最新刊期
卷 39 ， 期 1 ， 2011
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- 摘要：by studying the characteristics of the constellations for different transmitted signals,we modify the cost function of Constant Modulus Algorithm (CMA) and propose a new CMA based on coordinate transformation.The proposed algorithm changes the modulus of transmitted signals to zero,which can lead the output error to converge to zero even for nonconstant modulus signals.Furthermore it can achieve blind equalization without any priori statistical information of transmitted signals.Theoretic analysis and computer simulation results demonstrate that the proposed algorithm offers high performance.关键词：constant modulus algorithm;coordinate transformation;blind equalization2|1442|6更新时间：2025-07-16
- 摘要：According to different characteristics of chaotic signals and Gaussian noises,an adaptive noise reduction method is proposed based on dual-lifting wavelet.Singular spectrum analysis (SSA) and gradient decent algorithm are respectively used for the analysis of coarse approximation and detail information.The former removes smaller singular value representing noises in a greater degree,while the latter employed for the adaptive choice of wavelet coefficients further improves the positioning accuracy of signals.The chaotic signals generated by Lorenz model as well as the observed monthly series of sunspots are applied for simulation analysis,the numerical experiment results confirm that the adaptive method in this paper is effective for noise reduction of chaotic signals.关键词：dual-lifting wavelet;singular spectrum analysis;gradient decent algorithm;chaotic signals;noise reduction3|1292|8更新时间：2025-07-16
- 摘要：A new blind sparsity iterative greedy reconstruction algorithm is presented based on studying the signal reconstruction algorithm for compressed sensing without the prior information of signal sparsity.A stage-wised and backtracking method is employed to adaptively adjust the candidate list at each iteration in order to estimate the true supporting set of the approximated signal.The theoretical analysis and experiment simulation prove that the performance of the algorithm outperforms that of the existing state-of-art iterative greedy matching pursuit algorithms,and provides a generalized greedy reconstruction framework.The orthogonal matching pursuit and subspace pursuit can be viewed as its special case,and it also gives the best trade-offs between computational complexity and reconstruction performance.This makes it a promising candidate for many practical applications for compressed sensing signal reconstruction.关键词：compressed sensing;blind sparsity;matching pursuit;reconstruction algorithm3|4081|19更新时间：2025-07-16
- 摘要：To improve the performance of bit error rate of keyhole channel,a rate one quasi-orthogonal space time polarization block code (QSTPBC) is proposed in this paper.The fast maximum likelihood sequence decoding method is used.This QSTPBC is compared with the traditional quasi-orthogonal space time block code (QSTBC) for keyhole channel,single relayed QSTPBC for Rayleigh channel and keyhole channel,respectively.Simulation results show that the performance of the new QSTPBC is better than that of the traditional QSTBC in the same SNR and that of the two kinds single relayed QSTPBCs in the higher SNR.关键词：keyhole channel;quasi-orthogonal design;space time block code;bit error rate;fast maximum likelihood decoding2|1187|2更新时间：2025-07-16
- 摘要：Determining the Hamming distances and Lee distances of codes is the key of decoding.In this paper,the structures of cyclic codes over ring F2+uF2 are classified.The Hamming distances and Lee distances of some cyclic codes of length 2e over ring F2+uF2 are determined.The upper bound of Hamming distance of other cyclic codes of length 2e over ring F2+uF2 are given,and the upper and lower bound of Lee distances of these cyclic codes are also given.关键词：cyclic codes;Hamming distance;Lee distance2|1341|11更新时间：2025-07-16
- 摘要：In this paper,based on the quantum Fourier transform,we give a new quantum algorithm for prime factorization.The algorithm turns r to be phase factor under repeated application of Fourier transform and variate transform,where r is the order of a selective element in the ring of integers modulo N.Furthermore the amplitude of the non-target states except zero state is modified to be 0.Our algorithm's success probability,which is more than 3/4 and higher than Shor's algorithm,doesn't depend on the size of r other than Shor's algorithm.Meanwhile,we present a comparison of the required resource between the new algorithm and Shor's algorithm.关键词：quantum algorithm;prime factorization;public key crypto;quantum Fourier transform2|1609|3更新时间：2025-07-16
