最新刊期
卷 31 ， 期 4 ， 2003
- 摘要：IP QoS is a research focus.Recently IETF propose the Differentiated Services(DS) architecture to implement QoS in Internet.However,there exists unfairness in DS network.This paper proposes to use a Direct Congestion Control Scheme(DCCS) and Dynamic Traffic Conditioning(DTC) to achieve the fairness.It maintains the fairness between responsive and unresponsive aggregates as well as better allocations for responsive flows(TCP) with different packet length,micro-flow number,Round Trip Time,etc.关键词：quality of service(QoS);differentiated service;congestion control;fairness2|1093|2更新时间：2025-07-16
- 摘要：The system capacity and performance of MC-CDMA communication systems can be significantly enhanced by jointly employing MAP-based multiuser detection(MUD) and channel decoding techniques.In this paper,a Turbo space-time MUD based on the combinations of smart antennas and iterative MAP-based MUD is presented.The proposed method is featured as a novel technique for further improving the system capacity and performance.It is shown that the proposed Turbo space-time MUD algorithm can significantly reduce the computational complexity compared with the conventional optimal MAP-based MUD schemes.Furthermore,it is demonstrated that the performance of the proposed algorithm can approach that of a single user coded MC-CDMA system with an antenna array in both AWGN and frequency selective fading channels.关键词：multi-carrier CDMA;multiuser detection;channel decoding;smart antennas;Turbo processing2|960|0更新时间：2025-07-16
- 摘要：Given an undirected graph,the vertex coloring problem is to assign a different color for vertex mutually adjacent.This problem is an NP-complete one and has no effective solving method.But Adleman[1]introduced firstly the DNA computing in 1994,with which the NP-complete problems are likely to be solved.DNA-based algorithm simulates molecular biology structure of DNA by means of molecular biology technological computation.This paper first introduces the DNA algorithm for the vertex coloring problem based on bio-molecular technology.The key of the algorithm is coding for the vertex and the color of the vertex The problem is solved by tube operation that performs the basic core processing and extraction that makes the results visible.On the basis of the experimental bio-molecular method,the algorithm is an effective method.Finally,the advantage and disadvantage are discussed,and the future research directions are pointed out.关键词：DNA computation;NP-complete problem;vertex coloring problem;endonucleases2|1854|12更新时间：2025-07-16
- 摘要：This paper proposes a Turbo equalization algorithm,which consists of Kalman Filter channel tracing and soft-output decision-feedback equalization (DFE) and soft-input soft-output channel decoding,to realize iterative channel estimation,channel equalization and channel decoding for frequency-selective fast-fading channels.The simulations show the proposed algorithm can efficiently trace the fast-fading channel and reduce greatly the inter-symbol interference (ISI) after two iterations.关键词：ISI;DFE;Kalman filter;channel estimation;channel decoding2|1484|1更新时间：2025-07-16
- 摘要：A biological neural network composed of a great amount of neurons interconnected by synapses has the ability to process information and generate a specific pattern of electrical activity.It is significant to the biology to cognize the mechanism for generating and transmitting its information.As there exists complicated nonlinear feedback inside it,it is very difficult to do experiment on it from its microstructure.Through analyzing its biophysical and biochemical structure and integrating information science into biology,its interior structure and exterior properties can be understood by use of the computer simulation.Therefore,this computer simulation system was designed and realized.It deals with the equivalent circuit,mathematical modeling,data representation,signal processing,and parallel computation,etc.It has got practical applications in lots of institutes and universities.In this paper only the mathematical modeling and signal processing were described.关键词：computer simulation;biological neural network;mathematical modeling;signal processing2|1499|2更新时间：2025-07-16
- 摘要：In the mobile communications system,the ratio of signal-to-interference used as a criterion of evaluating the signal quality,is adopted in power control.Also,in heavily populated areas,cell splits are unavoidable to increase the capacity of the cellular system.The reverse link capacity of an SIR-based power controlled cellular system with mixed cell is derived.The analytical results show that the system can increase the link capacity greatly.关键词：link capacity;power control;signal-to-interference2|1150|0更新时间：2025-07-16
