最新刊期
卷 39 ， 期 10 ， 2011
- 摘要：Multi-frame integration is commonly used in image enhancement technology as a method,which has some limitations when dealing with low light level image.Further discusses and experiments are done,and an approach based on the mode theory is carried out.It is called mode multi-frame integration.Mode multi-frame integration is making the grey scale value statistics of all the pixels inside the neighborhood frames and taking the grey scale mode as the filtering result,so the processed image is closer to the truth.The experimental results show that it can suppress the light and the dark noises of low light level image effectively,and as for the protection of the image edge,the property of it is better than that of multi-frame integration.It has important practical value.关键词：noises;multi-frame integration;mode multi-frame integration;low light level image;peak signal-to-noise ratio2|1056|3更新时间：2025-07-16
- 摘要：In terms of Shannon formula,multiple-input multiple-output (MIMO) theory tries to derive the formula of wireless channel capacity (WCC),which is proportional to the number of transmitting and receiving antennas in MIMO system.As multi-antenna is used in MIMO system to transmit signals with the same carrier frequency in the same time,one physical channel in MIMO system will contain multi-virtual independent Rayleigh fading channel.So,the definition in MIMO theory for the independent Rayleigh fading channel is most possibly to be invalid.This will lead space division multiplex (SDM) to be difficult to be realized,and the derived WCC formula in mathematics to be difficult to be established.Moreover,the directional transmission beams with uncertain directions are employed in the MIMO system.The interference among those transmitting signals can not be avoided,which would form a number of blind spots of radio coverage and an unreasonable wireless communication system.In this paper,the above views are firstly proved by mathematical analysis and the simulation of the transmitting radio beam produced by multi-antenna.Then,an SHPCA system is proposed,in which phase-controlled antenna array is used to produce a narrow directional radio beam with very high power efficiency to form SDM.Finally,the WCC formula for SHPCA system is presented in the paper,and its capacity is proportional to the numbers of antennas and SDM.It has higher efficiency for that WCC formula than Shannon formula.关键词：MIMO;Shannon formula;channel capacity;phase-controlled antenna array;physical characteristic of antenna3|3387|10更新时间：2025-07-16
- 摘要：Based on the idea of quantitative logic,the definition of the truth degrees of formulas is proposed in (3n+1)-valued propositional logic system R0L,and its main properties are discussed.The integral representation of the truth degrees of formulas is given,the truth degree modus ponens and truth degree hypothetical syllogism are proved.The concepts of similarity degree and pseudo-metric among formulas are introduced by means of the truth degree.The work of this paper is the base for establishing the framework of approximate reasoning on (3n+1)-valued propositional logic system R0L.关键词：quantitative logic;R0Łsystem;truth degree;similarity degree;pseudo-metric2|622|7更新时间：2025-07-16
- 摘要：The performance of the system with maximal ratio combining and multiuser scheduling is studied in the multiuser uplink in the presence of unequal power cochannel interferences from other cells.The channels of useful and interference signals are assumed to be Nakagami-m and Rayleigh fading.The closed form expressions for outage probability and average symbol error ratio (ASER) of system are derived by using performance analysis method based on probability density function.Simulation results show that,the analytical curves of the derived expressions match well with the numerical simulations,and the increase of the number of receive antennas and users are both of benefit to the improvement of system performance due to multi-antenna and multiuser diversity,and the presence of a predominant interferer deteriorates the outage performance.关键词：cochannel interference (CCI);maximum ratio combining (MRC);multiuser diversity;outage probability;average symbol error ratio (ASER)2|2171|1更新时间：2025-07-16
- 摘要：Aiming at increasing the utilization of the substrate network resources,we model the VN embedding problem as an integer linear programming (ILP) with no assumption that substrate network needs to support path splitting.Then we propose a new VN embedding algorithm based on particle swarm optimization (short for VNE-PSO) for solving this problem.In VNE-PSO,the resource cost of VN embedding is considered as the fitness function and the parameters and operations of the particles in PSO are redefined according to the ILP model of the optimal VN embedding problem.The simulation results demonstrate that the proposed algorithm can increase the long-term average revenue and acceptance ratio while decreasing the runtime comparing with existing approaches.关键词：network virtualization;virtual network embedding;integer linear programming;intelligent optimization;particle swarm optimization2|2089|21更新时间：2025-07-16
