最新刊期
卷 47 ， 期 4 ， 2019
- 摘要：Considering resource allocation in Device-to-Device (D2D) communications,a joint link sharing and power allocation algorithm is proposed.On the premise of guaranteeing the Quality of Service (QoS) requirements of cellular users in the system,a candidate set of communication links composed of cellular users is generated for the D2D users by using the channel state information of the system.The optimal power allocation strategy for D2D users is obtained by using the convex optimization method in the candidate set of communication links.Finally,the Kuhn-Munkres (KM) algorithm is used to solve the maximum weight bipartite matching (MWBM) problem to find an optimal cellular user partner for each D2D pair to share the resources.Simulation results show that the proposed algorithm can significantly improve the throughput of the communication system and can select the optimal resource allocation strategy for D2D users.关键词：device-to-device (D2D) communications;link sharing;power allocation;maximum weight bipartite matching (MWBM)169|565|6更新时间：2025-07-16
- 摘要：In the image color space,the RGB channels have strong correlations.The quality change of an image will lead to the change of channel correlations.However,most traditional image quality assessment (IQA) methods,based on grayscale image statistics,ignore such correlation information among color channels.In this paper,to utilize the color information,we propose a blind IQA method based on the recent proposed complementary color wavelet transform (CCWT).We provide models for the complementary color nature scene statistics,multi-resolution and multi-directionality energy distributions of an image.The analysis shows that our models not only cover the information of traditional methods,but also provide the relation information among color channels.A group of high-efficiency image quality features is then given.Based on these features,our blind IQA method can effectively extract the distortion statistic features and provide assessment results.Our IQA results are agreeing with the human subjective,better than the state-of-the-art blind IQA results,and close to the full-reference ones.关键词：image quality assessment;no reference;complementary color wavelet transform;color image185|549|3更新时间：2025-07-16
- 摘要：In this paper,the weighted Schatten p-norm minimization (WSNM) method is proposed to implement magnetic resonance imaging (MRI) reconstruction.The nonlocal self-similarity of magnetic resonance images,Schatten p-norm and the weighting factors of the importance of different rank elements are integrated together as the low rank constraint to regularize the MRI reconstruction.In addition,the Alternating Direction Method of Multipliers (ADMM) algorithm is used to solve the non-convex minimization problem of MRI reconstruction based WSNM.Compared with other state-of-the-art methods in numerical experiments,the proposed method achieves a higher reconstruction quality with higher peak signal to noise ratio (PSNR) and better structural similarity (SSIM) index.关键词：magnetic resonance imaging (MRI) reconstruction;nonlocal self-similarity;weighted Schatten p-norm minimization80|364|2更新时间：2025-07-16
- 摘要：How to improve the generalization ability to unknown noise types is an important problem to be solved urgently in supervised speech enhancement approaches.By modeling a large number of types of noise,the deep neural network(DNN)becomes an effective way to solve this problem.In order to further improve the generalization ability of speech enhancement approaches based on DNN,this paper designs NoiseGAN based on Generative Adversarial Networks (GAN) to generate new noise types from real noise data.By adding generated noise to training set,the diversity of noise types in training set is increased,and thereby the generalization ability of speech enhancement model is improved.The results of speech enhancement experiments under different structures of networks show that the proposed NoiseGAN can generate new noise types,increase the diversity of noise types in training set,and effectively improve the generalization ability of speech enhancement models under unknown noise types.关键词：speech enhancement;generative adversarial networks;generalization ability;deep neural network317|513|2更新时间：2025-07-16
