最新刊期
卷 37 ， 期 7 ， 2009
- 摘要：Fabricated in a standard 0.35 μm CMOS process,a new type detector designed for high energy particle tracking was studied in this work.The detector is based on monolithic CMOS active pixel sensor (MAPS) technology.Using standard CMOS process,signal processing circuits are integrated on the same substrate as the sensors and correlated double sampling (CDS) operation is realized inside pixel.The prototype consists of a 128×32 pixel array and pixel pitch is 25×25 square of micrometer.Measured by a radioactive source55Fe,the temporal noise is only about 12 electrons and the residual offset is only about 4 electrons.The charge-to-voltage conversion factor (CVF) is about 60 μV/e- .During the tests,readout speed reaches 12 μ /frame.关键词：high-energy particle tracking detector;CMOS active pixel sensors;correlated double sampling;temporal noise;fixed pattern noise2|1019|1更新时间：2025-07-16
- 摘要：This paper concerns with the threshold control problem in a shared memory switch fabric.Traditional threshold control schemes are insensitive to the runtime traffic scenarios,and lack an efficient support for multicast forwarding.A novel scheme is presented in this paper,which aims to balance traffic pressure to the output ports and keep the system in an equilibrium state.Derived from a further exploitation of the developed effective bandwidth theory,the proposed scheme delineates an expressive formula that can calculate the shift of bandwidth burden to memory allocation.The association between bandwidth and memory utilization can be used to balance the traffic pressure by adjusting the per-queue thresholds in the shared memory.Furthermore,the presented framework can also encompass the support for multicast cells.The result of simulation shows that the scheme outperforms the traditional dynamic threshold in terms of efficiency and fairness under variant traffic modes.关键词：switch fabric;shared memory;queue threshold;effective traffic;multicast2|1229|0更新时间：2025-07-16
- 摘要：Recent years,discrete time queueing systems have been receiving attention due to their wide applications in design and control of manufacturing and teleconmunication systems,and in modeling and analyzing of computer communication networks.In this paper we consider the discrete time Geom/G/1 queue with multiple vacations and bulk arrival. By using the total probability decomposition technique and u-transform,we discuss the transient and equilibrium distributions of the queue length with the beginning of the any initial state,and obtain the recursion expressions of the u-transform for the transient queue length distribution and the steady queue length distribution.Furthermore,we also obtain the stochastic decomposition of the queue length at a random point in equilibrium.Especially we can obtain some corresponding results under some especial cases.关键词：discrete time queue;bulk arrival;Geom/G/1;transient distribution;steady distribution;recursion expression2|1332|6更新时间：2025-07-16
- 摘要：Based on the algebraic degree and the algebraic thickness of Boolean functions,the relationship of algebraic thickness between a Boolean function and their decomposing Boolean functions is given,and the upper bound on the algebraic thickness of Boolean functions with n variables is 2* *(n-1) by the recurrence method and the reduction to absurdity.The upper bound answers the open problem:"whether there exists a Boolean function with n variables whose algebraic thickness is strictly greater than 2* *(n-1)".At the end of this paper,according to this fact an upper bound on algebraic thickness of elementary symmetric Boolean functions of n variables with algebraic degree k(2≤k≤(n-1)/2) is improved,and some properties on algebraic thickness of Boolean functions are derived.关键词：Boolean functions;algebraic normal form;algebraic thickness;elementary symmetric Boolean functions2|890|2更新时间：2025-07-16
- 摘要：The echo of stepped-frequency pulse series for the point target with rotation,as well as the micro-motion’s influence on one-dimensional range profile,is analyzed in detail.The time-range profile can be synthesized by utilizing slow-time correlations between frames.The varying laws of the range for the rotary point target and the target position in range profiles are contrastively analyzed.Based on this time-range profile,a novel feature extraction method of wideband micro motions is presented,and the theoretical expressions of micro-motion parameters,such as rotation center,rotation radius and angle velocity,are given.The theoretical precision of the micro-motion feature extraction method is deduced.Finally,to verify the results,the outfield experiments of two reflectors with symmetrical rotations are successfully designed and operated for the ground-based millimeter stepped-frequency radar.The idea can be extended to the feature extraction of multiple kinds of motions for stepped-frequency radar,such as vibration and tumbling,and can be adopted in other high resolution radar systems with linear frequency modulation signals.关键词：stepped-frequency radar;time-range profile;rotation;correlation;feature extraction;error analysis2|1416|8更新时间：2025-07-16
