最新刊期
卷 34 ， 期 1 ， 2006
- 摘要：Considering the methods of detecting DS-CDMA signal in multipath fading channels,a new method based on time-frequency two dimensional spread-spectrum is proposed in this paper.The received signals in the symbol duration are transformed into the frequency domain by Nf-point DFT where Nf is less than the processing gain N,then the signals are combined both in the frequency and time domain.The complexities of the RAKE receiver,the method proposed in the paper and the receiver with channel sounding with path selection are compared.Finally computer simulation results show that the performance of the proposed receiver is the best among the three methods in the channels which have small root mean square (r.m.s.) delay.关键词：two dimension spread-spectrum;DS-CDMA;RAKE;error probability2|854|0更新时间：2025-07-16
- 摘要：Mobile ad hoc networks (MANET) are autonomous,infrastructureless networks that support multi-hop communication through IP routing.MANET and the Internet have many differences.These differences are not only the structure and topology of networks,but also communication patterns of nodes in both networks.Integrating MANET and the Internet into a hybrid network is a challenging problem due to these differences.In order to MANET node to possess Internet connectivity,it must be able to find an Internet gateway.This issue consists of how to find and maintain contact with Internet by gateway.Additionally,how to handover to a more suitable neighboring gateway is also related to this issue.In this paper,we propose the dynamic gateway concept that it acts as an interface between MANET and the Internet.With model analysis,it is proved that the dynamic gateway architecture is appropriate for ad hoc Internet connectivity.Our simulation results show that the performance of networks with dynamic gateways is superior to that of fixed gateway architecture.关键词：mobile ad hoc networks (MANET);Internet;hybrid networks;dynamic gateway2|1046|7更新时间：2025-07-16
- 摘要：This paper introduces a Relay Aided Media Access (RAMA) protocol by taking advantage of the existence of multihop high rate links.The mechanism in RAMA protocol is demonstrated by replacing one low rate link with two high rate links with the assistance of relay.One of the key novelties in the proposed RAMA protocol is that the transmission from the immediate relay node to the destination node is free of contention.Results from analysis and simulations show that RAMA can significantly improve the network throughput and reduces the delay.关键词：media access control;multi-rate transmission;IEEE 802.11;wireless networks2|803|0更新时间：2025-07-16
- 摘要：A novel modulation technique is proposed in this paper,Non-orthogonal Multiple Modulation(NOMM).Based on estimation theory analysis,various well-performed modulation methods are presented in terms of signal constellations.Relevant error probability and bandwidth efficiency are also discussed.The result of numerical experiments shows that these completely new multiple modulations outperform the conventionals in bandwidth efficiency,which is owed to the unrestrainedness in orthogonality.NOMM offers a more effective method in practice and indicates a broad perspective of development for modulation techniques in theory as well.关键词：digital communication;non-orthogonal modulation;signal constellations;bandwidth efficiency2|917|7更新时间：2025-07-16
- 摘要：Maximum-ratio combining (MRC) is a simple and effective combining scheme for adaptive antenna arrays to combat fading.However,it requires estimation of the spatial signature (i.e.,the channel gain and phase at each antenna element) of the desired signal across the array.Assuming the channel estimation is obtained by N symbols' correlation using common pilot channel (CPICH),we proceed to develop a fully analytical assessment of the impacts of Gaussian error and Doppler spread on the MRC performance.The originality of the approach revolves around the derivation of the closed-form expression for average bit error probability for coherent BPSK.The expression is then applied to find the optimal correlation length of channel estimation.As a result,the computing method of optimal correlation length has been given.It is also proved that the optimal correlation length N was only correlative with maximal Doppler spread fd and symbol duration.关键词：antenna arrays;maximal-ratio combining;imperfect channel estimation;Gaussian error;Doppler spread2|982|0更新时间：2025-07-16