- 摘要：Cognitive networks can perceive the external environment,and intelligently and automatically change their behavior to adapt to the environment,so it is more suitable to provide users security with QoS.Designing a high-precision traffic prediction model can improve the cognitive feature of cognitive networks.For the models of low forecasting precision,highly independence to training samples and bad description of network traffic,we propose a new model.It trains BP with Ant Colony Algorithm,which avoids slow convergence speed and easily falling into local optimum problems existed in the gradient descent method.Besides,we reject the abnormal data using BP1,do wavelet decomposition,and predict the network traffic with hybrid model.Experimental results show its high-precision in cognitive networks.关键词：cognitive networks;network traffic prediction;neural network;ant colony algorithm;wavelet2|1692|7更新时间：2025-07-16
- 摘要：To satisfy the increasing bandwidth requirement of Fibre Channel (FC) switched networks,Virtual Channel (VC) architecture was proposed in new version FC protocols,in order to allocate traffic flows by logical communications channels.Under hard real-time constraint,VC has been expanded from "point-to-point" to "end-to-end",and this paper proposes the allocation scheme of VC based on Network Calculus and token bucket to reduce the end-to-end delay of traffic flows in whole FC networks.Thus it has been solved the three hard works in FC protocols:how to determine the number of each kind of VC;how to guarantee each VC's credit;and how to choose the path of each VC.Computer simulations results show that VC allocation scheme has good flexibility with traffic increasing intensity,thus enhance the availability of VC architecture into FC switched networks.关键词：fibre channel;packet switched networks;virtual channel;hard real-time guarantee;allocation scheme;network calculus2|1146|0更新时间：2025-07-16
- 摘要：Congestion in wireless sensor networks (WSNs) can lead to longer delay,higher packet loss ratio,and higher energy waste due to a large number of packet retransmissions and packet drops after several retransmission failures.To detect congestion precisely and regulate it fairly,a congestion control protocol based on cross-layer design,i.e.upstream congestion control (UCC) protocol,is proposed.In the protocol,each node takes advantage of unoccupied buffer size and predicted traffic flow at medium access control (MAC) layer as congestion level indication,and combines node priority to assign the upstream traffic rates of its last-hop nodes.Based on this congestion detection and priority-based rate adjustment schemes,the UCC protocol utilizes a cross-layer optimization and mitigates congestion with the help of hop-by–hop rate adjustment.Finally,simulation results show that the proposed protocol achieves higher throughput,better priority-based fairness and lower packet loss ratio than both congestion control and fairness (CCF) protocol and priority-based congestion control protocol (PCCP).关键词：Wireless sensor networks;congestion control;cross-layer optimization;fairness2|1436|8更新时间：2025-07-16
- 摘要：Considering time hopping impulse radio ultra wide band (TH-IR UWB) sensor networks composed n sensor nodes which are placed according to a Poisson point process on a square and a Sink.The results demonstrate that the bounds on the lifetime of dense network increase with the increase of the number of nodes n,and that of extended network decrease with the increase of the number of nodes n.The results also indicate the bounds on the lifetime of clustering sensor networks is far more than that of non-clustering network,thus clustering can evidently improve network lifetime.Furthermore,the bounds on the lifetime of clustering TH-IR UWB sensor network which the nodes are distributed according to a Poisson point process are different from that of clustering network which the nodes are placed according to uniform distribution,thus the behavior of nodes deploying can remarkably affect the lifetime bound.关键词：wireless sensor network;ultra wide band;lifetime;clustering;energy dissipation2|982|0更新时间：2025-07-16
- 摘要：The problem of waveform adaptation to maximize information rate in a multiple-in multiple-out cognitive radio (MIMO-CR) network is investigated from a non-cooperative game theoretic viewpoint.The existence and uniqueness of the Nash equilibrium under certain circumstances is proved and a decentralized iterative water-filling algorithm with punishing price,MIMO-CR IWFA,is proposed to solve the above problem,the pricing mechanism is used to satisfy the interference-temperature constraint while achieving the Nash equilibrium,the conditions for the convergence of MIMO-CR IWFA are also provided.Simulation results show our MIMO-CR IWFA can satisfy the interference-temperature constraint perfectly and is fast convergent;and though constrained by PU's interference-temperature,the performance of MIMO-CR IWFA can still approach the classical MIMO IWFA,which does not consider the interference-temperature constraint,with the increase of co-channel interference between MIMO-CRs.关键词：multiple-in multiple-out (MIMO);iterative water-filling algorithm (IWFA);nash equilibrium;game theory;cognitive radio2|1195|0更新时间：2025-07-16
- 摘要：Thresholding method based on graylevel co-occurrence matrix is a basic image segmentation method.The means of the object region and background region are defined based on symmetric co-occurrence matrix,and thresholding segmentation method is proposed.Compared with the common thresholding method based on symmetric co-occurrence matrix,the method is more adaptable to images.Simulation results verify the effectiveness of the method.关键词：image segmentation;threshold selection;symmetric co-occurrence matrix2|1285|7更新时间：2025-07-16