- 摘要：Based on the two-layer media imaging problem that high-resolution imaging glacier penetrating radar (HRI-GPR) system has,this paper analyzes the spatial geometry and studies a modified nonlinear chirp scaling algorithm which can compensate the refraction effects and the propagation velocity changes in different medium automatically.This algorithm also can improve the focusing feature of the scatter.According to the model of echo signal,the phase compensation factors and realized steps of algorithm are given.Raw data of the radar is simulated,and image is achieved by using the algorithm proposed.The imaging quality is compared with theoretical value.Experimental results demonstrate the validity of the proposed algorithm.关键词：glacier penetrating radar;nonlinear chirp scaling algorithm;ice thickness;nadir-looking2|905|1更新时间：2025-07-16
- 摘要：During the past long period,the mathematical modeling researches for multi-star LAN have been focusing on single-star LAN,for which all models and performance evaluation of the Contention-Collision Cancellation (C-CC) access mode have already finished.As there exists difficulty in math aspect,the breakthrough of mathematical modeling for double-star LAN is very late,and only deduced the time delay which is the mean waiting time of customers generated by the observing terminal A,on the condition that at the observing time point,there is i customers in system (i is greater than 0,i.e.based on heavy load) and terminal A has 1 customer.In this paper,the type I system model for double-star LAN based on heavy load is revaluated,and get the mean period of time from time point to the end of service for the customer generated firstly by terminal A,on the condition that at observing time point,there are i customers in system (i is greater than 0) and no customer in observing terminal A.This paper consummates the type I mathematical model for double-star LAN,and simulation.The conclusion provides the integrated theoretical foundation to the application of double-star LAN based on heavy load.关键词：double-star LAN;contention-collision cancellation access mode;mathematical modelling2|890|2更新时间：2025-07-16
- 摘要：This paper proposes a novel cross-layer design scheme,named selective-node-based retransmission scheme(SN-RT).It efficiently combines cooperative diversity at the physical layer and automatic repeat request(ARQ) at the data link layer.At the stage of retransmission,the source together with an optimal relay,which is selected based on the instantaneous signal-to-noise ratio of relay-to-destination link,transmit signals to the destination node by following Alamouti-based space-time coding.The explicit expressions of throughput with MPSK modulation over Rayleigh fading channels are derived.The simulation results show that compared to the fixed-node-based retransmission scheme(FN-RT),SN-RT scheme can notably improve system throughput.关键词：cooperative communication;cross-layer design;throughput;automatic repeat request(ARQ);space-time coding2|1325|5更新时间：2025-07-16
- 摘要：The problem of router buffer size is one of the hotspots in recent router research.Existing research focuses on traffic pattern,network topology and configuration,router architecture and configuration,network dynamic and performance evaluation criterion.Based on the existing study on evaluation criterion and traffic pattern,this paper proposes a new evaluation criterion named Flow-Completion Time Ratio,which does not rely on the network property.Based on this criterion,we perform simulations using self-similar traffic as traffic pattern.Observing SFCTR,AFCTR and FCU,we conclude that too large and too small buffer size will both degrade the network performance.We also provide reasonable method of setting router buffer size.关键词：router;buffer;TCP;congestion control2|1226|2更新时间：2025-07-16