- 摘要：This paper proposes fast inter prediction methods for real-time video coding based on H.264.These methods include storing structure of 1/4-pel resolution interpolating image,four-step search algorithm for fast block motion estimation and fast decision of inter prediction mode.Simulation results show that inter macroblock encoding is obviously speeded up by using above methods.Furthermore,these algorithms are compatible with H.264 standard,and can be used in practice.关键词：video communication;H.264;1/4-pel resolution;estimation of motion vector;prediction mode2|1111|4更新时间：2025-07-16
- 摘要：The paper proposes an area-directed interpolation algorithm for color images.The basic idea is to first estimate first and second direction derivatives around interpolated pixels along the gradient directions from a low-resolution image and then identify constant zones,linear zones,and non-linear zones based on these direction derivatives in color image.Thus different filters are applied only to zones that require it.Experiment results demonstrate that our new interpolation algorithm substantially improves the quality of the interpolated images over conventional bilinear interpolation and possesses reconstruction cost less than pure complex filters.In addition,the proposed method can be used irrespective of the magnification factor (MF).关键词：color space;edge feature;adaptive interpolation;image reconstruction2|854|1更新时间：2025-07-16
- 摘要：A novel semi-fragile blind watermark algorithm based on H.264 low bit-rate video stream was proposed in this paper,copyright protection and content authentication can be achieved jointly by embedding the robust watermark and fragile watermark spectively during the process of interior prediction and motion vector prediction which are characteristic for H.264 standard.Through introducing the quantization factor of H.264 in the embedding and prediction mode choice,the proposed scheme can strengthen the watermarking resistance to video recoding and strike a good rate-distortion balance for the watermark of lower bit-rate video stream,which relieve bit-rates lossness from the watermarking embedding.Experimental results also demonstrate that this scheme is very computational efficient during watermarking embedding and extraction.关键词：semi-fragile blind watermark;H.264;low bit-rate;Lagrange function2|1146|11更新时间：2025-07-16
- 摘要：Robustness is one of the important requirements of digital watermarking.To improve robustness,CDMA (Code Division Multiple Access) technologies have been introduced into digital watermarking.However,most existing CDMA-based watermarking parameters are usually determined via experience.With the side-information embedding scheme,we have analyzed the relationship between PSNR,embedding strength,orthogonal codes length,and number of users,in the case of CDMA additive embedding.The expression for estimating the embedding strength is derived in terms of PSNR.Experimental results show the estimating is effective.Furthermore,while keeping the PSNR constant,the relationship between spread code length and watermark bit error rate is analyzed.As a conclusion,when keeping the length of watermark bits and PSNR constant,the choice of orthogonal spreading code does not influence watermark bit error rate.The conclusion can be used to guide the actual watermarking system to choose the correct embedding parameters.关键词：digital watermarking;CDMA;watermark channel;side information;additive embedding2|1015|7更新时间：2025-07-16
- 摘要：Annihilators of cryptographic Boolean functions have been shown to be closely related to algebraic attacks to stream ciphers.However how to construct annihilators of a given Boolean function remains a hard problem.As an approach to this problem,it gives an important characterization of annihilators with low degrees of a given Boolean function in terms of the set of x values on which f(x)=0.This gives a way to find annihilators of a given Boolean function,however how to find an annihilator of the lowest algebraic degree still remains unsolved.关键词：cryptography;Algebraic attack;annihilator of Boolean functions2|979|11更新时间：2025-07-16
