最新刊期
卷 ， 期 10 ， 1998
- 摘要：A key escrow cryptosystem can not only provide protection for user’s privacy, while at the same time,allows for the wiretapping when lawfully authorized. In this paper, a new secret sharing threshold scheme is proposed, then a split secret key escrow system baed on the secretsharing threshold scheme is given and its security is analysed.关键词：key escrow;Secret sharing;Wiretapping;threshold scheme2|252|11更新时间：2025-12-08
- 摘要：In this paper, two equlizer structures based on orthogonal wavelets bases are presented, named wavelet based linear equalizer（WBLE） and decision feedback equalizer（WBDFE）. The equalizer is represented by a set of orthogonal wavelets and the corresponding corresponding. The peper also gives the adaption algorithm. Theoretical analysis shows that the WBLE and WBDFE converge faster than the conventional FIR LMS based linear equalizer and decision feedback equalizer, while the increase in the computational complexity is very slow.关键词：Equalization;wavelet analysis;adaptive filtering;decision feedback equalizer2|108|2更新时间：2025-12-08
- 摘要：This paper presents a multiple access control protocol （PPBMA） for wireless cellular network,which is based on packet priority, and ISDN services can be easily implemented. The theory performance and computer simulating results arc given.关键词：MAC;wireless cellular networks;Wireless ISDN;wireless ATM2|41|1更新时间：2025-12-08
- 摘要：For near-far effect in multipath fading channels of CDMA systems, we proposed multiuser blind equalization detection algorithm and compared it with multistage detection. Numerical simulations show that the nearfar resistance of our proposed algorithm is better than that of 2-stage detection when there are no estimate errors of channel parameters.关键词：CDMA;Multiuser blind equalization;multipath fading;Near-far effect2|80|1更新时间：2025-12-08
- 摘要：Wavelength control is important in optical WDM communication systems. The control precision is discussed when FP resonator is used as a wavelength control device. Both noise and crosstalk are considered in the calculation of precision.The control precision result of an example, 16×2.488Gb/s system with channel spacing （200GHz）, is calculated.关键词：WDM;Wavelength control;F-P filter2|60|0更新时间：2025-12-08
- 摘要：A new Frame-based Packet Reservation Multiple Access（F-PRMA） protocol under time-division duplex is proposed for microcellular mobile networks. A three-state Markovian model of the F-PRMA system is developed based on Markov process theory. The performance of the protocol is analyzed by means of Equilibrium Point Analysis（EPA）, which was presented by Tasaka, and the important measures such as packet dropping probability, system throughput are derived. The effects of the system parameters and protocol variables on the efficiency of the multiple access protocol are examined through numerical analysis and system simulation.关键词：Time-division duplex;performance analysis;system simulation;Equilibrium point2|30|0更新时间：2025-12-08
- 摘要：Burst-level loss system input by bursty bursty with the same peak rate is an important queueing model in the study of resources allocation and call admission control in ATM networks. In this paper,a fast recurrent algorithm is proposed to estimate time congestion probability and cell loss rate of this system. Computation shows that this algorithm can present real-time estimation of both parameters above with high accuracy for applications.关键词：Burst sources;Burst-level loss system;Peak rate;Asynchoronous transfer mode（ATM）2|25|0更新时间：2025-12-08
- 摘要：In this paper the definition of chaos is described at first, and then experimental rules are presented to declare whether a time series is chaotic. These rules are that time series should have an attractor with a finite dimensions, have a positive Lyapunove exponent at least, and be locally predicted. Neural network’s abiltity to restruct phase space of chaotic time series and in the condition of populared by noise is also discussed. Based on the neural network’s powerful ability of studying and nonlinear processing and local predictibility of chaos,a method to detect transient signal in the background of chaos is presented applying neural nerwork. The experimental results show this method can detect out a very weak target signal in the background of chaos.关键词：chaos;neural network;signal detection2|498|15更新时间：2025-12-08