- 摘要：This paper proposes a Tree-Based Ant Colony Optimization based on the positive feedback mechanism and uses it to resolve the Degree-Constrained Multicast Routing.The ant in the new algorithm chooses some link according to the possibility distribution and adds it into the multicast sub-tree,while it checks the node where the new link is added.If the node has reached its degree constraint,the ant will never choose the adjacent links of the node.Computational simulation and analysis show validity of the new algorithm.The simulation result shows that the convergence of the new algorithm is much faster than the old one,the performance of the resolution is better,and it also has a lower space complexity when used to resolve the degree-constrained multicast routing.关键词：degree-constrained;multicast routing;ant heuristic algorithm2|1099|3更新时间：2025-07-16
- 摘要：In this paper,based on the priority-based applications we propose the Two-class Priority Based Polling System,which uses Gated and Exhaustive services to realize the priority-based scheme.The model of the new system is set up by method of imbedded Markov chain theory and generation function and the key system performance characteristics such as mean queue length and information packet waiting time are explicitly analyzed.Theoretical and simulation results are identical and show that the new system efficiently differentiates priorities and meets the practial demands of priority-based applications well.关键词：polling system;priority-based scheme;gated service;exhaustive service2|935|5更新时间：2025-07-16
- 摘要：The increasing demand for grid computing resources calls for an incentive-compatible pricing mechanism for differentiated service qualities.The Time-Cost tradeoff problem for grid workflow applications described by Directed Acyclic Graph (DAG) becomes a significant problem.DAG-based optimization problem has been shown to be NP-hard in general cases.In this paper,a new concept called TCS (Time-dependent Coupling Strength) is introduced,which is identified for a given activity the maximum number of time-dependent coupling activities.By incorporating it into priority rule BF (Best Fit) which only takes into account the ratio of the cost improvement to the increase of duration of an activity,a novel priority rule BFTCS (Best Fit with Time-dependent Coupling Strength) is proposed,which is implemented in a heuristic to improve further the feasible initial solutions.Computational experiments indicate that rule BFTCS based heuristic can perform better than other existing heuristics but require a little more computation time.As well,the impact of problem parameters on the heuristics is discussed.关键词：grid computing;workflow;directed acyclic graph (DAG);priority rules;time-dependent coupling strength2|1431|12更新时间：2025-07-16
- 摘要：Adaptive modulation techniques can improve the BER (bit error rate) performance or the average throughput by employing a suitable modulation mode depending on the instantaneous channel SNR (signal-to-noise ratio).In this paper the optimum SNR thresholds over a 6-path Rayleigh channel are derived,which shows a superior BPS (bit per symbol) throughput performance while maintaining the target average BER.The 6-path Rayleigh channel is often applied to mobile environment with high-speed.The results achieved in this paper can be applied to the adaptive modulation system with the channel of ITU-R M.1225 Vehicular Test A mode.Performance simulation of the derived thresholds in the IEEE802.16e OFDM system is presented and then the simulation results are analyzed.关键词：adaptive modulation;AQAM;optimum switching-levels;IEEE802.16e;OFDM2|1118|3更新时间：2025-07-16
- 摘要：A novel method for voice conversion based on Viterbi algorithm is proposed in this paper.This method uses the matrix of transition probabilities of the target speaker’ frames to represent the timing information of the speech sequence,and then determines the most appropriate component of the GMM by utilizing the Viterbi algorithm for converting each frame of the source speech.It avoids the spectral discontinuities caused by losing the relationship between the adjacent speech frames,and alleviates the spectral smoothing due to the weighted averaging in the traditional GMM-based algorithms and then enhances the formant.Both objective and subjective evaluation’s results have demonstrated that the proposed method improves the performance of the conventional voice conversion system based on GMM.关键词：speech processing;voice conversion;prosody transformation;Viterbi algorithm2|1236|0更新时间：2025-07-16
- 摘要：A new perfect correlation signal is proposed,which can be called as pseudorandom punctured binary array pairs.The transform properties,Fourier spectrum characters and combinatorial admissibility conditions of the pseudorandom punctured binary array pairs are studied.By making use of these properties and conditions,the efficiency of searching the pseudorandom punctured binary array pairs can be improved significantly.As a computational illustration,a set of pseudorandom punctured binary array pairs are given.The searching results show that the existent range of pseudorandom punctured binary array pairs is so wide that they are suitable for engineering applications.关键词：perfect correlation signal;array pairs;pseudorandom;information theory2|875|1更新时间：2025-07-16
