最新刊期
卷 46 ， 期 2 ， 2018
- 摘要：Software as a man-made system is a typical complex system, understanding its evolution contributes to better software engineering practice. In this paper, we construct software network model from a multi-granularity perspective, namely the level of package, class and feature respectively. Then we analyze the evolutions of three open-source software systems in terms of network scale, quality and structure control indicators, using complex network theory. Finally, taking Lehman's evolution laws as the benchmarks, we compare the evolution of software networks based on multi-granularity. The results show that: (1) the evolution characteristics are varied under different granularity levels, and software network built in the level of class supports the most Lehman laws; (2) the laws of continuing growth, increasing complexity, self-regulation and conservation of familiarity are independent of the levels of granularity; (3) the impact of software evolution in the level of package on software quality is trivial, but feedback system is only supported in the case of class level.关键词：software evolution;software network;complex networks;complex system315|507|6更新时间：2025-07-16
- 摘要：Application such as aircraft stealth, ionospheric communication based on the plasma electromagnetic scattering theory has drawn deep attention from plasma technology field. A detailed theoretical analysis of plasma column antenna radiation characteristic which also based on such plasma electromagnetic scattering theory is presented. According to the azimuthally symmetric surface wave dispersion relation in the non-magnetized plasma column with presence of electron-neutral atom collisions and non-uniform plasma densities both radial and axial, the complex surface wave-vector with real and imaginary parts is studied as function of signal frequency and plasma density. Together with wave-vector, exponential distribution of the plasma column surface current model, the plasma impedance, we derived the dependence of antenna radiation pattern, the largest antenna gain and radiation impedance on signal frequency, also the dependence of antenna radial energy radiation on the plasma density. The theoretical results show that the signal frequency and plasma density have great influence on antenna radiation pattern; the antenna radiation impedance and the maximum antenna gain change obviously with signal frequency, these theoretical results are in good agreement with the experimental measured results.关键词：plasma column antenna;radiation pattern;maximum gain;dispersion relation256|267|0更新时间：2025-07-16
- 摘要：This paper proposed a new system of two-class priority polling based on multi-times gated service policy. A queuing model of the polling system is constructed, in which the number of waiting customers in each site is set together as random variables of the system state. Moreover, iterative equations are set up by taking second-order partial derivatives of the generating function, and then the integral mathematical analytical expressions of the key indexes are derived via simultaneous solution, concerning the mean queue length, the mean waiting time of the key queue and common queues, and the mean polling period time of the server. Finally, computer simulations are conducted on the system and it is found that theoretical and simulation results are identical. The analysis shows that this new polling system satisfies the demand of service diversity and flexible service in the process of resource allocation in a periodic system, and demonstrates that the polling control protocol has wider applications.关键词：polling;priority services;multi-times gated service;the mean queue length;the mean waiting time274|201|8更新时间：2025-07-16
- 摘要：Mining the outliers that are different from normal data objects in the network is one of the important tasks in data mining. At present, the research aiming at outlier detection in bi-typed heterogeneous information network is relatively small. The methods which are applicable to homogeneous network can not be applied to bi-typed heterogeneous networks. Therefore, we propose a Rank-Kmeans Based Outlier detection method, called RKBOutlier, in heterogeneous information network. The two kinds of the objects and the connected semantic information are extracted from the heterogeneous information network. One type of the objects is regarded as the attribute objects, another type of the objects is regarded as the target objects. We perform cluster partitioning on target objects to detect the distribution of the attribute objects in each cluster. The objects which are abnormal at data distribution are considered to be the outliers. Ranking and clustering are combined to significantly improve the accuracy of clustering. The experimental results show that RKBOutlier can effectively detect outliers in bi-typed heterogeneous information network.关键词：outlier detection;ranking;clustering;target object;attribute object226|298|2更新时间：2025-07-16