- 摘要：How to localize the neural active source areas effectively and precisely from the scalp EEG recordings is a critical issue for clinical neurology and cognitive neuroscience.In this paper,based on the sparsity assumption of brain activities,proposed is a novel iterative EEG source imaging algorithm,which is a modified FOCUSS iteration procedure combined with lp norm sparse constraints.In this algorithm,the sparse constraint of solution,lp norm,is integrated into the modified iterative procedure of FOCUSS,and it is the renewed weight subjected to the lp norm constraints that forces the solution to converge to the active sparse source position effectively.The conducted simulation studies for a random underdetermined system,a 3-shell sphere model and a realistic head model all showed its validation for solving of underdetermined system and EEG source imaging.关键词：EEG source imaging;underdetermined system;sparsity;focal underdetermined system solver(FOCUSS)2|1247|1更新时间：2025-07-16
- 摘要：This paper puts forward a new edge-directed enhancing based anisotropic diffusion model.Since edge enhancing diffusion can not get right edge direction,and coherence enhancing diffusion often induces false edges in image denoising,our new model adapts a new operator for edge orientation based on nonlinear smoothing operator,and defines eigenvalues on edge's orientation such that the new tensor has large eigenvalues in both gradient direction and edge direction on the slippy region of image,but has small eigenvalues in gradient direction and large eigenvalues in edge direction on the edge region of image.So it can remove noise efficiently and keep edges better at the same time to get good result on the whole image.Both theory analysis and numerical results show that the new model has better denosing results than the known diffusion model,and has higher peak signal to noise ratio and higher edge preserved index.关键词：image denoising;partial differential equation;diffusion tensor;eigenvector;eigenvalue;edge orientation2|1561|20更新时间：2025-07-16
- 摘要：The concept of equivalence matrix and its operation are discussed in this paper.Based on a Rough Attribute Vector Tree (RAVT),two kinds of fast matrix computation algorithms—Recursive Matrix Computation (RMC) method and Parallel Matrix Computation (PMC) method are proposed for data cleaning and rules extraction finished synchronously in rough information system.The algorithms emphasize the practicability and efficiency of rules generation.A case study of PMC is analyzed in detail and its feasibility is shown,and a comparison experiment on computational complexity of RMC algorithm shows that it is valuable for knowledge discovery and knowledge-based modelling and control.关键词：equivalence matrix;RAVT;rules extraction;RMC;PMC2|969|7更新时间：2025-07-16
- 摘要：The classic Zoom-FFT,which is for continues sections of signal sequence,is reviewed.A novel method for Zoom-FFT,which is used for disconnected sections of signal sequence noted as R ms＜1,is offered.The algorithm and the computing cost of it are discussed.A formula for the spectrum inversion form a Zoom-FFT spectrum under onto the practical spectrum from which the former is imaged is established and proved.Examples of application of Zoom-FFT for hopping-frequency signals in HF band and inversion of the Zoom-FFT spectrum of disconnected sections of six-tone signals in voice band are offered.The new Zoom-FFT method will be useful for resolving the contradiction between quickly searching for signals and precisely analyzing signals in practical engineering.The time-frequency localization function of Zoom-FFT,similar to that of wavelet analysis,is stated and analyzed.关键词：signal analysis;FFT;FFT Zoom-FFT;spectrum inversion;time-frequency localization2|1726|3更新时间：2025-07-16
- 摘要：An approach of constructing interpretable and precise fuzzy classification system based on fuzzy clustering and genetic algorithm is proposed.First,the precision index is defined,and the necessary conditions of interpretability are analyzed.Second,the number of fuzzy rules is determined by cluster validity indices,and the initial fuzzy classification system is identified using a fuzzy clustering algorithm.Subsequently,the method of merging similar fuzzy sets is used to enhance the interpretability of the initial model.A genetic algorithm is used to improve the precision of the model.The process continues iteratively until the stop criteria are satisfied.The proposed approach is applied to the Iris benchmark classification problem,and the results show its validity.关键词：fuzzy classification system;fuzzy clustering;genetic algorithm;interpretability;precision2|1610|7更新时间：2025-07-16