- 摘要：Geometry transformation is the basis of many image processing procedure.The linear interpolation method need little computation and can maintain image quality to some extent,so it is selected for the image geometry transformation in many cases.But the linear interpolation still need to be speed up when real-time processing is needed or being computed on devices with poor computing capacity.In this paper,two rules are concluded to integerize operands of an expression computed on digital devices.Based on the two rules,a scheme is proposed to integerize bilinear image interpolation (trilinear interpolation can be as the same),under conditions that the result of which has no loss in precision compared to the result of the original method.Then,the most frequently used transformation,affine transformation,is taken as an example to give a scheme and its analysis to integerize the whole image transformation procedure.The experiment on PC shows that the proposed scheme is much faster than the original method.In addition,the scheme proposed in this paper is highly parallel.关键词：interpolation;bilinear;trilinear;integerize2|1276|4更新时间：2025-07-16
- 摘要：Nowadays,there is a great development in sequential estimation technology,which is the main field of sequential acquisition.But the sequential estimation algorithms lack of an effective and compatible analyzing model to meet this development.The paper presents a 2-dimensional accumulating space analyzing model,and the analyzing model gives the corresponding relationship of the amplitude accumulating space and the probability accumulating space.Based on the analysis results of the model,we could design some other sequential estimation algorithm with better performance.The simulation results show that they accord with the theory analysis results and the analyzing model can be used to analyze much of the existing sequential estimation algorithms.关键词：pseudo-noise(PN) sequence;analyzing model;sequential estimation;acquisition;2-dimentional accumulating space2|798|0更新时间：2025-07-16
- 摘要：In this paper,we present a multiscale texture image segmentation algorithm based on adaptive window fixing and propagation.After raw segmentation based on wavelet domain hidden markov tree model,we use the fine consistency in coarse scale and accurate edges in fine scale of the raw segmentation result,label the homogeneity region and discontinuity region with different markers according to the characteristics of Markov between the node and its neighborhood and its father node,then we fix the homogeneity region and transfer their labels into their childrens;To discontinuity region,we determine a weight context by the neighbor information and transfer into the next scale to instruct the segmentation with the information of this scale,finally we maintain the uniformity of regions and accuracy of edges.At the same time,we use an algorithm based on the Local polynomial approximation and Intersection of Confidence Intervals(LPA-ICI) to find out the physical location of centers of each texture due to the feature of aggregation of textures,then integrate them into the weight context so as to lead better segmentation.The experimental results shown that both on segmentation accuracy and boundary localization are greatly improved to synthetic texture images,and the proposed method is fast and does not need training.2|2139|0更新时间：2025-07-16
- 摘要：Based on the analysis results of ultrasonic signal acquired in an actual system,an empirical model named double exponential model using the linear sum of two exponentials is proposed.The full width half maximum and the rise time of double exponential model are analyzed,and the methods of model’s parameters estimation are introduced.Further the fitting accuracy and TOF( time of flight) estimation variance of double exponential model are compared to those of hybrid exponential model.It is shown that the double exponential model is suitable for the ultrasonic signal in which the ratio of the full width half maximum and the rise time is more than 2.5.关键词：ultrasonic;double exponential model;Prony method;Nelder-Mead method;TOF2|1450|10更新时间：2025-07-16