- 摘要：Considering that the classical concept learning algorithms are difficult to deal with the massive data set, a MapReduce-based parallel algorithm for granular concept cognitive learning is proposed. The parallel algorithm is based on the cognitive thoughts of perception and attention in cognitive psychology, and it is combined with the granule transformation principle of granular computing. Specifically, a parallel algorithm is developed to compute granular concepts in big data environment, and a comparative analysis of the parallel algorithm and the classical granular concept construction algorithm is made. Granular concept cognitive computing systems are also constructed from the perspectives of extension and intension. Then, cognitive concept learning is performed by a given object set or attribute set. Experimental results show that the proposed parallel algorithm is effective and can be suitable for granular concept cognitive learning of massive data.关键词：concept lattice;concept learning;cognitive computing;granular computing;MapReduce309|226|12更新时间：2025-07-16
- 摘要：In order to improve the memory capacity of hardware reservoir computing (HRC) based on a single feedback loop, a HRC scheme based on multiple feedback loops is proposed. Adding extra loops can feedback the responses stimulated by past input signals into the reservoir to increase the HRC memory capacity. Investigations on the performances of HRCs based on a single and multiple feedback loops were carried out by numerical simulation for the memory capacity and a NARMA30 task which needs a long memory capacity. Results show that the HRC memory capacity is increased to 40.2 at ten loops from 18.2 at a single loop when the node number is 50. For the NARMA30 task, the Normalized Root Mean Square Error is decreased to 0.09 at two loops from 0.27 at a single loop when the node number is 1000. Therefore, specific memory capacity needed by a task can be designed through setting the parameters of feedback loops, partially solving the adaptive problem of reservoir computing.关键词：recurrent neural network;hardware reservoir computing (HRC);multiple feedback loops;memory capacity;30th-order nonlinear auto regressive moving average (NARMA30)190|255|1更新时间：2025-07-16
- 摘要：Difference Set Pairs have interesting applications in cryptigraphy and coding theory, and precisely in order to study the new form of ideal sequence pairs, presented as a mathematical tool. In this paper, three classes of new difference set pairs with higher energy are constructed by using the cyclotomic method. And there are larger difference between the main peak and the side peak in the binary sequences which constructed by these difference set pairs. Also, it can expediently find plentiful periodic complementary binary sequence pairs.关键词：difference set pairs;cyclotomy;efficiency of enery;periodic complementary binary sequence pairs145|190|1更新时间：2025-07-16
- 摘要：To settle the contradictory between convergence speed and precocity in artificial bee colony with elite-guided equations (ABC_elite), an enhanced ABC_elite (EABC_elite) is proposed. In the employed bee phase of EABC_elite, the global best (gbest) individual is introduced to the search equation to accelerate convergence, while the ordinary individual is also introduced to the search equation to balance the gbest's great lead ability, thus the information of gbest and ordinary individuals can all be used and the balance between exploration and exploitation can still be maintained. In the onlooker bee phase of EABC_elite, the ordinary individual is also introduced into the search equation to avoid the precocity. EABC_elite can keep good balance between accelerating convergence and averting precocity. It has no bias to any search directions and the global search ability of ABC_elite is enhanced. The experimental results demonstrate that EABC_elite performs significantly better than ABC_elite and other recently-developed state-of-the-art variants of artificial bee colony algorithm.关键词：artificial bee colony;balance strategy;search equation;function optimization447|439|7更新时间：2025-07-16