- 摘要：In order to estimate the time difference of arrival (TDOA) of frequency hopping signal accurately,the ambiguous characteristic of the correlation function is analyzed,and the TDOA estimation method of frequency hopping signal based on multi-hop coherent integration is investigated.The periodic peaks in the multi-hop correlation function will lead to ambiguous estimation of the TDOA;so two approaches to eliminate ambiguity are proposed:the approach of ambiguity elimination by TDOA averaging of single-hop (TASH) and by envelope fitting of correlation function (EFCF).Ambiguity elimination is achieved through fine peak searching between a small interval nearby the main peak,and the small interval is determined by the coarse TDOA obtained by means of TASH or EFCF.The difference between TASH and EFCF is that the first approach obtains the coarse TDOA by incoherent averaging of TDOA estimation of single-hop,while the second approach obtains the coarse TDOA by the envelope of correlation function which is fitted by using multiple periodic peaks found by whole searching.Numerical simulations demonstrate that the performance of the two proposed methods is obviously superior to the conventional CAF,and the requirement for the correlation output SNR of unambiguous estimation can be reduced,the frequency interval for unambiguous estimation can be increased.The EFCF has better performance but greater computational complexity.关键词：frequency hopping signal;TDOA ambiguity;TDOA averaging of single-hop (TASH);envelope fitting of correlation function (EFCF);ambiguity elimination100|357|4更新时间：2025-07-16
- 摘要：Perfect Gaussian integer sequences (PGIS) applied to spread spectrum communication systems can not only restrain disturbance,but also obtain high transmission efficiency and spectrum efficiency.Therefore,this paper presents a class of PGIS with odd length and nonzero level (i.e.degree) for 2 and 3 based on cyclotomic classes.Simultaneously,using coefficient sequence and interleaving method,the odd length PGIS is extended to even length PGIS.Under certain conditions,based on the construction method of cyclotomic classes,a large number of high energy efficiency PGIS can be obtained,and the maximum energy efficiency is close to 1,which is of great practical significance to the engineering application.The result of this paper provides more address selection space for broadband spread spectrum communication systems.关键词：perfect Gaussian integer sequence (PGIS);cyclotomic classes;energy efficiency;autocorrelation function70|311|3更新时间：2025-07-16
- 摘要：By combining the Physical Unclonable Function (PUF) with the certificateless public key cryptosystem on the elliptic curve,a secure communication scheme for IoT is proposed.The secure transmission of messages is realized on the condition of node devices not storing any secret parameters.The proposed scheme eliminates the need for bilinear pairing whose computing complexity is high and provides a message authentication mechanism.Security analysis demonstrates that the scheme can not only resist the traditional attacks such as eavesdropping,tampering and replay,but also protect the node device from replication attacks.Compared with related schemes,the proposed scheme obviously decreases the resource overhead of devices.关键词：Internet of Things;Physical Unclonable Function (PUF);elliptic curve cryptosystem;secure communication;message authentication125|361|6更新时间：2025-07-16
- 摘要：During wireless network transmission,when the feedback information from the destinations is lost or partially lost,the source cannot achieve the real accepting status of destinations.To improve the retransmission efficiency of wireless networks with imperfect feedback,a retransmission scheme based on network coding is proposed.The retransmission procedure with imperfect feedback is modeled based on POMDP (Partially Observable Markov Decision Process) theory.According to the system observation status and the maximum confidence degree,the source updates the system estimation status.And the source gives preference to select the encoding packet that can recover the earliest lost packet and the most lost packets according to the packet sending sequence.To increase the coding and the decoding opportunities the destination can buffer the encoding packets that cannot be decoded.During retransmission procedure the source focuses on the destination requirements.In the same conditions the relay with higher transmission reliability is preferentially selected to improve the transmission efficiency.Simulation results show that the scheme proposed can effectively improve the retransmission efficiency compared with the traditional retransmission scheme with imperfect feedback in wireless multicast network.关键词：imperfect feedback;retransmission;network coding53|295|1更新时间：2025-07-16
- 摘要：The communication station will be affected by interference signals of multiple frequency in complex electromagnetic environment.Assuming the interference signal is strong enough,the communication station will be blocked even if the interference signal is out of band,which makes it unable to receive useful signal and lose combat effectiveness.The out-of-band signal needs significant energy to block receiver;so we can use vector superposition method to analyze useful signal and interference signal,from which the interference prediction model can be derived.Conducting dual-frequency interference test by two independent interference transmission system,and the system should be adjusted before the test.Taking error rate to be 0.1 and no link test as the critical interference criterion respectively,and then two independent tests are conducted.The test result shows that the presented model is able to predict whether or not the equipment under test reaches critical interference state,and the prediction error is within 2dB.This model applies to both critical interference criteria.关键词：communication station;out-of-band interference;blocking effect;modeling63|417|6更新时间：2025-07-16
