最新刊期
卷 47 ， 期 2 ， 2019
- 摘要：Overlap between community pairs is commonplace in large-scale social networks.The most existing overlapped community detection algorithms may falsely identify overlaps as communities because the overlap area is denser than others,and those algorithms are computationally demanding and cannot scale well with the size of networks.In this paper,we propose a fast overlapping community discovery algorithm based on some locally computed information-Local information based Fast Overlapped Communities Detection (Li-FOCD).Firstly,we introduce two local information metrics for each network node-community connectivity score and neighborhood connectivity score,to model the relationship between nodes and communities;secondly,based on local metrics,we can concurrently execute the iterations of reduction,expansion,and duplication removal to find the approximately optimal communities instead of the optimal community,and achieve a low complexity O(m+n).Experimental analysis based on real large-scale social networking datasets shows that our algorithm outperforms some popular overlapped community finding algorithms in terms of computational time while not compromising with quality.关键词：overlapping communities detection;Local information;community connectivity;neighborhood connectivit257|576|0更新时间：2025-07-16
- 摘要：The characteristics of strong global search ability with small population size lead to the quantum genetic algorithm is well popular in solving optimization problems.In order to further improve the convergence speed,search stability and overcome the pre-matureness of the quantum genetic algorithm,an improved adaptive mechanism based quantum genetic algorithm was presented in the paper.For the presented algorithm,the individual similarity evaluation operator,individual fitness evaluation operator and population mutation adjustment operator were defined and added into the self-adaptive based quantum genetic algorithm.The way of calculating the three operators were also proposed.Therefore,the current population state can be evaluated by the operators cooperatively,and the individual's mutation probability can be determined according to the current population state.The proposed algorithm can improve the global optimization ability and convergence speed,and reduces the probability of falling into local optimization.In addition,a parallel multi-universe mechanism is employed to improve the time efficiency of the algorithm.Experimental results show that the proposed algorithm has a good performance in the global search performance and time efficiency.关键词：genetic algorithm;parallel computing;adaptive mechanism;quantum mutation222|475|5更新时间：2025-07-16
- 摘要：Considering the fact that there exists the strong correlation between the first several eigenvalues (in ascending order)of the covariance matrix of the raw patches extracted from a noisy image and its noise level,we proposed a novel fast multiple image-based noise level estimation (FMNLE)algorithm using the principal component analysis (PCA)and the deep neural network (DNN).Specifically,we selected the first several eigenvalues of the raw patches to form a feature vector characterizing the noise level of an image.Then,we employed deep neural network to train an estimation model on a large number of representative natural images corrupted with known noise levels,by which the feature vector can be directly mapped into the corresponding noise level.To obtain higher estimation accuracy,a two-step estimation strategy was adopted.Extensive experiments show that,the estimation accuracy of the proposed algorithm is stable at each noise level with good efficiency,demonstrating a better comprehensive advantage as the pre-processing module for denoising algorithms.关键词：image denoising;noise level estimation;principal component analysis;deep neural network;coarse-to-fine strategy212|914|2更新时间：2025-07-16
- 摘要：For the whole evaluation strategy in cuckoo search algorithm in the face of multi-dimension function optimization problems,the coupling phenomena among dimensions will deteriorate the search speed and convergence accuracy.Therefore,a new cuckoo search algorithm based on the equilibrium single evolution mechanism is proposed.Then,a new equilibrium single evolution evaluation strategy is also used to update randomly the single dimension of the objective function on each iteration.Note that the randomly updated dimensions obey the uniform distribution to avoid mutual interference between dimensions.Furthermore,two new random walking update laws are proposed to improve the global search speed and convergence accuracy.The results of the 10 benchmark functions and statistical significance demonstrate that ESCES algorithm has a great improvement in global optimization performance,search speed and convergence accuracy compared with the five modified CS algorithms and seven other state-of-the art algorithms.关键词：evolution;evaluation strategy;cuckoo search algorithm;discovery probability90|349|6更新时间：2025-07-16