- 摘要：For generalized 3x+1 function T(x),the feature of fixed points and their existence-domain analysis is an important problem in fractal.T(x) is a complex transcendental function and its fixed point in C-plane is hardly to solve.Meanwhile,the feature of fixed point is difficult to analyze.All these become an obstacle for the further study of T(x) dynamic system.In this paper,Because of the topological invariance of T(x),we constructively proved its fixed point in C-plane firstly.Then we give the analysis for the existence domain of fixed points as well as their feature.Based on the existence domain of T(x) fixed points,we estimated their distributions in C-plane.So we put forward a numerical algorithm for solving the fixed points of T(x) by analyzed the basis of distributions.Furthermore,we obtained some convergence domains of T(x) in C-plane and drew fractal image of these domains.The result of numerical experiment shows that the algorithm in this paper is correct and easy to implement.关键词：fractal;generalized 3x+1 function;fixed point;existence domain;escape time;numerical algorithm2|1082|1更新时间：2025-07-16
- 摘要：For the image retrieval task which combines machine learning theory with relevance feedback mechanism,this paper focuses on the graph-based semi-supervised learning algorithm with application to region-based image retrieval.Different schemes which both incorporate the region saliency into the graph-based semi-supervised learning framework are applied to deal with two types of feedback.Firstly,in the case that no sample or only positive samples are available from the user's feedback,the retrieval task can be resolved via a transductive learning manner,a hierarchical graph model which incorporates region saliency information is constructed and the manifold-ranking algorithm is adopted subsequently for positive label propagation.Secondly,in the case that the user provides both positive and negative samples,the region-level adjacency matrix will be constructed via the feedback samples,and the manifold-ranking algorithm is also adopted here to choose instances which truly represent the user's query semantics.The selected instances are then used to retrieve the relevant samples.The experiments have proved the effectiveness of the proposed method.关键词：content-based image retrieval;region saliency;graph learning;manifold-ranking;relevance feedback2|1498|11更新时间：2025-07-16
- 摘要：This paper proposes a robust and efficient needle detection method,which is used to localize and track the needle in three-dimensional (3D) transrectal ultrasound (TRUS) guided prostate therapy.First,all voxels are grouped into different line support regions (LSR) based on the outer product of adjacent voxels' gradient vectors.The needle axis is extracted by least square fitting in LSR.The needle endpoint is localized by finding an intensity drop along the needle axis.Evaluation results in synthetic data,tissue-mimicking agar,chicken breast phantoms and 3D TRUS patient images obtained during the prostate cryotherapy show that the proposed methods is with a relatively higher robustness and accuracy.The result of the in-vivo test also shows that our method outperformed several alternative methods in needle endpoint localization accuracy and TP rate.It is concluded that the proposed method is suitable for 3D TRUS guided prostate transperineal therapy.关键词：needle segmentation;phase grouping;3D ultrasound images;3D transrectal ultrasound;prostate therapy2|963|1更新时间：2025-07-16
- 摘要：The particle filter (PF) algorithm has been successfully applied to synthetic aperture radar (SAR) image despeckling.In this paper,we propose a modified PF despeckling algorithm based on Markov random field (MRF) in stationary wavelet domain.It is shown that the wavelet coefficients of SAR images which exhibit significantly non-Gaussian statistics can be described accurately by generalized Gaussian distribution (GGD) in stationary wavelet domain.MRF is introduced to redefine the weight of the particles to amend the weight deviation.Furthermore,the sampling interval is updated according to the new weight.To enhance the efficiency of the proposed algorithm,region-divided processing is implemented.Experiment results and analysis demonstrate the ascendant performance of the proposed algorithm in noise reduction,preservation of the textural features,single target and edges of SAR images.关键词：SAR image despeckling;SWT-GGD;weight selection of particle;MRF-PF;region-divided processing2|1328|1更新时间：2025-07-16
- 摘要：A new model about BRDF defined by microfacet was developed for spatial object optical reflection modeling based on the principle of optical geometry and the technique of ray tracing.This model briefly contains the contribution to spatial object reflection characteristics by the microfacet normal direction,reflectivity and the shelter relation among microfacets.The diffuse reflection and the mirroring reflection are employed by this model in order to calculate the whole luminance characteristic and the local high luminance characteristic of spatial object.The result of validating work showed that the BRDF microfacet model curve is basically consistent as the actual measurement data curve.The rendering experiment expressly proved that the BRDF microfacet model could be used to simulate the effect exactly and calculate the optical reflection characteristic accurately of spatial object.关键词：spatial object;realistic imaging;microfacet;bidirectional reflectance distribution function(BRDF)2|1291|0更新时间：2025-07-16