- 摘要：To improve the diversity and convergence of optimal solutions in multiobjective particle swarm optimization (MOPSO) algorithm, a multiobjective particle swarm optimization algorithm, based on the diversity information and convergence degree, named dicdMOPSO, is developed in this paper. Firstly, a global optimal solution selection mechanism, based on the distribution of optimal solutions in the knowledge base with the diversity information of non-dominated solutions,is introduced to balance the evolutionary process of population to improve the diversity and convergence of non-dominated solutions. Then, to enhance global exploration and local exploitation abilities of particles, a flight parameter adjustment mechanism is proposed to obtain the particles with better diversity and convergence by using the population diversity information. Finally, the experiment results demonstrate that, compared with other multiobjective algorithms, this proposed dicdMOPSO algorithm can not only obtain the optimal solutions with better diversity, but also be faster to catch the Pareto front.关键词：intelligent optimization algorithm;multiobjective particle swarm optimization;population diversity information;diversity information of non-dominated solutions;convergence degree220|408|4更新时间：2025-07-16
- 摘要：Time series anomaly detection is an important area of data mining. Traditional methods of time series anomaly detection usually find the surprise, outlier, etc., by comparing the data with the historical data. However, there are some limits with these methods, such as the inaccurate separation of the sequence, the false decision of the state and the window size or the incorrect definition and judgement of the anomaly. This paper proposes a time series anomaly detection model based on hierarchical temporal memory (HTM) to overcome the shortages of the traditional methods. This method can recognize and learn the intrinsic patterns in the time series and build a prediction model to determine an anomaly by comparing the real value with the predicted one. First, sparse distributed representation (SDR) is used to represent the raw data; then, the SDR is entered into the HTM model to make prediction; lastly, the proposed model evaluates the data by computing the difference of the actual value and the predicted one. The experiments on the artificial data and the real data show that HTM can detect anomalies accurately and quickly.关键词：anomaly detection;neuron network;hierarchical temporal memory;sparse distributed representation423|951|6更新时间：2025-07-16
- 摘要：A new quantum chaos particle swarm optimization (QCPSO) was proposed to accurately estimate the uncertain parameters of the fractional order hyper chaotic system. The QCPSO algorithm was realized by analyzing the mechanism of quantum behaved particle swarm optimization (QPSO) and combining the correlation between quantum entanglement and chaotic system. Firstly, the center of potential well was replaced by a fixed point of chaotic attractor. The particles which outside the attractor were gradually converged to the attractor, and the particles which inside the attractor were quickly diffused. Secondly, in order to guarantee the diversity of the initial value of the chaotic particles, the particle update mechanism based on random mapping was proposed. Finally, a scale adaptive strategy was proposed to solve the problem of search stagnation of the algorithm. The parameters of fractional order hyper chaotic system were estimated by the QCPSO algorithm, and the results showed that the QCPSO algorithm has faster convergence speed and higher accuracy than improved differential evolution algorithm, adaptive artificial bee colony algorithm and improved QPSO algorithm.关键词：quantum behaved particle swarm optimization;chaotic maps;strange attractor;fractional order hyper chaotic system452|289|4更新时间：2025-07-16
- 摘要：FLTL (Fuzzy Linear Temporal Logic) is used as the specification language of fuzzy system, the realizability focuses on judging whether there exists the model for open system satisfying the FLTL formulea. The basic idea of FLTL realizability and synthesis problem is as follow:given a specification, verifying whether there exists a system whose truth value of satisfying the specification is greater than zero. If existed, then we call FLTL formulae described the specification is realizable. First, fuzzy game graph with Büchi objective was proposed, which is used as the model to verify whether FLTL is realizable. Second, we studied the property of fuzzy game graph with Büchi objective by the method of reduction. Last, realizability of fuzzy linear temporal logic was studied and the procedure of system synthesis was given, their time complexities were analyzed.关键词：fuzzy linear temporal logic;fuzzy Büchi automata;realizability;fuzzy game247|197|4更新时间：2025-07-16
- 摘要：Current support vector machines (SVMs) for large-scale datasets classification problems are almost sensitive to noises. To overcome this problem, a new soft kernel convex hull support vector machine called SCH-SVM is proposed based on the soft kernel convex hull and pinball loss function. SCH-SVM extracts the soft convex hull vectors in the kernel space, which can represent geometric profile of data in the kernel space. Then SCH-SVM represents the original samples which projected as the soft convex hull vectors for the training samples, and finds the maximum quantile distance between soft kernel convex hulls belonging to two classes by using pinball loss function. Theoretical analysis and numerical experiments show that SCH-SVM has distinctive ability of training time, noise resistibility, and the number of support vectors.关键词：large scale datasets;noise;soft kernel convex hull;pinball loss function;classification206|316|3更新时间：2025-07-16
