最新刊期
卷 46 ， 期 12 ， 2018
- 摘要：DSSS-Signal (Direct Sequence Spread Spectrum Signal) has the ability of anti-jamming and anti-interception, it is widely used in electronic countermeasures, satellite communications, measurement and data transmission. It is simplex to improve signal anti-interception by the method of fixed PN (Pseudo-Noise) code, code hopping and variable symbol period chaotic sequence. Therefore, we combine the strong-signal masking technology with direct sequence spread spectrum technology, and propose a waveform design method to enhance the signal covertness. The data of different security levels are modulated hierarchically to make strong-signal mask weak-signal, also the parameters of waveform are designed in the aspects of power and period to highlight the characteristics of strong-signal and hide the confidential signal. Simulations show that the designed signal waveform can resist conventional blind detection. Moreover, setting the waveform parameters reasonably can achieve demodulation loss less than 0.5 dB.关键词：communication countermeasure;strong-signal masking;anti-interception;direct sequence spread spectrum signal;waveform design;anti-blind detection296|584|8更新时间：2025-07-16
- 摘要：Ensuring the correct behavior of cyber physical systems (CPS) at runtime is critical, and it is more so in safety-critical area, such as aerospace, automotive, nuclear power and medical. A method of runtime safety verification based on hidden Markov model (HMM) is proposed for the CPS with stochastic behavior and unobservable states. First, a runtime safety verification framework of the CPS is constructed where the system model is represented by HMM, and the negation of safety property is specified by deterministic finite automaton (DFA), and then the product automata of DFA and HMM is used as a runtime monitor. Thus, the problem of CPS runtime safety verification is reduced into a probabilistic inference problem on the monitor. Second, an incremental iterative safety verification algorithm and a counterexample generation algorithm are proposed. The experimental results show that the prediction error rate of the safety verification algorithm is nearly 20% lower than that of the particle filter algorithm. When the system violates the safety property, the proposed method can product a counterexample which the particle filtering method cannot do.关键词：cyber-physical system;runtime verification;hidden markov model;deterministic finite automaton;safety;counter-example211|317|0更新时间：2025-07-16
- 摘要：Synthetic aperture radar (SAR) dual-channel cancellation technique can suppress various kinds of jamming signals including the scatter-wave jamming signals, so utilizing the azimuth intermittent sampling scatter-wave jamming method to counter the dual-channel cancellation system via slow-time intermittence is put forward. First, the SAR dual-channel cancellation principle of scatter-wave jamming is derived. Then the azimuth intermittent sampling scatter-wave jamming model is built, and its jamming performance to traditional SAR is analyzed. Next, its jamming performance to SAR dual-channel cancellation system in two kinds of phase compensation conditions is studied. Theoretical analysis and experiment results show that, when the phase estimated by the automatic phase searching algorithm is used, this jamming method can produce chaotic dark and bright speckles and false scattering scenes in the scene cancellation imaging; when the exact phase is used directly, this jamming method can produce multi-false scattering scenes and cancellation dark stripes.关键词：synthetic aperture radar (SAR);dual-channel cancellation;intermittent sampling;scatter-wave jamming;electronic countermeasures114|279|4更新时间：2025-07-16
- 摘要：This paper investigates the problem of locating a target using a passive radar system with multiple transmitters and multiple receivers. The bistatic range (BR), which corresponds to the sum of transmitter-to-target and target-to-receiver distances is used as the measurement. An algebraic solution employing three-step weighted least squares (3WLS) minimizations is proposed. In the first stage, the BR measurements are linearized by introducing multiple additional parameters and a WLS minimization is used to obtain a rough estimate; then in the latter two stages, the relationship between the additional parameters and the target location parameters is utilized to refine the estimate. Theoretical accuracy analysis indicates that the proposed algorithm can achieve the Cramer row lower bound (CRLB), and Monte-Carlo simulations demonstrate the proposed algorithm outperforms existing algorithms.关键词：passive location;multi-transmitter multi-receiver;bistatic range;weighted least squares134|291|4更新时间：2025-07-16