- 摘要：The fuzzy c-Means algorithm is a kind of iterative algorithms based on greedy algorithms.It converges to a local minimum value along the iteration sequence,yet it has the insufficient searching ability and can easily fall into local optimum solution.This paper,based on tabu search,introduces a fuzzy clustering algorithm.It uses tabu search in a solution's neighborhood and adopts the tabu strategy of long-term tabu lists based on the local convergence of FCM,which guarantees to move the search starting point constantly and avoids repeated searching.In addition,chaos optimization and dynamic step strategies are utilized to strengthen its global search ability in order to achieve global optimal solution.Experimental results show that this algorithm improves the accuracy of clustering considerably and has great stability.Compared with group-wise algorithm and genetic algorithm,this algorithm also has some advantages.关键词：fuzzy c-means;tabu search;global minimum81|429|1更新时间：2025-07-16
- 摘要：The image database of crime scene investigation (CSI)has the characteristics of high confidentiality,rare image content and so on.Aiming at the complexity of the content and the ambiguity of the target object,the DCT-DCT wave texture feature is proposed,which is fused with HSV color histogram feature and GIST feature to form the fusion feature.Compared with the commonly used image features,DCT-DCT wave texture feature can get higher retrieval efficiency,and the average retrieval precision rate of the fused features is higher than that of the three features.Finally,the semantic analysis technology is introduced into the retrieval process,and an image retrieval algorithm based on the optimization of retrieval results is proposed.Support vector machine (SVM)classifier was used to extract the semantic of the query image.The semantic analysis of the results of the first retrieval is carried out,and the second retrieval scheme is selected according to the proportion of semantic categories in the initial retrieval results.The algorithm can further improve the average retrieval accuracy based on case-by-case query.关键词：crime scene investigation image;crime scene investigation image retrieval;multi-feature fusion;retrieval method;support vector machine274|410|3更新时间：2025-07-16
- 摘要：Aiming at the high complexity in blind separation of PCMA mixed signals with non-cooperative reception,the separation algorithm based on feedforward neural network is proposed.By setting up a neural network separation platform and avoiding the traditional idea of maximum a posteriori probability,the blind separation algorithm with low complexity and high performance can be realized.Simulation results show that the neural network can greatly exploit the intrinsic information of the signal,and 10-3 orders of bit error rate performance is achieved with 7 dB of signal-to-noise ratio to QPSK modulated PCMA signals,accompanied by the declining complexity of the arithmetic square root level compared with the PSP algorithm.关键词：neural network;non-cooperative;Paired Carrier Multiple Access (PCMA);blind separation98|328|5更新时间：2025-07-16
- 摘要：The author studied the QR factorization and generalized inverse of universal extended matrix.and the system parameter estimate is discussed.In addition,the formula of the QR factorization and generalized inverse of universal extended matrix were given.The results show that the algorithm is simple and fast,and it does not reduce the numerical accuracy.Another some results of paper[8,9] are generalized.关键词：universal extended matrix;QR factorization;generalized inverse;signal processing;parameter estimate78|277|0更新时间：2025-07-16
- 摘要：For the problem of beam distortion and detection blind zone by time domain interferences suppression method,a modified interferences suppression method by the energy compensation in time domain is proposed.Firstly,constructs energy compensation factor according to the frequency band of processing data and attenuation curve.Then,preprocesses the received data via time domain interferences suppression method,and obtains the output beam.Lastly,utilizes the energy compensation factor improve the output beam,reduces the beam distortion and detection blind zone,and achieves the expected results of interferences suppression and detection.The numerical simulation and data processing results show that,this method improves the time domain interferences suppression method by constructing energy compensation factor,reduces the impact of the "wide concave" or "convex" beam of time domain interferences suppression method on detecting target,achieves the beam correction,reduces detection blind zone,and achieves detecting the targets in old attenuation interval.That fundamentally solves the problem of beam distortion and detection blind zone by time domain interferences suppression method.关键词：time domain interferences suppression;beam distortion;detection blind zone;energy compensation;beam correction90|304|3更新时间：2025-07-16