- 摘要：Glint error is one of the primary error sources in the homing guidance of radar tracking on extended targets.Many scholars have done much theoretic and experimental research on glint,mainly discussed on the statistical dependence between glint and RCS.One opinion supports that the relation between glint and RCS has a negative relativity,the other one is that there is no relativity,but not independent.This understanding on the nature of glint is still explored.In this paper,we analyze the nonlinearity of the glint series,study the glint series based on the criterions of chaos feature,and then conclude that the glint series have chaos feature for complex targets.关键词：radar target;glint error;chaos2|1075|6更新时间：2025-07-16
- 摘要：Using air-borne Ultra-WideBand Synthetic Aperture Radar (UWB SAR) to detection underground unexploded ordnance (UXO) has the advantages of safety and efficiency.UXO detection is composed of prescreening and discrimination.Prescreening is to extract several suspected targets from SAR imagery of wide areas and discrimination is to classify these suspected targets into UXO and clutter to reduce false alarms.In this paper,the Hidden Markov Model (HMM) kernel HyperSphere Support Vector Machine (HS-SVM) UXO discriminator is proposed.HMM kernel HS-SVM employs the structural risk minimization theory and uses hypersphere in kernel feature space to classify UXO and clutter,which can solve the two problems of a small training set and without typical clutter samples.In addition,the HMM,which describes the UXO multi-aspect feature,is used as the kernel function of HS-SVM can improve the UXO discrimination performance further.The field data processing discrimination results show that HMM kernel HS-SVM outperforms the HMM and the Gaussian kernel HS-SVM in UXO discrimination.关键词：ultra-wideband;synthetic aperture radar (SAR);hidden Markov model (HMM) kernel;hypersphere support vector machine;unexploded ordnance2|1053|0更新时间：2025-07-16
- 摘要：In order to mark occluded regions explicitly on the disparity map,the dynamic programming is employed to search optimal disparity curve on base of the calculating disparity space at first.Each point on the optimal disparity curve must be in one of three states:matching state or other two occlusion states.To guarantee the disparity curve passing through ground control points (GCP),an algorithm of dynamic programming in segments is proposed,that is,the disparity space image is divided into ground control regions and non-ground control regions.In the ground control region,the searching path is forced to pass GCPs.In the non-ground control region,the optimal path searching is under dynamic programming.For the reliability of the GCP,four criterions are presented to choose a point as a GCP.Experimental results show that the new algorithm has certain enhancement in the precision of occlusion detection and matching,and is more reliable and faster than conventional dynamic algorithms.关键词：dynamic programming;occlusion detection;stereo matching;disparity estimation2|1181|2更新时间：2025-07-16
- 摘要：Based on independent sub-band functions and wavelet analysis,the paper presents a new technique of signal processing to accomplish blind source separation when a single-channel mixture signal in noise is given.Firstly we analyzed the compositional principle of independent sub-band function and the method how to get independent sub-band function.And combining independent sub-band function into the single mixture signal,a single mixture signal can be transformed into a multi-dimensional vector from one-dimensional.Then we discuss the problems of second de-noising with wavelet and the order’s uncertainty of data segments.The paper also presents a determine method of the number of independent sub-band function and the similar phase diagram.Through an experiment of eliminating the artifact of transient evoked otoacoustic emissions,the feasibility and effectiveness of this method have been proven.关键词：blind signal separation;independent sub-band function;noise;wavelet;independent component analysis;transient evoked otoacoustic emissions2|1405|4更新时间：2025-07-16
- 摘要：Image guided radiotherapy (IGRT) has a wide application in numeric radiotherapy with high locating accuracy and real time track.Exact matching is the precondition of IGRT.This paper presents a new way of fast registration using the Legendre moment,and monitoring the patient in real time by detecting and tracking infrared markers.Firstly,the steps of the new way are introduced.Secondly,compared to the traditional means about relaxation,the new way has obvious advantages in reducing misidentification ratio and escaping ill-conditioned equations.Lastly,the effectiveness about accuracy and real time track,have been testified in clinic application using the new way.关键词：Legendre moment;image matching;image guided radiotherapy;real time track2|865|2更新时间：2025-07-16