- 摘要：In this paper,a matrix form of Sym wavelet decomposition and synthesis is deduced,keeping the length of the coefficient no more than the length of original speech signals,and then we propose a framework of speech Multiscale Compressed Sensing (MCS) and an Adaptive Multiscale Compressed Sensing (AMCS) method by analyzing sparsity of different wavelet levels of speech signals .We compare AMCS with MCS by applying both methods to speech compression and reconstruction,and the reconstructed speech signal evaluated by the objective and subjective evaluation is applied to speaker recognition.The experimental results show that the reconstruction performance of speech signal based on AMCS is superior to MCS.关键词：Sym wavelet;multiscale compressed sensing;adaptive multiscale compressed sensing;speech compression and reconstruction;basis pursuit2|1835|14更新时间：2025-07-16
- 摘要：The model of GPS signals is given in the multipath environment,and the multipath effects to tracking loop in GPS receiver are analyzed.A multipath mitigation method of GPS signals is proposed using equalization technology in tracking loop.In this method,fractionally spaced blind decision feedback equalization is applied.Meanwhile,because GPS signals are BPSK signals and the illegibility of C/A codes appears when C/A codes are modulated with navigation data,the coefficients of the equalization are updated with modified constant module algorithm.Simulation results show that the method can mitigate the multipath effects effectively and feasibility of the method is validated.关键词：GPS receiver;tracking loop;multipath effects;blind decision feedback equalization;modified constant module algorithm2|1793|3更新时间：2025-07-16
- 摘要：One of the basic issues in pattern recognition is to calculate the boundary between different categories.In this paper,we propose a novel method for that based on computational geometry named active expansion.At first,we quantize the description space.And then term the set as base and non-base points according their distribution,by active expanding for base points,any point in the whole space could express the category information and the boundary is obtained.Using this method,we design the scatter classifier which incorporates the active expansion with combining feature attribute of scatter plot,that mapping the data from low dimension to high dimension and conforming a visual combing classifier.The experiments against UCI datasets show that performance of the novel classifier has been equivalent to the popular classifiers,and outweigh in some dataset.关键词：computational geometry;active expansion;boundary;visualization;combining classifier2|1131|5更新时间：2025-07-16
- 摘要：This paper addresses range-spread target detection in spherically invariant random vector clutter.The modified detector based on scatterer density dependent (MSDD) is introduced,and the formula relating false alarm probability to detection threshold is deduced.It shows that MSDD performs best when the target energy is uniformly distributed in range cells;moreover,it is also robust for various target range extent.However,when the estimated number of scatterers is smaller than the actual one,MSDD is degraded sharply.To improve the robustness of MSDD,a detector with dynamic threshold (DT) is proposed.For DT,the dynamic estimated number of target scatterers is adjusted according to the observations,which can improve performance and robustness of detector effectively.关键词：non-Gaussian clutter;high range resolution radar target detection;dynamic threshold;robustness2|1460|7更新时间：2025-07-16
- 摘要：Affine invariant feature extraction methods have been one of the key issues of computer vision research.This paper proposes a normalized histogram algorithm based on the density function of multi-scale autoconvolution transform and researches the normalization method of the density function,and constructs a method to extract the histogram affine invariant feature,and implements affine invariant pattern recognition based on multi-scale autoconvolution normalized histograms.Simulation results show that this algorithm has good adaptability for a certain range of noise,partial occlusion,illumination and view angle variance.The recognition rate of this algorithm is superior to multi-scale autoconvolution and other multi-scale autoconvolution based histogram algorithms,especially under a variety of environments.关键词：object recognition;affine invariant feature;normalized histogram;multi-scale autoconvolution(MSA)2|1566|4更新时间：2025-07-16