- 摘要：A new method for joint time delay and Doppler shift estimation based on the fractional lower-order cyclic cross ambiguity function (FCCA) and multi-cycle frequencies is proposed.The relationship among fractional lower-order cyclic correlation,second-order cyclic correlation and pth-order cyclic correlation is analyzed.By using fractional lower-order cyclic statistics and exploiting cyclostationarity property of more than one cycle frequency,the new algorithm share the signal selectivity and is highly tolerant to SαS noise and interfering signals.The performances of different methods in various environments are tested in simulations.Simulation results indicate that the proposed algorithm outperforms the methods which is based on the conventional cyclic cross ambiguity function (CCA) and pth-order cyclic cross ambiguity function (PCCA) respectively.关键词：cyclostationarity;symmetric α stable distribution (SαS);ambiguity function;time delay;Doppler shift2|1227|0更新时间：2025-07-16
- 摘要：Based on the single-channel mixed signal's separation technology and the layered principles,a novel blind source separation (BSS) algorithm of single mixed signal is proposed.its characteristic does not need to use the prior knowledge.How to make the layered work of this original signal? It can be separated into many layers? Based on single-channel mixed-signal layered technique and joins a reference signal to this original signal,the above question has found the very good answer.And the equal length layered technique of using improved cyclic convolution decomposition,and the gain independent sub-band functions technology are studied too.Using these independent sub-functions,it can be expanded become a multi-dimensional signal that the original signal,and realized its blind separation.Finally through the separation experiments confirmed this method validity and the feasibility.关键词：blind signal separation;independent sub-band functions;single-channel signal;layered technique;improved cyclic convolution2|1246|0更新时间：2025-07-16
- 摘要：Malware variants are one of the major challenges in malware detecting today.Obfuscation,as a most popular technology to generate these variants,can change the signatures of malware to avoid the current signature-based malware preventing method,which is a big threat to information system.This paper proposes a novel anti-obfuscate malware detecting method.By making use of dynamic taint analysis methods and trigger-based behavior processing engine,this method can abstract the essential behavior logic of malware in fine-grained and form it as signatures of a class of malware,and identify variants more precisely associated with signature merging optimizing process and fuzzy matching methods.Experiment results show that the detecting method in this paper can identify malwares and its variants efficiently.关键词：malware variants;dynamic taint analysis;behavior analysis;obfuscation2|2655|8更新时间：2025-07-16
- 摘要：In order to evaluate the performance of the new dynamic spectrum anti-jamming (DSAJ) system in anti-jamming communications,channel capacity and bit error rate (BER) of DSAJ systems under partial-band noise jamming are studied via theoretical analysis and simulations.Capacity and BER of both DSAJ systems and conventional frequency hopping (FH) systems are compared.Results show that within a wide range of partial-band jamming factor values,DSAJ systems achieve larger capacity than FH systems.Even without jammer state information (JSI),DSAJ systems still achieve larger capacity than FH systems with JSI.At medium to high signal-to-jamming ratios (SJR),DSAJ systems achieve smaller BER than FH systems under worst-case partial-band jamming.Moreover,error correction coding can further improve the performance of DSAJ systems.关键词：dynamic spectrum anti-jamming;spectrum hole;partial-band jamming;channel capacity;noise normalization metric3|1462|3更新时间：2025-07-16
- 摘要：Block-sparse signal is a typical sparse signal.As to the feature of block-sparse signal for compressed sensing,a subspace matching pursuit algorithm for block-sparse signals recovery has been proposed in this paper.The algorithm determines an estimate of the correct support set during each iteration,which includes a subspace of the correct support set,then calculates the residual,additionally,the estimate support set will be refined at next iteration using the backtracking and least mean square criterion.The correct support set will be found until the residual reduces to zero;finally,the recovery signal can be determined by the pseudo-inverse.A sufficient condition for the proposed algorithm is given and proved,which shows it's universally applicable.The algorithm has two important characteristics:high recovery probability because of the backtracking idea;low computational complexity.The simulation results demonstrate its high recovery probability than most existing algorithms,which makes it a promising candidate for block-sparse signals compressed sensing.关键词：compressed sensing;block-sparse;subspace;recovery probability2|1804|5更新时间：2025-07-16