- 摘要：An algorithm of extraction of vehicles based on random projection depth function is proposed for accurately extracting vehicles with different colors in outdoor parking lots.The random projection depth function can effectively distinguish the center and outlier of the data set in RGB color space,and in this way,the vehicles whose color characteristics act as outlier are highlighted.First,the random projection depth function is used to sort the color characteristic of each pixel to obtain random projection depth value,forming the depth field image; Then,morphological closed operation is carried out for the depth field image,and an appropriate random projection depth value is selected as the threshold to binarize the image; Finally,the vehicles are accurately extracted from the parking lot by decision tree algorithm and morphological operations.The experimental results show that the random projection depth function can effectively deal with the "same body with different spectrum" phenomenon of various color vehicles in remote sensing images.The vehicles of different colors are highlighted in the depth field image,which can effectively improve the efficiency of vehicle extraction,and extraction of vehicles from parking lot of remote sensing images can be realized accurately by combining random projection depth function and simple post-processing.关键词：remote sensing image;random projection depth function;extraction of vehicles in parking lot;morphological operations167|324|0更新时间：2025-07-16
- 摘要：In order to solve the problems such as high dimension of encrypted key,low degree of update flexibility and low search speed in the field of encrypted search,we propose a novel classificatory group index method-CGIM.The method extracts category keywords from classified data to create group index,and uses group encryption method to transform a high-dimensional secret key into several low-dimensional keys to reduce the encryption time of indexes and query requests.In addition,each group in the index is corresponding to different category.Thus,the method can not only achieve classification update to improve the flexibility of document update,but also can generate a targeted trapdoor in the retrieval process to improve the search speed and efficiency further.Through security analysis and performance test,we prove that the method is feasible and effective.关键词：encrypted search;group index;key transformation;category update;targeted search214|377|1更新时间：2025-07-16
- 摘要：Hash proof systems,which was first introduced by Cramer and Shoup in 2002,is still one of the hottest research topics in cryptography.And then Wee proposed the concept of extractable hash proof system in 2010 and it is a concept extension on the hash proof system and as a paradigm of constructing PKE from search problems.On the basis of the extractable hash proof system,this paper expands the application scope of the extractable hash proof system by redefining the meaning of system parameters.We construct a basic All-But-One extractable hash proof system based on Diffie-Hellman relations by using the framework of extractable hash proof system.Based on this,fine-grained auxiliary input and weighting calculation are introduced.A new variable-policy CCA encryption scheme based on tag is proposed,and the security proof is also given in details.In particular,this scheme is a richer abstraction of extractable hash proof system that it is All-But-N,which means that the number of branches determined by the tag in the extraction mode could be n.At the same time,the scheme is based on the difficulty of the search problem and is essentially based on the computational Diffie-Hellman problem.关键词：Diffie-Hellman relations;chosen ciphertext attack;hash proof systems;extractable Hash proof system;multi-policy77|279|0更新时间：2025-07-16
- 摘要：According to the existing dynamic three-way decision model based on the updating of attribute values,in this paper both the uncertainty of attribute knowledge connotation and the difference of excellent degree between objects are fully considered in the process of updating the object.More concretely,both the experience value of character attribute objects and the concept on comprehensive evaluation value of experience are firstly defined to describe the object initially,and the knowledge connotation of the object is expressed by the revised value of character attribute objects.Next,the optimal closeness degree based on the Euclidean distance calculated by the revised value is used as the revised comprehensive evaluation value of the object.Then,the extraction method of dynamic feature on objects with character attributes is presented,and a dynamic three-way decision model is established.Finally,a large number of simulation experiments have been made to validate the efficiency and applicability of the proposed model.关键词：intelligent decision making;three-way decisions;dynamic updating;granular computing;feature extraction168|274|2更新时间：2025-07-16
