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A 3D Finite Radon Transform 预览
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作者 Mustapha Boukour Abderrahim El Omri 《数学和系统科学:英文版》 2019年第2期64-69,共6页
The present work is devoted to the development of the extension of FRT (Finite Radon Transform) to the tridimensional case. One simple formulation is proposed and it is shown that it is the exact discretization of the... The present work is devoted to the development of the extension of FRT (Finite Radon Transform) to the tridimensional case. One simple formulation is proposed and it is shown that it is the exact discretization of the continuous Discrete Radon Transform. More precisely this is the case when the sampling is given on a regular grid i.e. the continuous function is filtered by the mean of the box function. Relation of this transform with the Discrete Fourier one is given and is for some help in numerical implementation. 展开更多
关键词 RADON TRANSFORM DISCRETE RADON TRANSFORM FRT DISCRETE FOURIER NUMERICAL COMPUTING
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Solutions in the Discrete Fractional Forms of Two Differential Equations with Singular Points
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作者 Okkes OZTURK 《应用数学学报:英文版》 SCIE CSCD 2019年第3期638-644,共7页
In present note,we apply the Leibniz formula with the nabla operator in discrete fractional calculus(DFC)due to obtain the discrete fractional solutions of a class of associated Bessel equations(ABEs)and a class of as... In present note,we apply the Leibniz formula with the nabla operator in discrete fractional calculus(DFC)due to obtain the discrete fractional solutions of a class of associated Bessel equations(ABEs)and a class of associated Legendre equations(ALEs),respectively.Thus,we exhibit a new solution method for such second order linear ordinary differential equations with singular points. 展开更多
关键词 FRACTIONAL CALCULUS DISCRETE FRACTIONAL CALCULUS DISCRETE FRACTIONAL SOLUTIONS Nabla OPERATOR
Discrete symmetrical perturbation and variational algorithm of disturbed Lagrangian systems
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作者 夏丽莉 戈新生 陈立群 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第3期77-83,共7页
We investigate the perturbation to discrete conformal invariance and the adiabatic invariants of Lagrangian systems. A variational algorithm is proposed for a system subjected to the perturbation quantities. The discr... We investigate the perturbation to discrete conformal invariance and the adiabatic invariants of Lagrangian systems. A variational algorithm is proposed for a system subjected to the perturbation quantities. The discrete determining equations of the perturbations to conformal invariance are established. For perturbed Lagrangian systems, the condition of the existence of adiabatic invariant is derived from the discrete perturbation to conformal invariance. The numerical simulations demonstrate that the variational algorithm has the higher precision and the longer time stability than the standard numerical method. 展开更多
关键词 VARIATIONAL INTEGRATOR DISCRETE PERTURBATION to conformal INVARIANCE DISCRETE adiabatic INVARIANTS disturbed Lagrangian systems
A holistic computational model for prediction of clay suspension structure 预览
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作者 Yuan Guo Xiong (Bill) Yu 《国际泥沙研究:英文版》 SCIE 2019年第4期345-354,共10页
The formation of clay suspensions involves complex interactions among clay particles subjected to the geochemical environment during the sedimentation process. The structural characteristics have a major influence on ... The formation of clay suspensions involves complex interactions among clay particles subjected to the geochemical environment during the sedimentation process. The structural characteristics have a major influence on the physical and mechanical behavior of the suspension. A modeling framework involving a Discrete Element Method (DEM) model with customized particle mechanical interactions is proposed in this paper for the holistic prediction of the physical structure of clay suspensions. The particle interaction force model is based on the Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory that accounts for electrostatic repulsion, van der Waals attraction, contact repulsion, etc. Kaolinite is used as the model clay to demonstrate the model performance. The surface charge density of kaolinite is obtained through Atomic Force Microscope (AFM) force measurement and is implemented in the particle interaction force model in the subsequent simulations. Influencing factors, such as centrifugal acceleration, ionic concentration, platy structure of particles, and particle size, on the formation of kaolinite suspensions are studied with the numerical model and compare favorably well with the experimental data. This work lays down a unique framework consisting of computational modeling and microscale characterization of clay particles to holistically predict the characteristics of clay suspensions, which paves the basis to model and predict their bulk physical and mechanical behavior. 展开更多