- 摘要：Based on the concepts and principles of quantum computing,a novel quantum-inspired evolutionary algorithm for data clustering (QEAM) is proposed in this paper by using a novel distance measurement index called manifold distance which can measure the geodesic distance along with the manifold.The clustering problem is viewed as an optimization problem.Our main motives of using QEAM consist in searching for appropriate cluster center by using the principles of quantum evolutionary computation,so that a similarity metric of clusters are optimized more quickly and effectively.The experimental results on six artificial datasets and three UCI datasets show the superiority of QEAM over an immune evolutionary clustering algorithm with manifold distance (IEAM),a genetic algorithm for clustering (GAC) and fuzzy c-means algorithm (FCM).关键词：quantum computation;quantum-inspired evolutionary algorithm;data clustering;manifold distance2|1651|15更新时间：2025-07-16
- 摘要：A novel method of constructing the cost-sensitive decision trees based on multi-objective optimization is proposed in this paper.The average misclassification cost and the average test cost are treated as the two optimization objectives.NNIA (Nondominated Neighbor Immune Algorithm) is exploited to optimize the decision trees.And some Pareto decision trees are finally obtained.Experimental results show that,compared with the C4.5 algorithm and CSDB (Cost Sensitive Decision Tree) algorithm,the proposed method in this paper can not only outperform these two methods in terms of the two above objectives but also achieve smaller size of the decision trees and stronger generalization ability.关键词：cost-sensitive;misclassification costs;test costs;multi-objective optimization;decision tree2|1938|4更新时间：2025-07-16
- 摘要：To reduce energy consumption in wireless multimedia sensor networks,a greedy algorithm about sensing direction adjustment is proposed which enhances network coverage and reduces the sensing overhead.A type of compression cost estimation method is also described to minimize the node's power on transmission and the network lifetime is optimized according to the regularity of multimedia event stream.Simulation results show that this method obtains satisfactory performance on prolonging networks lifetime.关键词：wireless multimedia sensor networks;energy consumption;greedy algorithm;coverage optimization;compression cost estimation2|835|1更新时间：2025-07-16
- 摘要：The computational complexity of traditional Ant-Q algorithm shows factorial growth with the scale of the studied problem,which greatly reduces the convergence speed.Moreover,the traditional Ant-Q algorithm only focuses on a single task,therefore,the solution for the task cannot be reusable and the algorithm will handle a series of related tasks with low efficiency.In order to improve the convergence speed,a kind of Ant-Q algorithm based on knowledge transfer is proposed.At first,the similarity between each source task and a target task is computed according to the Bayesian theory.Then the obtained similarities are viewed as the weights to determine the number of samples transferred from every source task.In the third step,the samples from source tasks are listed in a descending order according to its transfer values and some valid samples are selected.In this way,the selected samples can guide an Agent to make a rational decision quickly.Simulation results involving a traveling salesman problem att532 illustrate that the knowledge transfer technology can effectively reduce the difficulty of learning a new task and quickly find an optimal solution.关键词：knowledge transfer;ant-Q algorithm;Bayesian theory;sample selection;traveling salesman problem2|1318|3更新时间：2025-07-16
- 摘要：A lane detection algorithm is proposed using intersecting cortical model (ICM) in view of the weak universality and high complexity of the traditional methods in detecting the unstructured lane whose circumstance is complex and diverse.ICM has the superiority which is much closer to the information processing mechanism of biological vision.The ICM can distinguish objects and background dynamically according to the relevance between pixel and its neighbor pixels.As the best threshold and cyclic iterative times of ICM is artificially given it can not realize segmentation automatically.Therefore the decision mechanism of the minimum cross entropy is introduced to determine the cyclic iterative times and the best threshold automatically.The result of experiments show that the precision of the algorithm is high,and it also has very strong adaptability to some unconventional lanes.关键词：unstructured lane;image segmentation;intersecting cortical model (ICM);minimum cross-entropy2|1028|1更新时间：2025-07-16
- 摘要：The aim of this paper is to study the construction of fuzzy systems and their approximation capability.Firstly,a new fuzzifier method called parameter singleton fuzzifier is introduced.By the use of the new fuzzifier method,the construction of fuzzy systems based on six classes of fuzzy implication operators is studied when the antecedent part and consequent part of the fuzzy inference are chosen as triangular membership functions with two-phase.Secondly,the approximation capability of the fuzzy systems is discussed and their approximate error formulas and the error estimate formulas are built.关键词：fuzzy control;fuzzy implication operators;fuzzy systems;universal approximations2|1364|7更新时间：2025-07-16