- 摘要：It is challenging to learn efficient features in person re-identification task due to complex variations of viewpoints,illumination,pose etc.In addition,deep neural network still suffers from overfitting with a small training set.To solve these problems,a Multi-information Flow Convolutional Neural Network(MiF-CNN)is designed for person re-identification which contains a specific convolutional architecture.In this architecture,features from each convolution layer are concatenated with all subsequent convolution layers so that it can improve the flowability of feature information and the efficiency of backpropagation gradient.In this way,the proposed network can learn more discriminative features.Moreover,a combination of three loss functions is used to train proposed network.Finally,the identification accuracy is obtained by ranking the similarity of extracted features measured by Euclidean distance.Experimental results on the VIPeR and CUHK01 datasets demonstrate that MiF-CNN outperform most of existing methods of person re-identification and reduce overfitting more effectively.关键词：person re-identification;multi-information flow;feature extraction;convolutional neural network129|381|5更新时间：2025-07-16
- 摘要：In network theory,it is interest to study the influences of different nodes on the key nodes in the network,and build or select the proper node importance index to model it.This paper selects seven node importance indices to calculate and analyze their contributions in nodes' importance evaluation with Principal Component Analysis.Seven empirical networks are used for experiments.Moreover,the order of different contributions of indices is obtained,and the correlation analysis between the most important index and the other indices is carried out using the Kendall coefficient,and factors affecting the correlation coefficient are also discussed.This paper provides a way to select the node importance index in the network,and the results could also be used for studying the relationships between different nodes.关键词：principal component analysis;node importance index;contribution analysis;Kendall coefficient89|384|10更新时间：2025-07-16
- 摘要：The interconnection structure is a key part between the electrical device and the printed circuit board as the mechanical fixing and electrical interconnection.Aiming at the difficulties in real-time monitoring and extracting characterization signals for the health status of interconnects,firstly,a degenerate electrical model was established in this paper,by analyzing the failure modes and mechanisms of the QFP interconnect structure.Then,according to the degraded electrical model of the interconnect structure,a real-time monitoring circuit was built,with the charging time of the external capacitor selected as the characterization signal,and the relationship between the electrical parameters of the degradation model and the charging time was established.Afterwards,the Multisim and the development board had been used to simulate and verify the relationship between the equivalent electrical model parameters and the charging time in the degradation process of the interconnect structure.Finally,in order to analyze the degradation process of interconnects,a small system test board was used for random vibration test.From the results,combined with the electron microscope image of the interconnect structure,it was found that the charge time can characterize the failure process and failure mode of the interconnect structure well.关键词：interconnect structure;electrical model;degradation process;charging time;failure characterization149|292|0更新时间：2025-07-16
- 摘要：In order to neutralize the advantage of asymmetric operations owned by UAV swarms,UAV swarms were investigated from the perspective of negativing the coordinated flight control for them.Firstly,UAV swarms are described as a complex system with the emergence.Secondly,based the mechanism for flocking behaviors generated from UAV swarms,f-divergence based quantitative model was established to measure the emergence of them.It was firstly proposed that the suppression principle of swarms' emergent behaviors in term of three heuristic rules followed by general flocking control algorithms.Moreover,it was firstly constructed that the failure judgment model of flocking control for swarms under man-made interference.Finally,simulation experiments showed that the interference intensity and opportunity played an effect on suppressing emergent behaviors of swarms.266|506|9更新时间：2025-07-16
- 摘要：A lot of practical application problems can be modeled as structured nonlinearprogramming,and these problems always have two type of coefficients matrices:sparse and dense.Combining the principle of primal dual interior point method(PD-IPM) and the distributed parallel technology can solve the problem efficiently.The unit commitment(UC)is a classical engineering problem which can be formulated as a structured nonlinear programming with sparse coefficients matrices.In this paper,according to the PD-IPM principle,the UC model is continuous relaxation preprocessed,and the Newton correction equations are decoupled by using the fast decoupling technique,which can be used to obtain the independent sub problems.Then,a CPU-GPU collaborative parallel method is proposed to solve the sub problems in parallel and the results are compared with the results of structured nonlinear programming with dense sub problem.The experimental results show that the proposed method for solving two different types of structured nonlinear programming has achieved a certain speedup.关键词：nonlinear programming;interior point method;unit commitment;CPU-GPU cooperative;parallel computing50|343|0更新时间：2025-07-16