- 摘要：Beidou satellite navigation system (BDS) contains subtle nominal deformations. The traditional research focuses on deformation of single satellite and cannot quantitatively calculate the ranging biases due to nominal deformations. This paper analyzes BDS B1I signal nominal deformations based on time waveform, channel characteristics and ranging biases. The data are from big antenna receiving system combined with software receivers. Firstly, the cumulative averaging method and standard chip correlation technique are used to extract the details of signal deformations, and the digital distortion value of each satellite is calculated. Then, channel characteristics of all satellite signals are analyzed based on least square method. Lastly B1I signal natural ranging biases and the maximum ranging biases are analyzed quantitatively by S-curve bias. The nominal deformations of B1I signal are comparatively studied from multiple dimensions and the results presented could provide a new thought for signal-in-space assessment and receiver design.关键词：satellite navigation;nominal deformations;ranging biases;time waveform;channel characteristics170|323|1更新时间：2025-07-16
- 摘要：There is a problem of the poor applicability of clutter models under high resolution with the existing constant false alarm rate (CFAR) detection methods in polarimetric synthetic aperture radar (SAR) imageries. To solve the problem, a CFAR detection method with an analytical expression for the false alarm rate is proposed. Firstly, the probability density function (PDF) of the polarization whitening filter (PWF) metric is derived based on product model combining the hypothesis of the Fisher distribution texture. Secondly, the PDF of the PWF metric is integrated, and the analytical expression of the false alarm rate with respect to the detection threshold is obtained. The process of the proposed CFAR detection method is also designed. Finally, the CFAR detection performances of the proposed method are compared via airborne SAR (AIRSAR) real data with the existing detection methods, such as the two-parameter CFAR (2P-CFAR) detector and the detection methods based on K distribution, G0 distribution and Wishart distribution. The results show that the proposed method can detect the targets effectively, and the robustness of the method is strong. Compared with other detection methods, the figure of merit (FoM) of the proposed method is on average higher than 32.66%.关键词：synthetic aperture radar (SAR);constant false alarm rate (CFAR);product model;Fisher distribution;polarization whitening filter (PWF);false alarm rate;figure of merit149|247|0更新时间：2025-07-16
- 摘要：In this paper, a multi-model based floorplanner named UPRFloor is proposed to save reconfigurable resources and reduce communication overhead during the floorplanning of FPGAs. According to the shape of logical functions, a description model which can depict both rectangular and non-rectangular shapes is firstly defined. Then, the Mixed-Integer Linear Programming (MILP) ideology is used to optimize an objective function which takes the waste of resources and all kinds of communication costs into account to obtain a desirable floorplan. Finally, the UPRFloor strategy has been simulated on FPGA chips and the results show that the strategy saves reconfigurable resources as much as 25.59%. The proposed method is validated on the data set from MCNC standard benchmark. The UPRFloor reduces 22.49% global wire length at most with almost the same time-consuming as other algorithms. Experiments conducted on the SDR design also demonstrate that the strategy saves reconfigurable resources as much as 29.41% and reduces 13.41% global wire length at most, which effectively reduces the wasting of resources the communication cost.关键词：field programmable gate array;reconfigurable computing;floorplan;mixed-integer linear programming89|242|0更新时间：2025-07-16
- 摘要：Traditional cognitive radio spectrum allocation algorithms tend to ignore the influence of transmission power on network interference and have the drawback of high interaction cost between nodes. In response to these problems, by quantifying transmission power levels, we formulate the channel assignment and power control problem as a distributed non-cooperative game, in which each second user's purpose is to maximize the elastic traffic rewards. Formally, the formulated game is proved to be an exact potential game and converges to Nash equilibrium (NE) point. Furthermore, introducing the stochastic learning theory into game model, we propose a strategy selection algorithm based on stochastic learning, then the sufficient condition and strict proof for the convergence of this algorithm to pure strategy NE point are given. Finally, Simulation results show that the proposed algorithm can achieve high system throughput and improve users' satisfaction with a small amount of interactions.关键词：cognitive radio networks;stochastic learning;game theory;channel assignment;power control120|285|9更新时间：2025-07-16