- 摘要：A new application of chaotic filter in underwater acoustic signal processing is described.After frequency modulation and high-pass IIR filtering,the chaotic signal generated by the Chua's circuit was transmitted through a underwater sound channel.The received acoustic signal shows similar frequency band characteristic with chaotic circuit.Furthermore,nonlinear dynamic analysis is applied to compare the underwater acoustic signal and the original circuit signals.The results show that the acoustic signal has more irregular phase space and higher fractal dimension than chaotic circuit signals.Chaotic filter increases the complexity of the underwater signal.关键词：chaotic filter;underwater acoustic signal processing;nonlinearity3|1160|3更新时间：2025-07-16
- 摘要：In the process of inverting evaporation duct profile from radar clutter,traditional genetic algorithm presents a slow speed of seeking best parameters and premature convergence.In this paper,immune algorithm is used and realizes the inversion.The principle of immune algorithm is briefly described,and the procession of selecting the best parameters for the algorithm is emulated according to the characters of inversion question.The immune algorithm is compared with genetic algorithm and its advantage In RFC(Refractivity from Clutter) is analyzed.Finally,according to the sea clutter and hydrometeorological data collected from China Sea,the immune algorithm is tested (verified).It is indicated that immune algorithm is better than genetic algorithm in solving the question of retrieving evaporation duct profile from sea clutter.关键词：immune algorithm;sea clutter;evaporation duct;inversion2|1393|4更新时间：2025-07-16
- 摘要：A novel training method for recurrent neural networks,which is called reservoir computing,was proposed with the purpose of dealing with difficulties in the training of the traditional recurrent neural networks.The main idea of the reservoir computing is training only parts of the connection weights of the networks,and generating the rest parts randomly.The connection weights generated randomly remain unchanged during the training process.Then training process of the network can be carried out by solving a linear regression problem.The reservoir can be considered as a temporal kernel function which extends the applications of the reservoir computing.In fact,the reservoir computing is not only a modification of the training algorithm to recurrent neural networks.In this paper,we firstly introduce the mathematical model of the reservoir computing and analyze the current related researches and applications in detail in the view of reservoir adaption which has attracted much interest of the researchers recently.关键词：machine learning;recurrent neural network;reservoir computing;echo state networks3|4909|9更新时间：2025-07-16
- 摘要：Wireless Sensor Networks (WSN) are mainly characterized by dense deployment of resource-constrained sensor nodes which collectively transmit information about sensed events to the sink.In this paper,a Spatial Correlation-based Mobile Agent Routing (SCMAR) algorithm is proposed to exploit the spatial correlation between the sensed data to estimate the event with energy efficient way using the mobile agent paradigm.The simulation results show that SCMAR achieves better performance than existing Mobile Agent Routes for Data Fusion (MARDF) routing algorithm from perspectives of energy consumption in a variety of correlated data gathering applications.关键词：wireless sensor networks (WSN);mobile agent;spatial correlation;routing2|1159|0更新时间：2025-07-16
- 摘要：Tailored for the WLAN,we propose a cross-layer resource allocation schemes based on multi-packet reception.Firstly,the condition of sharing the subchannel by more than one user is obtained.Secondly,the subchannel allocation scheme including "exclusive" and "share" modes are proposed.Finally,the expression of power and bit loading which meets the QoS requirement is derived.Analysis and simulation show that proposed scheme not only improves the system throughput efficiently but also reduces the average packet delay and has low computational complexity.关键词：WLAN;multi-packet reception;cross-layer design;MIMO-OFDM;distributed coordination function protocol4|984|1更新时间：2025-07-16
- 摘要："Hotspot" problem is an important factor of causing the load imbalance and then affecting the retrieval efficiency in structured P2P networks.In this paper,the mechanisms for managing the amount of node's download and upload as well as the information of the "hotspot" nodes and the "cold spot" nodes are described and then the push and pull combined "hotspot" load migration strategy in structured P2P network is proposed by utilizing the complementary nature of "hotspot" nodes and "cold spot" nodes.Since the load migration processes are triggered by their neighbor nodes of "hotspot" or "cold spot",the non-cooperative problem brought by the nodes due to their selfishness for the load migration can be eliminated.The experimental results show that the proposed strategy is effective in handling "hotspot" problem in structured P2P networks and easy to put into practice.关键词：P2P;DHT;hotspot problem;load migration;push-pull2|1230|2更新时间：2025-07-16