- 摘要：In the field of cluster analysis,the fuzzy k-means,k-modes and k-prototypes algorithms were designed for numerical,categorical and mixed data sets respectively.However,all the above algorithms assume that each feature of the samples plays a uniform contribution for cluster analysis.To consider the particular contributions of different features,a novel feature weighted fuzzy clustering algorithm is proposed in this paper,in which the ReliefF algorithm is used to assign the weights for every feature.By weighting the features of samples,the above three clustering algorithms can be unified,and better classification results can be also achieved.The experimental results with various real data sets illustrate the effectiveness of the proposed algorithm.关键词：cluster analysis;fuzzy clustering;numeric feature;categorical feature;feature weighte5|2260|51更新时间：2025-07-16
- 摘要：The architecture of an M-ary two dimensional spread spectrum (M-2DSS) system which is motivated by combining two dimensional spread spectrum with M-ary spread spectrum is proposed.It employs a group of orthogonal matrixes to present the input M-ary codes and performs two dimensional spread spectrum on the orthogonal matrixes in the transmitter.In order to evaluate the bit error rate (BER) performance of the proposed system,we have analyzed the theoretical BER performance of the M-2DSS system over Rayleigh fading channels.Finally,compared with the computer simulation results,it shows that the analyzed results agree well with the simulation results.It also supports the correctness of the theoretical BER analysis.关键词：two dimensional spread spectrum;M-ary;DS-CDMA;MC-CDMA4|821|3更新时间：2025-07-16
- 摘要：According to the theory of t-designing,the corresponding relation between points array in finite Galois field and Steiner system has firstly been found,and then the existence of Steiner system in finite filed is researched.By connecting part points array with Steiner system,the parameter correspondence between optical orthogonal code and Steiner system has been established.After that,the designing process of ST-OOC has been researched in detail.The designing results of ST-OOC(qk,k,1) has been given.The result indicates that ST-OOC has excellent performance and characters,such as the lowest cross-correlation,large cardinality and flexibility to choose code-length and code-weight,therefore ST-OOC is very appropriate to OCDMA system.At last,the application of ST-OOC have been has been discussed.关键词：optical code-division multiple access;optical orthogonal code;finite field;Steiner system3|882|3更新时间：2025-07-16
- 摘要：We present a comprehensive analysis for the capacity and bit-error rate (BER) performance of orthogonal space-time block codes (STBCs) over Nakagami fading channels in the presence of keyholes of in multiple-input multiple-output (MIMO).We first derive a tight lower capacity bound.We also present the exact expression for the outage probability and an approximated BER formula.On this basis,we analyze the antenna selection problem over keyhole MIMO channels.Finally numerical results are presented to verify our analysis.It is shown that the diversity order,with antenna selection,is maintained as that of the full complexity system.关键词：multiple-input multiple-output (MIMO);space-time block codes;keyhole;Nakagami fading;antenna selection2|773|2更新时间：2025-07-16
- 摘要：The problems of carrier synchronization in MIMO-OFDM communications system are investigated in the paper.Based on a general model where multiple frequency offsets exist between transmit and receive antennas,a special pilot allocation scheme-sub-band method for the estimation of multiple different frequency offsets is proposed to convert the problem of multiple frequency offsets estimation into a set of single frequency offset estimation problems,which can reduce the complexity.Meanwhile this method is effective in suppressing the inter-carrier interference (ICI) and multi-antenna interference (MAI) and therefore improves the estimation performance.关键词：MIMO-OFDM;frequency offset estimation;sub-band method4|811|4更新时间：2025-07-16
- 摘要：Proactive routing algorithm in Ad Hoc network has the advantages of low routing delay and updated topology maintenance,and it is very suitable to be applied in heavy load network environment.In this paper,aiming at reducing routing overhead and dropping packets,an optimal routing maintenance model for proactive routing protocol of ad hoc network is provided.With the analysis of the model,we draw conclusion that:1)Optimal update time interval of proactive routing protocol has the character of "reverse stability";2)The node number n in the network has the direct ration of h multiply exp (3/2).With simulation results and numerical results,the optimal model proves to be effective.The optimal model introduces an important theory analysis,which is very useful for routing update mechanism and routing scalability in proactive ad hoc routing protocol.关键词：wireless communication;mobile ad hoc network;proactive routing protocol;optimal routing model;protocol performance simulation2|1149|1更新时间：2025-07-16