关键词 CLAY SUSPENSION Discrete element method DLVO theory Atomic force MICROSCOPE KAOLINITE Surface potential
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Streamline modeling of fluid transport in naturally fractured porous medium 预览
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作者 ZUO Lihua YU Wei +2 位作者 MIAO Jijun VARAVEI Abdoljalil SEPEHRNOORI Kamy 《石油勘探与开发:英文版》 2019年第1期130-137,共8页
To better understand the roles natural fractures play in porous media, an embedded discrete fracture model and streamline modeling method were combined to model natural fractures and compute the flow trajectory and ti... To better understand the roles natural fractures play in porous media, an embedded discrete fracture model and streamline modeling method were combined to model natural fractures and compute the flow trajectory and time of fluid in matrix and fractures systems. The effects of fracture conductivity, number of fractures and fracture locations on fluid flow trajectory and time were examined through analyzing the differences in water breakthrough time and sweeping volume of reservoirs with different fracture networks. When other conditions are the same, compared with homogeneous reservoir without fractures, the fractured reservoir has water breakthrough time 30% sooner and swept volume 10% smaller. Although increase of single fracture can lead to faster water breakthrough and smaller swept volume, adding more fractures wouldn’t necessarily reach the same effect. The effect of water flooding is also related to the strike and position of fractures. Fractures in different strikes and positions can result in 20% discrepancy in water breakthrough time and 9% gap in swept volume. The shorter the fracture, the less its effect on fluid flow trajectory and time will be. The position of fracture has a strong influence on sweeping efficiency, and the change of one fracture position could bring about 1% variation in swept volume. 展开更多
关键词 MULTIPHASE flow water FLOODING embedded DISCRETE FRACTURE model STREAMLINE simulation natural FRACTURE
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Voice Recognition by Neuro-Heuristic Method
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作者 Dawid Pofap Marcin Wozniak 《清华大学学报自然科学版(英文版)》 EI CAS CSCD 2019年第1期9-17,共9页
The amount of digital data is increasing every day.At every step of our daily lives,we deal with technologies in which our data are stored (e.g.,mobile phones and laptops),and this is one of the main reasons for the d... The amount of digital data is increasing every day.At every step of our daily lives,we deal with technologies in which our data are stored (e.g.,mobile phones and laptops),and this is one of the main reasons for the design of various types of encryption and user identity verification algorithms.These algorithms are meant not only to fulfill the desire of protecting data but also to address the possibility of granting access of specific digital data to selected individuals.This process brings with it the problem of identity verification.This paper discusses the problem of voice verification and presents a voice verification method based on artificial intelligence methods. Numerous tests are performed herein to demonstrate the effectiveness of the presented solution.The research results are shown and discussed in terms of the advantages and disadvantages of the solution. 展开更多
关键词 neural network HEURISTIC ALGORITHMS DISCRETE FOURIER TRANSFORM (DFT) image processin
Aperiodically intermittent stochastic stabilization via discrete time or delay feedback control
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作者 Lei LIU Matjaz PERC Jinde CAO 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第7期183-195,共13页
In this paper,we present stochastic intermittent stabilization based on the feedback of the discrete time or the delay time.By using the stochastic comparison principle,the Ito formula,and the BorelCantelli lemma,we o... In this paper,we present stochastic intermittent stabilization based on the feedback of the discrete time or the delay time.By using the stochastic comparison principle,the Ito formula,and the BorelCantelli lemma,we obtain two sufficient criteria for stochastic intermittent stabilization.The established criteria show that an unstable system can be stabilized by means of a stochastic intermittent noise via a discrete time feedback if the duration timeτis bounded byτ*.Similarly,stabilization via delay time feedback is equally possible if the lag timeτis bounded byτ**.The upper boundτ*andτ**can be computed numerically by solving corresponding equation. 展开更多
