control;Dynamic adjust;Leaky bucket;fairness;Multi service2|84|34更新时间：2025-12-08
- 摘要：In this paper,we analyze the superposition of AR1 process.We discover that when the parameters of these AR1 processes satisfy some specified conditions,the superposition process has the property of self similarity.This can be a physical explanation of the self similar nature of the packet network,and partly answers the question why the short range dependent traffic sources can cause the fractal phenomena in modern network.We present the mathematical analysis and simulation result,and a fast algorithm to generate long run time series is also derived.关键词：自相似性;长期相关;AR1模型;累加过程;分形高斯噪声2|195|23更新时间：2025-12-08
- 摘要：In this paper,an improved recursive knockout switching （RKS） fabric with the crossbar input interconnection and input buffered architecture （CIB RKS） is proposed.In this architecture,the number of switching elements （SWEs） is decreased and the contradiction of the cell transmission sequence and the cell loss performance measure are eliminated due to the crossbar interconnection structure.The number of the switch stage and the delay of cells through the switch fabric are decreased resulting from input buffers.In addition,the function of each SWE is simplified by separating the cell address filter with the cell concentration.We conclude that CIB RKS architecture is better than the traditional RKS architecture from the view point of the performance/complexity characteristics.关键词：Large scale ATM switching fabric;Recursive Knockout switch;Crossbar input interconnection;Input buffer;performance2|27|3更新时间：2025-12-08
- 摘要：This paper presented the general methodology of quantitative analysis for Disaster based SDH/ATM bidirection self healing ring network survivability performance,and derived the survivability function in closed form for SDH/ATM Bidirection Self Healing Ring （BSHR） under link and node failures and multiple failures.Various single value survivability measure such as the worst case survivability and expected survivability etc.can be easily obtained from the derived survivability function.The analysis of the result of derived survivability function show that the methodology in this paper is feasible for analyzing large scale disaster based survivability and designing cost effective high survivability communications network.关键词：Network survivability function;Failures;SDH/ATM self healing ring;Survivability measure2|113|12更新时间：2025-12-08
- 摘要：In this paper,we use parsimonious LAN and WAN traffic traces to examine the effectiveness of multifractal traffic modeling.We find that Hurst index may vary when we use different moment estimation while the multifractal property remains on a long range time scale.Traffic based simulation reveals that using fractional Brownian Motion model is not accurate enough to capture the queueing behavior of real trace exhibiting multifractal phenomena.In order to describe multifractal property,we propose a multi window wavelet transform method for the purpose of estimating the time varying scaling Hlder exponent.Numerical results are also given to show that the proposed method gives lower estimation variance than directly using coarse grain method.关键词：Self similar traffic;multifractal;Hlder exponent;Multi window wavelet analysis;Traffic modeling2|212|25更新时间：2025-12-08
- 摘要：This paper presents a new algorithm of symbol timing rapid acquisition for π/4 DQPSK with Doppler frequency offset in low rate digital mobile burst signal.This algorithm can be done in parallel with signal acquisition and frequency offset acquisition.It has advantages over serial systems.That detect signal energy,then estimate Doppler frequency offset,and finely acquire symbol timing.A very simple symbol timing tracking algorithm is also presented in the paper.Finally,the results of computer simulations are given.关键词：mobile communications;π/4 DQPSK;Symbol timing recovery2|522|54更新时间：2025-12-08
- 摘要：In this paper,we develop a new near optimum detector especially for synchronous code division multiple access system.The detection method is based on rotating orthogonal method algorithm for 0 1 programming,and the new detector is proved to be more effective than some of other optimum （or sub optimum） detectors.With the increase of user’s numbers,its complexity of calculation is O（m） in a specific statistical sense and can be controlled under different conditions.关键词：Sub optimum multi user detector;Synchronous code division multiple access;Rotating orthogonal method;0 1 programming;detection probability2|61|0更新时间：2025-12-08