- 摘要：We proposed a blind inverse halftoning algorithm with discrete Sibson interpolation.In our algorithm,a unified framework based on discrete Voronoi diagram is used to recover continuous-tone (contone) images from halftone images.At first,the halftone dots’ intensity is estimated by the corresponding Voronoi diagram information.We further perform the discrete Sibson interpolation based on discrete Voronoi diagram to get the contone image.This algorithm is universal to all types of halftone images since it is independent of any prior information.Compared with existed algorithms,this algorithm is able to remove artifacts in both sparse and dense halftone dots regions and produces visually pleasant contone images.关键词：digital halftoning;inverse halftoning;error diffusion;discrete Voronoi diagram;discrete Sibson interpolation2|1175|0更新时间：2025-07-16
- 摘要：CT scanning and CT reconstruction are similar to rendering process of computer graphics,so using GPU to accelerate CT reconstruction algorithm become one of the focuses of the CT study in recent years.Based on features of Single-slice helical CT,we construct the parallel perspective projection model,and using GPU to accelerate the single-slice helical CT three-dimensional image reconstruction.Numerical experiments show that reconstruction efficiency improved by ten times than conventional algorithm.关键词：single-slice helical CT;graphic processing unit;three-dimensional reconstruction;projection model2|1478|2更新时间：2025-07-16
- 摘要：The SWCL(Static Weighted Centroid Localization) based on RSSI is widely used,owing to it's low cost,convenience and no need of additional equipment.However,as the RSSI ranging is vulnerable to various interference,the SWCL cannot figure out both the average errors and the max errors simultaneously.Thus,a new dynamic weighting centroid algorithm using Gaussian fitting method is proposed,and the algorithm is performed on the ZigBee platform,The experimental results indicated that the accuracy of RSSI positioning can be well improved,and the positioning average error is only one-third,and the maxium error is quarter of SWCL level.关键词：rssi;gauss fit dynamic weighted centroid localization;static weighted centroid localization;dynamic weighted centroid localization;gaussion fit2|3515|27更新时间：2025-07-16
- 摘要：Node scheduling scheme of sensor nodes is one of the most important method to solve the energy-constrained wireless sensor networks.Traditional methods of node scheduling that without location information are aim at node sensing area coverage.It leads to a node in the border of monitored region first death due to no more chance enter into sleep state,and then the death spread to the central region.We call this phenomenon as inequality sleep problems.To address this problem,from the theoretical analysis of the sensor node coverage model,we proposed the concept of tolerable coverage area,and propose a node scheduling scheme based on tolerable coverage area.Simulation results demonstrate that the proposed method not only alleviates the inequality sleep problems,but also prolonged network lifetime.关键词：wireless sensor networks;tolerable coverage area;node scheduling algorithm2|1656|15更新时间：2025-07-16
- 摘要：Aiming at the problem of spectrum sharing in multiuser multi-input multi-output cognitive radio networks,a spectrum sharing method based on Frobenius norm is proposed,which is designed to maximize the throughput of cognitive radio (CR) users as well as guarantee the quality of service of primary (PR) users.Multiuser diversity of the cognitive radio network is obtained by user selection,which is according to the Frobenius norm of channel matrices,while twice selection is adopted to reduce the complexity of our method,and then the interference from CR users to PR users is canceled by null-space projection.At last,the singular value decomposition method is employed to derive the parallel spatial sub-channels for each user while the waterfilling power allocation method is used to enhance system capacity.Compared with the existing spectrum sharing strategies,the proposed method can acquire larger ergordic capacity of CR system and reduce the outage probability of PR users.Simulation results show that when the total transmitting power of the CR system is 100w,the proposed method has 13% ergordic capacity gain of the cognitive network over the existing methods.关键词：cognitive radio;multi-input multi-output;spectrum sharing;Frobenius norm;null-space projection2|1720|7更新时间：2025-07-16
