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耦合优化蚁群算法与P-Median model的选址模型设计
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作者 顾梓程 胡新玲 《现代电子技术》 北大核心 2024年第3期109-114,共6页
为节省城建部门对于公共体育设施的投入成本以及提高城市人民生活质量,以运动场所优化选址为例,提出一种新型设施选址模型。该模型主要基于P-Median model(最小化阻抗模型)根据需求点数量从全部候选设施选址中选择设施空间位置,让用户... 为节省城建部门对于公共体育设施的投入成本以及提高城市人民生活质量,以运动场所优化选址为例,提出一种新型设施选址模型。该模型主要基于P-Median model(最小化阻抗模型)根据需求点数量从全部候选设施选址中选择设施空间位置,让用户达到离自己最近设施距离成本总和最小的目的,对选址的基本原则和实际情况提出要求,构造目标函数用于优化后蚁群算法求解进行选址工作。优化蚁群算法实现基于Python语言模块,通过改进蚁群原始信息素,提升原有算法的收敛速度,求出目标函数最优解,可以很好地模拟对于运动场所的选址。用二者耦合进行优势互补所设计的选址模型来搜寻研究区蚁群信息素浓度残留最大的栅格像元,从而确定未被已有设施点服务半径覆盖的最佳设施点建立位置。实验结果表明,该新型选址模型相较于最小化阻抗模型与最大化覆盖模型,新增优化设施点使整体服务半径覆盖率分别高出10.42%和6.95%,适合求解较为精确且小规模空间下的选址问题。 展开更多
关键词 蚁群算法 p-median model 选址模型 GIS 运动场所 位置分配 pYTHON
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水平受荷桩“p-y+M-θ”分析方法
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作者 王立忠 赖踊卿 +1 位作者 洪义 张友虎 《岩土工程学报》 EI CAS CSCD 北大核心 2024年第5期905-918,共14页
中国近海海上风电机组开发建设中,大直径单桩基础形式使用占比超70%。现行p-y曲线设计方法主要适用于小直径柔性桩,对大直径单桩侧向及桩底受荷描述能力不足,导致其严重低估刚柔性桩和刚性桩(分别常用于中国和欧洲的近海风电工程)的变... 中国近海海上风电机组开发建设中,大直径单桩基础形式使用占比超70%。现行p-y曲线设计方法主要适用于小直径柔性桩,对大直径单桩侧向及桩底受荷描述能力不足,导致其严重低估刚柔性桩和刚性桩(分别常用于中国和欧洲的近海风电工程)的变形和承载能力,过于保守的设计给海上风电降本带来挑战。为此建立了能以统一的方式预测柔性、刚柔性和刚性单桩水平单调受荷响应的“p-y+M-θ”模型,并将该模型推广到循环荷载下单桩的响应分析。通过与相关试验结果比对发现,“p-y+M-θ”模型能较为准确地预测桩基水平加载响应。力图为水平受荷单桩工程设计提供简洁而可行的响应分析方法。 展开更多
关键词 软黏土 p-y%pLUS%m-θ”模型 水平受荷桩循环加载 试验结果对比
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Nonlinear optimal model and solving algorithms for platform planning problem in battlefield 被引量:2
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作者 WANG Xun YAO Peiyang +1 位作者 ZHANG Jieyong WAN Lujun 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第5期983-994,共12页
Platform planning is one of the important problems in the command and control(C2) field. Hereto, we analyze the platform planning problem and present nonlinear optimal model aiming at maximizing the task completion qu... Platform planning is one of the important problems in the command and control(C2) field. Hereto, we analyze the platform planning problem and present nonlinear optimal model aiming at maximizing the task completion qualities. Firstly, we take into account the relation among tasks and build the single task nonlinear optimal model with a set of platform constraints. The Lagrange relaxation method and the pruning strategy are used to solve the model. Secondly, this paper presents optimization-based planning algorithms for efficiently allocating platforms to multiple tasks. To achieve the balance of the resource assignments among tasks, the m-best assignment algorithm and the pair-wise exchange(PWE)method are used to maximize multiple tasks completion qualities.Finally, a series of experiments are designed to verify the superiority and effectiveness of the proposed model and algorithms. 展开更多
关键词 platform planning nonlinear optimal model Lagrange relaxation method m-best algorithm pair-wise exchange(pWE)
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McCulloch-Pitts人工神经元模型80周年纪念:思想、方法与意义 被引量:2
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作者 缪青海 王雨桐 +2 位作者 吕宜生 那晓翔 王飞跃 《智能科学与技术学报》 CSCD 2023年第2期133-142,共10页
1943年,Warren McCulloch和Walter Pitts发表论文《神经活动内在思想的逻辑演算》,证明可以使用逻辑演算描述神经网络的运行机理,拓展了计算神经科学的领域前沿,奠定了人工神经网络的发展基础。恰逢M-P论文发表80周年之际,结合时代背景... 1943年,Warren McCulloch和Walter Pitts发表论文《神经活动内在思想的逻辑演算》,证明可以使用逻辑演算描述神经网络的运行机理,拓展了计算神经科学的领域前沿,奠定了人工神经网络的发展基础。恰逢M-P论文发表80周年之际,结合时代背景和作者学术生涯的变迁,探索M-P理论的思想源泉;借助原文中的示例,概述M-P模型的基本原理;以作者对循环因果和反馈机制的研究为主线,探讨M-P模型对信息科学发展的影响、对控制论发展的贡献,及其在当今人工智能大模型时代的意义。 展开更多
关键词 m-p模型 人工神经网络 循环因果 控制论 平行系统 人工智能
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Analytical Comparison of Resource Search Algorithms in Non-DHT Mobile Peer-to-Peer Networks 被引量:1
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作者 Ajay Arunachalam Vinayakumar Ravi +2 位作者 Moez Krichen Roobaea Alroobaea Jehad Saad Alqurni 《Computers, Materials & Continua》 SCIE EI 2021年第7期983-1001,共19页