- 摘要：According to the spectrum sensing demand under complex electromagnetic environment in cognitive radio (CR) network,a truncated sequential probability ratio test (SPRT) algorithm by utilizing signal proceeding in segment is proposed based on theory and application of energy detection (ED) and SPRT in this paper.By utilizing energy calculation of received signal in segment and introduction of the central limit theorem,the log-likelihood ratio of energy detection approximates Normal distribution,which greatly simplifies the following calculative process and theoretical deduction.Simultaneously,in order to make decision and reach the best test results in a limited sensing time,a truncated SPRT algorithm is introduced and its optimal truncated threshold is derived.Performance analysis and simulation results show that under same performance conditions,the proposed detection reduce average sample number (ASN) and sensing time required around 40%~60%,comparing with the fixed-sample-size (FSS) detection.It guarantees rapid and effective perception of unknown target signal under the complex electromagnetic environment.关键词：truncated sequential probability ratio test (SPRT);energy detection;spectrum sensing;cognitive radio;complex electromagnetic environment2|1116|4更新时间：2025-07-16
- 摘要：Considering velocity-measure capabilities of vehicle terminals and high-speed mobile supporting features of WiMAX network,this paper proposes a speed adaptive vertical handoff algorithm with variable weight cost function for a vehicle terminal in heterogeneous networks.The proposed algorithm uses speed adaptive strategy in the discovery phase of vertical handoff,which overcomes the drawbacks of the fixed and single network discovery methods by the received signal strength.Moreover,a cost function weight-variable algorithm is used during handoff decision,which selects the network with the maximum cost function value as the handoff network.Simulation results show that the proposed algorithm can effectively improve the update rate,lower the blocking probability,reduce the switching frequency,ensure effectiveness and fairness of vertical handoff.关键词：heterogeneous network;vertical handoff;speed adaptive;cost function;weights optimization2|1630|8更新时间：2025-07-16
- 摘要：Traditional GNSS (Global Navigation Satellite System) receiver tracks only one signal,which is the composite of direct path and multipath components.Multipath error can be generated if the signal is used for navigation processing.This paper presents a new anti-multipath technique for GNSS receiver.It is based on MRake (Modified Rake) model that separate the direct path and multipath components,and keep tracking with them.In the Finger that track direct path component,multipath components tracked by other Fingers are subtracted from the composite signal,so multipath error can be reduced.MRake model's principle is introduced,and then its function is verified by simulation.It is implemented in an FPGA based GPS receiver,and test results show that receiver using the new technique can improve its positioning accuracy in presence of multipath propagation.关键词：GNSS receiver;modified Rake(MRake);anti-multipath;FPGA2|1237|3更新时间：2025-07-16
- 摘要：In this paper,a joint estimation algorithm of frequency and two-dimensional (2-D) direction of arrival (DOA) is presented for L-shaped array.It constructs a parallel factor (PARAFAC) model by covariance matrices from different sub-arrays,and calculates frequency and 2-D DOA parameters using the trilinear alternating least square (TALS) algorithm.The main attractions emphasize that this method efficiently eliminates nonuniform noise,while avoids multi-dimensional searching and parameter-pairing.Simulation results of root mean square error (RMSE) show the efficacy of the new method.关键词：nonuniform noise;parallel factor;frequency estimation;2-D DOA estimation2|1103|6更新时间：2025-07-16
- 摘要：Aiming at extracting the time-varying micro-Doppler feature of the vibrating target in ground clutter environment,the method of micro-Doppler extraction based on dual-channel ATI technique and Radon transform is presented.The ATI technique is utilized to suppress ground clutter and obtain the interferometric signal of the vibrating target,which is presented as a straight line along the azimuth direction in the range-compressed data domain.The Radon transform is utilized to detect the weak straight line and find out which range cell it locates at.And the mathematical expressions of micro-Doppler with different vibrating directions are derived and discussed in detail.Compared with the single-channel situation,it is no need to compensate for the Doppler shift caused by the radar's translation,and the target vibrating along the azimuth direction could be effectively detected,whose micro-Doppler presents remarkably nonperiodic feature.Simulated results verify the accuracy and availability of the proposed method.关键词：micro-Doppler;clutter suppression;along-track interferometry (ATI);Radon transform2|1141|0更新时间：2025-07-16
- 摘要：In the direct blind MMSE equalization algorithm based on cross-correlation vector estimation,two auto-correlation matrix of the received signal is usually used to compute the outer-product of cross-correlation vector.A novel blind MMSE equalization algorithm is proposed,which requires only one auto-correlation matrix to obtain the outer-product based on the property of shift matrix.The computational complexity is reduced by two times.Then an efficient fast adaptive implementation of the novel algorithm is presented to recursively update the equalizer coefficient vector real time.It has the computational complexity of O(K2).Numerical simulations show that the proposed algorithm has better performance then the old algorithm and it is robust to channel order mismatch.Furthermore,the adaptive implementation has good convergence performance.关键词：blind equalization;MMSE (Minimum Mean Square Error) rule;cross-correlation vector;channel order2|1025|0更新时间：2025-07-16