- 摘要：In recent years,covert communication techniques have become important gradually in communication fields.In this paper,a novel real-time covert communication scheme has been proposed.This method makes use of good properties of chaotic sequences,such as ease of generation,sensitive dependence on their initial condition and noise-like statistic characteristics.Two key problems,synchronization and receiving burst messages,have been solved effectively.Experimental results indicate that these techniques are very effective.关键词：information hiding;covert communication;synchronization;burst messages;chaotic sequences5|1394|0更新时间：2025-07-16
- 摘要：In this paper,two resource allocation schemes are proposed to minimize the transmission time in multimedia CDMA systems.When the time is expressed as a function of various data rates,the optimum set of data rates for concurrent user groups to achieve minimum transmission time can be derived. The approach of calculating the optimum set of data rates and the minimum transmission time is presented and proved.For various traffic conditions,we proposed dynamic resource allocation schemes according to various QoS requirements and the number of users.Finally,the two new schemes are compared with the maximum throughput resource allocation scheme,and the differences of these schemes in throughput and transmission time are presented.关键词：CDMA;dynamic resource allocation;mobile communications;multimedia2|866|0更新时间：2025-07-16
- 摘要：This paper firstly investigates the integrated services model of wireless mobile networks.It argues that real-time service commitments shall be sorted according to its mobility dependence and if the allocated resource is exclusive.As a result,it defines five constituent service commitments of the integrated services model.This paper also discusses the resource reservation schemes related to mobility independent services and mobility dependent services.These schemes are proposed to establish end-to-end reservation along all active and passive paths using mobile agent while providing mobility independent services,and to establish end-to-end reservation along active path and passive reservation only in related wireless links while providing mobility dependent services.关键词：wireless mobile network;Quality of Service;integrated services model;resource reservation2|780|0更新时间：2025-07-16
- 摘要：Considering the problem of small samples in engineering,we analyze the effect ofa priori information credibility and samples in Bayesian statistical decision.The relation of samples,a priori information and Bayesian statistical decision adventure is studied by introducing a priori cost and testing into the Bayesian loss function.Under the condition of given the decision adventure limitation and total cost,two relation formula about samples,a priori information credibility,total cost and Bayesian statistical decision adventure have been deduced on theory.Therefore,under the condition of small samples,a kind of theorical method to find the bottomline of a priori information credibility is presented.关键词：small samples;bayesian statistical decision adventure;a priori information;a priori cost;testing cost;credibility2|961|8更新时间：2025-07-16
- 摘要：This paper proposes a concept of all phase data space,and based on the DFT/IDFT filtering brings about a new type of zero-phase filter,the all phase DFT (APDFT) digital filter.The paper gives the transform and inverse transform between its impulse response and corresponding DFT response vector,demonstrates some important properties of this filter.The APDFT method is a new scheme for FIR filter design,possessing concurrently the merits of the windowing and the frequency sampling method.It has the advantage of the conventional methods in overall filter characteristics that have been verified by theoretical analysis and simulation experiments.The APDFT digital filter can be implemented with common convolution structure,and a direct frequency domain network as well.This paper gives the architecture of the network and an associate simplified algorithm.This network has real-time self-design function.It can constitute a time-variant system applied to the occasion that requires filter's transfer function variable in real-time,can be easily integrated into a universal zero-phase digital filter with all of its length and frequency response programmable,and can be used to realize sub-band filtering with strictly complementary.关键词：DFT/IDFT filtering;all phase data space;zero-phase filters;all phase DFT digital filter4|2281|39更新时间：2025-07-16