- 摘要：Image classification is an important research direction in the field of computer vision analysis.The key to classification depends largely on the feature representation of the image.In order to be able to classify images better,this paper presents a locality-constrained sparse coding for image classification by introducing ranking locality adaptor as distance regularization.The proposed ranking locality adaptor has previously been used in Neural Gas (NG) method for vector quantization,which originally remedies the K-means by using this soft-competitive learning scheme.In the new proposed method,a closed-form solution can be derived at sparse coding step.In addition,dictionary updates are generally determined by the error term of the objective function.Some classical algorithms have used this method to update the dictionary.This paper uses the ORL database and COIL20 database to compare the proposed algorithm with the existing algorithm Locality-constrained Linear Coding,and Metaface Learning algorithm.The experimental results show that the proposed algorithm has an accuracy of more than 95% in image classification and has stronger performance than the current excellent algorithms.In addition,the recognition rate of the algorithm does not change greatly with the change of the data feature dimension.It can be seen that this paper provides a valuable solution for the classification of computer vision images.关键词：image classification;neighborhood-ranking;locality-constrained;dictionary learning109|324|1更新时间：2025-07-16
- 摘要：A variety of analytical models were established for the study of node selfish influence assessment in the opportunistic network in the past.However,how to apply these theoretical models was not considered.In this paper,we analyzed the impact of the evaluation model on the selfish nodes of the networks with or without TTL limitation,and proposed a self-private model based on message classification to evaluate the influence of selfish nodes on delay and message delivery rate.The analysis shows that the opportunistic network is affected not only by the number of selfish nodes,but by the speed of the nodes and the range of message transmission.Therefore,we can improve the performance of the network by adjusting these parameters and reduce the impact on selfish nodes.Firstly,we obtain the message transmission range of the number of cooperative nodes under the delay guarantee of 2-hop routing and epidemic routing and the TTL of the message of the epidemic routing guaranteed by the message delivery rate through the theoretical derivation.Subsequently,we proved that the theoretical value of the network performance under the influence of selfish behavior is similar to the experimental value and the parameter values obtained by theoretical analysis are also similar to the experimental values through the evaluation of the influence of the ONE simulation platform on the selfish nodes.关键词：opportunistic networks;selfish nodes;message classification;evaluation scheme;regulation strategy98|288|2更新时间：2025-07-16
- 摘要：In Through-the-Wall Imaging (TWI),the target image is often buried in the wall reflections and other clutter waves,and the target image cannot be obtained.Subspace technique uses the received echo matrix Singular Value Decomposition (SVD) to remove the wall subspace,it is a mature technique and has broad applications in TWI.In order to distinguish the wall subspace and the target subspace,this paper presents a new wall subspace extractive method based on the stationarity of left-singular vector.SVD is applied to the echo matrix and the left-singular vectors are used to determine the subspace belonging to the wall or the target.Compared with the traditional subspace technique,this method has a better performance in wall subspace extraction.Meanwhile,the capability of suppressing wall clutter is enhanced,and the quality of the target imaging is improved.关键词：through-the-wall imaging (TWI);target detection;singular value decomposition (SVD);subspace technique;clutter mitigation65|317|3更新时间：2025-07-16
- 摘要：In this paper,we propose a signal extraction algorithm based on the property of chaotic signal.Each chaotic signal corresponds to a different chaotic attractor in phase space.We define proliferation exponent(PE) using the property above;PE is used as a statistic feature to classify chaotic signal and computationally less dissipative compared with Kullback Leibler divergence.We firstly model the problem of blind source extraction into an optimization problem with constrained.The objective function based on PE is non-convex or multi-model and solving the optimization problem with gradient search method may lead to local optimum.We use particle swarm optimization(PSO) algorithm to solve the above optimization problem,the algorithm is improved by adjusting the inertia coefficient dynamically and the global optimal position is disturbed to diversify the particle population and increase the probability of escaping from local trap.The experimental results show that the proposed signal extraction algorithm can extract the mixture of chaotic signals and multi-channel Gaussian signals efficiently.关键词：blind source extraction;proliferation exponent;particle swarm optimization algorithm;chaotic signal174|321|1更新时间：2025-07-16