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The Optimum Interference Suppression Technique Based on Kalman Filtering for Spread Spectrum Systems
摘要：In this paper,the interference suppression of spread spectrum systems is treated as constrained minimum mean output energy (MMOE).After an orthogonal decompose procedure for transforming the MMOE problem to unconstrained minimum mean square error (MMSE) one and a construction for state equation and observation equation,and then the blind Kalman filtering (BKF),i.e.,absence of a desire signal,is developed and analyzed.The research results indicate that the BKF algorithm is insensitive to variations in the correlation matrix,fast response to the changing environment,and close to level of optimization with iterative operation.Hence,it is superior to the blind least mean square (BLMS) and blind recursive least squares (BRLS) algorithms.关键词：spread spectrum;interference suppression;minimum mean output energy (MMOE);blind least mean square (BLMS) algorithm;blind recursive least squares (BRLS) algorithm;blind Kalman filtering (BKF)3|972|0更新时间：2025-07-16 - 摘要：We study the structure of the linear codes over ring F-p+vF-p,and prove that the Gray images of the dual codes are also dual.We define counting formulas of Lee weight、Hamming weight and generalized systematic weight distributions of linear codes over ring F-p+vF-p.By the relationship of linear codes and their dual codes over F-p and the proposition of the Gray map,we give the MacWilliams identities between the linear codes and their dual codes.According to the identities,we can get the weight distributions of the dual codes directly without obtaining the dual codes of linear codes over ring F-p+vF-p,which can instruct us to have a thorough understanding for the inner structure of codes over ring F-p+vF-p and their Gray images.关键词：linear codes;dual codes;gray map;weight distribution2|1797|8更新时间：2025-07-16
- 摘要：This paper presents a swarm-based neighbourhood search algorithm(SNS) to minimize the maximum completion time of fuzzy job shop scheduling problem(FJSSP).SNS uses an ordered operation-based representation,tournament selection and swap operation in which probability is 1 and swap-time is adjusted dynamically.The theoretical analyses on scheduling results show that fuzzy makespan can be used to evaluate the quality of solution.Theoretical analysis and a large number of experiments demonstrate that SNS has strong global and local optimization capabilities,faster convergence speed,and promising performance on FJSSP.关键词：fuzzy job shop scheduling;swarm-based neighborhood search;swap2|1050|1更新时间：2025-07-16
- 摘要：Taking QR Code as an example,the detection and recognition technology of the two-dimensional bar code for industrial control is researched in this paper.First,Retinex theory is used for illumination correction of images captured under poor illumination.Then according to the character of QR Code,a segmentation algorithm based on edge information is proposed,and a fast bar code detection algorithm is designed.At last,the model of blurred bar code image caused by Gaussian function is analyzed.After the variance of Gaussian function is obtained,the algorithm based on Inverse filter is proposed to recover the image.The experimental results show that the algorithm proposed in this paper is promising in terms of both reliability and computational efficiency.It can locate the barcode in complicated background effectively,and achieve higher recognition rate,which suffices to the requirement of the practical use in industrial control.关键词：two-dimensional bar code;QR code;industrial control;detection;recognition;inverse filter2|1466|4更新时间：2025-07-16
- 摘要：This paper presents a visual navigation method based on guideline visual recognition for wheeled robot to inspect equipment and instrument in unattended substation.Wheeled robot collects the road information via camera and recognizes the guideline.According the deviation of the guideline's actual location and intended location use the PID control technology controls the left and right wheel's speed to control the robot moving direction.The practical application in substation shows that the navigation method is simple and reliable,fully able to meet the navigation requirements of substation patrol robot.关键词：visual navigation;guideline recognition;PID control;substation patrol robot4|2309|5更新时间：2025-07-16
- 摘要：In the calibration procedure for two-port vector network analyzer (VNA) with three measurement channels,the length-unknown 50 ohm line is used in short-open-load-thru (SOLT) calibration algorithm instead of Load standard.It is aimed to decrease the measurement cost and simplify the measurement process.Via this calibration procedure,the systematic error terms are not required and the accurate scattering parameters of a two-port device under test (DUT) can be obtained by the measured scattering parameters during the calibration and measurement procedure.Experimental verification was carried out through SOLT method,and excellent agreement is observed.关键词：vector network analyzer;calibration;error model;scattering parameters2|2100|1更新时间：2025-07-16
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