关键词 BROWNIAN motion STOCHASTIC STABILIZATION INTERMITTENT CONTROL discrete time FEEDBACK timedelay FEEDBACK
A novel matrix approach for the stability and stabilization analysis of colored Petri nets
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作者 Jiantao ZHAO Zengqiang CHEN Zhongxin LIU 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第9期102-115,共14页
In this study, the stability and stabilization problem of a colored Petri net based on the semitensor product of matrices is investigated. First, the marking evolution equation of the colored Petri net in a Boolean al... In this study, the stability and stabilization problem of a colored Petri net based on the semitensor product of matrices is investigated. First, the marking evolution equation of the colored Petri net in a Boolean algebra framework is established, and the necessary and sufficient condition for the stability of the equilibrium point of the colored Petri net is given. Then, the concept of the pre-k steps reachability set is defined and is used to study the problem of marking feedback stabilization. Some properties of the pre-k steps reachability set are developed. The condition of the stabilization of the colored Petri net is given. The algorithm of the optimal marking feedback controller is designed. The proposed method in this paper could judge the stability and stabilization of the colored Petri net by matrix approach. The obtained results are simple and easy to implement by computer. An example is provided to illustrate the effectiveness of the proposed method. 展开更多
关键词 discrete event system COLORED PETRI net semi-tensor product of MATRICES stability EQUILIBRIUM point stabilization
Productivity analysis of a fractured horizontal well in a shale gas reservoir based on discrete fracture network model 预览
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作者 Yu-long Zhao Nan-ying Li +1 位作者 Lie-hui Zhang Rui-han Zhang 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第3期552-561,共10页
The treatment of horizontal wells with massive hydraulic fracturing technology is important for the economical development of shale gas reservoirs, but sometimes is complex because of the induced fractures during the ... The treatment of horizontal wells with massive hydraulic fracturing technology is important for the economical development of shale gas reservoirs, but sometimes is complex because of the induced fractures during the fracturing process. The studies of the fluid flow characteristics in such formations are rare. In this study, a numerical method based on a finite element method (FEM) is developed for the productivity analysis of a horizontal well in a shale gas reservoir with complex fractures. The proposed method takes into account the adsorbed gas and the complex hydraulic fracture branches. To make the problem more tractable, the dimension of the fracture system is reduced from 2-D to 1-D based on the discrete fracture network (DFN) model. The accuracy of the new method is verified by comparing its results with those obtained by the Saphir commercial software. Finally, the productivity of the fractured horizontal wells in shale gas reservoirs with complex fractures systems is evaluated and analyzed. Results show that if a well is produced with a constant bottomhole pressure, the well productivity is much increased due to the existence of fracture branches that can increase the stimulated reservoir volume (SRV). In addition, the number of hydraulic fractures (Nf) and the fracture halMengths (Lf) have an important influence on the well's productivity. The larger the values of Nf,Lf,the greater the well productivity will be. The existence of adsorbed gas can markedly improve the well productivity, and the greater the Langmuir volume, the greater the productivity will be. The conclusions drawn by this study can provide a guidance for the development of unconventional shale gas reservoirs. 展开更多
关键词 Fractured HORIZONTAL well DISCRETE fracture network (DFN) MODEL finite element method (FEM) PRODUCTIVITY analysis SHALE gas RESERVOIR
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离散Leslie-Gower食物链模型的动力学行为研究 预览
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作者 苏倩倩 《数学杂志》 2019年第1期53-59,共7页
本文研究了一类离散Leslie-Gower三维食物链模型动力学行为.利用差分不等式,获得了在一定的条件下种群x1;x3持久而x2绝灭,然后构造适当的差分Lyapunov函数,得到了该系统全局吸引性的充分性条件,推广了Huo在文[2]中的结果.