- 摘要：Empirical wavelet transform is a recently proposed method for non-stationary signal analysis. In view of its shortcomings, an enhanced empirical wavelet transform (EEWT) is proposed in this paper. Meanwhile, combining the new definition of instantaneous frequency, a new time-frequency analysis method for non-stationary signal is put forward. Firstly, EEWT is used to decompose a non-stationary signal into a number of intrinsic mode functions (IMFs) that have compact support set spectrum. Secondly, the time-frequency distribution of original signal can be obtained by demodulating each IMF Also, the proposed method is applied to analyze experiment data of rolling bearing by comparing with Hilbert-Huang transform (HHT) and the results show that the proposed method can effectively diagnose the faults of rolling bearings and get a better effect than that of HHT.关键词：time-frequency analysis;Hilbert transform;empirical wavelet transform;rolling bearing;fault diagnosis361|477|16更新时间：2025-07-16
- 摘要：In order to solve the problem of positioning errors caused by spoofing to the satellite navigation signals, a spoofing detection and elimination method based on antenna array is proposed. The carrier phase double difference measurement value of the receiving antenna array is used as the basis for interference detection. The direction vector of the spoofing is obtained by the single difference measurement value of the carrier phase. A method for improving the precision of the spoofing's direction is proposed too. The orthogonal vector is used to form a nulling in the direction of spoofing. By adjusting the beam direction, the array gain is formed in the direction of the signal to be measured, so as to achieve the purpose of resisting interference and enhancing the navigation signal at the same time. Using this method can effectively identify and eliminate the spoofing in the navigation signal, which is suitable for aircraft navigation in complex environment.关键词：navigation;spoofing;beam forming;antenna array;carrier phase222|311|9更新时间：2025-07-16
- 摘要：Aiming at the equalization problem of sparse channels in single-input multiple-output (SIMO) systems, a new iterative frequency-domain equalization algorithm is proposed based on the maximum likelihood (ML) criterion. The equalization of multiple signals is first modeled as the maximum likelihood frequency-domain signal sequence estimation from incomplete observations, and approximately solved by means of the expectation-maximization (EM) algorithm in an iterative manner. Analytic expression of the equalization output is finally obtained in the form of weighted summation of each discrete-frequency signals. In each iteration, the proposed scheme alternates between equalization output update and channel posterior distribution update. During the later step, the inherent sparse nature of the channels is exploited by employing sparse promoting prior distributions. Then, the sparse Bayesian learning iterative inference method is applied to the proposed model in order to obtain joint conditional posterior distribution of the channel parameters. Simulation results show that the proposed scheme has a good convergence and steady-state performance, and approaches the steady-state symbol error rate (SER) with known channel parameters, at moderate and high signal-to-noise ratio (SNR) values.关键词：frequency domain equalization;single-input multiple-output system;expectation-maximization algorithm;sparse channel250|245|5更新时间：2025-07-16
-
Influence of Ocean Clouds and Precipitation to Shipborne High Frequency Band Satellite Communication
摘要：Firstly we introduced the characteristics of ocean clouds and precipitation as well as their influence on electric wave absorption, and described the rainfall space structure appearance of ocean layer rain and convection rain and their influence on high frequency band satellite communication rain decline. Then we analyzed the reasons of high frequency band satellite communication rain attenuation, and pointed out that the electromagnetic wave absorption, hot noise and de-polarization are important aspects that lead to high frequency rain attenuation. Finally, considering the ocean working environment characteristics, we put forward some methods to resist rain attenuation such as uplink power control, frequency diversity、velocity diversity and self-adaptive modulation etc.