最新刊期
卷 33 ， 期 4 ， 2005
- 摘要：Scheduling algorithms make a great impact on the performance of input queueing switches.From Internet traffic characteristics,it is pointed out that short packets should be guaranteed higher priority and lower delay in scheduling algorithms.In general packet-mode scheduling,short packets suffer from long waiting time due to the continuous transferring of cells of long packets.To solve this problem,we study the low-complexity preemptive packet-mode scheduling and propose the algorithm called preemptive short packets first (P-SPF).P-SPF improves the TCP performance by means of the fact that round-trip delays of TCP flows are greatly reduced.Both the analysis in queueing theory and the simulation results with respect to a real traffic model show that P-SPF can achieve almost zero average packet waiting time for short packets,while keeping a high overall throughput up to 94%.关键词：input queueing switches;packet-mode;preemptive;short packets first2|1191|7更新时间：2025-07-16
- 摘要：Packet one-way delay traces are important measurements for analyzing and evaluating end-to-end performance of the network.These measurements can be quite inaccurate due to the relative clock skew,i.e.,the frequency difference between two clocks,and clock reset which is the abrupt adjustment of clock at end systems.In this paper we introduce a new algorithm to estimate and remove the relative clock skew and clock resets from measurements based on the fuzzy clustering analysis.Numerical experiments demonstrate that this algorithm is more accurate and robust than existing algorithms.Additionally,the new algorithm has time complexity of O(N).关键词：network measurement;one-way delay;relative clock skew;clock reset;fuzzy clustering analysis2|1316|5更新时间：2025-07-16
- 摘要：This paper presents NDPR,a scheme of low-latency mobile IPv6 handoff for IEEE 802.11 wireless LANs.Without using L2 triggers,NDPR employs Nonuniform Detection Model to reduce the latency and the cost of L2 handoff detection.Furthermore,NDPR reduces the latency of mobility detection by making the map between IP address and MAC address,and reduces the latency of Care-of Address (CoA) configuration using CoA pre-registering mechanism.The simulation indicates that NDPR can lower the MIPv6 handoff latency efficiently and outperforms its counterparts.关键词：Mobile IPv6;wireless LAN;handoff;movement detection4|1139|1更新时间：2025-07-16
- 摘要：Mobile Ad hoc network is a special peer-to-peer network that is infrastructureless,self-organizing,dynamically reconfiguration and mobile.And now people pay more attention to the using of ad hoc network in emergence area such as battle field and disaster rescue.Each node in mobile ad hoc network can be regarded as either a computer or a router,so it is very vulnerable to routing information attacks.However,little information about the security problem has been considered in the routing protocols that have been proposed.In this paper,an overview of the research about attacks against routing information is given firstly,and then we present that a security routing protocol S-DSR based on reputation systems can be used in ad hoc networks.The simulation environment and results is given and the simulation results show that S-DSR protocol can get better than DSR protocol while there exists attacking nodes.关键词：mobile Ad Hoc network;network security;reputation systems;security protocol2|1604|13更新时间：2025-07-16
- 摘要：In time-varying frequency-selective fading channel,a time-frequency chip-level differential detection (TF-CLDD) in two-dimension spread spectrum is proposed.The bit error rate (BER) performance of TF-CLDD is analyzed,and the theoretical results are evaluated by simulation.The results of research indicate that TF-CLDD exhibits a performance to make the system resistant to both frequency-selective and time-selective fading,and it exhibits a better performance in selective fading channels than that in flat fading channels.We compare the performance of TF-CLDD with that of multicarrier spread spectrum chip-level differential detection (MC-SS-CLDD),and the TF-CLDD effectively reduces the effect of intercarrier interference on the system.关键词：two-dimension spread spectrum;time and frequency chip-level differential detection;frequency-selective fading;time-selective fading;multicarrier spread spectrum2|792|0更新时间：2025-07-16