- 摘要：A sea surface microstructure optical measuring device can be used to obtain images color-coding slope information of capillary and capillary-gravity surface waves on the water surface.According to the slope of local region on the water surface,the slope wave number spectrum of the original image is computed.Because the size of the image is limited,the gravity waves are cut off within a period and the phenomenon of frequency aliasing will appear.This is called Gibbs phenomenon mathematically.So,the wavelet analysis is employed to filter the gravity waves,which can lead to the frequency aliasing.Then the slope wave number spectrum of the micro-scale wave is computed.关键词：slope wave number spectrum;microstructure optical measuring device;wavelet analysis2|1090|2更新时间：2025-07-16
- 摘要：In this paper,we propose a multilevel coded modulation system based on superimposed LDPC codes.Compared with traditional multilevel coding techniques,superimposed coded modulation system is symmetric among different layers and hence can be expanded easily.By comparing the decoding complexity of LDPC codes with that of turbo codes,we point out that the proposed superimposed LDPC coded modulation system can be easily designed and implemented.Simulation results show that superimposed LDPC coded modulation system has good performance without sacrificing bandwidth.关键词：LDPC codes;superimposed multilevel coded modulation;Turbo codes3|1308|5更新时间：2025-07-16
- 摘要：DNA encoding is how to design the DNA sequences in the initial solution space of DNA computation.Reasonable DNA codes could improve the reliability and stability of experiment and the successful rate of computation.In this paper,we propose the definitions of the weight of a DNA codeword,the Watson-Crick Hamming Distance between two DNA codewords,and the design of DNA Golay codes.Then,we analyze the properties and the size of DNA Golay codes.Comparing with the stochastic search algorithm,DNA Golay codes are easier and more feasible to generate good code.关键词：DNA computation;DNA encoding;Golay code;Hamming distance2|1028|2更新时间：2025-07-16
- 摘要：In order to meet the challenge of real-time processing of G-level pixel frame,to solve such problems as high-volume calculation and lack of parallelism in conventional DCT,a parallel computation method implemented on SIMD PE array for DCT transform is presented in this paper.With the inherited customizability of PE array,this method can be applied to various embedded application systems regardless of their requirements on parallelism.A specific data parallel operation method using PE identifier is proposed.It not only solves the problem of "PE autonomy" in local operation,but also eliminates the cost of time in data addressing.This well-structured and compact data operation satisfies the high-regularity required by SIMD operation,and conforms to the trend of parallel processing technology.关键词：parallel processing;DCT;SIMD PE array;mapping language2|984|1更新时间：2025-07-16
- 摘要：This paper proposes a distributed model termed as Tower-like Master-Slave Model (TMSM) for the artificial immune systems.Based on TMSM,a distributed immune memory clonal selection algorithm (DIMCSA) is put forward for solving numerical optimization problem.Using the theorem of Markov chain,we have proved the convergence of DIMCSA.In order to get away from the influence of network conditions and get a veracious estimation on the DIMCSA’ efficiency,Multi-thread simulative parallel computing system (MSPCS) is designed here and a novel performing index in which the searching time and network communication time are considered respectively is also proposed for distributed stochastic searching approaches.Experimental results indicate that DIMCSA can achieve better solutions with less computing and fewer communications,and it is capable of solving massive and complicated optimization problems.关键词：distributed artificial immune model;numerical optimization;clonal selection;Markov chain4|1042|6更新时间：2025-07-16
- 摘要：Distributed denial of service(DDoS)attacks remain a serious threat on the Internet and again it is very difficult to devise a perfect DDoS defense mechanism.In this paper,we investigate the damage caused by the DDoS attacks and analyze the root reasons why DDoS attacks take place.After that,we make a survey on the new solutions against DDoS attacks especially after year 2005,which mainly includes 1)Network filters based on ISP;2)Proof-of-work;3)Overlay network;and 4)Network capabilities.We analyze the advantages and disadvantages of these solutions,and conclude the features of the deployed solutions.Finally,we discuss possible future defense strategies against the DDoS attacks.关键词：DDoS(distributed denial of service);survey;network capabilities;reverse turing test3|2237|13更新时间：2025-07-16