- 摘要：Conventional shadow image connection based(t,s,k,n) sharing is prone to different size shadow images and Birkhoff interpolation based(t,s,k,n) sharing leads to low recovery efficiency,while in double authentications based self-recovery image sharing,the recovery capabilities of secret image and backup image are very limited.To address these problems,random participation values were used to construct master key based(t,s,k,n) sharing by means of(k,s) and(k-t,n-s) schemes and MD5 values stored in the third party were used to prevent cheating.The proposed scheme scrambled LL subband of secret image by master key and formed multi-version backup images with different scrambling degrees where more backups for more significant bits.Restricted double authentication strategy can embed as many backup bits as possible while maintaining authentication accuracy by(k,n) sharing over GF(2^8) field to form stego carriers.Theoretical and experimental results show,master key based(t,s,k,n) scheme can be solved efficiently.Random participation values avoid the disclosure of participant numbers and prevent tampering distributed information or guessing authentication bits.Multi-version backup strategy can restore backup images with high confidence while authentication capability of restricted double authentication strategy is no less than that of double authentications based self-recovery image sharing scheme.关键词：image sharing;restricted double authentications;Galois field;multi-version backups;(t,s,k,n) sharing;(k,n) sharing;inverse matrix modulus p56|222|1更新时间：2025-07-16
- 摘要：Majority gate is core element of Majority logic circuit that affects the overall performance of circuit.The majority gate designed in Quantum-Dot Cellular Automata(QCA)has the advantage of simple structure.In this paper,a five-input majority gate with triple-layer design is proposed.Based on the designed five-input majority gate,full adder,adder and multiplier are designed.Compared with previous design,the simulation results show the number of QCA cells and area of the proposed adder are improved up to 43% and 87.2% respectively while those of the proposed multiplier are improved up to 48.2% and 100% respectively.关键词：quantum-dot cellular automata;multilayer gate design;five-input majority gate;full adder;multiplier48|257|2更新时间：2025-07-16
- 摘要：The intuitionistic fuzzy inference(1,2,2)-a type universal triple I methods based on intuitionistic fuzzy set are discussed,the expression form and decomposition form of solutions of intuitionistic fuzzy inference(1,2,2)-a type universal triple methods based on IFMP and IFMT problems are given.Then,based on the natural distances between intuitionistic fuzzy sets,the sensitivity of intuitionistic fuzzy connectives and intuitionistic fuzzy sets are defined,the sensitivity of intuitionistic Lukasiewicz implication,intuitionistic Gödel implication and their corresponding triangular norm are provided.On this basis,it is proved that intuitionistic Lukasiewicz implication is the most robust residual implication on intuitionistic fuzzy sets.Finally,robustness of intuitionistic fuzzy inference(1,2,2)-a type universal triple I methods are investigated,corresponding sensitivity of solutions of intuitionistic fuzzy inference type universal triple methods are obtained for two kinds of specific implications.These results indicated that the robustness of intuitionistic fuzzy inference methods directly depended on the selection of intuitionistic fuzzy connectives.关键词：robustness;intuitionistic fuzzy inference;universal triple I methods;sensitivity of solutions57|264|1更新时间：2025-07-16
- 摘要：After studies on the frequency jitter mechanism,a design of true random number generator(TRNG)based on voltage-controlled oscillator(VCO)is proposed.The scheme amplified the thermal noise of resistance and took it as the control signal of VCO.Its oscillation frequency thus randomly jittered around the centre frequency.The slow oscillating signal generated by the VCO generated an raw random sequence by sampling the period-fixed fast oscillating signal,then used the post-processing circuit to improve the uniformity of sequence and to eliminate the autocorrelation.Applying the thermal noise generator to adjust the centre frequency of VCO is able to trade off the bit rate of sequence and the randomness.The proposed circuit is designed in SMIC 55nm CMOS technology with a chip area of 0.0124mm2,a bit rate of 10Mbps and an average power of 0.81mW.The output of randomly sequence passed the NIST SP 800-22 randomness test.关键词：true random number generator (TRNG);thermal noise;voltage-controlled oscillator (VCO);trade off117|422|3更新时间：2025-07-16