关键词：sea;clouds;precipitation;rain attenuation;satcom;self-adaptive150|326|3更新时间：2025-07-16 - 摘要：A new-type dual-band bandpass filter using a novel quadruple-mode resonator is proposed. This quadruple-mode resonator consists of four open-stubs and one short-stub. The odd-and even-mode method is adopted twice to analyze this resonator and good conclusions are given. Each resonant mode of the quadruple-mode resonator can be tuned independently. Each two modes form a passband of the filter. Source-load coupling is introduced to improve out-band rejection. To testify the proposed theory and resonator structure, a high-selectivity dual-band bandpass filter is designed and fabricated. The measured results show that it has four transmission zeros and four transmission poles. This filter is centered at 2.08/6.07 GHz with 3dB bandwidths 11.06%/7.74% respectively and it has a compact size, only 0.28 λg×0.11λg.关键词：bandpass filter;dual-band;quadruple-mode resonator;odd-and even-mode method;high-selectivity306|248|7更新时间：2025-07-16
- 摘要：The electronic system or equipment can be easily disturbed by Electrical Fast Transient (EFT) induced by coupling between power lines and communication lines. EFT immunity of data communication is directly influenced by communication protocol. Hence, a MCU data communication system which contains four kinds of data communication protocol including I2C, USART, SPI and RS232 was designed for EFT immunity test by means of cable coupling. The test data was analyzed by mathematical statistics method for obtaining the EFT immunity of MCU data communication system under different communication protocols. The optimal Gamma model is used for researching distribution law of EFT interference threshold voltage of MCU data communication system under different communication protocols, which was selected by chi-square goodness of fit test and Hannan Quinn information criterion through hypothetical models. The model parameters were estimated by maximum likelihood method based on test data. For MCU communication protocols, EFT immunity from low to high is in the order of I2C, USART, SPI, RS232 under the same baud rate.关键词：MCU data communication system;cable coupling;EFT immunity analysis;maximum likelihood estimation;Hannan Quinn information criterion;comparison of data communication protocol180|275|1更新时间：2025-07-16
- 摘要：The wide-band noise jamming method fails to conceal the azimuth information of the target in the power condensation pattern. Therefore, a scattered-wave jamming method is proposed. The fake clutter signal is generated by scattering radar signal with Doppler shifting to the certain areas from jammers. The jamming signal acquires space-time coupling and is continuous both in space domain and time domain. The trajectory of jamming space-time power spectrum is controllable. The effect of radar target detection is analyzed by deriving the mathematic model of jamming signal. Furthermore, according to the Doppler trace feature and the Doppler isoplethic curves characteristic of the jamming signal, the estimation algorithm of the clutter and jamming covariance matrix eigenvalue number is proposed. The simulation results indicate that the shape of jamming space-time power spectrum is similar to bias, which leads to the improvement factor of STAP radar appearing more than one notch.关键词：STAP;clutter;scatter;spatial continuity;the Doppler trace;characteristic spectrum318|206|5更新时间：2025-07-16
- 摘要：Intraditional WLANs, when a user with a station (STA) accesses the Internet through AP (Access Point), due to the mobility of the user, the STA may move out of the coverage area of current AP and enter the coverage area of anotherAP. Thus, STA needs to handover between APs. In traditional WLANs, such a handover often incurs a sudden increase of the network delay, a sharp decrease of throughputs and even disconnection. This paper presents a new handover scheme based on the AP virtualization and OpenFlow technique. By developing an OpenFlow switch network, we can realize a fine-grained control on the traffic of STAs, and realize the roaming of STA among different APs. Furthermore, we build up a practical WLAN testbed and real experiments show that the proposed scheme will only lead to a handover delay of about 5ms, a throughput reduction of about 1s and delay of 16ms when a handover happens. Compared with other existing schemes, the proposed scheme has smoother handover process since it does not need re-authentication and re-routing.关键词：wireless local area networks(WLAN);seamless handover;OpenFlow;AP virtualization427|293|1更新时间：2025-07-16