- 摘要：A novel multiple access control protocol with dynamic token algorithm for MANET is proposed in this paper.The algorithm does not need to establish the virtual token transfer ring in advance.The path through which the token transfers is automatically formed according to the current network topology,which makes the path adapt to the dynamic network topology.To simplify the maintenance process of token and satisfy the QoS requirements of real-time service,the token is periodically established and the lifetime of each token is strictly limited.Furthermore,an interactive synchronization method is presented in this protocol,which make the system operation completely independent on the other system (such as GPS etc.),as well as has the reliable performance and lower complexity.关键词：MANET;multiple access;TDMA;token;QoS2|838|3更新时间：2025-07-16
- 摘要：Based on orthogonal space-time block code,a scheme for constructing unitary space-time code is proposed.The conclusion that the proposed scheme can achieve full diversity is proved.Compared with original scheme,the advantage of proposed scheme is its higher code rate.However,the disadvantage of proposed scheme is its high complexity needed for decoding.In view of high complexity of the optimum decoding algorithm a suboptimal decoding algorithm is employed.The complexity of suboptimal algorithm is almost the same as the fast decoding algorithm of original scheme.Monte-Carlo simulation shows that the required SNR of the proposed scheme is reduced by 5dB relative to original scheme at the same BER and spectrum efficiency.Meanwhile,simulation results indicate that the SNR of the suboptimal algorithm loses about 1dB compared to that of the optimum algorithm.关键词：orthogonal space-time block code;unitary space-time code;space-time code2|809|3更新时间：2025-07-16
- 摘要：In coherent orthogonal frequency division multiplexing systems,the pilot symbols are often inserted into time-frequency grid to tracking the real time variation of the channel response.The frequency synchronization algorithm using these pilot symbols was further analyzed.By modifying the derivation procedures both in time domain and frequency domain,and by the proper approximation,the approximate maximum likelihood estimation result in time domain was derived.Meanwhile,a different form of likelihood function in frequency domain was derived,and the analytical estimation result was also given.The new tracking algorithm decreases the computational complexity greatly,and increases the accuracy of the frequency synchronization.关键词：OFDM systems;carrier frequency offset;maximum likelihood;tracking2|801|1更新时间：2025-07-16
- 摘要：An amplifier with novel configuration is presented.It consists of two parts:a transconductance amplifier and a transresistance amplifier formed by resistor feedback.The combination of these two amplifier forms a voltage amplifier with low output impedance,and the pole at the output node is hardly affected by the loading capacitor.It is used as preamplifier to drive a single stage amplifier and thus a two stage operational amplifier is implemented.Simulation results show that more than 1GHz gain bandwidth product is achieved(4-pfload) with a power consumption of 25mW only.Transient simulation indicates a settling time of less than 10ns for 0.01% accuracy with a close loop gain of 8.This two stage operational amplifier is appropriate to be used in high speed high accuracy pipelined analog to digital converters.关键词：amplifier;gain bandwidth product;pipelined analog to digital converter2|1360|2更新时间：2025-07-16
- 摘要：As one of the current most potential low bit rates speech coding schemes,waveform interpolation model with its high performance,has been paid more and more attention.Based on a kind of Singular Value Decomposition method for decomposing Characteristic Waveform in WI speech coding,the magnitude spectrum of CW is perceptually divided into basic matrix,transitional matrix and supplemental matrix to be quantized respectively,which effectively reduce the computational complexity;In addition,there are three patterns to represent the magnitude spectrum of CW combined by the matrixes above,and then Periodic Factor and Energy Entropy are introduced to indicate the periodicity of matrix,which solved the problems for quantization of parameters after SVD and improved the efficiency of coding.Subjective A/B listening tests indicated that the reconstructed speech quality of the 2.4kbps SVD-WI codec is a little better than that of 2.4kbps MELP coder.关键词：speech coding;waveform interpolation;characteristic waveform;singular value decomposition;periodic factor2|984|11更新时间：2025-07-16