- 摘要：As the combining form of the orthogonal frequency-division multiplexing (OFDM) technique and the vertical Bell Labs layered space-time (V-BLAST) architecture,the OFDM V-BLAST system can better meet the demand of next-generation (NextG) broadband mobile wireless multimedia communications.This paper investigates the decoding problem of the downlink OFDM V-BLAST system under the frequency-selective fading environment.The joint space-frequency demultiplexing operation in the OFDM V-BLAST system is firstly addressed.Successively,one novel half-rate rotational invariance joint space-frequency coding scheme is proposed for the OFDM V-BLAST system.By elegantly exploiting the above rotational invariance property,one direct decoding algorithm without knowing channels state information (CSI) is derived for the downlink frequency-selective OFDM V-BLAST system.Extensive simulation results demonstrate the validity of the novel half-rate rotational invariance joint space-frequency coding scheme and the performance of the direct decoding algorithm.关键词：OFDM;V-BLAST;decoding algorithm;frequency-selective fading;rotational invariance2|975|2更新时间：2025-07-16
- 摘要：The notion of service level agreement (SLA) has been proposed to capture qualitatively and quantitatively defined performance contract between the service provider and the customers.Connection reliability and restoration time are two important SLA-parameters of the customers' main concerns and should be carefully considered in survivable WDM networks.A sound scheme should carefully guarantee the two SLA-requirements simultaneously and benefit a network operator in resource efficiency and service scalability.Under the two SLA-parameter constraints,a novel dynamic constraint shared path-protection algorithm (DCSP) in WDM mesh networks is proposed.Based on the basic ideas of the K-shortest path and partial link-disjoint protection,DCSP can provide differentiated services for customers according to their SLA-parameters.Simulation results show that DCSP not only can efficiently guarantee the specific SLA requirements of customers,but also can achieve significant performance gain and lead to remarkable reduction in blocking probability.关键词：service level agreement (SLA);connection reliability;restoration time;shared path-protection;dynamic routing2|892|1更新时间：2025-07-16
- 摘要：A novel family of frequency hopping sequences based on iterated block cipher is proposed for frequency-hopping multiple-access (FHMA) communications.The design offers a class of nonlinear FH codes with high security,large linear span and a uniform spread over the entire frequency bandwidth.Moreover,FH sequences among the family are independent from each other and they perform as well as random patterns in terms of multiple access interference in anti-jamming applications.With the performance of packet error and throughput for FHMA network being derived in theory,numerical results of the 3DES sequences are presented,comparing with those of shift register sequences and chaotic FH sequences.Efficiently implemented in field-programmable-gate- arrays (FPGA),the generator prototype of the proposed sequence has been realized and incorporated into fast FH radio.关键词：block cipher;FH sequences;FHMA;VHDL;FPGA2|1083|2更新时间：2025-07-16
- 摘要：Proposing a dynamic scheme of channel estimation for 802.16a OFDM system with the trade off between estimation performance and arithmetic complexity.In addition,we find a set of excellent irregular LDPC codes and examine the performance of them in multipath fading channel.Simulation shows that these codes have nice performance in SUI-3 and SUI-5 fading channels.Furthermore,we find that,under the multipath environments,the performance of LDPC codes is superior to that of the convolution turbo codes which is proposed by IEEE 802.16a standard.关键词：OFDM(Orthogonal Frequency Division Multiplexing);LDPC codes;Turbo codes;channel estimation2|994|3更新时间：2025-07-16
- 摘要：We study the multiuser diversity with constellation selection based on a virtual representation of realistic MIMO correlated channels.To realize multiuser diversity in slow fading correlated channels,We adopt random beamforming technique and propose to construct random beamforming matrix exploiting virtual channel representation.Simultaneously,adaptive coded modulation is applied to each sub-channel of the selected user to improve the system performance further.Two cases are considered:minimizing the BERs in each sub-channel and maximum the sum of data rate.关键词：MIMO;multiuser diversity;beamforming;virtual channel;adaptive modulation3|917|2更新时间：2025-07-16