- 摘要：Traditional fitting-based trajectory prediction algorithms cannot meet the requirements of high accuracy and real-time prediction. A dynamic Kalman filter based TP approach was proposed, which performs state estimation of dynamic behavior with regard to moving objects, updates the state variable estimation value based on the estimation of the previous and current observation states, in order to infer the next location of moving objects. Extensive experiments are conducted on real datasets of moving objects and the results demonstrate that the average prediction error (root mean square error between the predicted location and the actual location) of the TP algorithm based on Kalman filter is around 12.5 meters on the GeoLife datasets. The prediction error is reduced by about 555.4 meters by compared to the fitting-based TP algorithms, and the prediction accuracy is increased by 7.1% on the T-Drive datasets as well. The dynamic TP approach based on Kalman filter can handle the problem of low prediction accuracy with the guarantee of efficient time performance.关键词：moving objects databases;state estimation;trajectory prediction;Kalman filter;trajectory fitting2523|1829|47更新时间：2025-07-16
- 摘要：Low illumination images had the problems of fuzzy, low contrast and so on. In order to solve these problems, we put forward a low illumination image enhancement algorithm. Firstly, we established the gradient sparse and least square constraint model and decomposed the image into structure layer and detail layer. Then, the detail layer was enhanced by multi-scale edge-preserved algorithm and we used the Guided Filter to eliminate noise. Finally, the enhanced image was mapped by modified Retinex, we got the details enhanced, suitable brightness image. Experimental results show that performance is good, the 1D example figure of the contour is better than others, the figures of the details enhanced image NIQE(5.5202), BRISQE(31.1893) and PSNR(25.3625) are better, the Entroy(7.4421), Edge-Intensity(128.3231) and L-mean(121.1827) of the completed image are better as well. So the proposed algorithm shows a good performance in image enhancement.关键词：low illumination image;gradient sparse constraint;details enhancement;modified Retinex271|283|2更新时间：2025-07-16
- 摘要：The equivalent number of looks (ENL) is a key parameter that affects the constant false alarm rate (CFAR) detection performances in polarimetric synthetic aperture radar (PolSAR) imageries. At present, the estimated value of the ENL mostly is not an integer, resulting that existing CFAR detection algorithms are no longer applicable. To solve this problem, a new analytical CFAR algorithm of target detection is proposed in PolSAR imageries. Firstly, the probability density function (PDF) of multi-look polarimetric whitening filter (MPWF) metric is derived based on Wishart distribution assumption;Secondly, the analytical expression of CFAR detection threshold with respect to the ENL is obtained by integrating the PDF of MPWF metric;Finally, the CFAR detection performances of the new algorithm are compared with other CFAR detection algorithms via simulation data and AIRSAR measured data. The results show that the real false alarm probability in the new algorithm is the closest to the given constant false alarm probability, which better guarantees the hypothesis of the constant false alarm probability in the CFAR detection.关键词：polarimetric synthetic aperture radar;equivalent number of looks;Wishart distribution;constant false alarm rate detection;analytical expression272|258|10更新时间：2025-07-16
- 摘要：In computer vision tracking, the traditional model updating has poor robustness in solving the problem of occlusion, illumination change and self rotation. To improve these problems, this study proposes a new visual object tracking method. The algorithm firstly builds a candidate update sub-model library. Secondly, it determines the position and information of the current target by fusing the three complementary features of the tracking based on particle Filter. Finally, the algorithm divides the three characteristic histogram of the target and the candidate model library to calculate the similarity of the reliability weights, then determines whether the candidate sub-model library and current sub-model can be updated. Results show that the algorithm can effectively select to update the sub-model. Rather than the contrast algorithms, our method can achieve a better tracking accuracy to deal with the situation of occlusion, illumination change and self rotation. The proposed method updates the target model effectively and keeps the good robustness under various tracking scenarios.关键词：visual tracking;particle filter;model update;multi feature fusion;candidate sub-model library;weighted similarity170|202|3更新时间：2025-07-16