- 摘要：A human face detection & recognition system on color image sires is implemented in this paper.The key technologies involved are skin hue analysis,motion analysis,primary component analysis (PCA) and support vector machine.The human faces can be detected through their hue,motion,geometry and grayscale distribution features.PCA analysis can be done through the relation between face patterns,and then the features can be extracted and selected.Using the selected features to train multiple SVMs,which can finally classify human faces.The system structure is according to the following principle:Firstly simple methods are used to reduce the search space,and then more complicated methods are used in the reduced space.So the system can have a quick response speed as well as holding high detection and recognition rate.关键词：face detection;face recognition;skin analysis;motion analysis;primary component analysis;support vector machine2|1245|3更新时间：2025-07-16
- 摘要：Abstract:MPEG-2 and MPEG-4 are two most popular international video compression standards.They will coexist in different systems and networks for a long time.For compatibility of these two video standards,this paper put forward three transcoding algorithms on the basis of detailed analysis of computational complexity.In the paper,the principle and implementation of two efficient transcoding algorithms are emphasized.Both of them are compromise between the computational complexity and reconstructed video quality.One is motion-information reusing algorithm,which meets the highest video quality requirement of studio.The other is real-time low complexity transcoding algorithm,which applies to lowest delay requirement of the network server and user terminal with limited computational performance.The simulation results of many test sequences testified the excellent performance of the algorithms.关键词：MPEG-2;MPEG-4;transcoding;data compression;video signal processing2|958|0更新时间：2025-07-16
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Implementation of an Automatic Focusing Algorithm Based on Spatial High Frequency Energy and Entropy
摘要：A new advanced automatic focusing algorithm is proposed.After discussing the principle how image is blurred by the lens system,we presented spatial high frequency energy and entropy as the sharpness criteria and analyzed their performance detailedly.Aiming at the limitation of conventional MCS,the concept of direction-test frame is proposed.The reliability,speed and sensitivity of auto focus are enhanced by using more definition criteria together and self-adjust step.The proposed algorithm has been successfully tested to be effective on a high definition image processing system developed by the authors.Experimental results demonstrate that the new criteria work according to the fact and the proposed algorithm.关键词：auto focus;spatial high frequency energy criterion;entropy criterion;MCS;direction-test frame2|1816|26更新时间：2025-07-16 - 摘要：A novel method of interactive error-resilience for video communication is proposed in this paper.At beginning,the mechanism of error-propagation caused by block-encode algorithm is analyzed.Then,the new method of error concealment and error-propagation prevention is present.Simulation results show that error propagation can be prevented using proposed method of interactive error-resilience for video communication.Furthermore,this method is compatible with H.263+,and can be used in practice.关键词：video communication;error propagation;interactive error-resilience;error concealment;H.263+2|1058|2更新时间：2025-07-16
- 摘要：1/f-Type noise,specially modeled by fractional Brownian motion (fBm) has attracted much attention in many fields.A multiscale Wiener filter based on biorthonormal wavelets and equipped with Wiener filter is proposed in this paper for signal restoration embedded in 1/f family of fractal signals.First,the signal with 1/f noise is transformed via the analysis filter bank into multiscale subsystems in time-scale domain based on biorthonormal wavelets.Some nostationary properties,e.g.self-similarity,long-term dependencies of fractal signals are attenuated in each subband by wavelet multiresolution decomposition so that the Wiener filter bank can be applied to estimate the multiscale input signals.Then the estimated multiscale input signals are synthesized to obtain the estimated signal.Some simulation examples are given for testing the performance of the proposed algorithm.With this multiscale analysis/synthesis design via the technique of the wavelet filter bank,the multiscale Wiener filter can be applied to treat the signal restoration problem from nonstationary 1/f fractal noise.1/f fractal noise was restrained effectively and the signal to noise is improved evidently.关键词：1/f noise;biorthonormal wavelet transform;nultiscale wiener filter2|1273|10更新时间：2025-07-16