- 摘要：A new ROI video coding method is presented based on MPEG-4.In order to improve the video coding gain and the compression quality,the intra macroblock prediction,adaptive block-size transformation (ABT) and adaptive block-size motion estimation (ABME) are applied to ROI coding,then error propagation from other regions to ROI is prevented by encoding border macroblocks of the ROI in intra mode.Furthermore,content-based bit allocation strategy is proposed according to MPEG-4 rate-distortion model.Software simulation results show that the method can improve the image quality both objectively and subjectively compared to MPEG-4 and other ROI coding methods.关键词：video coding;ROI;MPEG-4;adaptive block size;scalable encoding;bit allocation2|1268|4更新时间：2025-07-16
- 摘要：In this paper,we proposed a new rayleigh distribution based wavelet model for video traffic.With Haar wavelet mutiresolution analysis,we use different models to modeling the scaling coefficients and wavelet coefficients,and by inverse wavelet transform,we can get the whole generated traffic trace.In the coarsest scaling space,we use a rayleigh distribution based AR model to generate the scaling coefficients,for the scaling coefficients are approximately rayleigh distributed.While in the wavelet spaces,we use wavelet independent guassian model to generate the wavelet coefficients.Because the proposed model uses different models in scaling space and wavelet,it can capture the probability distribution and the long-range dependence of the VBR video traffic very well.Moreover,under the multiscale queue (MSQ) framework,we give a theoretic formula of the queuing analysis.Finally,by the video traffic trace-driven simulation and queuing analysis,we show the effectiveness of the proposed model.关键词：Video traffic;Rayleigh distribution;queuing analysis;wavelet2|1256|6更新时间：2025-07-16
- 摘要：To improve conventional methods for contrast enhancement,this paper presents a novel approach based on wavelet transform and fuzzy logic.Firstly,normalize the low contrast image to reduce the effects of different illuminations.Then choose a specific wavelet transform to convert the normalized image and obtain wavelet coefficients.The low-pass coefficients are fuzzified by the linear operator and use both the global and local information to define and enhance the image's global contrast.For high-pass coefficients,utilize nonlinear operator to enhance the details of images.Finally,the inverse wavelet transform is applied to map the result into space domain. Experimental results of the proposed approach and other conventional methods are compared and analyzed to demonstrate that the proposed approach is very effective in enhancing the low contrast image without over-enhancement and under-enhancement.关键词：wavelet transform;fuzzy logic;contrast enhancement2|1878|8更新时间：2025-07-16
- 摘要：Recent researches indicate that pulse coupled neural network (PCNN) can be implemented on image segmentation effectively.However,it is necessary to determine the near optimal parameters of the network to achieve satisfactory segmentation results for different images.Up to now,the parameters are always adjusted manually and there is no method of adaptive parameter determination,which impedes its application in automatic image segmentation.To solve the problem,this paper brings forward an adaptive segmentation method based on a simplified PCNN with the parameters determined by images' spatial and grey characteristics automatically.Segmentations on various images are implemented with the proposed method and the experimental results demonstrate its validity and robustness.关键词：pulse coupled neural network (PCNN);adaptive;parameter determination;automatic image segmentation2|1465|34更新时间：2025-07-16
- 摘要：The fully decoupled adaptive filtering problem of nonlinear Volterra system is investigated with the input and output observation data corrupted by noise.Based on the total least mean square technology and the pseudo-linear combination structure of Volterra filter,a total fully decoupled adaptive filtering algorithm is built by using the analysis method of the constrained optimization problem to investigate Volterra filtering process.And the parameter feedback-adjusting model is also built for the convergence analysis of the proposed algorithm.The analysis indicates that the Volterra kernels can evenly converge to the real values by using this algorithm.Simulation results show that the proposed total fully decoupled adaptive filtering algorithm takes on higher robust resistance noise performance and filter precision than the fully decoupled LMS adaptive filtering algorithm,when the input and output observation data are all corrupted by noise.关键词：nonlinear system;fully decoupled filter;volterra adaptive filtering2|879|2更新时间：2025-07-16