- 摘要：The multi-user security transmission scheme on physical layer in a massive multiple-input multiple-output (MIMO) relay based network is studied. There are direct links between the eavesdropper and the source nodes and between the eavesdropper and the relay nodes, so the eavesdropper can receive the signals sent by the source nodes and the relay. The relay employs simple maximum ratio combining in the first stage and maximum ratio transmitting in the second stage by using this scheme and assisted by the null-space artificial noise sent by the relay and the collaboration interference sent by the destination node, security transmission of information between the multi user-pairs is realized even though the channel state information of the eavesdropper cannot be obtained. The secrecy rate and its asymptotic value when the number of antennas of the relay grows to infinity are analyzed. The simulation results show that the secrecy sum rate of the system increases with the number of relay antenna, and eventually reaches the asymptotic value. Furthermore, a considerable secrecy rate can be achieved even if the eavesdropper has the capability to cancel the multi-user interference and to intercept the signals sent by the source nodes and the relay.关键词：massive MIMO;relay;multi-user;physical layer security81|226|5更新时间：2025-07-16
- 摘要：Channel coding identification is often required in modern digital communications. As the existing blind identification methods for RS code are complicated for the reason that all spectral components in high-order domain need to be calculated, a method based on binary equivalence is proposed. Firstly, RS code is equivalent to binary linear block code according to finite field properties, with the establishment of the association model between code length, information block length, generator polynomial and primitive polynomial. Then, the various parameters of RS code are identified by traversing primitive polynomials and verifying parity check vectors of the binary linear block code. Simulation results and theoretical analysis show that the proposed method can improve error-resilient performance and reduce computation cost as well, which proves its availability in intelligent communication and communication reconnaissance systems.关键词：intelligent communication;communication reconnaissance;channel coding;RS code;blind identification;finite field208|212|6更新时间：2025-07-16
- 摘要：The measurement for transmitter inter-modulation (IM) is developed, taking a directional coupler and an adjustable attenuator as core equipment. The IM signal models at each port of the directional coupler are established; and the regularity of how the IM signal level at coupler ports change with the attenuation of the adjustable attenuator is analyzed. According to theoretical analysis, the paper investigates methods for elimination of several error factors, like the first-order reflected IM signal from the interference signal source, and the second-order reflected IM signal from the transmitter under test and coupling signal power; and then gives the detail measurement procedures relies on the attenuation adjustment of attenuator. A practical measurement of a broadcasting station indicates that using the proposed method, a very good agreement of measurement and theoretical analysis can be achieved, which validates the rationality and accuracy of proposed method.关键词：transmitter intermodulation;intermodulation attenuation ratio;adjustable attenuator;error items cancelling methods;IM measuring method procedure58|218|0更新时间：2025-07-16
- 摘要：In order to improve the performance of the ISAR imaging method based on compressed sensing under sub-sampling and low SNR, a new high resolution ISAR imaging method for chirp frequency stepped signal is proposed, based on the unique characteristics of the stepped frequency waveform, and the two-dimensional sparse structure information of the target. The proposed method is deal with the cross range focusing first and then the range resolution. Firstly, the pulse compression is performed on the sub-pulse echo, and then based on the analysis of the sparse structure of the stepped frequency ISAR echo in cross range dimension, a distributed compressed sensing model is constructed; Secondly, the DCS-SOMP algorithm is used to reconstruct the model, then the high cross range resolution imaging in low SNR is obtained; Finally, an arbitrary sparse representation model is constructed by using the echo characteristics in range dimension. Because the proposed method, which is cross range focusing first and then the range resolution, makes full use of the target structure, it not only avoids the migration through range resolution cell effect on the cross range resolution, but also has strong anti-noise performance, high reconstruction accuracy and low sampling rate. The validity of the proposed method is verified by simulation and experimental data.关键词：ISAR imaging;joint sparse model;arbitrary sparse model;chirp frequency stepped;distributed compressive sense68|211|0更新时间：2025-07-16