- 摘要：Most network communication based on TCP treats data as an ordered sequence of packets.This ordered-sequence paradigm of TCP is too restrictive when the data is large or is to be distributed to a large number of users.In the data transmission paradigm based on digital fountain codes,obviating the need for ordered data simplifies data delivery.Thus,digital fountain codes are a class of efficient codes which are suitable for reliable communication,and have been widely used in many respects.This paper surveys the principles of a few types of digital fountain codes and their advantages and disadvantages,and investigates their engineering applications.Some key problems needed to be solved in the study of digital fountain codes are pointed out.Finally,the future development and research directions of digital fountain codes are discussed.关键词：digital fountain codes;erasure codes;erasure channel;LT codes;Raptor codes2|5106|14更新时间：2025-07-16
- 摘要：To overcome the shortcomings of conventional measure criterion of evidence conflict and solve the invalidation problem of Dempster-Shafer evidence combination rule with high conflict,a novel measure criterion of evidence conflict is defined through pignistic transformation.Based on this definition,a new improved D-S algorithm is proposed in this paper.According to the decision idea that the minority is subordinate to the majority,the proposed algorithm first preprocesses evidence through introducing weight coefficients which represent the importance degree of evidence,then combines preprocessed evidence using Dempster's rule.The numerical study shows that,compared with other methods,the new algorithm has made good performance in dealing with evidence conflict and can accelerate convergence and reduce the decision risk.关键词：D-S theory;evidence conflict;combination rule;pignistic transformation;information entropy2|1516|50更新时间：2025-07-16
- 摘要：Orthognal Frequency Divison Multiplexing (OFDM) has been adopted by many high speed transmission standards.Pilot tone assisted modulation (PTAM) is well known technique to achieve timing synchronization information in OFDM but is not bandwidth efficient.To achieve high bandwidth efficiency,we proposed to carry out sperimposed a transparent genralized chirp-like (GCL) training with lower power in the guard band onto the time domain to improve the timing synchronization quality.The power ratio of the GCL sequence is determined by minimizing the system bit error rate (BER) using simulation experiments.Simulation results demonstrate that under medium to low SNR conditions,combing superimposed training with synchronization yields BER performance that is comparable with PTAM;the benefit of the former is that bandwidth efficiency is preserved.关键词：bandwidth effieciency;frame synchronization;superimposed training;guard band.2|1083|2更新时间：2025-07-16
- 摘要：In view of the adaptive selection of step-size factor in sequential blind source separation,a novel variable step-size algorithm is presented based on the correspondence between separating performance index and step-size.The proposed algorithm restructures the performance index by adopting an auxiliary separation system with some restriction and attains the adaptive updating rule of step-size in the light of the index descending in an exponential form.Simulation results show that the convergence and steady-state performance of the proposed method outperforms the fixed step-size and the recently proposed adaptive step-size algorithms in both stationary and non-stationary environments.关键词：blind source separation;auxiliary system;adaptive variable step-size;convergence4|992|4更新时间：2025-07-16
- 摘要：Shortest Path Problem in network can be acted as a model for many application problems,but the iteration process of the conventional solution algeorithm is complex.In this paper,the shortest path algorithm based on the matrix multiplication in a weighted-graph are described,and its time complexity is as same as Dijkstra algorithm.In a given network graph,this algorithm delete spare nodes or edges and reach the goal that reduced network graph and improved speed of solving problem under the condition of unchanged shortest parth.Finally,we give examples,e.g.Traveling Salesman Problem,shortest path problem,to illistrate its advanteges,possessing merits of simple operation and easy understanding,compared with dynamic programming technology.关键词：matrix multiplication;shortest path problem;reduced principle;traveling salesman problems2|1905|1更新时间：2025-07-16