关键词 离散 食物链 持久性 绝灭性 全局吸引性
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Modelling and control of a spatial dynamic cable 预览
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作者 Bo Tian Subhrajit Bhattacharya 《力学学报:英文版》 SCIE EI CAS CSCD 2019年第4期866-878,共13页
We study the problem of dynamically controlling the shape of a cable that is fixed at one end and attached to an actuated robot at another end. This problem is relevant to unmanned aerial vehicles (UAVs) tethered to a... We study the problem of dynamically controlling the shape of a cable that is fixed at one end and attached to an actuated robot at another end. This problem is relevant to unmanned aerial vehicles (UAVs) tethered to a base. While rotorcrafts, such as quadcopters, are agile and versatile in their applications and have been widely used in scientific, industrial and military applications, one of the biggest challenges with such UAVs is their limited battery life that make the flight time for a typical UAVs limited to twenty to thirty minutes for most practical purposes. A solution to this problem lies in the use of cables that tether the UAV to a power outlet for constant power supply. However, the cable needs to be controlled effectively in order to avoid obstacles or other UAVs. In this paper, we develop methods for controlling the shape of a cable using actuation at one end. We propose a discrete model for the spatial cable and derive the equations governing the cable dynamics for both force controlled system and position controlled system. We design a controller to control the shape of the cable to attain the desired shape and perform simulations under different conditions. Finally, we propose a quasi-static model for the spatial cable and discuss the stability of this system and the proposed controller. 展开更多
关键词 LAGRANGIAN MECHANICS DISCRETE model of CABLE Control of under-actuated systems
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Discrete element simulation of cylindrical particles using super-ellipsoids
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作者 Yongzhi Zhao Lei Xu +1 位作者 Paul B. Umbanhowar Richard M. Lueptow 《颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第5期55-66,共12页
A discrete element model based on super-ellipsoids was used to simulate cylindrical particle flow. The model can describe a cylindrical particle accurately provided the shape indices of the super-ellipsoids are set to... A discrete element model based on super-ellipsoids was used to simulate cylindrical particle flow. The model can describe a cylindrical particle accurately provided the shape indices of the super-ellipsoids are set to appropriate values. To achieve more rapid calculations, we implemented an "oriented bounding box algorithm"(OBBA) for the initial contact detection of cylindrical particles. Several types of Simulations were performed to validate the super-ellipsoid model and the contact-detection algorithm. First, the effect of shape index of the super-ellipsoids on model accuracy was investigated through three simulations: impact of a cylindrical particle on a flat wall, flow of cylindrical particles in a rotating tumbler, and segregation of cylindrical particles of different length flowing down a bounded heap. The simulation results show that the super-ellipsoids describe cylindrical particles accurately when the shape index that specifies the sharpness of the cylinder edges is sufficiently large. The efficiency of the OBBA is measured by simulations in which a box is filled with cylindrical particles and a tumbler that contains cylindrical particles is rotated. The simulation results show that the OBBA can accelerate the calculations significantly. The effect of particle shape (such as aspect ratio and shape index) on the calculation speed was obtained. The simulation of rod-like particles tended to take more calculation time than that of disk-like particles, and the simulation time increased with an increasing particle-shape index. 展开更多
关键词 Discrete element method Super-ellipsoid Super-quadric Cylindrical PARTICLE NON-SPHERICAL PARTICLE GRANULAR material
A note on “Lattice soliton equation hierarchy and associated properties”
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作者 徐西祥 郭敏 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第1期669-670,共2页
We demonstrate that the new hierarchy of integrable lattice equations in Chin. Phys. B 21 090202(2012) can be changed into the integrable lattice hierarchy in Chin. Phys. B 13 1009(2004) by using a very simple transfo... We demonstrate that the new hierarchy of integrable lattice equations in Chin. Phys. B 21 090202(2012) can be changed into the integrable lattice hierarchy in Chin. Phys. B 13 1009(2004) by using a very simple transformation. 展开更多