- 摘要：Since the task scheduling algorithm directly affects the performance of the P2P computing,the task scheduling with multi-objective constraints is presented by using immune algorithm.The population initialization operator considering load balance,the clone selection operator controlled by entropy,the new crossover operator,mutation operator and vaccine with apriori knowledge are designed for task scheduling based on model definition.And then the multi-objective task scheduling strategy is proposed after describing the mechanism for searching and managing the available P2P nodes.Experimental results indicate the validity of the proposed scheduling strategy in shortening the execution time and communication time,as well as saving the scheduling costs.关键词：P2P;task scheduling;immune algorithm;multi-objective constraints2|1795|7更新时间：2025-07-16
- 摘要：In this paper,an intrusion response decision-making model based on the risk evaluation is proposed to improve the routing performance in hierarchical Ad Hoc networks.In this model,the attack behaviors were in clustering analyzing according to self-organizing map,and the risk degree was calculated in real time and quantity,in order to evaluate the threaten extent of the current attack.Combined with the related information such as the node statue,we could forecast the sustainable extent and scale of the attack,and thereby adopt the relevant decision-making to the attack node.Simulation results show that,the model proposed in this paper can real-time quantize the intimidation that hierarchical Ad Hoc networks meet,and alleviate and even contain the network harm caused by the routing attacks.关键词：hierarchical Ad Hoc networks;risk evaluation;dynamic decision-making;clustering analyze2|1371|2更新时间：2025-07-16
- 摘要：A new five elements joint sparse form is proposed and is researched deeply in this paper.It is proved that every pair of integers has an unique five elements joint sparse form and average joint hamming weight of this five elements joint sparse form is 1/3l if the binary representations length of this pair of integers is l.We apply this five elements joint sparse form to fast Shamir algorithm.Comparing with three elements joint sparse form,this algorithm saves 0.167l addition operations.Comparing with existed five elements joint sparse form,this algorithm saves 0.054l addition operations.关键词：new five elements joint sparse form;average joint hamming weight;elliptic curve cryptography;pairs of scalar multiplication2|1191|1更新时间：2025-07-16
- 摘要：In content-based access control systems,the subject is only allowed or denied to access the object.There are partial orders between different subjects and objects.The traditional access control policy manages these subjects and objects independently,and does not consider the partial orders which may improve the efficiency.By considering the partial orders,a hierarchical key assignment scheme is proposed in this paper,so as to make the assignment of keys to achieve secure communication and access control,improving the efficiency.The objects can be formed into a Directed Acyclic Graph (DAG) using the partial orders between these objects.Then,assign each vertex in the DAG an encryption key based on Diffie-Hellman algorithm,while each vertex may derive the encryption keys of its child vertices by the encryption key of itself.These assigned keys are used to encrypt the resources of the vertices.Thus,the access control of the resources can be achieved by the assignment of the encryption keys.The proposed scheme consists of the phases of system initialization and key updating,and supports user dynamics and topology changes.The security is based on DDH assumptions.It can be used for content-based hierarchical access control.关键词：hierarchical key assignment;DH algorithm;hierarchical access control;group key management2|1795|5更新时间：2025-07-16
- 摘要：This paper presents the algebraic structure of the conditional equations set for multi-output Boolean functions,proves that the algebraic immunity of multi-output Boolean functions is equal to that of a certain Boolean function,which is a combination of the component functions for multi-output Boolean functions,and among all combinations,this one has the minimum algebraic immunity.Hence,it can be concluded that the algebraic immunity of multi-output Boolean functions is equal to the minimum of algebraic immunities of all combinations.关键词：Algebraic attack;multi-output Boolean functions;algebraic immunity;conditional equations2|1355|2更新时间：2025-07-16
- 摘要：Subset sum problem is one of the NP complete problems,which is the foundation of knapsack encryption schemes.Its computational complexity is O(n2exp(n/2)) in classical algorithms.We present the quantum mechanical meet-in-the-middle algorithm,which can solve the subset sum problem in O(n2exp(n/3)) with O(2exp(n/3)) memory cost,and O(2exp(n/2)) in quantum mechanical algorithm.The NP complete questions are minimized in O(n2exp(n/3)) under this algorithm because of their equivalence.关键词：quantum algorithm;subset sum problem;computational complexity;meet-in-the-middle2|1564|3更新时间：2025-07-16