- 摘要：Emergency needs full information. To transfer it from the disaster area without the ground base station needs a quick and a reliable network. It is a good solution to use emergency mobile Internet of Things (emIoT). This type of IoT is energy efficient and suit for long-distance transmission. Consider UAVs as an air-based communication platform. We researched on the long-distance communication in emIoT with mass mobile energy-constrained devices. An energy saving strategy based on UAVs is proposed. First, model this type of IoT. Second, according to the disorderly scattered ground devices in the stereo disaster area, the strategy optimizes UAVs deployment. It can provide a reliable communication and reduce the energy consumption of the communication at the same time. Third, given the ground equipment moves randomly and widely. A joint motion pattern about UAVs and ground mobile devices was analyzed. It avoids long-distance moving caused by frequent changes of cluster coverage with UAVs and reduces the mobile energy. Finally, from transferring to moving energy-saving, the effect of the proposed strategy is verified through experiments.关键词：emergency mobile internet of things;space based communication;unmanned aerial vehicle (UAV);energy saving101|300|7更新时间：2025-07-16
- 摘要：Direction-of-arrival (DOA) estimation is a research hotspot in wireless location. To deal with the lack of the array freedom, this paper presents a coprime array with a high degree of freedom based on the reconstruction of virtual array, realized the super-resolution estimation of multi received angles. This algorithm first vectors the received signal covariance matrix to build the virtual structure model with coprime array, and then, to fit out the lack virtual array response, this paper reconstruct the virtual array, finally, the spatial smoothing is used to realize the super resolution angle estimation. The complexity of the algorithm and the degree of freedom of the array are analyzed in theory detailedly. The simulation results show that the proposed method has a higher array degree of freedom than that of continuous spatial smoothing detection algorithm and the iterative interpolation algorithm under the condition of a same physical element, compared to the iterative interpolation algorithm, the performance of the algorithm is improved greatly with a slightly increased in complexity.关键词：coprime array;virtual array;degree of freedom;super resolution154|247|2更新时间：2025-07-16
- 摘要：The open source software (OSS) is widely used in various software fields, such as operating system, container, etc. But there is no method to measure open source software comprehensively. Based on the measurement of user interest and the development of participation metrics, we propose a method that can overcome the single limitation of the metric dimension. Based on DM model, software viability model and other relevant literature research, mining of software repository, we consider the OSS development process and propose an OSS success evaluation model through clustering, principal component analysis and regression analysis. By comparing the metric score of user interest method and development participation method, the evaluation model can be used to measure the success of OSS projects based on the data collected automatically without interference. The evaluation model can be applied to select high quality open source projects, academic research, intelligent project recommendation, etc.关键词：open source software;principal component analysis;success measurement model;data mining;quantitative analysis;software engineering;DM model;software viability model208|259|2更新时间：2025-07-16
- 摘要：In order to meet the multiple access requirements of LEO (Low Earth Orbit) satellites when accessing to data relay satellite, the delay-optimal backoff (DOB) algorithm based on IEEE 802.11 scheme is proposed, which shows a better performance in access delay and throughput compared with the traditional binary exponential backoff (BEB) algorithm at large-spatial and temporal-scale inter-satellite links. In this paper, we construct the communication coverage of a data relay satellite to LEO spacecrafts based on the space position relation between LEO spacecrafts and data relay satellite. The DOB algorithm can dynamically adjust the values of backoff window depending on the access request probability which is related to the number of user satellites in the communication coverage. Research results show that average access delay of DOB algorithm is decreased by about 10s, the traffic threshold is increased to 0.6 and the maximum throughput has doubled compared to BEB algorithm, which improves the network performance on multiple access.关键词：space information network;IEEE802.11;access delay;contention window (CW);backoff algorithm;inter-satellite links;throughput;satellite communications;data relay satellite208|255|1更新时间：2025-07-16
- 摘要：Through extensive measurements in our wireless long-distance network test-bed, we analyze fundamental reasons that cause low link throughput, and find characteristics of frame error pattern and loss rate. AdaCode is therefore proposed to improve link throughput, which is an adaptive coding algorithm at MAC (Media Access Control) layer. AdaCode integrates inter-coding and intra-coding algorithms, where inter-coding adopts LT (Luby Transform) codes to combat frame loss, whereas intra-coding uses RS (Reed Solomon) codes to recover corrupted frames. It chooses the optimal coding rate to decode all frames according to frame bit error rate and loss rate during transmission. When all frames are decoded, it is unnecessary to retransmit them, thus improving link throughput. We evaluate AdaCode via simulation in MATLAB using real-network trace. The simulation results show that AdaCode can improve link throughput efficiently at both fixed and variable physical-layer rate.关键词：long distance;wireless mesh networks;802.11n;RS code;LT code108|331|1更新时间：2025-07-16