关键词 INTEGRABLE lattice HIERARCHY transformation between POTENTIALS discrete zero CURVATURE equation LAX PAIR
多弹性支撑设备的同步定相振动控制研究 预览
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作者 黄迪 杨铁军 +2 位作者 刘志刚 Michael J.Brennan 李新辉 《船舶与海洋工程学报:英文版》 CSCD 2019年第2期195-204,共10页
This paper describes an analytical investigation into synchrophasing,a vibration control strategy on a machinery installation in which two rotational machines are attached to a beam-like raft by discrete resilient iso... This paper describes an analytical investigation into synchrophasing,a vibration control strategy on a machinery installation in which two rotational machines are attached to a beam-like raft by discrete resilient isolators.Forces and moments introduced by sources are considered,which effectively represent a practical engineering system.Adjusting the relative phase angle between the machines has been theoretically demonstrated to greatly reduce the cost function,which is defined as the sum of velocity squares of attaching points on the raft at each frequency of interest.The effect of the position of the machine is also investigated.Results show that altering the position of the secondary source may cause a slight change to the mode shape of the composite system and therefore change the optimum phase between the two machines.Although the analysis is based on a one-dimensional Euler– Bernoulli beam and each machine is considered as a rigid-body,a key principle can be derived from the results.However,the factors that can influence the synchrophasing control performance would become coupled and highly complicated.This condition has to be considered in practice. 展开更多
关键词 DISCRETE SUPPORTED machines Vibration ISOLATION RAFT Synchrophasing control.Different FORMS of EXCITATIONS
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考虑异质车流的信号交叉口实时排队估计 预览
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作者 陈之锴 成卫 +1 位作者 李黎山 李冰 《物流科技》 2019年第5期73-78,共6页
信号交叉口排队长度是交通信号控制的一项重要指标,为了提高排队估计精度以及实用性,文章以相邻信号交叉口的下游交叉口排队长度作为研究对象,在关联信号交叉口排队长度计算模型基础上,提出了一种考虑异质车流的影响下的实时排队长度的... 信号交叉口排队长度是交通信号控制的一项重要指标,为了提高排队估计精度以及实用性,文章以相邻信号交叉口的下游交叉口排队长度作为研究对象,在关联信号交叉口排队长度计算模型基础上,提出了一种考虑异质车流的影响下的实时排队长度的估计方法。通过异质车流的行程时间,拟合双峰模型得到车辆离散模型,研究表明:利用该模型分析上游车辆离去流量,得到下游到达流率;通过信号控制方案以及停车波波速,估计交叉口车辆排队长度。大量实证研究检验平均绝对误差在0.3veh/lane/s内,提高了信号交叉口排队长度估计的有效性与实用性,从而为后续异质交通环境下信号配时优化提供理论依据。 展开更多
关键词 智能交通 排队实时估计 离散 异质车流
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Diagnosability of a class of discrete event systems based on observations
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作者 S.RESHMILA Devanathan RAJAGOPALAN 《控制理论与技术:英文版》 EI CSCD 2019年第3期265-275,共11页
The diagnosability of discrete event systems has been a topic of interest to many researchers. The diagnosability conditions for various systems have evolved based on a regularity condition that is imposed on faulty t... The diagnosability of discrete event systems has been a topic of interest to many researchers. The diagnosability conditions for various systems have evolved based on a regularity condition that is imposed on faulty traces with respect to their observable continuations. Improving upon this weak but necessary condition, a new model of diagnosability that is based on sensor outputs, which are called observatio ns, upon a command in put is proposed in this paper. Necessary and sufficient con ditions are derived for the proposed diagnosability model. The search performance of the proposed diagnosability condition is of linear complexity in terms of the power set of the system events and observations, compared to the exponential complexity of the search with the existing diag nosability regularity condition. Moreover, a system that is not diag no sable according to the existi ng diag nosability condition may be diagnosable in the proposed diagnosability model, which includes observations. 展开更多
关键词 DISCRETE EVENT system DIAGNOSABILITY FAULT diagnosis mealy AUTOMATA finite state AUTOMATA
DEM parameter calibration of cohesive bulk materials using a simple angle of repose test
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作者 Thomas Roessler Andre Katterfeld 《颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第4期105-115,共11页