- 摘要：Security and safety are important and related factors that baffle the development and practicality of modern distributed system.However,most of researches on distributed system focus on security.Unfortunately,since software is being used largely in the complex distributed systems,the possibility of serious damage resulting from a software defect is considerable and growing,and then the complex distributed systems are plunging into safety crisis.In fact,distributed systems are in urgent need of new safety assurance technologies.After analyzing security and safety requirements of distributed system,we put forward new ideas for setting up the security and safety assurance structure of distributed system.We also analyze characteristics,designing aims for this structure.Since there are a lot of shortcomings in the current methods of realizing safety kernel (that is a new concept of safety assurance) in distributed system,we advance a program for RTOS to supply safety kernel mechanism.Based on all of these,we set up SADS (security and safety assurance structure of distributed system).At last,taking the control system in the traffic lights as example,prototype experiment of SADS has been done on the RT-Linux platform in the lab,and this experiment has proved the validity of SADS.关键词：distributed system;safety kernel;security and safety assurance structure;safety policy;RTOS2|1334|5更新时间：2025-07-16
- 摘要：Based on existing routing Algorithm,we propose a fast algorithm called FGMRA (Fast Group Multicast Routing algorithm) for group multicast by using two strategies.One is to make the best of calculation in existence.Another is to enlarge the storage spaces to get high speed.Compared with algorithm proposed by C.P.Low and N.Wang,the total cost of multicast trees created by two algorithms is almost equal,but our algorithm is faster.The simulation result shows that FGMRA is fast,stable and efficient,and can be used widely.关键词：group multicast tree;routing algorithm;bandwidth;minimum cost2|956|3更新时间：2025-07-16
- 摘要：An algorithm to determine the most vital edges of a communication network is presented in this paper.Since a spanning tree consisting of non-failed edges must exist in order for a success state to occur in the all-terminal problem,the number of such spanning trees is a measure of reliability.For a given edge e in the graph G,G*e is the graph with the edge contracted,where the edge denotes a link and the vertex denotes a node respectively.The relative importance of the two edges in the graph can be compared by computing the number of spanning trees of G*e for each of the two edges.The most vital edge in G is an edge whose contraction maximizes the number of spanning trees and whose proper functioning contributes most to system reliability.Experimental results and theoretical analysis show that the edge-contraction algorithm is effective and feasible.关键词：communication networks;number of spanning trees;edge-deletion;edge-contraction2|1372|12更新时间：2025-07-16
- 摘要：The main trouble that IP VPN (Virtual Private Network) service management has to face is the continuously developing requirements of service management layer in TMN (Telecom Management Network) model.It is an effective approach to reduce management complexity and neatly customize IP VPN services by providing reusable service management components.In this paper,we first analyze the basic service requirements of IP VPN,then bring forward and conclude the concept of "IP VPN service feature".On this foundation,we design a partition of IP VPN service management functions from the viewpoint of service features and form some reusable service management components.Finally,a mapping instance is given from service management functions to service management components.关键词：IP VPN;software reuse;management component;service feature2|871|1更新时间：2025-07-16
- 摘要：A distributed key generation protocol for public key cryptosystem based on discrete-log is proposed using generalized verifiable secret sharing.The protocol is applicable to arbitrary access structures,and has the following properties:the amount of secret information needed to be stored by each participant is small,and it can guarantee the randomness and uniformity of the distribution of the generated secret key.Hence it can be more widely used in group oriented cryptosystems than those protocols based on threshold access structures.关键词：verifiable secret sharing;distributed key generation;discrete logarithm;access structure2|952|0更新时间：2025-07-16