- 摘要：How to resist combined geometric attacks effectively and improve the embedded capacity of the watermark has always been a challenging topic in the field of digital watermarking.In view of this situation,a watermarking algorithm that resists combined geometric attacks and has a larger embedded capacity is proposed in this paper.Firstly,feature points from the attacked image are extracted with SURF algorithm,then they are matched with a small amount of feature points of strong robustness,which are extracted from the original image.The matching point pairs are used to estimate the affine matrix accurately and then the geometric attacks are corrected to resynchronize the embedded watermarks.Due to positioning errors introduced during the attacking/correction process,some positioning watermarks are embedded in the spatial domain to improve the accuracy of the resynchronization.Considering the excellent erasure correcting performance of LT codes,the watermark bit sequence is encoded by LT-code such that the anti-cropping performance of the algorithm can be improved.The experimental results show that the proposed algorithm not only has a larger embedding capacity,but also is resistant to the cropping and combined attacks.关键词：digital watermarking;geometric attacks;high capacity;affine matrix estimation;precise resynchronization;LT-code148|368|1更新时间：2025-07-16
- 摘要：The traditional saliency detection method is difficult to detect different kinds of saliency target simultaneously.In order to solve this problem,an algorithm based on unsupervised SDAE network is proposed in this paper.The stacked denoising auto-encoder (SDAE) network is used to sparsely reconstruct original image in multiple scales.The difference between the original image and the reconstructed image is used as a saliency map,and the binaryzation of the saliency map is used as salient detection result.In the process of SDAE network training,the original image is used as the original data and the reconstructed images are treated as observed data.In order to improve the efficiency of network training,the deep belief network (DBN) is trained by greedy method in each layer without supervising,and the network parameters are delivered to stacked denoising auto-encoder (SDAE) network as initial parameters.Then,the mutual information between the original data and the observed data is used as loss function,and the network parameters are tuned by backpropagation.The experiments show that the proposed algorithm can accomplish the saliency detection of various targets,which has the advantages of good universality and high accuracy.关键词：saliency detection;unsupervised network;stacked denoising auto-encoder (SDAE);deep belief network (DBN);mutual information266|390|3更新时间：2025-07-16
- 摘要：In order to drive the switched mode power amplifier (SMPA) for full-digital transmitter,the input Radio Frequency (RF) signal of full-digital transmitter first needs to be transformed into pulse sequences by using the digital RF modulator.Considering the disadvantages in modulation performance and system realization of existing digital RF modulation strategies,especially the Pulse Width Modulation (PWM) and Delta-Sigma Modulation (DSM),a digital RF modulation strategy was proposed and analyzed in this paper by using the area equivalent theory.The theoretical analysis and simulation results show that,compared to the PWM and DSM,the proposed modulation strategy not only reduces the hardware implementation difficulty,but also achieves better performance of the SNR and coding efficiency.关键词：digital RF modulation;full-digital transmitter;area equivalent theory;coding efficiency101|319|0更新时间：2025-07-16
- 摘要：Personal willingness is one of the most important factors influencing the construction of social community and the information dissemination in social network.In this paper,we propose a social community structure and information detection scheme based on personal willingness in social network.In our proposed scheme,the social community detection algorithm uses the node attributes to detect social community structure and further find overlapping communities;the information dissemination method is based on the exponential model,which constructs the feature vector by the edge feature and the node feature,the willingness vector by the personal willingness and the community willingness,and the basic relationship by the dissemination probability and dissemination delay.Experimental results show that our proposed scheme can ensure the effectiveness of social community detection and the initiative and reliability of information dissemination.关键词：social network;personal willingness;community detection;overlapping community;information dissemination190|336|3更新时间：2025-07-16