- 摘要：Inheritance theory of ontologies is a very important unsolved problem.By extending the inheritance mathematical theory,the semantics of ontology inheritance and the mechanism of ontology inheritance are analyzed.The creative works are as followed:(1)The mathematics of inheritance systems isn't powerful enough to explain the ontology inheritance system.The "False conflict" will occur when we use the old theory of inheritance to describe the inheritance of class/property with exceptions.In order to solve this problem,the old theory is extended by adding tokens and redefining the definitions of conclusion set,inheritable and grounded expansion,etc.(2)Most theorems and corollaries prove to be correct on the new definitions.Above these new definitions,some new theorems and corollaries are got.(3)Transferring the representation of ontology (D,P,U,V,H) into triple (F,E,I).And proving the capability of the triple representation equals to the quintuple representation.The ontology is mapped into the extended inheritance system.The problem of consistency and un-ambiguity of ontology inheritance are explored with the extended theory.(4)The up-scan and down-scan algorithms are designed to detect the conflict in order to maintain the consistency of the system.The analysis of consistency of the ontology inheritance system effectively supports the ontology-oriented engineering methodologies booming now.2|1129|1更新时间：2025-07-16
- 摘要：The insertion of dummy metals is necessary to reduce the pattern-dependent variations of the dielectric thickness in the CMP process.This makes conventional tools of capacitance extraction exhibit prohibitive calculation time.This paper presents an efficient method for 3-D capacitance extraction with taking the floating dummies into account.Based on the QMM-accelerated BEM,our method inherits high computational speed while considering the floating conditions and using a new preconditioner.While preserving high accuracy,our method shows an excellent speed with 1000x speed-up over Raphael,about 10x speed-up over the method in Ref.[5].Finally,we carried out a series of experiments on cases which contain floating dummy-fills.The influence of dummy-filling on interconnect capacitance is analyzed and conclusions are drawn to benefit the design of high performance integrated circuits.关键词：extraction of parasitic capacitance;floating dummy;chemical-mechanical polishing;boundary element method;quasi-multiple medium2|854|0更新时间：2025-07-16
- 摘要：For the BPSK alphabet,this paper presents a novel concept of an ε-equalization qualitatively different from the classical zero-forcing equalization,educes a necessary and sufficient condition for existence of the ε-equalizer.The paper takes the complementary projection operator of a received data matrix as the annihilator of a transmitted sequence vector to be detected,and then formulates the blind detection problem of BPSK signals into a quadratic programming with binary constraints.Finally,the paper extends and applies the above ε-equalization concept and blind detection algorithm successfully in the QPSK case with complex channels,by redefining a complex argument as a real one.Simulations demonstrate its superior performance to the subspace method and linear prediction method whether SIMO channels have common zeros or not and the zeros lie within the unit circle or not.关键词：blind detection;equalizability condition;SIMO channel;BPSK;QPSK2|1045|5更新时间：2025-07-16
- 摘要：Power/energy has been an important constraint for development of electronic system.Power/energy is consumed by hardware when software runs on it,for accessing data and executing instructions of software can both make hardware consume power/energy.Compiler can change the behavior of software running on the hardware by optimized scheduling,such that the power/energy consumption of certain program decreases.This paper comprehensively reviews low power/energy compilation technology related researches from two aspects,how to evaluate software power/energy consumption and how to achieve low power/energy by means of compilation technologies.In the end,we analysis the existing problems in current researches on low power/energy compilation Technology,and predicate some new directions on the low power/energy compilation technology.关键词：low power/energy;compilation technology;power/energy model2|2298|9更新时间：2025-07-16