- 摘要：SEED is the Korean encryption standard.It was pointed by designers that the complexity for the linear cryptanalysis of SEED is 2335.4.Using the linear approximations in this paper,the complexity for the linear cryptanalysis of SEED is 2328.To analyze the differential cryptanalysis of SEED,the modified SEED was considered.It was pointed out that 9-round modified SEED was secure against the differential cryptanalysis.There are 9-round truncated differentials available to the truncated differential cryptanalysis in the modified SEED.Hence,10-round modified SEED is not immune to truncated differential cryptanalysis.Although the results can not threaten the application of SEED,they show the security of SEED is not as strong as that designers predicted.关键词：block cipher;security;differential cryptanalysis;linear cryptanalysis;truncated differential cryptanalysis.2|1454|0更新时间：2025-07-16
- 摘要：In order to solve the key technical problem that how to efficiently buffer high-speed traffic under the architecture of optical bus switching network,this paper proposes an output-queued two-stage packet buffer structure and related LBF-MMA (Longest beffer first-memory management algorithm) based on the combination of SRAM (Static radom access memory) and DRAM(Dynamic random access memory) technology.Analysis shows that such technique gives a good solution that meets both high speed and large capacity requirements in packet buffering for the optical bus switching network.关键词：high-speed router;packet buffer;optical bus switching fabric2|899|0更新时间：2025-07-16
- 摘要：A method for deriving the audio data index is proposed in this paper,which aim at query-by-example and query-by-content in audio multimedia databases.Here,first we discuss the process of wavelet packet decomposition and the method for choosing the best base and cost function.Second we prepare two schemes,which has been used,that deal with deriving the index of wavelet transform.And we propose the method to derive the audio data index that it is based on the best base transform in the wavelet packet.In the third,we take the part of energy for the audio data index which come from the highest value coefficients of the best base transform in the wavelet packet.In the last,we take our method comparing with the method that derived the index directly form the wavelet transform.The experiment shows that there are higher and robust for retrieving precision in the new method.关键词：audio data;data retrieval;wavelet transform;wavelet packet;best base choose2|858|0更新时间：2025-07-16
- 摘要：Disparity estimation and segmentation are vital tasks in stereo image coding and stereo vision matching.This paper proposes an algorithm for disparity estimation based on hierarchical MRF/GRF model and overlapped block matching (HMOM),and for disparity segmentation and extraction using active contour model.By combining the advantages of variable size block matching,overlapped block matching and MRF model,the HMOM scheme estimates a more smoother and accurate disparity field with lower computational complexity.In terms of PSNR of the disparity compensated image,the proposed disparity estimation algorithm achieves about 2.5dB higher PSNR,as compared to conventional variable block matching.A smooth and consistent disparity field with sharp boundary can be obtained by pixel-wise disparity refinement on the HMOM disparity field,and the disparity contour of OOI (objects of interest) can be extracted by the active contour model.The resulting disparity field and corresponding disparity contours can further be used in stereo image coding and video object segmentation.关键词：stereo image;disparity estimation;Markov random field(MRF);Gibbs random field(GRF);overlapped block matching(OBM);active contour model2|1763|2更新时间：2025-07-16
- 摘要：Huffman codes are most prevalent in practical operation.Other than compressing efficiency,there are other criteria,such as codewords' MSE,channel bit-error resilience,etc.This paper discusses the problem of the probabilities of 0,1 bits in codeword stream after Huffman coding.Mathematical modeling and analysis is given,which shows that accustomed Huffman codes are the worst according to this criterion.The optimal case is derived,and a sub-optimal algorithm is constructed to make the probabilities of 0,1 bits equal.The algorithm can be included in the original Huffman coding,and the complexity added is small.Experiments are given in the end,which attest our ideas.2|1543|1更新时间：2025-07-16