- 摘要：In order to maximize the coding efficiency,H.264 adopts RDO(rate distortion optimization) at the cost of a very high computational complexity.A special research effort is made on fast intra prediction mode selection in this paper.To reduce complexity associated with intra prediction mode selection,an efficient fast mode selection for intra prediction is proposed.First,the Pan's fast algorithm based on edge direction histogram is improved.Second,a 4×4 intra prediction mode selection algorithm based on the feature of the reference pixels is proposed,and then joined together with the improved Pan's algorithm.Experimental results show that,compared with the H.264 encoder JM61,the proposed scheme reduces coding time by 61%~66% for I-frame while maintaining the PSNR unchanged and increasing bit rate slightly.Furthermore,compared with Pan's scheme based on edged direction histogram,the proposed scheme reduces coding time 12%~33% for I-frame while keeping PSNR and bit rate almost unchanged.关键词：intra prediction;encoder complexity;Intra prediction mode selection2|932|12更新时间：2025-07-16
- 摘要：2-D image correlation tracking is a key factor for the 1m optical system on SST (Space Solar Telescope) to reach its 0.1″spatial resolution.The image correlation algorithm's FPGA implementation methods are introduced:2×2 radix butterfly-algorithm,modular structure,two levels infinite state machine,dynamic block float-point,and parallel processing sequence.Only 713us is needed to realize a 32×32 image correlation algorithm on XCV800 FPGA chip with 20MHz clock.Tracking precision is better than 1/50 pixel.关键词：space solar telescope (SST);image correlation;FFT;FPGA2|1004|1更新时间：2025-07-16
- 摘要：H.264/AVC is the newest video coding standard with high compression efficiency.Because it will take a long time to code,it can not achieve the real-time application.An efficient algorithm based on autocorrelation is proposed in this paper.This algorithm will predict every macroblock before coding,then selecting one of the two prediction modes.Therefore,coding time can be reduced dramatically.Experimental results show that the compression time of proposed algorithm is 26.9% less than that of H.264/AVC,only increases a little bit,and the SNR is invariable.关键词：H.264/AVC;Intra-Frame Prediction;histogram;autocorrelation2|1090|15更新时间：2025-07-16
- 摘要：The Gray Level Co-occurrence Matrix (GLCM) has been proved to be a promising method for image texture analysis.However,the parameters in computing the GLCM of an image can be selected from a wide range,which results in a large amount of computation to be needed and makes it difficult to analyze the image textures.To simplify the computation of GLCM,we analyze the computation of GLCM by using Markov Chain property.We prove that GLCM is independent of distance and angle when distance is large enough.According to our analysis,the computation of GLCM is simplified by reducing the number of selected values of distance and angle.Finally,we give simulation results on natural texture images and SAR images to validate the theoretical analysis.关键词：gray level co-occurrence matrix;texture analysis;Markov chain;synthetic aperture radar2|3928|104更新时间：2025-07-16
- 摘要：It is important for improving the image quality to study adaptiv filter algorithm.In this paper,we study the relations and differences between nonlinear diffusion and 2D Haar wavelet shrinkage de-noising,and explain that nonlinear diffusion is superior to Haar wavelet shrinkage in essence.Afterwards,a hybrid de-noising algorithm,based on 2D Haar wavelet shrinkage and total variation (TV) diffusion,is given,which is a tradeoff between restoration quality of images and computing complexity.This algorithm applies TV diffusion to low frequency part of image decomposed by Haar wavelet,and shrinks the wavelet coefficient.Some experiment results show that this hybrid algorithm has the better general performance.关键词：nonlinear diffusion;wavelet shrinkage;total variation;image de-noising2|1195|27更新时间：2025-07-16