- 摘要：Chaotic oscillator can detect very weak signals,and has many merits compared with other detection methods. In this paper, the equation of the maximum SNIR is determined with the analysis of the statistical characteristics of the output noise from the Duffing system, based on the theory of linear system and stochastic differential equations. The equation provides a guidance to practical application. Additionally, we put forward a new approach to solve the output statistical characteristics of the linear differential equation with cyclic parameters under the perturbation of noise.关键词：duffing equation;chaotic oscillator;signal detection;stochastic differential equation2|732|27更新时间：2025-12-08
- 摘要：A cumulant-based method is presented to estimate the DOA of non-Gaussian wideband sources.It is efficient even in the non-Gaussian noises environment without a priori knowledge of powerspectral density of the noises.关键词：DOA;array signal processing;Cumulants;Non-Gauss signal2|188|3更新时间：2025-12-08
- 摘要：Although Hidden Markov Model （HMM） is the most popular model for speech recognition, there has ho an intrinsic defect that, commonly assuming the output observations of a state are independent and identically-distributed（IID）,it is unable to describe the time-correlation properties of the speech phenomena. The new model proposed in this paper introduces the inter-frame correlation information into Duration-Distribution-Based HMM （DDBHMM ） by modeling separately the static and dynamic charactedstics of output observation vector sequences of speech states using parametric models and combining them into an nitegrated model. This new HMM including the inter-frame correlation information can characterize the real speech phenomena more presisely. After introducing the structure of the new model, we give the estimation formulas for the parameters of the new model and the algorithms for training and recognition.The experiment for speaker-independent recognition of all Chinese syllables shows that including the inter-frame correlation information improves the perfomance of HMM distinctively.关键词：speech recognition;Hidden Markov model（HMM）;Inter-frame correlation2|160|3更新时间：2025-12-08
- 摘要：Chinese Phonetic-Character Conversion（CPCC） is an important issue in speech recognition and Chinese sentence keyboard input system.The appoaches based on large amount of corpus statisties Markov models become more and more popular today,The CPCC based on Chinese character N-gram （C-CPCC） has the advantage Of having a smaller statistics data library and simple algorithm. but has the drawback of lower accuracy of conversion,while that based on Chinese word N-gram（W-CPCC） is on the contrary.This paper presents a word-self-made CPCC algorithm based on the Chinese Character Bigram. which not only has foe C-CPCC’s advantage of having a smaller statistics data library, but also can take advantage of the W-CPCC. The experiment shows it can be easily realized with a higher accuracy of conversion.关键词：CPCC;Bigram;Word-self-made2|148|2更新时间：2025-12-08
- 摘要：In this paper the genaralized sequential machine with generalized input signals is the starting point for studying Dynamic sequential Circuits （DSC）. The dynamic unit circuits characteristic equation is derived by leading capacitor into network. According to the analogy of storaging information to capacitors and flip-flops,a unified theory of sequential circuits is set up to intergrating theory of convention sequential circuits and DSC. This paper shows the conditions for realizing or and deals with the equivalent transform between the different switch structures of DSC, pseudo-DSC and static sequential circuits in the light of practical example.关键词：动态时序电路;广义时序机;电路三要素2|35|1更新时间：2025-12-08
- 摘要：A motion estimation method of triangular venice based on epipolar geometry constraint is proposed first, and then the motion compensation method using affine transformation is analyzed. Compared with the past method, it may decrease some computational cost and improve the compensation efficiency.关键词：epipolar geometry;F matrix;affine transformation;motion compensation2|151|2更新时间：2025-12-08
- 摘要：Pyramidal wavelet decomposition provides a hierarchical data structure for image representation-wavelet subtree, which is composed of the coefficients at different resolution and different orientation but with same spatial location. In this paper, the conventional fractal coding in spatial domain is extended to wavelet domain by employing the self-similarities between different wavelet subtrees through proper affine transformation. Further, in order to achieve a good trade-off between image quality and compression ratio.an adaptive partition algorithm is given which can split the wavelet subtree into children subtrees according to local image complexity. Experimental results show that the new hybrid image compression algorithm can obtain much better coding performance in terms of PSNR and subjective quality as compared to JPEG at roughly the same compression ratio.关键词：fractal coding;wavelet transform;image compression;hybrid coding2|149|7更新时间：2025-12-08