- 摘要：Multi-tags collision has been considered as a critical problem in RFID system.Recently,many query tree protocols based on bit tracking technology have been presented for resolving the tag collision efficiently.However,their performance need to be further improved because of unused collided bits and idle slots.In this paper,a bit query based method is presented,which requires the tag to respond a mapped bit string instead of its ID sequence.Compared with traditional ID query,it not only eliminate idle queries,but also can separate collided tags into many smaller subsets and make full use of the collided bits as well.Based on this method,a novel query tree protocol bit query based M-ary tree(BQBMT)is proposed,which recursively resolves collisions by forming a M-ary tree,and optimally switches from bit query mode to ID query mode for quickly identifying the tags when tag is readable.Theoretical analysis and simulation results show that the system efficiency of BQBMT is close to 0.89,which outperforms the other existing QT-based and hybrid algorithms.关键词：RFID (Radio frequency identification);anti-collision;bit query;system efficiency110|265|3更新时间：2025-07-16
- 摘要：The degree distribution greatly influences the performance of Luby transform(LT)codes.In order to obtain a better degree distribution,a method is proposed to design the degree distribution for LT codes based on improved binary exponential distribution(IBED)and bionic algorithm.The decoding performance of IBED outperforms robust soliton distribution(RSD)when the overhead is small,and its successful decoding rate reaches more than 90%.The successful decoding rate for IBED rises slowly as the overhead increases,while RSD performs better.In order to combine the advantages of IBED and RSD,we use artificial fish swarm algorithm(AFSA)to search the optimal degree distribution between these two.The expected ripple size is employed to present the objective function for AFSA,and the optimal degree distribution is obtained by maximizing the objective value.Simulation results show that compared to other optimized degree distributions and RSD,the new degree distribution reduces the overhead,and saves the average consuming time per encoding/decoding process.关键词：luby transform (LT) codes;improved binary exponential distribution (IBED);robust soliton distribution (RSD);artificial fish swarm algorithm (AFSA);ripple size116|356|1更新时间：2025-07-16
- 摘要：Insulated gate bipolar transistor(IGBT)is one of the hot topics in microelectronics research.The related circuit simulation urgentlyneeds the equivalent model of the device.The physical model of the 1200V field-stop IGBT solving ambipolar diffusion equation(ADE)based on the Fourier transformis proposed in this paper.The ADE is solved accurately by the distribution of carriers in equivalent drift region of the RC circuit.The model is based on the working principle of high-power IGBT.The high-level injection hypothesis is used.The complex effect of the 1200V field-stop IGBT is considered according to the characteristics of the 1200V field-stop IGBT.After extracting the key parameters of the model,the simulation results are verified by the actual measurement results.The average error of simulation and experiment is less than 8%.The accuracy of the model and parameter extraction method is proved by analyzing the static and turn-off transient characteristics.关键词：field stop insulated gate bipolar transistor;ambipolar diffusion equation;physical model61|251|2更新时间：2025-07-16
- 摘要：The estimation process of nonlinear system is a process of multi-sensor information fusion.During the process of data processing,Kalman filter has high computational complexity.Especially when there are random deviations in the system model,the amount of calculation increases greatly after dimension expansion,which is easy to cause system overflow and operation failure.By embedded the two-stage Cubature Kalman filter into the extended information filtering framework,Two-stage High degree Cubature Information Filter(TSHCIF)is proposed.The algorithm is easy to initialization and small in computation.It takes advantage of the equivalence relation between the inverse of covariance matrix and information matrix to participate in the process of filter recurrence,and reduces the computation of filter gain matrix.In the solution of the covariance matrix,there is a coupling relationship in the covariance matrices of the two-stage algorithm.Therefore,there is a coupling relationship between the two stage information matrix.In the algorithm,the nonlinear T transformation and the inverse of the matrix should be applied to the information matrix.The coupling relationship between the two-stage information matrix and the covariance matrix is obtained.Through the simulation experiment of bearings only tracking system,it is verified that TSHCIF is superior to CKF in accuracy,and the running time is also shorter than CKF,which proves the availability of the algorithm.关键词：extended information filter framework;cubature information filter;five-order spherical-radial cubature rule;two-stage high degree cubature information filter (TSHCIF)56|255|0更新时间：2025-07-16