- 摘要：In the case that the clutter of the polarimetric synthetic aperture radar (PolSAR) imagery follows K distribution,the existing constant false alarm rate (CFAR) detection algorithms based on multi-look polarization whitening filter (MPWF) cannot be applied to the condition that the equivalent number of looks is a non-integer.To solve the problem,a CFAR detection algorithm with analytical false alarm probability expression is proposed.After introducing the Gamma distribution texture under the product model,the probability distribution function (PDF) of the MPWF metric is integrated to obtain its cumulative distribution function (CDF),and then the analytical form of the false alarm probability with respect to the detection threshold is obtained.The simulation results show that the new algorithm has a good false alarm fitting effect.In addition,when the target clutter ratio (TCR) is large,the new algorithm has a higher detection probability.Otherwise,the detection probability is lower than the existing algorithm.It is worth pointing out that the current false alarm probability expression of multi-look polarization matched filter (MPMF) under K distribution is wrong,so the current detection algorithm based on MPMF detection metric is modified and the correct expression of the false alarm probability is derived.关键词：CFAR detection;the equivalent number of looks;K distribution;MPWF;MPMF;target clutter ratio223|373|1更新时间：2025-07-16
- 摘要：For adaptive monopulse technology in phased radar system,a novel algorithm for suppressing mainlobe and sidelobe interferences based on two sum and three difference channels is proposed in this paper.Weighting approximation method is adopted to produce weights to form sum,azimuth difference,elevation difference and double difference beams for irregular subarrays.Then azimuth difference,elevation difference beams and sum beam in the direction of sidelobe interference work as the auxiliary beams of static sum beam,while double difference beam works as the auxiliary beam of azimuth difference and elevation difference beams.Based on the principle of Wiener filter,the auxiliary beams are weighted in the optimized way to cancel the mainlobe and sidelobe interferences in the sum beam and mainlobe interference in azimuth difference and elevation difference beams.The proposed algorithm is of simple structure and high accuracy.It is able to simultaneously suppress the mainlobe and sidelobe interferences without distortion of monopulse ratio.Finally,the simulation results and analyses prove the effectiveness of the method.关键词：dimension reduction;adaptive monopulse;mainlobe and sidelobe interferences;auxiliary beam;Wiener filter228|312|1更新时间：2025-07-16
- 摘要：The computer vision based scene classification technology is widely developed and applied in different fields.In this paper,the typical scene classification technology is analyzed and compared from the different directions.First,the background,application and development situation is introduced.Then,the related researches both at home and overseas are analyzed,compared and summarized from the perspectives of feature extraction,semantic analysis and machine learning.Finally,the problems that the current researches are facing and potential future development are discussed.关键词：scene classification;feature extraction;semantics analysis;deep learning270|998|12更新时间：2025-07-16
- 摘要：Information technology has penetrated into all aspects of politics,economy and culture in the whole society.The information revolution has changed the way of communication all over the world,promoted the development of human society,and made the problem of network security get unprecedented attention.The research on network security has mainly experienced 4 main stages:idealized design ensures safety,passive defense after auxiliary detection,actively analyze and formulate security strategies,forecast trend after comprehensive perception.Under the background of the new strategic commanding point for the power of digital control in all countries,the research on the Cyber Security Situation Awareness Analysis (CSSA) has presented new features in both academic research and industrialization.This paper makes a detailed literature survey on CSSA.First,it introduces the status of the research and the difference and connection between CSSA and traditional awareness analysis.Then the logical analysis framework of CSSA is proposed from the perspective of data value chain.The whole process is decomposed into five continuous stages of processing,including factor collection,model representation,measurement establishment,solution analysis and situation prediction.After that,the role and the mainstream method of each stage are expounded,and the application results on the experimental object and the horizontal comparison between the methods are explained.The purpose of this paper is to provide a panoramic knowledge of CSSA,and to provide an auxiliary idea for the network security industrialization scheme,and hope that it can serve as a reference for scientific research and engineering personnel in this field.关键词：network security;network situation awareness;attack model;intrusion detection;data fusion analysis127|666|7更新时间：2025-07-16