- 摘要：Although as the most popular model for speech recognition,HMM takes no account of the dynamics of the speech trajectory,since it assumes the outputs of a state to be independent and identically distributed.In this paper,based on a more flexible statistical framework for speech description-the generalized DDBHMM,a particular polynomial-fitting speech-trajectory model is proposed with new algorithms for training and recognition.It describes the real characteristics of speech more reasonably.With the effective path-pruning algorithm additionally proposed,it becomes a practicable model.Experiments on Chinese large-vocabulary speaker-independent continuous speech recognition showed that with this path-pruned polynomial-fitting speech-trajectory model,the recognition performance is improved distinctively at relatively low computational cost.关键词：continuous speech recognition;hidden Markov model(HMM);duration distribution based HMM(DDBHMM)2|769|0更新时间：2025-07-16
- 摘要：Designing nonlinear algorithms with kernel functions satisfying the Mercer condition,has become a novel nonlinear technique in the machine learning. By using kernel idea the kernel perceptron algorithm nonlinearly generalizes the linear perceptron algorithm.It can handle the linearly non-separable classification problems in the original input space and the linearly separable ones in the feature space.The linear pocket algorithm improves the perceptron algorithm and can deal with the linearly non-separable problems directly.In order to improve the linear pocket algorithm and kernel perceptron algorithm,in this paper the nonlinear pocket algorithm based on kernels (i.e.kernel pocket algorithm) is proposed,whose objective is to find a nonlinear discriminant function that can minimize the number of misclassified training samples.Its convergence is also proved.Its advantage is to implement a nonlinear classifier using a simply iterative procedure and kernel functions.The experiment results from some benchmark data sets show that the performance of our kernel technique is prior to that of the linear pocket algorithm and kernel perceptron algorithm.关键词：kernel function;perceptron algorithm;nonlinear;pocket algorithm;support vector machines2|1354|1更新时间：2025-07-16
- 摘要：For a class of sparse-sequences presented by Yupu Hu,this paper gives several methods of construction which have practical application value,to maximize the least period.关键词：sparese sequence;information hiding;the least period;linear complexity2|865|0更新时间：2025-07-16
- 摘要：In this paper we analyze security of the Modified Tseng-Jan group signature which was presented.We show that the scheme is universally forgeable and linkable.That is,anyone can produce a valid group signature on any message without being traced by authority and makes it computationally hard to distinguish whether two different signatures are produced by the same group member or not.关键词：group signature;universally forgeable;linkable;cryptanalysis2|916|1更新时间：2025-07-16
- 摘要：Orthogonal Multi-carrier Code Division Multiple Access (MC-CDMA) has attracted much attention in recent years.In this paper,an overview of MC-CDMA detection techniques is presented,and we point out the necessity and possibility of introducing multi-user detection (MuD) techniques into MC-CDMA uplink reception,based on an analysis of the Multiple Access Interference (MAI) in both uplink and downlink.Moreover,by comparing Direct Sequence (DS) CDMA and MC-CDMA and analyzing the duality between them,we discuss the future development of MC-CDMA MuD.关键词：MC-CDMA;multiple access interference;detection2|1065|0更新时间：2025-07-16
- 摘要：This paper designs an integrated coding algorithm based on DT-mesh according to depiction of MPEG-4 standard.Firstly,a framework about mesh object coding is proposed,on which we study mesh motion coding,and propose a new series estimation algorithm for triangle motion and a corresponding method for residual image.Finally,data structure is transformed in order to fulfilling the coding order of MPEG-4.Compared with H.263 standard,this algorithm has utilitarian value as a method of MPEG-4.关键词：mesh object;series estimation;Delaunay triangulation;datastructure transformation2|1118|2更新时间：2025-07-16
- 摘要：This paper presents a hybrid scheme for calculation many dielectric spheroids in arbitrary orientations.Firstly,the T matrix of single particle with symmetrical axis is obtained by extend boundary condition method,and that of the prolate spheroids,as an example,can be work out easily.Then combining with vector spherical wave functions rotation theory and recursive T matrix algorithm,the scheme can figure out the scattering field of many spheroids in arbitrary orientations.Verifications of the method are provided with numerical examples.关键词：dielectric spheroid with arbitrary orientation;extend boundary condition (EBC);T matrix method;electromagnet scattering2|1122|1更新时间：2025-07-16
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