- 摘要：Considering the data collection problem in wireless sensor networks, a matrix completion based data collection scheme is proposed. By transforming the data collection problem into two correlated convex sub-optimal problems according to the low rank matrix factorization model, an imporved Kaczmarz iteration based matrix completion algorithm is proposed to solve these two sub-optimal problems alternatively and iteratively. Furthermore, dimensional reduction operations are excecuted before projections in the Kaczmarz iteration according to the Johnson-Lindenstrauss lemma with the goal of accelerating the speed of the algorithm. Experiment results show that the proposed algorithm presents superior reconstruction performance in terms of reconstruction accuracy, the probability of successful reconstruction, and reconstruction time than the existed algorithms.关键词：Wireless sensor networks;data collection;matrix completion;optimization;data reconstruction65|250|0更新时间：2025-07-16
- 摘要：In order to improve the robustness of the formation system and reduce the system demands for communication conditions, concerning the formation control problem of multi-agent systems, a control approach is proposed based on impulsive control for the formation control problem of heterogeneous multi-agent systems. Considering problems in multi-agent systems with switching topology and time-varying delays, an impulsive control algorithm is proposed based upon leader-following models by using the consensus theory. In formation control of heterogeneous multi-agent systems, the time-varying delays problem is transformed into the upper bound of time-delays problem by the matrix theory. A Lyapunov function is constructed. By the Lyapunov theory, a sufficient condition for solving the formation control problem of heterogeneous multi-agent systems is obtained. Aiming to compare the control protocol with others, the average communication cost index of multi-agent systems with switching topology is proposed. The simulation results illustrate the validity and the superiority of the proposed impulsive control approach.关键词：heterogeneous multi-agent systems;impulsive control;time-varying delays;consensus;average communication cost index135|188|3更新时间：2025-07-16
- 摘要：Chip Process variations cause yield degradation after manufacturing. To improve yield, the sequential circuit buffer insertion algorithm for yield improvement of chips is proposed. The locations of buffers are determined by sequential circuit simulating chips after manufacturing based on Monte Carlo simulations. The proposed method not only maintains a good yield improvement, but also reduces area cost. By using ISCAS89 benchmarks and TAU 2013 circuits, the simulation results show that the number of inserted buffers is no larger than 1% of the number of flip-flops in the circuits, and the yield is improved up to 35.98%.关键词：process variations;yield;buffer85|243|0更新时间：2025-07-16
- 摘要：The current research of link prediction mainly focuses on single node pair link prediction for social network, in which the topology doesn't change frequently. In this paper, for the opportunistic network with frequent topology change, we propose a multi-nodes link prediction method based on pattern classification. This method employs chaotic time series theory to determine the slicing time of opportunistic network, and the topology of the network is depicted by the state diagram. The structural features of opportunistic network can be extracted from the evolution of the state diagram in terms of the advantages of the deep convolution neural network on the feature extraction. The evolution pattern of the future link is inferred from the current features so as to realize the multi-nodes link prediction. The experimental results on the Imote-Traces-Cambridge dataset show that the proposed method has better precision and stability than the prediction methods based on CN (Common Neighbor), Adamic-Adar and Katz.关键词：opportunistic network;multi-nodes;link prediction;convolutional neural networks;pattern classification171|401|11更新时间：2025-07-16