- 摘要：With the rapid development of big data,it becomes more and more important to effectively solve the problems of copyright protection of data,preservation of data information,traceability of data,etc.Database watermarking is the most effective protection technique.The biggest challenge of this technology is how to carry out the embedded watermarking without affecting the data,and how to withstand the various attacks without affecting the extraction of watermark information.In this paper,we first describe the basic concepts and principles of database watermarking;Then,we introduce and classify common database watermarking techniques;Next,we summarize the attack behavior against database watermarking and analyze the anti-attack ability of specific watermarking technology;Moreover,we analyze the typical watermarking technologies based on distortion or not and the existing technical methods of database fingerprint briefly;Finally,we point out the key and shortcomings of current researches,and propose the development direction in the future.关键词：database watermarking;database fingerprint;copyright statement;robustness268|650|2更新时间：2025-07-16
- 摘要：Aiming at the problem that parameter estimation for extremely/super low frequency channel noise model is so complicated that it is difficult to perform optimal nonlinear processing and according to the time-domain analysis of the noise waveforms,a noise suppression method was proposed based on median filtering (MF) across local variance.It utilized the local variance to extract the structural information so that the noise impulsiveness would be enhanced and the performance of MF would be improved;utilized the constant false alarm rate outlier detection method to achieve the blind determination of the noisy samples and the adaptive MF algorithm to achieve the blind suppressions.Simulations and real tests verified its effectiveness.Due to no parameter estimation,this method is more practical than the optimal nonlinearities.关键词：E/SLF communications;channel noise suppression;median filtering;constant false alarm rate123|320|3更新时间：2025-07-16
- 摘要：There is a problem that the image features extracted by trace transform lack description of texture edge information,and the computation cost is high,too.Based on the advantages of wavelet transform in image contour representation,a new fusion feature extraction algorithm,multi-resolution trace transform,is proposed and applied to texture image classification.Firstly,the wavelet transform was introduced in trace transform,low frequency feature sub images and high frequency edge sub images of texture images at different frequencies are obtained by using nonsubsampled wavelet transform.Then,we carried out a set of functional trace transform on each level sub images to obtain the fusion features of texture image,which not only obtains the edge information of the image,but also avoids the problem of high cost.Finally,the fusion features were fed into support vector machines to classify the images.The experiment results show that the fusion features of multi-resolution trace transformation have better texture description ability and achieves higher recognition rate than the original trace transform and MCM contrast method,the time efficiency is greatly improved compared to the traditional trace transform.关键词：texture classification;trace transform;nonsubsampled wavelet transform;multi-resolution247|424|2更新时间：2025-07-16
- 摘要：A new microstrip tri-band bandpass filter is presented.The filter is composed of a stepped-impedance resonator loaded with short stub,a pair of E-shape resonators loaded with open stub,and the external coupling structure with input/output direct-coupling.Due to the multi-mode characteristics of the resonators,the filter size can be significantly miniaturized,and each passband can be separately controlled.In addition,the proposed filter can generate six transmission zeros on both sides of each passband,resulting in improved frequency selectivity.Such a demonstrative tri-band bandpass filter with center frequencies of 2.0GHz,3.95GHz and 6.35GHz were designed and fabricated.The measured results show that the insertion loss is less than 2.5dB,and the return loss is better than 14 dB for each passband,which is in agreement with the simulated ones.关键词：microstrip bandpass filter;tri-band bandpass filter;stub-loaded resonator;stepped-impedance resonator;transmission zero125|393|3更新时间：2025-07-16
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