- 摘要：Ultra-Wideband (UWB) has the ability of achieving the better ranging and localization precision than current wireless system.The research and application of UWB localization are studied on this paper,in which the main topics include the different UWB localization methods like TOA/TDOA(Time/Time Difference of Arrival),multipath delay estimation theory,non-light-of-sight localization,cooperative localization,MB-OFDM(Orthogonal Frequency Division Multiplexing) and other ultra-wideband signals localization.Then its development and actuality are discussed in details.The existing problems and several future valuable research directions are summarized finally.关键词：UWB;localization;time of arrival;time delay estimation;NLOS localization;cooperative localization;MB-OFDM5|6999|30更新时间：2025-07-16
- 摘要：Compressive sensing,by means of the non-adaptive measurements with a well below the Nyquist frequency and optimization methods,reconstruct signal with high probability.In this paper,we introduce the basic theory of compressed sensing and the main reconstruction algorithms,including iterative algorithms as well as our improved MBOOMP algorithm.Meanwhile,the simulation of radom signal which is composed of 0 and 1 are adapted to compare their performance.It is shown that our algorithm is better than typical OMP algorithm.关键词：compressive sensing;sparse representation;signal recovery;wireless sensor networks;analog-to-information conversion2|5292|76更新时间：2025-07-16
- 摘要：It is not suitable to use conventional wireless sensor networks (WSNs) routing protocols to transfer multimedia content such as video and audio streams on wireless multimedia sensor networks (WMSNs).In order to address those problems,a few new routing protocols were introduced recently.The QoS guarantee routing problem for WMSNs is defined firstly and some facing challenges are discussed in the field.Secondly,after classifying conventional WSNs routing protocols into five groups according to their features,the QoS routing protocol requirements for WMSNs are analyzed,along with their design principles,strategies and limitations.Thirdly,as the main content,the representative QoS routing protocols for WMSNs are surveyed in detail,including their design objective,core idea,basic strategy,main procedure,advantages and drawbacks.Ultimately,open research issues for WMSNs routing protocol are also pointed out.关键词：Wireless sensor networks;multimedia;routing protocol;QoS;survey2|2111|14更新时间：2025-07-16
- 摘要：A new model changes detecting method in fast fading channel structure was proposed.The new method aimed at the amplitude of the signal to detect the sample time points that channel suddenly changed.It educed the theoretic expression of model changes detecting method in fast fading channel by dynamic programming (DP) algorithm ,and constructed the principle of vary structure channel model switching.The result of theoretic analysis and simulation experiment show that the method can detect the sample time points of model changes effectually by detecting the amplitude of the signal,and switch the channel model in these time points to approach a good estimator precision.关键词：dynamic programming;model changes detecting;wireless channel2|1172|3更新时间：2025-07-16
- 摘要：The performance of dual-hop communication systems with fixed gain amplify-and-forward relay is analyzed over non-identical Nakagami-m fading channel.First,Closed-form expressions for outage probability and average symbol error rate (ASER) are derived based on probability density function (PDF) method for the system without cooperative diversity.Then,the expressions for outage probability and ASER and closed-form expression of the n-th moment of received SNR are derived based on moment generating function (MGF) method for the system with cooperative diversity.Simulation results show that,the derived expressions match well with the numerical simulations,and cooperative diversity and larger m values are both of benefit to the improvement of system performance,and the channel quality of the first hop and that of the second hop have different effects on the system performance.关键词：amplify-and-forward relay;cooperative diversity;Nakagami-m fading channel;outage probability;average symbol error rate (ASER)2|1704|3更新时间：2025-07-16