- 摘要：Based on the effective contention access and polling transmission,a novel multiple access protocol—UPMA+ + protocol is proposed.It overcomes the overhead in UPMA (User-dependent Perfect-scheduling Multiple Access) protocol by using collision resolution method and regaining channel resource in time.By employing the limited polling period and adjusting the length of contention access period adaptively,it resolves the conflicts between active nodes and transmission nodes,in which active nodes expect to access the channel quickly and transmission nodes want to transmit packet as soon as possible,thus improving the throughput greatly.Theoretical analytical is given through the queuing theory,and its numerical result is agreed with the simulated result on the whole.关键词：wireless local area network;contention access;polling;multiple access protocol;self-organizing algorithm2|737|1更新时间：2025-07-16
- 摘要：Collision resolution is an effective strategy to improve the performance of medium access control protocol.Both tree splitting algorithm and First Come First Service (FCFS) splitting algorithm are classical algorithms of Splitting algorithm.But both of them have some limitations.In this paper,a novel splitting algorithm - Hybrid Splitting Algorithm (HSA) has been presented.Based on the tree splitting algorithm and FCFS splitting algorithm,the HSA has the packet transmitted in the order of their arrival partially,while if the packet generation time is too near to split using by FCFS,the HSA adopts the tree splitting algorithm.So,the whole splitting procedure has relations with both the generation time and the generation interval of packets.Simulation results show that HSA outperforms tree splitting and FCFS splitting algorithm.2|815|1更新时间：2025-07-16
- 摘要：In packet-based real-time network,packet loss can not be avoided,which may greatly damage the speech quality.This paper proposed a main-sub speech codec method based on AMR for reducing influence of the packet loss.The simulation results show that the speech quality over the IP network was improved efficiently with the proposed method.关键词：speech coding;network telecommunication;packet loss;communication quality2|1117|0更新时间：2025-07-16
- 摘要：In order to enhance the security of web service as well as to support the differentiated service,the paper puts forward an adaptive model which is based on active defense strategy.It uses a predictive network model on base of self-similar sequence theory to estimate current states of transfer servers in end-system,then classifies them with Fuzzy-C-means clustering method. Finally we bring forward a load balancing algorithm that is founded on the classification results and grading users' requests.In that way,it optimizes the allocation of system resources and ensures data security and reliability.Moreover,this model,not dependent on the original operating system,is transplantable and extensible.关键词：data security;dynamical load distribution;active defense;measurement and prediction2|1008|1更新时间：2025-07-16
- 摘要：The effects of phase noise on the performances of MPSK and MDPSK are investigated in this paper.Firstly,under a unified framework,the symbol error rates (SERs) of MPSK coherent and MDPSK differential demodulation with phase noise are derived in AWGN,Nakagami-m fading and Rician fading channels.Secondly,the relationships between SERs and phase noise are validated by using computer simulation and numerical method.Finally,the importance of our work for system design and performance evaluation is demonstrated by an application instance.关键词：M-ary phase shift keying;M-ary differential phase shift keying;performance analysis;phase noise2|1085|0更新时间：2025-07-16
- 摘要：This paper presents a new frequency offset correction technique for OFDM receivers,which is based on time oversampling.The proposed technique uses the correlation property of frequency domain sequences corresponding to odd and even sequences.It estimates integer frequency offset first,then it uses the tracking loop to track the fraction frequency offset.This technique doesn't depend on the channel,so it adapts to multipath fading channel.Simulation demonstrates that proposed method can still correct large frequency offset under multipath fading channel.关键词：OFDM (orthogonal frequency division multiplexing);frequency offset estimation;oversampling;frequency synchronization;mobile channel3|1201|0更新时间：2025-07-16
- 摘要：While the partial power training sequences is used for synchronization in Orthogonal Frequency-Division Multiplexing (OFDM) system,the received data signals will be interfered by the training sequences.we give a method for suppressing the interference caused by the training sequence.Especially we focus on only one OFDM symbol in a packet transmission.Both theoretical and simulated results of the above technique are presented under indoor multipath Rayleigh fading channel.It is shown that the better BER performance can be achieved as compared with no separation,and only one OFDM symbol can accomplish user data communication.关键词：OFDM;separation;training sequence;BER2|1148|2更新时间：2025-07-16