- 摘要：Sparse-to-dense depth conversion is an important task in semi-automatic 2D-to-3D conversion. Existing methods do not handle structural difference between texture image and depth map, and the error-tolerance of 2D-to-3D is not considered. Inspired by compressive sensing studies, we address these problems in an optimization framework via L1 norm. First, data term is built with L1 norm to measure the fidelity between estimated depth and user assigned depth. Second, local regularized term is defined by using feature weighted L1 norm to measure difference between local neighboring pixels. Third, super-pixels are generated from input image and global regularized term is introduced by using feature weighted L1 norm to measure difference between representative pixels from these super-pixels. Then, the energy function for sparse-to-dense depth conversion is defined based on the data term, local regularized term and global regularized term. The split Bregman algorithm is used to solve the energy. Experimental comparisons with optimization based interpolation, random-walks, hybrid graph-cuts and random-walks, soft segmentation constrained interpolation and nonlocal random-walks show that our method demonstrates significant advantages over hole and ghosting artifacts for viewpoint synthesis. The PSNR is improved by more than 0.9 dB compared with these methods when user assigns error depth.关键词：2D-to-3D conversion;optimization;random-walks;graph-cuts;L1 norm278|281|1更新时间：2025-07-16
- 摘要：Isogeometric analysis (IGA) based on the non-uniform rational B-splines (NURBS) realizes the unification of the geometric model, the computational model and adaptive mesh generation process in solving electrostatic problems.However, IGA based on one single NURBS patch is difficult to deal with the non-convex electrostatic field with corners and inhomogeneous electrostatic field because of limitation of the NURBS patch topology. In this paper, IGA based on the patch splicing is used to solve two-dimensional electrostatic problems of this kind while IGA extends from one single NURBS patch to multipatches. The control points and meshes of different patches must coincide on the interface, even after refinement. Due to lack of interpolation properties for the NURBS basis functions, Lagrange multiplier method is adopted to deal with non-homogeneous Dirichlet boundary conditions. Numerical examples are presented to show that modified multi-patch IGA can solve two-dimensional electrostatic problems of this kind well and possess the advantages of better convergence on a per-degree-of-freedom and high accuracy.关键词：electrostatic field;isogeometric analysis;NURBS;patch splicing199|224|0更新时间：2025-07-16
- 摘要：Wheelchair-mounted robotic arm (WMRA) is a typical assistive robot system for the elder/disabled people. This paper studies the motion mapping from a human master arm to a heterogeneous slave WMRA for manipulation in activity of daily livings. The motion of the human master arm is measured via a wearable motion capture system, and then the motion captured data is transformed into the joint space of the heterogeneous slave robot arm using a corresponding joint-set motion mapping algorithm, and an autonomous obstacle avoidance algorithm is also developed. As a result, the motion of the heterogeneous slave WMRA can be easily controlled by the user via the motion of his/her arm. This method possesses two remarkable advantages that are vital to the application of the WMRA systems:the elder/disabled user can operate the WMRA system intuitively and conveniently, and the fatigue degree and error rate of the user can be significantly reduced; the safety of WMRA in an unstructured and constrained home environment can be significantly improved.关键词：WMRA;heterogeneous master/slave arm;motion mapping127|356|2更新时间：2025-07-16
- 摘要：NTS cache augments the direct-mapped main cache with a small fully-associative cache that holds those blocks predicted as holding non-temporal locality characteristics. The most outstanding difference of the NTS cache from the victim cache lies in the NTS cache doesn't have direct data path between the two caches, so its advantages are lower power and easier structure design. In this paper, an improvement of the NTS cache scheme, called Selective Conflict Prediction cache (SCP cache), is proposed. In this scheme, incoming blocks into the cache are placed selectively in the direct-mapped cache or the fully-associative cache by the use of a conflict prediction algorithm which detects the locality of data blocks in the cache. Simulation results show that the performance of SCP cache is always better than that of NTS cache with similar area.关键词：cache performance;conflict prediction;miss ratio178|178|0更新时间：2025-07-16