- 摘要：In this paper,a biorthogonal multicode CDMA system （called BMC CDMA） is proposed so as to transmit higher rate data to fit the requirement of technical development of wide band CDMA system.Similar to multicarrier modulation,the higher rate data are transmitted at first by serial to parallel conversion,then the lower rate data streams are spreaded in spectrum by a set of biothogonal code.Being different from multicarrier modulation,all lower branch data streams use a single carrier.The performance of the system in fading channel is calulated,and numerical result is analyzed.关键词：CDMA;Biorthogonal multicode CDMA;fading channel2|66|7更新时间：2025-12-08
- 摘要：In this paper,fuzzy theory is used for routing of communication networks.Firstly,factors of the routing are considerd.Next,total numerical results are estimated by using fuzzy evaluation.Then,optimal routing between two sites is obtained by means of the strongest pass of fuzzy diagrams.Finally,the presented approach is compared with simulation,which shows that the approach is able to raise the call completing rate and the communication system performance is not decreased.关键词：Fuzzy set;routing;Call completing rate2|67|4更新时间：2025-12-08
- 摘要：The secure communication service between mobile station and base station has been provided by digital mobile communication networks available.The end to end secure communication between two mobile stations is an new topic. This paper firstly analyzed the security of the end to end authentication schemes available.Then we presented a new intra domain private key end to end authentication scheme and a new inter domain private key/public key hybrid end to end authentication scheme.The analytical results show that the new scheme has higher security,is easy for the mobile to implement the cryptographic algorithms and for the network to manage the keys of all parties.关键词：Mobile communications network;authentication;key distribution2|55|8更新时间：2025-12-08
- 摘要：This paper proposed a simple and practical method for evaluating the growth of telecommunication network reliability,which directly shows the change of reliability.And taking a telephone network as an example,it sets up an evaluation model,and gives out the analysis results.关键词：Telecommunication Network;reliability;Evaluation method2|156|38更新时间：2025-12-08
- 摘要：This paper presents a new reduced state,decision feedback Viterbi equalizer （RSSDF PSP） with two channel estimators and it works in blind.RSSDF PSP uses maximum likelihood sequence estimation （MLSE） to handle the precursors and the main cursor and the decision feedback filter to handle the post cursors.The channel estimator 1 obtains the precursors and the main cursor by the Per Surviving Processing techniques;the channel estimator 2 obtains the post cursors.Simulation results show that the RSSDF PSP has nearly the same performance as the MLSE.It provides the best tradeoff between complexity and performance of MLSE.关键词：Maximum likelihood sequence estimation;Decision feedback;Channel estimator2|168|18更新时间：2025-12-08
- 摘要：A composite method for constructing perfect binary array pairs of high dimension and high order with known perfect binary array pairs is proposed and verified.The type of perfect binary array pairs constructed with constant weight perfect binary array pairs is discussed.The method can be used to construct infinite perfect binary array pairs.关键词：information theory;Perfect binary arrays;array pairs;signal theory2|110|64更新时间：2025-12-08
- 摘要：In this paper,a novel multiple symbol differential detection （MSDD） scheme is proposed.The complexity increases linearly with the number of observation symbols （N） while for the optimum MSDD proposed by Divasalar the complexity increases exponentially with N.The results of the analysis and computer simulations show that the performance of new scheme appoachs to that of optimum MSDD.关键词：Multi symbol differential detection;low complexity;Conventional differential detection2|120|3更新时间：2025-12-08
- 摘要：本文研究了汉语语音识别中的拼音多候选问题，提出了引入语言知识后的一种拼音多候选选择方法，并给出了采用Ｎ元拼音文法模型时的候选选择算法．实验表明，该方法取得了很好的效果．关键词：语音识别;拼音多候选2|126|10更新时间：2025-12-08