- 摘要：Characteristic waveform (CW) decomposition based on discrete cosine transform (DCT) is proposed firstly in waveform interpolation (WI) speech coding.The complicated CW alignment operation is cancelled by using this method.Secondly,a new unvoiced/voiced phase decision method and the classification method of voiced phase are proposed with respect to phase reconstruction.Finally,DCT-WI coders at 2.0kbps and 1.6kbps are designed,respectively.The subjective MOS test results indicate that the 2.0kbps DCT-WI coder outperforms 2.4kbps MELP coder and the 1.6kbps DCT-WI coder also has a good performance.关键词：speech coding;waveform interpolation;characteristic waveform;discrete cosine transform;alignment of characteristic waveform;phase reconstruction2|1228|3更新时间：2025-07-16
- 摘要：In order to fasten and improve the bearing estimation method for wideband Linear Frequency Modulated(LFM)sources by exploiting the temporal information of this kind of signals,a new direction finding method based on the product of the array output with its temporally delayed version is proposed.The new method succeeded to estimate the direction-of-arrival(DOA)of the incident wideband LFM signals via narrowband subspace-based method,and exceeded normal wideband direction finding methods in computational efficiency and applicable inter-element spacing.Sufficient numerical examples are carried out to demonstrate the dominance of the novel method over normal wideband Coherent Signal-Subspace Method(CSM)in performance.关键词：array signal processing;bearing finding;linear frequency modulation;delay-and-product2|1234|5更新时间：2025-07-16
- 摘要：Through the analysis of characteristics about background and target in visible optical image of deep outer space,the matching of image sequence at sub-pixel is realized by the method of iterative computing which is proposed to adaptive searching the pixel-mass center of fixed star and the model of characteristics which is constructed on spatial distribution.Based on image sequence matching and dividing,the arithmetic of real-time detection for dim moving target is designed by the clustering on 8-neighbour-pixel.关键词：visible optical image of deep outer space;dim moving target;real time detection;iterative computing of pixel-mass center2|1235|7更新时间：2025-07-16
- 摘要：The conventional subspaces based tracking methods usually have low precision of object matching and tracking,because they lose the inherent partial structure and neighborhood information.In this paper,an incremental tensor subspace learning algorithm is proposed to model and update the object appearance in tensor subspace.Simultaneously,by combining the proposed learning algorithm with Bayesian inference,an adaptive object tracking method is presented.Firstly,we represented the appearance of the object in tensor subspace;secondly,obtained the optimal estimation of the state parameters by Bayesian inference;finally updated the tensor subspace by using the optimal observation.Due to the construction information is maintained,the proposed method is able to track targets effectively and robustly under pose variation,short-time occlusion and large lighting and so on in the experiments.关键词：tensor subspace;incremental learning;bayesian inference;affine motion3|1436|7更新时间：2025-07-16
- 摘要：The modes propagation characteristics and modular interference beat length in Elliptical-core Polarization Maintenance Fiber(E-core PMF) are very important parameters for designing optic-fiber sensors based on modular interference.They play an important role in deciding the work wavelength,dynamic range and linearity of optic-fiber sensors.This paper calculates the modes propagation characteristics and modular interference beat length theoretically.The propagation characteristics of several low order modes in E-core PMF are calculated,and as a result,the modular interference beat length of LP01 and LPe11 is obtained.An experiment is designed to investigate the modular interference beat length in an E-core PMF,and the experiment result shows that the beat length is about several hundreds micron,which is very suitable for designing applicable and reliable optic-fiber sensors.关键词：polarization maintenance fiber;modular interference beat length;optic-fiber sendsor;Marcatili method2|1436|3更新时间：2025-07-16
- 摘要：Utilizing the feature selection in the intrusion detection can delete the redundant features on the base of protecting the integrity of original data and improve the detection speed of the system efficiently.This paper proposes a new feature selection method that is based on KNN and Tabu search algorithm.The experiment result shows that this method can remove the redundant features,and reduce the time of feature selection.This method not only can guarantee the correct rate of detection but also improve the detection speed efficiently.关键词：intrusion detection;feature selection;feature relevance;tabu search2|2844|7更新时间：2025-07-16
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