- 摘要：An amplitude and phase compensation algorithm based on the best uniform approximation method is proposed. It overcomes the limitations of the traditional CORDIC when used in high-precision calculation of the amplitude and phase, such as too many iterations, long delay time, and slow phase convergence. By utilizing the vector information obtained from several iterations of traditional CORDIC, sectionalized first-order polynomial of best uniform approximation compensating for the amplitude and phase results is constructed, thus efficiently improving the computation accuracy. Simulation and test results show that, by using the proposed algorithm with 4 iterations of traditional CORDIC, the relative error of amplitude can reach 10-5 level, and the absolute error of phase can reach 10-5 degree level. At the same time, the maximum delay time is no more than 100 ns. And with the use of some dedicated multipliers, the registers and LUTs are reduced by 42.5% and 15.5% respectively. Moreover, the phase precision can be increased approximately one order with one more iteration. Hence, compared to conventional CORDIC algorithm, the proposed algorithm improves in iterations and computation precision, and is suitable for high-precision computation applications.关键词：coordinate rotation digital computer (CORDIC);phase compensation;best uniform approximation;FPGA125|309|1更新时间：2025-07-16
- 摘要：In order to solve the problems existing in the traditional battery-powered sensor network that the battery is not available to replace and the energy of nodes is easy to be exhausted, RF energy harvesting technology has been applied to the wireless rechargeable sensor network. Since the workload and harvested energy of sensor nodes in different positions are different, balanced distribution of nodes' energy can effectively improve the survival rate of nodes. Considering the scenario where mobile RF energy transmitter is employed for charging, we design a reasonable balanced routing scheme and charging algorithm under the conditions of known nodes' location information. First, the network area is discretized based on the cellular hexagonal grid where the grids and nodes are stratified respectively. A balanced routing scheme of hierarchical data transmission is proposed. Then we formulate mathematic model with pre-defined energy transmitter's moving path to minimize the variance of the nodes' residual energy in the adjacent two layers and derive the charging time at different charging spots from the inner layer to the outer layer. Simulation results reveal that compared with the existing balanced charging method, our proposed algorithm can significantly improve the balance of node's residual energy and prolong the network lifetime.关键词：RF energy harvesting;wireless sensor network;nodes' energy equalization;wireless charging88|205|5更新时间：2025-07-16
- 摘要：Aiming at the demand of predicting adaptive interface user's intention, This paper presents a method of human-computer interaction behavior classification and intention prediction based on eye movement characteristics. By establishing a simplified interface model, the user's operating behavior is divided into 5 categories, design visual interaction experiment to collect the relevant states' eye movement data. The SVM (Support Vector Machine) algorithm is used to establish the classification prediction model, combined with the difference analysis method to select the eye movement feature component. Finally, the position X coordinate, the position Y coordinate, the gaze time, the eye jump amplitude and the pupil diameter of the 3 consecutive sampling fixation points can be used as the characteristic parameters to obtain the better prediction effect, and the prediction accuracy can reach more than 90%.关键词：adaptive interface;eye movement characteristics;intention prediction;SVM149|335|7更新时间：2025-07-16
- 摘要：Common security technology for liquid dangerous goods is unreliable and inefficient. This paper proposes a approach which using characteristics of scattering parameters curve to identify liquid dangerous goods. When centimeter waves penetrate liquids that have different dielectric constants and viscosities, the characteristics of the corresponding scattering parameter curves are different. The instrument uses Ultra-wideband technology to collect a large number of sampling points. These points describe the scattering parameter curve accurately. The perceptron model classifies the liquid by identifying the characteristics of the scattering parameter curve. Experiments show that the recognition rate is over 96%.关键词：perceptron;liquid dangerous goods;scattering parameters;curve characteristics;ultra-wideband75|214|0更新时间：2025-07-16
- 摘要：Although the existing sphere decoding algorithm of the spatial modulation systems can greatly reduce the computational complexity of the maximum-likelihood (ML) detection, due to its loose updating radii and slow convergence, the level of computational complexity reduction is still very limited, especially in high-order modulation systems. To solve the problem, the statistical distribution is used in this paper to estimate the redundancy in the updating radii of the existing algorithm, and two improved sphere decoding algorithms are proposed. Theoretical analysis and simulation results show that the improved algorithms can greatly reduce the computational complexity of the traditional sphere decoding while achieving the same performance with ML detection, which have great theoretical and practical significance.关键词：MIMO;spatial modulation;ML detection;sphere-decoding;computational complexity138|180|1更新时间：2025-07-16