- 摘要：A technique for the residual carrier frequency offset (CFO) tracking and the peak-to-average power ratio (PAPR) reduction in multilevel quadrature amplitude modulation (MQAM) based orthogonal frequency division multiplexing (OFDM) systems is presented.The scheme is based on unknown pilot subcarriers modulated by the conjugate of the MQAM information data,cancelling their phases to reduce the maxim power.The conjugate code periodically inserted in the OFDM symbols allows the frequency tracking loop to estimate the phase offset using a derived formula.The simulation investigates the algorithm performance showing that the frequency can be precisely corrected and the PAPR can be reduced with several dB.关键词：orthogonal frequency division multiplexing(OFDM);peak-to-average power ratio(PAPR);carrier frequency offset(CFO);synchronization2|1313|4更新时间：2025-07-16
- 摘要：To estimate the frequency and phase information of the signals containing dense spectral components,a novel discrimination and correction method for dense all-phase FFT (apFFT)spectrums is proposed.Due to apFFT’s excellent performance in suppressing spectral leakage and the property of 'phase invariant’,this paper can distinguish the dense spectrum from single-tone spectrum by judging whether the phase spectral lines behave as flat distribution,when the conventional discrimination method by identifying peak amplitude lines malfunctions.Combining with all-phase time-shift correcting spectrum method and the phase relation between adjacent spectral lines,this paper deduces a novel method to estimate frequencies and phases for dense spectrums and gives the discrimination index for these two cases .Simulation shows that,for the different cases of SNR(Signal to Noise Ratio),the accuracy of the proposed method is higher than that of the conventional correcting dense spectrum method,guaranteeing that the proposed method is of high applied value when SNR＞20dB.关键词：all-phase FFT;spectral leakage;dense spectrum;correcting spectrum5|2517|18更新时间：2025-07-16
- 摘要：A class of systematic generalized low-density parity-check (GLDPC) codes with zigzag codes as component codes,termed ZS-GLDPC codes,is proposed on the basis of regular low-density generator matrix (LDGM) codes.The proposed codes have linear encoding complexity,and can be decoded by the sum-product algorithm iteratively.The decoding complexity of ZS-GLDPC codes is lower than GLDPC codes with Hamming component codes.Based on the uniform interleaver assumption,a union bound analysis of the bit error probability was presented for ZS-GLDPC codes when Signal-to-Noise Ratio is high.Density evolution using the Gaussian Approximation was used to analyze the convergence thresholds of ZS-GLDPC codes.Simulation results show that the bit error rate of ZS-GLDPC codes is better than or close to LDPC codes and GLDPC codes with Hamming component codes for short and medium code length.关键词：generalized low-density parity-check (GLDPC) codes;low-density generator matrix (LDGM) codes;concatenated codes;iterative decoding;zigzag codes2|1480|1更新时间：2025-07-16
- 摘要：To overcome the limitation of one single kernel in the traditional kernel function model,a new type of mixture kernel is constructed by combining two kernel functions linearly.Each individual regressor in RBF network is trained term by term using orthogonal least squares algorithm.In the training phase,a global k-means cluster algorithm is used to decide the kernel centers.For each clustering centers,Group search optimizer (GSO) is utilized to get the proper scale and weight within the kernel.The optimal kernel parameters which minimize the training error are used to shape each regressor.The experiments results show that the new RBF network is sparser than some traditional RBF network with one single kernel.关键词：mixture kernel;radial basis function (RBF) network;group search optimizer;orthogonal least squares2|1234|4更新时间：2025-07-16
- 摘要：This paper proposed a methodology of forecasting for mobile communication traffic with maximal overlap discrete wavelet transform (MODWT) according to priori knowledge.Fourier spectrum was chosen as the priori knowledge to avoid the blindness of wavelet decomposition.Then,MODWT which is easy to extract components with obvious physical meaning was employed to decompose the communication traffic data.Moreover,prior knowledge of fourier spectrum was taken as reference to synthesize relevant sublayers,leading to the trend and seasonal components.Further,seasonal autoregressive integrated moving average (ARIMA) model was applied to model and predict the previous trend and seasonal components,respectively.The results tested with real communication traffic data indicate:the methodology proposed in this paper can realize multistep prediction and the forecasting accuracy is superior to that of seasonal ARIMA models.关键词：mobile communication;traffic forecasting;maximal overlap discrete wavelet transform;prior knowledge2|2194|2更新时间：2025-07-16