- 摘要：In this peper. the relationship of the texture structure and Gabor filter is studied at first.then it is given out that using Shannon wavelet packets with compact support in frequency domain to detect the texture main frequency.Next. the method of designing wavelet packets decomposition adaptive Gabor function to segment texture algorithm is given out. This algorithm firstly Applies the texture main frequency detected by Shannon wavelet decomposition to design Gabor filter and then uses Gabor filter to convolute with the original texture image. The algorithm can produce very good step edge at the joining place of two textures joining. The experiment results show that the algorithm is very efficient and robust to noise.关键词：Gaber function;texture segmentation;Shannon wavelet packets2|241|2更新时间：2025-12-08
- 摘要：This paper defines the Feature Symbol Random Field（FSRF）, while presents a novel FSRF-Gibbs model for texture segmentation.The main function of FSRF is acting as 2D representation of texture feature vectors which come from the multichannel analysis. What should be emphasized is that all the employed features are spatial-changed, i. e. need not to be stable for certain texture region. By employment of FSRF, this poper also isgnificantly eases the problem in model estimation of Markov Random Field（MRF）. As a result, finer and more reasonable segmentation is expected by involving both multichannel analysis techniques and fine MRF model. Finally, a new algorithm is included, which is easy to perform and leads to satisfactory experiment results on Bredatz Textures.关键词：Feature symbol random field;Gibbs model;texture segmentation;Multichannel analysis;vector quantization2|114|10更新时间：2025-12-08
- 摘要：This paper considers the following two cases of missing cone problem: the limited angle tomography and time-varying object tomography.Based on the spatial and Fourier domain properties of Radon transform, a sinogram extrapolation technique is proposed.The missing data in sinogram is extrapolated using a novel least mean square error criterion and a complete sinogram can be restored. This complete sinogram is then used for image reconstruction by standard methods. The derivation of the sinogram extrapolation formulations is given. An iterative algorithm for solving these formulations is also given. Computer simulation results are presented to demonstrate the efficiency of the proposed technique.关键词：Tomography;Missing cone problem;Time-varying object;Sinogram;iteration2|101|1更新时间：2025-12-08
- 摘要：The human face is a complex pattern. It is very important for recongition to find human faces automatically in a scene. In this paper a new method to locate and segment human faces in a complex background is proposed.This system utilizes a hierarchical knowledge-based method and consists of three leVels. The higher two levels are had on detecting maximum（corropnding ic faces） and minimum （corresponding to eyes） in mutiresolution image using B-pline dyadic wavelet transform,and then we make initial selection using the relation of scale,involvement and symmetry. The last level will determine the position according to the feature of face. This method can locate and segment unknown human faces spanning a wide range of sizes in an intensity image. Some experimental results are also given.关键词：人脸检测;基于知识的模式识别;多尺度脊边缘;小波变换;目标检测2|280|2更新时间：2025-12-08
- 摘要：In this paper,we present a discriminating criterion of continuous stack filters, then obtain a sufficient and necessary condition for the equivelence of two weighted threshold filters.关键词：Continuous stack filters;Positive Boolen function;Weighted threshold filters2|37|1更新时间：2025-12-08
- 摘要：In this paper a three-layered feedforward self-organizing neural network model is proposed based on interval-valued fuzzy logic neurons in order to realize the interval-t,alued fuzzy C-means （IVFCM） clustering analysis. The inputs/outputs of the first and second layer neurons and weights between them belong to foe interval-valued fuzzy sets I [0, 1]. The neurons in the first layer are intervalvalued linear neurons; The neurons in the second layer are interval-valued fuzzy equality neurons （IVFEN） which realize the matching computation between the input samples and all of the clusters. Interval-valued fuzzy equality relation is used to compute matching. In order to define the model of IVFEN, the computation method of interval-valued fuzzy equality relation is deduced based on point-valued fuzzy equality relation. The neurons in the third layer are fuzzy competition neurons. The outputs of the third-layer neurons represent the fuzzy classification result of the input sample. Furthermore, intervalvalued fuzzy competition learning （IVFCL） is proposed to train the IVFCM neural network （IVFCMNN）关键词：Interval-valued fuzzy C-means clustering;Self-organizing neural network;Intervalvalued fuzzy equality relation;Interval-valued fuzzy competition learning2|169|3更新时间：2025-12-08