- 摘要：This paper describes an analytical method about performance optimization in MPLS (Multiprotocol Label Switching) Traffic Engineering,At first muitipath MPLS system model is described,Then we put forward an improved dynamic traffic partitioning algorithm on multipath based on the introducing of the conception of traffic splitting granularity g,which can realize the dynamical traffic regulation on LSPs (Label Switched Paths) and decrease computing quantity.This paper verifies the performance and stability of the algorithm by numerical analysis.关键词：multiprotocol label system (MPLS);traffic engineering;label switching path(LSP);traffic partitioning4|1102|3更新时间：2025-07-16
- 摘要：The low frequency ultra wide band synthetic aperture radar (UWBSAR) system has three peculiarities:low frequency,ultra-wideband and large processing angle.Based on these peculiarities,the scattering model of the targets is calculated and mapped to the SAR images.The calibration method is proposed in the end of the paper,and computer simulation is used to validate this method.关键词：low frequency UWB SAR;radiometric calibration;scattering model2|888|2更新时间：2025-07-16
- 摘要：Research on integrating spatial information into content-based image retrieval is aimed at solving the problem caused by global feature based algorithm.Most systems derive the spatial information from image segmentation.However,the description of images based on one-level description (OLD) and the inevitable inaccuracy of segmentation results limit the performance.The proposed two-level description (TLD) describes images by a rough description and a detailed description to avoid improper spatial constrain caused by OLD.Similarity measurement based on unbalanced region matching (URM) is introduced in taking the advantage of TLD to reduce the influence of inaccurate segmentation.The performance of the system is illustrated by experimental results with 700 query images randomly selected from a database of 7000 general-purpose images.关键词：content-based image retrieval;two-level description;unbalanced region matching2|771|2更新时间：2025-07-16
- 摘要：The no-linearity transform in image enhancement was researched deeply in the paper,its drawbacks were found.Then,an novel image fuzzy enhancement arithmetic operators was proposed,the arithmetic operators not only overcome the drawbacks of the old no-linearity transform,but also has close-character,adjusting-character and transplantable-character to other enhancement arithmetic.In addition,through quoting fuzzy entropy,make the select of threshold value in image enhancement have a certainty purpose.We use our new algorithm to extract image edges,with better result than that of now-available image fuzzy enhancement method.关键词：image enhancement;edge detection;membership function2|1235|16更新时间：2025-07-16
- 摘要：Disk array is a high performance storage system for exploiting intra-request concurrence and inter-request parallelism.Load balance among disks is necessary for better inter-request parallelism,and an I/O request should be served by multiple disks for intra-request concurrence.This can be achieved for optimal data placement.But file access pattern is changing.System should redistribute data blocks adaptively.In this paper,we present a strategy of balanced hypergraph-based adaptive data placement,and give two objective functions for the optimization of both load balance and intra-request concurrence.We have done lots of simulations to evaluate our method and compare it with traditional optimization strategies such as adaptive load-balance and hyper-graph placement for intra-request concurrency.The result manifests that our strategy is a useful one.关键词：disk array;intra-request concurrency;load balanced;balanced hypergraph-partition2|789|0更新时间：2025-07-16
- 摘要：Firstly,the error of fit must be defined for nonlinear least-square fitting of generalized geometry model.Then the nonlinear optimization algorithm can be used to obtain the optimum solution.In this paper,we proposed an error of fit based on the orthogonal distance between the given point and the fitting geometry model.The estimated parameters are invariant to coordinate transformation and we can easily find a physical interpretation of the fitting parameters by this way.关键词：fitting;super-ellipsoid;algebraic distance;geometric distance2|1131|0更新时间：2025-07-16