The numerical effort of discrete element method (DEM) simulations results in a general idealisation of DEM models that makes the calibration crucial to obtaining realistic simulation results. The angle of repose test ... The numerical effort of discrete element method (DEM) simulations results in a general idealisation of DEM models that makes the calibration crucial to obtaining realistic simulation results. The angle of repose test has become a standard test for the calibration of DEM parameters of cohesionless bulk materials and is extensively discussed in the literature. One of the most used test methods is the pull-up test of a hollow cylinder filled with bulk material. This paper presents how this basic pull-up test can also be used for the calibration of DEM parameters of cohesive materials by changing the analysis criteria. In contrast to analysing the static angle of repose, the focus lies on the macroscopic flow behaviour during the lifting of the cylinder. Reproducible phases of flow are identified in experiments: the build-up of a stable bulk material column, the convex bending of the column, and the beginning of collapse of the column. Furthermore, the phases are independent of the size and lifting velocity. The convex bending of the bulk-material column combined with the moment of first collapse are introduced as new measurable calibration criteria. These experimental results of wet sand are used for the calibration of related DEM parameters using a simplified JKR cohesion model. The DEM calibration including an analysis algorithm that fits the experimental flow behaviour and the final selection of the relevant parameters (i.e., sliding friction coefficient, rolling friction coefficient, and cohesion energy density) is presented in detail. 展开更多
关键词 DISCRETE ELEMENT method ANGLE of repose COHESIVE BULK material Calibration
Discrete Littlewood-Paley-Stein Characterization and L^2 Atomic Decomposition of Local Hardy Spaces
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作者 Wei DING Li Xin JIANG Yue Ping ZHU 《数学学报:英文版》 SCIE CSCD 2019年第10期1681-1695,共15页
Usually, the condition that T is bounded on L^2(R^n) is assumed to prove the boundedness of an operator T on a Hardy space. With this assumption, one only needs to prove the uniformly boundness of T on atoms, since T(... Usually, the condition that T is bounded on L^2(R^n) is assumed to prove the boundedness of an operator T on a Hardy space. With this assumption, one only needs to prove the uniformly boundness of T on atoms, since T(f)=∑iλi T(ai), provided that f =∑iλiai in L^2(R^n), where ai is an L^2 atom of this Hardy space. So far, the L^2 atomic decomposition of local Hardy spaces h^p(R^n), 0 < p ≤ 1, hasn't been established. In this paper, we will solve this problem, and also show that h^p(R^n) can also be characterized by discrete Littlewood-Paley functions. 展开更多
关键词 LOCAL HARDY space DISCRETE LOCAL Calderon's identity DUALITY atom
基于离散型制造企业的技术标准体系构建研究
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作者 杨汉 秦华 《模具工业》 2019年第1期7-10,共4页
企业技术标准体系是企业生产、经营、管理的技术依据,且各企业(行业)由于其特点,构建路径又有差别,在分析离散型制造企业汽车模具标准化现状和常用技术标准体系架构分类的基础上,以企业为例,并以标准化方法论为指导,阐释了汽车模具行业... 企业技术标准体系是企业生产、经营、管理的技术依据,且各企业(行业)由于其特点,构建路径又有差别,在分析离散型制造企业汽车模具标准化现状和常用技术标准体系架构分类的基础上,以企业为例,并以标准化方法论为指导,阐释了汽车模具行业技术标准体系的构建方案和实施策略,以期夯实企业的技术基础管理。 展开更多
关键词 技术标准体系 汽车模具 离散型 构建
MIMO-WiMAX system incorporated with diverse transformation for 5G applications
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作者 Lavish KANSAL Vishal SHARMA Jagjit Singh MALHOTRA 《中国光电子学前沿:英文版》 EI CSCD 2019年第3期296-310,共15页
Wireless systems and standards are now progressing toward the implementation of fifth generation (5G) to combat with an expected and explosive growth of demands of wireless services in future. Consequently, wireless i... Wireless systems and standards are now progressing toward the implementation of fifth generation (5G) to combat with an expected and explosive growth of demands of wireless services in future. Consequently, wireless interoperability for microwave access (WiMAX) with orthogonal frequency division multiplexing (OFDM) technology at its physical layer is being utilized for the uplink and downlink transmission to afford the high spectral efficiency in fading environments. However, the 5G implementation requires additional improvements to meet the futuristic stress. This work proposes an innovative solution that combines WiMAX system with multiple input multiple output (MIMO) technology to meet the required elevated data rates as desired by the growing application needs of 5G. MIMO is capable to fulfil the vision of 5G to realize a huge number of base stations equipped with a large number of terminals to be served in the same time-frequency resource without severe inter-user interference. Furthermore, the proposed system is demon- strated incorporation with discrete wavelet transform (DWT), and fractional Fourier transforms (FrFTs) in the physical layer of the WiMAX system. The evaluated outcomes exemplify a considerable improvement in bit error rate (BER) performance in contrast with the earlier reported work. 展开更多
关键词 wireless interoperability for microwave access (WiMAX) ORTHOGONAL frequency division MULTIPLEXING (OFDM) MULTIPLE input MULTIPLE output (MIMO) fast FOURIER TRANSFORM (FFT) discrete wavelet TRANSFORM (DWT) fractional FOURIER TRANSFORM (FrFT)
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