- 摘要：Effectiveness analysis is critical for making optimal network dynamic defense (NDD) strategies. Firstly, the attack success probability formula is derived by constructing the random sampling model from the perspective of vulnerability mutation, which can depict the influence caused by the mutation space, the mutation period and the number of vulnerabilities on the process of network attack. Then, two limit theorems of attack success probability are given and proved in single and multiple vulnerabilities cases respectively, and the calculating methods of optimal mutation space are given according to the two theorems. The simulation results show that the NDD's effectiveness improves with the mutation period reducing and the number of vulnerability attacked successively on a single attack path growing, meanwhile, although enlarging the mutation space is beneficial to improving the NDD's effectiveness in the beginning, the attack success probability would converge with the persistent enlargement of mutation space, which limits the continuous improvement of NDD's effectiveness.关键词：cyber security;network dynamic defense;security policy analysis;attack success probability;dynamic mutation;vulnerability mutation;random sampling190|192|2更新时间：2025-07-16
- 摘要：This paper presents a spectral clustering algorithm based image segmentation to correctly and automatically determine the number of classes. Firstly, the weighted matrix and the normalized Laplacians matrix are established with the similarity graph corresponding to a given image. Then, the eigenvectors corresponding to the smaller eigenvalues of the normalized Laplacians matrix are calculated to generate eigenvectors matrix and the pixel feature points set is constructed by means of treating each line of the eigenvectors as a different data point. Secondly, when the Laplacians matrix is in different approximate block diagonal structure, the proposed algorithm exploits the clustering property of the pixel feature points belonging to the same class and calculates the corresponding clustering degree of the different number of segmentation classes by defining the index of clustering degree. Finally, when the clustering degree is the last one to have a greater degree of jumping, the number of the segmentation classes is selected as the number of classes in this paper. The FCM algorithm is used to partition the pixel feature points set corresponding to the number of classes selected to realize the image segmentation. Synthesized and real remote sensing images are used for testing the proposed algorithm. The results show that the proposed algorithm can identify the number of classes in an image correctly.关键词：remote sensing image;Segmentation with unknown number classes;Spectral clustering;Similarity graph84|184|3更新时间：2025-07-16
- 摘要：Topic drift and word mismatch are a difficult problem in natural language processing. The combination of text mining and information retrieval can help to solve the problem. In view of this, this paper proposes an algorithm of Vietnamese-English cross language (VECL) query post-translation expansion based on all-weighted positive and negative association pattern mining. The algorithm utilized a computing method of support and correlation degree of all-weighted positive and negative itemset, and mined the all-weighted positive and negative association pattern related to the original query by the pattern evaluation framework in the user relevance feedback document set from the VECL first retrieval results. The expansion terms were extracted from the patterns in order to carry out VECL query post-translation expansion. A comparison between the proposed algorithm and the existing cross language query expansion algorithms based on pseudo relevance feedback and weighted association pattern mining is made, which shows that the former can effectively reduce the problems of query topic drift and word mismatch, and improve the performance of cross language information retrieval. And moreover, the method of pattern mining in this paper can be used in recommender systems and improve its accuracy.关键词：natural language processing;information retrieval;text mining;pattern mining;query expansion;recommender system128|253|8更新时间：2025-07-16
- 摘要：To the nonlinear dynamic response of folder system caused by the pair clearance and the bearing stiffness, the hypothesis of rigid role and spring combination is put forward, and the dynamics model of folder mechanism with clearance is established. The dynamics model which contains second order partial differential equations is solved by direct-integrating approach method. The kernel of nonlinear system analysis is the solving of system state equation. Therefore, for a general nonlinear control system, the concept of general time-state space comprising of state variables, control variables, and Time t is introduced. In order to solve the state equation of nonlinear control system, at the operation point of general time-state space, the right side of the state equation can be expanded as Taylor series about time. Then the series solution of the nonlinear control state equation, for which the solution is expression in the series, can be obtained by using direct-integrating approach. Dynamics model of the folder mechanism is a typical nonlinear system. Then we obtain the curves of input quantity and output quantity of this dynamics model by the direct-integrating method.关键词：web offset press's folding mechanism;dynamic model;nonlinear systems;state equation;direct-integrating70|172|0更新时间：2025-07-16