- 摘要：The purpose of the study was to reduce the noise and artifact in the phase-contrast computed tomography image of a tristructural-isotropic coated fuel particle.Three algorithms were proposed to reduce the noise and artifacts caused by the stochastic noise,non-linear drifting,and non-uniform sensitivity of the imaging detector,respectively.Subjective and quantitative evaluations were conducted before and after applying the algorithms.The results demonstrated that the proposed algorithms effectively reduced the three types of noise and artifacts,leaving the boundaries between different structures intact.关键词：phase-contrast computed tomography;tristructural-isotropic coated fuel particle;noise;artifact;reduction60|257|0更新时间：2025-07-16
- 摘要：In distributed photovoltaic(PV)generation systems,PV cells are in general connected to downstream power stage through interfacing DC-DC converters to fulfill maximum power point tracking(MPPT).Due to inherent current-source nature of the PV cell,the input voltage controlled PV-interfacing MPPT converter will become a current-fed(CF)converter which shows distinct dynamic features from those of the usual voltage-fed(VF)converters.In this regard,taking the Boost converter with an input capacitor as the case of study,this paper aims to investigate frequency responses of the CF MPPT converter.Firstly,small-signal models of the control system under both open-loop and input voltage controlled closed-loop are derived,and then the influences of load type on the system frequency responses are revealed.Secondly,the terminal impedances of the MPPT converter are modeled and analyzed,and the important factors affect the closed-loop input and output impedances are pointed out,which will provide theoretical guide for future stability design of the interfacing circuit.Finally,a laboratory prototype is built,and the analyses are verified by test results in both time-and frequency-domains.关键词：photovoltaic generation;MPPT converter;current-fed converter;small-signal model58|290|2更新时间：2025-07-16
- 摘要：To address the problems that hand-engineering visual features can't be optimally compatible with the Hash coding process and existing Hash methods can't differentiate images semantics information,a learning method of binary Hashing based on deep convolutional neural networks is proposed.The basic idea is to add a Hash layer into the deep residual network and to learn simultaneously image features and Hash functions.Meanwhile,we propose a more compact hierarchical Hashing structure to extract features closer to semantics information of images.Experimental results of MNIST,CIFAR-10 and NUS-WIDE datasets show that the method is superior to existing Hashing methods.This method not only unifies the process of feature learning and Hash coding,and at the same time,the deep residual network is able to get features closer to image semantics.Thus the retrieval accuracy is improved.关键词：image retrieval;deep residual network;hierarchical Hashing;semantics information73|383|0更新时间：2025-07-16
- 摘要：The traditional delegation computation require the verification party to verify the results,which leads to low efficiency of computation protocol.To solve this problem,this paper combines the game principal-agent theory and the fully homomorphic encryption technology to propose a rational delegation computation protocol.This protocol guarantees the correctness of the results through the utility function between the participants,without the validation of the prover.Firstly,we use the game principal-agent theory to construct a game model.Secondly,we combine the fully homomorphic encryption technology to construct the rational delegation computation protocol.Finally,we test and analyze the protocol,the results show that this protocol not only guarantees the safety and validity,and can achieve global Pareto optimality.关键词：rational delegation computation;game theory;utility function;Pareto optimality;fully homomorphic encryption67|276|0更新时间：2025-07-16
- 摘要：To cancel the effect on control performance due to joint acceleration constraints during humanoid robot walks,a new yaw moment control approach with consideration of joint acceleration constraints is proposed.After analyzing the effect on stability caused by the motion of arms swing,the undesired yaw moment which needs to be counteracted is computed.Then,the yaw moment control problem is formulated as a quadratic programming problem with inequality constraints.To solve this optimization problem effectively,an online variable step-size iteration method is designed to generate the trajectories of arms swinging.The experiment and simulation results verified that the proposed approach can effectively compensate yaw moment,avoid peak cut-off phenomenon and guarantee the stable walking.关键词：humanoid robot;yaw moment;joint acceleration constraints;quadratic programming;zero moment point180|313|2更新时间：2025-07-16