- 摘要：This paper describes an adaptive image enhancement algorithm based on human visual properties,which is an improved version of Lee’s image enhancement algorithm based on the LIP model.The algorithm can improve the overall contrast of an image and expand the dynamic range.According to the HVS,it can sharpen the image edges and avoid much enhancement of noise.The algorithm is easy to implement,and suitable for real time applications.Experimental results of the proposed algorithm and other algorithms are compared and analyzed to illustrate the effectiveness of the proposed method.关键词：image enhancement;dynamic range;adaptive filtering2|817|68更新时间：2025-12-08
- 摘要：In this paper,two important modifications in DCT based coding algorithm are suggested after making deep study on the generally used scheme of H.263 coder.First,we find plenty of invalid computation in the transformation part of the H.263 coder and an improved scheme based on the pre transform decision to avoid invalid computation is proposed.Second,in the motion estimation part of the coder,we find that normal search algorithms are not effective,which neglects different levels of motion in image sequences,and we suggest a new search algorithm which has variable search region based on the difference of motion level.Combining the pre transform decision scheme with variable search region method in motion estimation,a global decision coding scheme is provided,which greatly increases the coding speed of H.263 coder.关键词：Pre transform decision coding scheme;Variable search region method;Global decision coding scheme;image coding2|42|10更新时间：2025-12-08
- 摘要：Computerized Tomography needs projected images from all directions,while tomosynthesis doesn′t need the information from all directions,but its reconstruction image is indistinct.Frequency Domain Deconvolution Imaging（FDDI） overcomes this shortcoming,but FDDI′s calculation is large,and its zero frequency will be lost.In this paper,we solve convolution equation based on Vandermonde Matrix and the method of image displacement elimination in space domain that we propose,so that we can reconstruct sectional image quickly.We use computer simulation and obtain clear sectional image.关键词：Tomosynthesis;reconstruction;Vandermonde matrix2|68|3更新时间：2025-12-08
- 摘要：The Volterra operations are an effective way for the explorations of higher order statistical redundancies of signals.We present a design method for adaptive quadratic Volterra filters with application to edge detection of images.The filter is expressed as a linear combination of generalized Teager basis filters.The expression coefficients are determined by minimizing the least mean square （LMS）.This filter,like a local mean weighted highpass filter,can balance the reducing noise and enhancing feature.关键词：Non linear adaptive trasforms;Volterra filters;Edge detection2|134|11更新时间：2025-12-08
- 摘要：Picture quality evaluation methods could be utilized to assess image algorithms′ performance.The traditional objective methods cannot necessarily represent the perception of error,and subjective methods such as Mean Opinion Score（MOS）,extremely depends on observer′s experiences and motivations.Perceptual Mean Square Error（PMSE） is defined on the basis of Human Visual System（HVS） and then a model is developed to explain this definition.Three components such as Amplitude Nonlinearity,Modulation Transfer Function（MTF）,Orientation and Scale Selectivity contribute to the output perceptual error.In them,B Spline shiftable and Multiscale Wavelet Transform is used to match eye′s Orientation and Scalability.An error segmentation process decomposes perceptual error to four sorts of errors which are then calculated by Mean Square Measurement.PMSE is thus the weighted sum of several principal components after the Principal Component Analysis.The model is tested on images finally,and the results show that PMSE correlates well with MOS.关键词：Picture quality evaluation;visual perception;image compression;B Spline;wavelet2|960|70更新时间：2025-12-08
- 摘要：A cost optimal parallel algorithm for multiplication of a band cyclic matrix and arbitrary matrix,under wrapped connection array architectures,is proposed.Then according to the matrical representation of compactly supported and orthogonal wavelet transform of digital image,we design a cost optimal parallel algorithm,which is adaptive to the wrapped connection array architecture,for wavelet decomposition and reconstruction of an image.Finally,a simulating experimental result of 32×32 wrapped connection array is given.关键词：parallel algorithm;Wrapped connection array;Image wavelet transform;Band cyclic matrix2|55|0更新时间：2025-12-08