- 摘要：Based on parametric model of signal-multicomponent polynomial phase signal,a novel time frequency kernel is presented.It estimates the instantaneous frequency of each signal component by matched-phase transform,according to different features of phases between the autoterms and crossterms of the instantaneous correlation function of the signal under analysis.The novel time frequency kernel constructed not only shows ideal frequency concentration,but also suffers from few or no crossterms.So,compared with the existing multilinear time-frequency representations,it has advantages in exposing inner characteristics of signals.关键词：polynomial phase signal;instantaneous correlation function;crossterm;autoterm;matched-phase transform2|781|2更新时间：2025-07-16
- 摘要：This paper proposes Genetic Programming Modeling (GPM) algorithm on chaotic time series.GP is used here to search for appropriate model structures in function space,and Particle Swarm Optimization (PSO) algorithm is introduced for Nonlinear Parameter Estimation (NPE) of dynamic model structures.In addition,GPM integrates the results from Nonlinear Time Series Analysis (NTSA) to adjust the parameters and as the criterion of founded models.The simulation shows the effectiveness of such improvements on modeling chaotic time series.关键词：chaotic time series analysis;genetic programming modeling;nonlinear parameter estimation;particle swarm optimization;nonlinear system identification2|976|2更新时间：2025-07-16
- 摘要：The trapdoor one-way function in NTRU is different from previous ones.Its one-wayness depends on the randomness of session keys,and decryption needs not any information about the session key.Someone called this kind of functions as "probabilistic" trapdoor one-way function.We believe this cannot show all the particularities.So we proposed a new notion,i.e.trapdoor one-way function with an auxiliary random variable,by which we can also unify the trapdoor one-way function model of probabilistic public key encryptions.The concept has been extended to the situation of higher dimension,and possible use has been discussed finally.关键词：trapdoor one-way function;public-key encryption;NTRU;trapdoor one-way function with an auxiliary random variable2|1475|0更新时间：2025-07-16
- 摘要：The Cramer-Rao Lower Bounds(CRLB) of signal-to-noise-ratio(SNR) estimation for quadrature amplitude modulation (QAM) signals is derived,and then a blind SNR estimation algorithm for QAM signals base on a statistical ratio of observables over a block of data is present.Although the SNR estimation for QAM signals needs large numbers of observation symbols for good performance,the algorithm presented in this paper needn't any extensive memory to store those data.And the algorithm has very low computational complexity.The detail analysis and computer simulation for some kinds of QAM signals are also presented.It can be seen from the results that when there are enough observation data,this algorithm can work effectively for all kinds of QAM signals tested in this paper.关键词：quadrature amplitude modulation signals;SNR estimation;Cramer-Rao bounds;data fitting2|1574|4更新时间：2025-07-16
- 摘要：Multichannel blind equalization is an important task for numerous applications such as speech separation,dereverberation,communication,signal processing and control,etc.In this paper,we reconstruct a cost function based on second order statistics.To avoid trivial solution,an additional item is added to the cost function,which assures that the equalizer is irreducible.Then,an algorithm is derived with natural gradient search method for multichannel blind source separation and deconvolution of convolved signal mixtures.To avoid divergence of the algorithm,an iterative converging condition is also given,and is used to adjust the learning rate.Simulations indicate the ability of the algorithm to perform blind equalization under the weaker condition (the FIR system is equalizable).关键词：blind equalization;cost function;nature gradient;learning rate2|694|0更新时间：2025-07-16
- 摘要：This paper presents a new approach to determine the similarity parameters in the Evidence-Theoretic k-NN Classification Rule. Given a pattern recognition problem,we first compute a reference nearest neighbor distance to separate samples of one class from other samples with least error rate,and then calculate the similarity parameters based on the obtained distance. Under the condition of small scale samples with non-gaussian distribution,the proposed method can get more suitable parameters and thus reduce classification error rate.Furthermore,its computation complexity is 4-8 times lower than that of L.M.Zouhal's method.关键词：evidence theory;basic probability assignment function;k-nearest neighbor classification3|1667|7更新时间：2025-07-16
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