- 摘要：The existing physical layer secret key generation scheme is not sufficiently secure when the eavesdropper keeps close to the legitimate user to get the correlated channel characteristics.To solve the problem,this paper analyzes the secret key bit error rate and proposes a physical layer secret key generation scheme based on signal propagation characteristics.We calculate the large scale fading model which parameters is fitted by the measured sample,in order to get the small scale parameter of received signal strength indication under the effect of multipath fading to quantify into binary secret bit.The experimental results show that compared with the traditional scheme, in the indoor environment,after eavesdropping distance is greater than 0.6 wavelength,the eavesdropper key bit error rate is greater than 0.48.And in the outdoor environment,after the eavesdropping distance is greater than 1 wavelength,the eavesdropper key bit error rate is 0.47. Secure and reliable physical layer secret key generation is achieved.关键词：physical layer security;secret key generation;signal propagation characteristics;received signal strength indicator (RSSI);secret key bit error rate103|261|2更新时间：2025-07-16
- 摘要：In order to effectively distinguish the natural objects inside the town from outside objects,and completely identify the urban regions in remote sensing image,a fuzzy geographic object-based MRF method is proposed.Firstly,the seed points of the town,i.e.,the top and shadow points of artificial ground objects,are firstly obtained by analyzing spectral information and spatial gradient.Then the over-segmented regions of the origin image are obtained by Mean Shift algorithm.Finally,a MRF is established over regions.and the membership matrix in the fuzzy C-means clustering algorithm is replaced by the conditional probability matrix in the MRF in an iterative manner.Meanwhile the categories of the regions containing the seed points are kept unchanged.For QuickBird and Ikonos remote sensing images,the proposed model can simultaneously deal with both the stochastic and fuzzy nature of images,and effectively intergate the space information,and thus benefit the identification of town.关键词：urban identification;fuzzy C-means algorithm;spatial information;Markov random field model57|262|0更新时间：2025-07-16
- 摘要：In this paper,a new time-frequency model and analytical method are proposed for multiple modulated components with dynamic births and deaths.The proposed model takes the amplitude and phase of components as the state variables whose evolutions are described as polynomial prediction models.The observations of the signal are then viewed as the measurements of the states.In this way,a new state space model is built to describe the signal with multiple modulated components.In order to cope with the dynamic births and deaths of the components,a non-parametric iterative adaptive approach with a time window is employed to obtain the short time spectrums.The number of signal components is found under the rule of three times standard deviation of the noise in the spectrums.Now,the unscented Kalman filter can be used to analyze the dynamic births and deaths signals based on the proposed model.Simulation results verify the effectiveness of the proposed method while its performances shown in terms of accuracy,resolution and crossing spectrum separation are much better than the ones reported in literature.关键词：dynamic births and deaths;polynomial prediction model;iterative adaptive approach;unscented Kalman filter63|284|3更新时间：2025-07-16
- 摘要：Focused on the diversity of appearance and the complexity of configuration,laying,and occasion in human images,a coarse-to-fine method was proposed for effective human parsing.It can decompose a human image into semantic regions which consists of three phases.In the first two phases,two effective models were trained with Fast Region-based Convolutional Network(Fast R-CNN)to respectively detect human body and clothing items.In the third phase,parsing clothing items based on retrieving similar over-segmented images and morphing them into absolute image coordinates.Experiments are conducted on three public databases,and the experimental results show that proposed method has higher accuracy and promising performance.关键词：pedestrian segmentation;Fast R-CNN;over-segmentation;parts retrieval87|326|1更新时间：2025-07-16
- 摘要：The wideband underwater acoustic multipath channels are usually modeled as a multi-scale multi-lag(MSML)channel.Different paths possess different Doppler scales which brings great challenge to channel parameter estimation.In this paper,we propose a novel algorithm for parameter estimation of MSML channels,which is called modified particle swarm optimization(MPSO)algorithm.This algorithm creates a multi-path list to record positions and fitness values of particles which are local best(lbests),and uses these lbests to update particles' velocities at each iteration.At the end of the algorithm,the Doppler scale,the time delay and the amplitude can be estimated simultaneously for each path according to the multi-path list.Simulation results show that,the MPSO algorithm outperforms both the matching pursuit(MP)algorithm and the fractional Fourier transform(FrFT)algorithm in estimation accuracy.关键词：underwater acoustic communication;parameter estimation;multi-scale multi-lag (MSML) channel;particle swarm optimization (PSO) algorithm85|300|2更新时间：2025-07-16
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