- 摘要：This paper discussed the frame conversion for television image signal along time axis （such as compression and restoration,frame sorting and so on）,and the control method frame coding technology on the hardware environment.关键词：Image signal;Frame coding;Transform;Time domain;Space domain;memory2|25|1更新时间：2025-12-08
- 摘要：In the authentication codes with arbiter introduced by Simmons.five cheating attacks were mainly explored.The informationtheoretic lower bounds for the probability of successful deception for the five cheating attacks were obtained by Johnsson.In this paper,the information theoretic lower bounds for the probability of successful deception for spoofing attacks of order i by opponent and receiver are obtained.So the lower bounds for the probability of successful deception are perfected.关键词：authentication code;Authentication function;Spoofing attack of order i;Authentication code with arbiter2|52|10更新时间：2025-12-08
- 摘要：Broadband Integrated Services Digital Networks （B ISDNs） adopt Asynchronous Transfer Mode （ATM） as target transmission technology,with virtual path （VP） and virtual channel （VC） concepts introduced.In this paper,we propose a new VP routing algorithm based on Hopfield neural networks in B ISDN,set up the energy function and neuron state equation.Simulation shows that in accordance with the network topology and traffic pattern the proposed algorithm is both fast and effective to achieve VP routing and improve the network survivbility level.关键词：Hopfield neural networks;routing;B ISDN2|54|3更新时间：2025-12-08
- 摘要：This paper studies the global minimum conditions of the outer supervised feedforward neural networks （FNN） in the batch style and sequence style trainings.For the sequence style training,it is showed that there always exist N local minimum points in the error surface.For the batch style training,it is showed the sufficient and necessary condition that FNNs can obtain global minimum solutions with null cost is that the range space R（Y） of the outer supervised signal matrix Y must be included in the range space R（X） of the hidden output matrix X ,i.e., R（Y）R（X） .In addition,it is also showed that the sufficient condition that the FNN can obtain global minimum solutions with null cost is M≥N .It should be specificially stressed that under the conditions of R（Y）R（X） and M≥N ,there will exist not any local minimum points in the error surface.Further,it follows that if C≤M<N it is possible for the FNNs to obtain global minimum solutions with null cost,if M<C≤M it is impossible for the FNNs to obtain global minimum solutions with null cost.关键词：Feedforward neural networks;Batch style training;Sequence style training;Hessian;Global minimium solution;Local minimium solution;Embedded subspace2|44|1更新时间：2025-12-08
- 摘要：On the basis of steady analysis of switched capacitor DC DC converters,the steps to design a switched capacitor DC DC converter with desired performance are presented.Some technical problems for designing are discussed.An example with its experimental results shows that the designing method is feasible.关键词：Switched capacitor network;DC DC converters;efficiency;design2|390|14更新时间：2025-12-08
- 摘要：New services about ITU T intelligent network standards CS 2 and CS 3 are briefly introduced in this paper.Through the analysis of the integration of IN and mobile network,as well as the integration of IN and B ISDN,the study status and some key techniques of IN research in the recent several years have been surveyed.At last,some constructive optinions of IN development in our country are suggested.关键词：intelligent network;Mobile network;Broadband network2|103|13更新时间：2025-12-08
- 摘要：The generalized Hamming weight and the dimension/length profile are two new and important concepts in the coding field.In this paper,we introduce the two concepts and their properties,summarize all their applications,and give some results.关键词：generalized hamming weight;Dimension/Length profile;Trellis complexity2|56|5更新时间：2025-12-08
- 摘要：This paper analyses antijamming performance with grey system theory.We first study antijamming parameter model of communication system,then present an analysis algorithm with efficiency and wide applications.Finally an example which analyses antijamming performance is given.关键词：communication system;Antijamming;Grey system;Grey cluster2|105|4更新时间：2025-12-08