- 摘要：This paper proposes a fall detection approach to detect accidental falls for senior citizens using wireless sensor networks based health-care systems.Unlike traditional sensory-context based detection,this paper achieves this goal by using radio signals in wireless sensor networks.A group of the sensors on the senior citizens’body (wearable sensors) and several sensors as anchor nodes (anchor sensors) in their daily territories are deployed.The fall event is detected by comparing the difference of signal strengths from wearable sensors caused by the natural characteristics of the wireless radio signals attenuation through human bodies.Both centralized and distributed lightweight algorithms are proposed to compute the status of the fall event from senior citizens’normal daily behaviors.The obtained evaluation and experiment results using MicaZ motes show that this approach performs high accuracy,low overhead and less response delay in fall events detection and report.关键词：Wireless sensor networks;fall detection;Local cross-correlation coefficient3|1747|12更新时间：2025-07-16
- 摘要：Because of catadioptric imaging,two points in the world with same distance will have different distance in omnidirectional image when they are projected to the periphery or center on the image plane.Thus,traditional definition of the neighborhood cannot be appropriate for omnidirectional images.In this paper,make use of ratio of resolution between different position in image,we propose a new system of neighborhood adapted to the omnidirectional images and deduce a new formula for calculating resolution of a catadioptric sensor.We show that this definition of neighborhood for catadioptric omnidirectional image conduce a more coincident result than traditional one in application of moving target detection base on Markov random fields.关键词：catadioptric omnidirectional image;Markov random field;moving target detection;resolution;neighborhood2|1044|2更新时间：2025-07-16
- 摘要：The variational level set model for piecewise constant/smooth image segmentation on surfaces and the related dual methods are investigated in this paper.The implicit surface on which the image is defined is represented by zero level set of a static signed distance function,the spatial contour used to divide regions of image on the implicit surface is expressed by the intersection of another dynamic zero level set and implicit surface.The variational level set model for planar image segmentation has been extended to the one on implicit surface by means of intrinsic gradient and intrinsic divergence,which is transformed to a global convex minimization problem in this paper using a new binary label function and the concept of convex relaxation to void the effect of initialization of active contour on the result of segmentation.Finally,the dual methods for solving the global convex minimization problem is designed in this paper and some numerical experiments demonstrate the proposed method is superior to traditional method in computation efficiency.关键词：implicit surface;image segmentation;variational method;level set method;dual method2|1889|4更新时间：2025-07-16
- 摘要：A fast color image fusion algorithm for merging infrared and visible images is presented,which is named Architecture Optimized Version Color Transfer Based Fusion Method.The method directly uses the grayscale fused image and the difference signals of the input multiband images to construct the source YCBCR components,then uses statistical color transfer technique in YCBCR space to form a color fused image with similar color appearance as the target image.The paper mathematically proves that color spaces conforming to the general YCBCR space framework,such as YUV space,can be used as an alternative to YCBCR space in the proposed method.The approach is not only limited to fuse infrared and visible images,but also suitable for merging other dual-band image types.Experimental results show that the proposed color image fusion algorithm can effectively produce a natural appearing daytime-like color fused image,and even using the pixel averaging fusion scheme to implement the grayscale fusion can also provide a satisfactory result.关键词：color image fusion;color transfer;YCBCR transformation;infrared image;visible image2|1256|8更新时间：2025-07-16