- 摘要：In recent years,filtering in wavelet domain became an important research field.Also,some new methods were developed.Denoising based on the soft thresholding is the famous one of them.Simple and effective make it attractive in many applications of signal denoising.In this paper,the optimal soft threshoding is presented.Compared with the soft thretholding,the proposed approach can give better results in signal denoising.关键词：wavelet transform;soft thresholding;signal denoising2|1000|3更新时间：2025-07-16
- 摘要：This paper presents an equivalent formation via wavelet threshold of the diffusion equation defined by Lin-shi operator.Based on the equivalent formation,there are some revisions made for the diffusion coefficient by replacing the Gaussian filtered image with the translational-invariant nonlinear wavelet thresholded image when do estimation of all the derivation levels.This revision will be able to avoid the over-smoothness and edge movement resulting from the Gaussian filter.Finally,experimental results show that the new diffusion equation is effective to eliminate noise while maintaining the edge locations.关键词：anisotropic;diffusion equation;wavelet shrinkage2|1028|11更新时间：2025-07-16
- 摘要：Packet Marking Scheme have been proposed for achieving traceback of DoS attacks,which has several advantages such as short responding time and small resource consuming.Since the randomicity of the packet marking procedure,the number of the packets needed by the victim in reconstructing is much more than the minimum number of packets required,therefore resulting in the increase of the rate of false positives and the responding time.In this paper,a marking-in-order scheme is proposed,which need less packets in reconstructing procedure because of marking the packets in order by storing every target IP's marking state in a hash table.The scheme is more practical for its high efficiency.关键词：IP Traceback;denial of service;DoS;distributed denial of service;DDoS;Packet-marking traceback2|1015|5更新时间：2025-07-16
- 摘要：Lee's signcryption scheme with public verifiability is cryptoanalyzed and improved.By studying the confidentiality and non-repudiation of Lee's scheme,the fact that the confidentiality of Lee's scheme is lost during its public verification is found.Lee's scheme is modified,and the modification overcomes the security problem in Lee's scheme.So the modified scheme is a security signcryption scheme with public verifiability and it is of great benefit to solve the open problem "design signcryption schemes with public verifiability".关键词：signcryption;authenticated encryption;public verify;confidentiality2|835|10更新时间：2025-07-16
- 摘要：Routing scalability may degrade due to the increasing network scale.So the global communication network in the future will intend to a hierarchical routing architecture with multiple routing domains and routing layers.In hierarchical routing,each routing domain compact its internal topology by topology aggregation algorithm and propagates the aggregated routing information to outside.So the topology aggregation algorithm will affect the routing performance greatly.In this paper,a novel topology aggregation method—SHEF algorithm is proposed to compact the asymmetric directed graph.Based upon a heavy-edge-first rule,the source-oriented method and minimum spanning tree are integrated to aggregate the directed graph.Compared with the traditional method,the suggested algorithm can reduce the weight deviation by 75 percent.Simulation results show that SHEF has a good tradeoff between the routing information complexity and routing accuracy,as a result yields outstanding routing performance.关键词：topology aggregation;directed graph;minimum spanning tree;asymmetry network4|1053|1更新时间：2025-07-16
- 摘要：The scaler is widely used in the flat panel displayer (FPD) system,it zooms the input images which have different resolutions to the fixed resolution image.Based on the analysis of the system architecture of scaler chip used in Flat Panel Displayer,three constraints are proposed.When meeting these constraints,the FIFO and the line buffer will neither overflow nor underflow.The display frame will synchronize with the input frame.The simulating result and verification present that the proposed constraints can meet the requirement of system.Then the scaling engine based on bilinear-interpolation algorithm will be introduced.The total design is implemented by using Virtex-II FPGA of XILINX.Finally,the results of system simulation and logic verification are presented.关键词：scaler;constraints;flat panel displayer;scaling engine;FPGA2|927|3更新时间：2025-07-16
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