- 摘要：Error correcting output codes (ECOC) is a powerful tool to solve multi-classification problem. The existing methods of seeking the optimal coding matrix ignore the correlation between classes, which leads to bad performance in learning speed and classification accuracy. In order to construct data-driven coding matrix, an optimization strategy of coding matrix based on immune clonal selection algorithm (ICSA) is presented. The strategy reduces the multiple constraints non-deterministic polynomial problem (NP) of finding the optimal coding matrix to a finite heuristic search problem. Firstly, the affinity function based on accuracy and coding length is defined. Then, the mutation, crossover and selection operator are modified respectively. Meanwhile, the validity constraints are combined to execute the quick search. The experiment results based on UCI and traffic data prove that the proposed strategy can enhance the classification performance and accelerated the speed. The output coding matrix is more compact as well.关键词：multi-classification;ECOC;immune clonal selection algorithm;data driven;coding matrix;multiple constraints optimization63|215|0更新时间：2025-07-16
- 摘要：TrustSVD, a popular social collaborative filtering algorithm that incorporates both of the explicit and implicit trust information, has been widely used in recommender systems. However, there is a risk of disclosure of user privacy in TrustSVD. Privacy information inference based on background knowledge is one of the great hidden dangers of user's privacy disclosure. Differential privacy has attracted much attentiaon as a privacy protection mechanism that can provide a strict theoretical guarantee for protection objects. In this article, we propose DPTrustSVD, a novel collaborative filtering algorithm that applies Differential privacy to TrustSVD and has the ability of privacy preserving. Theoretical analysis and experimental results show that DPTrustSVD not only provides a strict theoretical guarantee for users' privacy information, but also maintains a high prediction accuracy.关键词：social collaborative filtering;personal privacy preservation;differential privacy;matrix factorization;trust relationship;implicit trust227|222|2更新时间：2025-07-16
- 摘要：Signal probability calculation is the key to power estimation when optimizing power of MPRM (Mixed Polarity Reed-Muller) circuits by using signal probability based power estimation models. A probability expression based power estimation method is proposed for MPRM circuits. The proposed method takes into account both efficiency and accuracy of signal probability calculation, for signals having not spatial correlation in MPRM circuit, their signal probabilities are computed by means of signal probability propagation in circuit, whereas for signals having spatial correlation, probability expressions are utilized to calculate their signal probabilities and are propagated in circuit to resolve spatial correlation problem, then the dynamic and static power of the circuit are computed respectively by using the established analytical power estimation models based on signal probability. In order to further improve time efficiency, the proposed method utilizes binary moment diagram to represent probability expression. The proposed method is validated by using several benchmark circuits, and compared to other power estimation methods using different signal probability calculation methods for MPRM circuits. Results show that the proposed method is accurate and effective.关键词：MPRM circuits;power estimation;signal probability;spatial correlation;probability expression;binary moment diagram100|217|1更新时间：2025-07-16
- 摘要：When switching frequency increases, the switching losses in the single-phase full-bridge hard-switching inverter will also increase significantly so that the inverter is in low efficiency. In order to solve this problem, a single-phase full-bridge three-level energy-saving inverter is proposed. By resonance in the auxiliary commutation circuit, the voltage across capacitors in parallel with the main switches decreases to zero and the main switches could achieve zero-voltage switching. Furthermore, two groups of bidirectional auxiliary switches can achieve zero-voltage switching and zero-current switching respectively in the process of commutation. The working state of the circuit is analyzed. Experimental results show that the main switch and auxiliary switch can achieve soft switching. Therefore, the single-phase full-bridge three-level inverter can operate in high efficiency.关键词：three-level;inverter;zero-voltage switching;zero-current switching;bidirectional switch96|208|8更新时间：2025-07-16
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