- 摘要：Accurate objective quality metric is crucial for various video processing applications.Although the area of image quality assessment has attained maturity in recent years,video quality assessment still has a long way to go before it reaches the levels of success achieved by still image quality metrics.In the paper,we present a new approach to video quality assessment based quaternion singular value decomposition(QSVD),which take the luminance,chrominance ,edge energy and motion energy of each pixel as the four parts of a quaternion, and the entropy as the degree of visual interest of regions to weight each block.We demonstrate the performance of our algorithm by testing it on the Video Quality Expert Group(VQEG)Phase I FR-TV dataset,the results show that our method is competitive with state of the art quality assessment methods and has good correlation with perceived video quality.关键词：objective video quality assessment;quaternion;singular value decomposition;VQEG2|1446|6更新时间：2025-07-16
- 摘要：An enhanced cooperative MAC protocol (ECoopMAC) is proposed for multi-hop Ad Hoc networks in this paper,which considers the transmission rate and the hidden node problem jointly.Through optimizing the order of handover and the strategy of helper selection,the saturated throughput and access delay are efficiently improved by ECoopMAC without introducing overhead and complexity.Furthermore,based on node’s behavior and state probability,we propose an analytical model to evaluate the performance of cooperative MAC protocols in multi-hop Ad Hoc networks.Finally,the performances of the proposed analytical model and protocol are evaluated by extensive simulations in multi-hop wireless Ad Hoc networks.Simulation results show that our proposed protocol significantly improves the saturated throughput compared with CoopMAC.In addition,the results of analysis and simulation match well,which confirm that the proposed analytical model is correct and effective.关键词：multi-hop Ad Hoc networks;cooperative communication;media access control;partner choice2|1146|0更新时间：2025-07-16
- 摘要：Semi-bent functions are a kind of Boolean functions with high nonlinearity.They have important applications in cryptography and communications.This paper gives three classes of semi-bent functions represented by trace.It is shown that the semi-bentness of the new functions is closely related to Kloosterman sums when the values of some parameters are restricted.It is also proved there exists a subclass of semi-bent functions with degree n/2 in each class of the new semi-bent functions on n variables.Several examples of the semi-bent functions in a small field are given by using the zeros of some Kloosterman sums.关键词：Boolean function;semi-bent function;Hadamard transform;Kloosterman sums2|1173|1更新时间：2025-07-16
- 摘要：The novel Hash algorithm whose security is based on the difficult of multivariate polynomial equations over a finite field is designed and implemented.We propose the idea of building a secure hash using higher degree multivariate polynomials as the compression function of MPH.The new algorithm compared with the current widespread use of the Hash algorithms has the following advantages:Security based on a recognized difficult problem of mathematics;Hash length can be free to change,according to the needs of the user;Hash function as a whole is Randomly selected;Design automation,users can be constructed to meet the actual needs of the specific Hash function.We analyze some security properties and potential feasibility,where the compression functions are randomly chosen 3rd polynomials,the experiment results show that the new algorithm has good properties in the efficiency and performance,and is comparable with other Hash functions.关键词：cryptography;hash function;MQ problem;multivariate polynomials2|1223|3更新时间：2025-07-16
- 摘要：Based on the theory of quadratic residues,the algebra structure of RSA arithmetic is researched in this paper.This work calculates numbers of quadratic residues and non-residues in the group Z*n and investigates their relationship. Z*n is divided up by the group made up with all quadratic residues in Z*n and all cosets form a quotient group of order 4 which is a Klein group.Studyed the structure of strong RSA further,it shows that the element of order ø(n)/2 exists and the group Z*n can be generated by three elements of quadratic non-residues.Let the facterization n=p·q, the order of each element can be calculated,and the biggest order of all element is lcm(p-1,q-1) in Z*n. It also shows how to find the element of the biggest order.So the algebra structure of RSA arithmetic is solved.关键词：RSA arithmetic;algebra structure;quadratic residues;euler’s phi function2|1715|4更新时间：2025-07-16
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