- 摘要：In this paper the adaptive beam former for Multiple Access interference （MAI） suppression in CDMA system is presented.To detect signal from a certain direction and suppress MAI in different directions and to improve performance for Multiple Access Interference（MAI）suppression are analyzed and proved in theory and in practice.关键词：Code Divide multiple Access;Adaptive Beam former;Multiple Access Interference Suppression;Direction Constrain2|73|4更新时间：2025-12-08
- 摘要：The design scheme of fiber optic industrial control network based on two types of switching （circuit switching and packet switching） is put forward.Its topology structure,system structure,MAC protocol,frame structure and Hybrid Ring Control （HRC） are presented.关键词：Optic fiber;industrial control;Ring network;Hybrid ring control2|44|7更新时间：2025-12-08
- 摘要：Based on the theory of orthogonal multicarrier technique and the time/frequency duality with DS/SSMA system,a new scheme of spread spectrum system,named Frequency Diversity Spread Spectrum Multiple Access System（FD/SSMA）is proposed.The principle of FD/SSMA system is given.The ability against jamming and multiple performance in FD/SSMA system over the additive Gaussion white noise channel（AGWN）is analyzed,and the average probability of error bit is given by means of Gaussion approximation and Monte Carlo simulating methods.关键词：FD/SSMA;CDMA;OFDM;spread spectrum2|107|3更新时间：2025-12-08
- 摘要：CDMA system has been widely studied and used as the third generation wireless access technology for mobile and personal portable communication,and the spread spectrum sequences in CDMA system has been the key question of CDMA technology.A new approach to the design of codes for S CDMA system was given by G.H.Khachatrian and S.S.Markirossian,but the method for constructing the spread spectrm sequences with error correcting capacity has not been discovered up to now.In this paper,a new family of spread spectrum sequences with error correcting capacity for S CDMA and its decoding algorithm are given.关键词：Spread spectrum sequences;Error corrcting codes;S CDMA2|77|0更新时间：2025-12-08
- 摘要：The shortcomings of packet reservation multiple access （PRMA） protocol are discussed,and a collision resolution packet reservation multiple access （CR PRMA） protocol is presented.Both the theoretic analysis and computer simulation show that the performance of CR PRMA protocol is better than that of PRMA.关键词：mobile communication;PCN;multiple access protocol;PRMA protocol2|37|10更新时间：2025-12-08
- 摘要：The concern here is to use cyclostationary approach to estimate the parameters of a complex linear FM signal with time varying amplitude from noisy observation.The asymptotic performance is analyzed and the variance of the estimates is shown to be the same order of magnitude as their Cramer Rao bounds.The statistical analysis is verified by simulations.关键词：Cyclostationary approach;Time varying amplitude;Complex chirp signal;parameter estimation;Asymptotic statistical performance2|132|18更新时间：2025-12-08
- 摘要：Based on the secure key distribution protocol in ,a key escrow system for digital mobile communication is proposed,which can achieve mutual authentication between network center and users,ensure privacy communication,and has ability to help law enforcement with tapping over the air.关键词：Mobile communication network;key escrow;key distribution;authentication2|80|17更新时间：2025-12-08
- 摘要：The characteristic of the ALE technique in MIL STD 188 141A is analyzed first to overcome the shortcomings of 141A’s 8FSK ALE Modem.Then a new type of ALE modem using a low rate DPSK modulation is designed to replace the 141A system.For comparison,the parameters of the chirp modem are set according to the 141A8FSK modem.From a large amount of data from the testing of these two modems,the good performance of the chirp modem to transmit data and its function of LQA are verified.The conclusions prove that chirp modem is a good ALE modem.关键词：Short wave;Automatic link establishment;Modem;Link quality analysis2|78|1更新时间：2025-12-08
- 摘要：The principle and implementation of a general parallel Cyclic Redundancy Code,or CRC computing are described in the paper.It is suitable for any generator polynomial and any parallel degree of generator polynomial between 1 and 32.Compare with Table Lookup Algorithm,it need not the high speed RAM which was used to store the remainder table,and decrease the delay.Thus,we can increase properly parallel degree to decrease the clock frequency of CRC computing in high speed digital systems.关键词：CRC parallel computing;CRC remainder;High speed digital system2|861|103更新时间：2025-12-08
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