- 摘要：Based on the proposal of spectrum approach to quadratic phase coupling analysis,the comparison is made between this new method and the bispectrum method. The spectrum method has much ies calculation burden and is apt to achieve higher resolution ability as well as can be easily performed.Then the analysis of quadratic phase coupling is extended to complex domain, different and interesting results are obtained. At last spectrum method is developed to deal with another kind of nonlinear phase coupling, cubic phase coupling, fine results are obtained. Simulation examples are presented to prove the results of this paper.关键词：非线性相位耦合;双谱;■维谱2|213|21更新时间：2025-12-08
- 摘要：The condition of FORDL as an potimum notch filter was derived. A method of utilizing the loop loss to realize this condition was advanced and thus the notch-depth of FDRDL was increased to over 65dB. The phase induced intensity noise（PIIN） of FORDL was also analysted and three ways of restrain PIIN were put forward.关键词：光纤环形延迟线;IIR滤波器;陷波滤波器;相位噪声2|42|1更新时间：2025-12-08
- 摘要：Wavelet neural network is the application of wavelet in neural network fields. This paper discusses the truncation of wavelet family fm the point of view of regression, then nas the orthogonal least square（OLS） to select the proper wavelet.关键词：wavelet;neural network;OLS2|386|11更新时间：2025-12-08
- 摘要：This paper gave a review of achievements of genetic algorithms in theory and application. Ways to improve the performance of GAs are concluded and the further efforts are presented.关键词：genetic algorithms;Global search;convergence;Mutation;Crossover2|455|8更新时间：2025-12-08
- 摘要：The basic conceptions, key technologies,key components and advantages of WDM all optical networks are introduced in this paper. And we review briefly some WDM all optical network demonstrators and the tendency around the world.关键词：WDM;All optical networks2|146|7更新时间：2025-12-08
- 摘要：This paper presents a high quality variable-rate speech coding at 2.4kbps, 1.2kbps and 800bps based on the algorithm of Multi-Band Excitation （MBE）. The techniques of smoothing pitch period using dynamic programming algorithm, LPC all-pole model to approximate the MBE spectral shape, formant enhancement, split vector quantizer （SPVQ）, multi-stage vector quantizer （MSVQ）, etc. Are adopted to improve this vocoder. It can be implemented in realtime using a single ADSP2181 fixed point DSP.The speech quality of the realtime systems reach the currrent international level. The synthesis speech is clear and intelligent,as well as intelligent being in the presence of background noise at 80dB.关键词：dynamic programming;Multi-band excitation;Split vector quantizer;Multi-stage vector quantizer2|172|16更新时间：2025-12-08
- 摘要：This paper bases on the definition of the correlation-immune m-valued logical function, where m is a positive integer（m>2 ）, gives several typical methods of constructing correlation-immune m-valued logical functions with the Chrestenson spetral and probabilistic methods, these are the corresponding methods to constructing correlation-immune Booleen metions.关键词：m-Valued logical function;Random Variable;Independence;Chrestenson spectrum;Correlation-immune2|30|1更新时间：2025-12-08
- 摘要：This paper reported our discovery on the cross-phase-modulation（XPM） imposed degradation of the signal-to-noiso ration（SNR） in on-off keying （OOK） coherence multiplexed systems, Analytical expression was obtained for one channel case and numerical results were given for multiple simultaneous channels case. According to our research. channel power and encoder delays should be as small as possible to minimize the phase-perturbation degradation.关键词：Coherence multiplexing;Pholonic code-division multiple-access;Cross phase modulation2|67|2更新时间：2025-12-08
- 摘要：In order to overcome slow convergence rate of the standard BP algorithm, this paper presents an adaptive backpropagation algorithm which can update learning rate and birr factor automatically based on dynamical training error rate of change. Simulation results of the XOR problem, nonlinear system and parameter wing system show much faster convergence rate can be obtained by this algorithm.关键词：neural networks;Adaptive backpropagation algorithm;XOR problem;nonlinear system;Parameter varying system2|111|7更新时间：2025-12-08
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