- 摘要：For the accuracy and robustness of the motion occlusion detecting from image sequence, this paper proposes a novel occlusion detection method based on the optical flow and Delaunay triangulation. Firstly, a TV-L1 optical flow model based on the non-local constraint is presented. Secondly, according to the results of the Delaunay triangulation and optical flow result of image sequence, the occlusion of the corresponding pixels and local triangles between the continuous frames is located and the motion occlusion regions could be detected. Finally, the evaluation sequences of the MPI Sintel and Middlebury databases are employed to test the performance of the motion occlusion detecting between the proposed method, the SMOD and GOSF methods. The experimental results show that the average omission rate and average false rate of the proposed method on the ten test image sequences are reducing 15.21% and 30.57% compared to the SMOD and GOSF methods, which indicates the proposed method has the higher accuracy and better robustness of the motion occlusion detecting under the non-rigid motion, complex scene, weak texture, brightness shadow and large displacement.关键词：image sequence;occlusion detection;optical flow;Delaunay triangulation189|217|2更新时间：2025-07-16
- 摘要：A novel magnetron memristor model based on the hyperbolic sine function is proposed. And then, a new type of five-dimensional dual-memristor chaotic circuit is built by replacing the nonlinear resistance in the Chua's system with the magnetron memristor model. It is found that the dual-memristor system has the equilibrium point set. In addition, the numerical simulation of the memristive system is carried out by selecting the different initial values of the system and the multistribution characteristics of the fifth-order chaotic system are analyzed in detail by using the bifurcation diagram and Lyapunov exponent spectrum. The results show that the dual-memristive chaotic circuit is different from the dynamic behavior of the chaotic system. The motion trajectory of system depends not only on the circuit parameters but also on the initial state of the circuit, resulting in the coexistence of different periodic motions and different chaotic attractors with different topologies.关键词：memristor;multistable characteristic;dynamical behavior;chaotic system139|396|11更新时间：2025-07-16
- 摘要：This paper improves the iterative structure of the CORDIC algorithm, and implements a multi-mode CORDIC algorithm. We reset the initial rotation to avoid the first two stage iterations and fix the error of the original algorithm by modify the judgment condition which determine the rotation direction of the vector. In the case of increasing few hardware resources, the sine, cosine, arcsine and arccosine operations are unified to the same iterative structure and be realized. The results show that the improved algorithm has higher accuracy and the hardware resources utilization can be effectively reduced in the application that need both of the two kinds of functions.关键词：multi-mode;coordinate rotation digital computer(CORDIC);double iteration algorithm;trigonometric functions183|281|2更新时间：2025-07-16
- 摘要：GaN high electron mobility transistors (HEMTs) are difficult to model because of their complex device characteristics. Although EEHEMT and Angelov models have been successfully applied to large-signal models of GaAs HEMT/MESFETs, but they are no longer accurate and complete when used in GaN HEMT modeling. In this paper, a compact model topology is proposed for GaN HEMTs which is based on the DC I-V, non-linear capacitance, parasitic elements, gate/drain lag and current collapse, thermal effects and noise characteristics of GaN HEMT devices. It is proved that this model topology has good convergence in simulation. It is suitable for the establishment of large-signal models of GaN HEMTs, and satisfies the demand for device model of the GaN-based microwave-wave circuit design.关键词：GaN high electron mobility transistor;large-signal model;nonlinearity;convergence185|335|1更新时间：2025-07-16
- 摘要：Traditional wireless Ad hoc networks have the problem of poor network performance under the circumstances of high traffic load.To solve this problem, a distributed full duplex MAC protocol, which combines TDMA and CCFD together, is proposed.In this protocol, all nodes need to do suppression inspecting according to link co-existing schemes before data transmission begins.Then, primary TDMA links start searching secondary links according to the scheduling priority, and send out corresponding requests.The four times hand-shaking process of scheduling process is accomplished within the head of the traffic slot.With no affect on the half-duplex transmissions of traditional TDMA networks, it can increase as many links coexisting with originla links in the same slot as possible.The simulation results show that this protocol actually improves throughput and time delay performances of the wireless Ad hoc networks.关键词：TDMA(time division media access);full duplex;link scheduling;distributed networks229|251|2更新时间：2025-07-16
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0