One of the key challenges in ad-hoc networks is the resource discovery problem.How efciently&quickly the queried resource/object can be resolved in such a highly dynamic self-evolving network is the underlying que... One of the key challenges in ad-hoc networks is the resource discovery problem.How efciently&quickly the queried resource/object can be resolved in such a highly dynamic self-evolving network is the underlying question?Broadcasting is a basic technique in the Mobile Ad-hoc Networks(MANETs),and it refers to sending a packet from one node to every other node within the transmission range.Flooding is a type of broadcast where the received packet is retransmitted once by every node.The naive ooding technique oods the network with query messages,while the random walk scheme operates by contacting subsets of each node’s neighbors at every step,thereby restricting the search space.Many earlier works have mainly focused on the simulation-based analysis of ooding technique,and its variants,in a wired network scenario.Although,there have been some empirical studies in peer-to-peer(P2P)networks,the analytical results are still lacking,especially in the context of mobile P2P networks.In this article,we mathematically model different widely used existing search techniques,and compare with the proposed improved random walk method,a simple lightweight approach suitable for the non-DHT architecture.We provide analytical expressions to measure the performance of the different ooding-based search techniques,and our proposed technique.We analytically derive 3 relevant key performance measures,i.e.,the avg.number of steps needed to nd a resource,the probability of locating a resource,and the avg.number of messages generated during the entire search process. 展开更多
关键词 mathematical model mANET p2p networks p2p mANET UNSTRUCTURED search algorithms peer-to-peer AD-HOC ooding random walk resource discovery content discovery mobile peer-to-peer broadcast pEER
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A Simple Predictive Performance Model of Solar Cell under Very Hot and Humide Climate 被引量:1
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作者 Mougang Yolande Christelle Ketchanji Essiane Salomé Ndjakomo Imano Adolphe Moukengue 《Journal of Power and Energy Engineering》 2019年第5期26-47,共22页
In the scope of solar energy-based electrical needs in rural tropical regions, the present article develops and confronts experimental power models from the using of manufacturer data and a new model made with the met... In the scope of solar energy-based electrical needs in rural tropical regions, the present article develops and confronts experimental power models from the using of manufacturer data and a new model made with the meteorological and electrical data acquired. These data are registered through an acquisition station around a monocrystalline photovoltaic panel, designed and realized in the scope of this work. After the acquisition of meteorological data, a choice of the most relevant meteorological variable as input vectors to express the output powers obtained was carried out. Around the Single-Diode model, seven models are performed with analytics equations, iterative methods and an optimization method with a multi-objective function to get internal parameters. The proposed experimental model is made by a combination of the solution got at STC of an iterative method, with the value of nameplate and the use of an open circuit voltage equation with experimental coefficient to predict power output in operating conditions, and it’s demonstrated more efficient. The optimization of a multi-objective function using Nonlinear Squares (NLS) through the Leveng-Marqued method to solve the parameter estimation of a PV panel has been well done and the results are useful, like classic iterative method and less time-consuming. 展开更多
关键词 Experimental modelling mAXImAL power OUTpUT (mpO) pHOTOVOLTAIC (pV) 1m5p
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基于EM-GIBBS算法的ARMA(p,q)测量误差模型的参数估计
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作者 郑斌斌 许淑婷 +1 位作者 李安水 张慧增 《杭州师范大学学报(自然科学版)》 CAS 2023年第4期438-448,共11页
本文对基于ARMA(p,q)的测量误差模型的参数估计提出了EM-Gibbs算法.由于无法给出模型参数的极大似然估计解析解,本文在EM算法框架下对参数进行估计.在实施EM算法M步骤过程中,为了计算高维正态分布的隐变量一阶、二阶矩,需要求出高阶矩... 本文对基于ARMA(p,q)的测量误差模型的参数估计提出了EM-Gibbs算法.由于无法给出模型参数的极大似然估计解析解,本文在EM算法框架下对参数进行估计.在实施EM算法M步骤过程中,为了计算高维正态分布的隐变量一阶、二阶矩,需要求出高阶矩阵的逆矩阵.为了避开计算高阶矩阵的逆矩阵,通过Gibbs抽样,给出了隐变量的一阶、二阶矩的估计,从而给出了EM算法M步骤中参数最优值的估计.最后通过对ARMA(1,1)测量误差模型进行了数值模拟,模拟结果验证了所提EM-Gibbs算法的可行性和有效性. 展开更多
关键词 Em算法 ARmA(p q)测量误差模型 GIBBS抽样
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基于粒子-人工蜂群算法的3RPUP_(c)-UPS并联机构运动学正解研究
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作者 常振振 张彦斌 +2 位作者 张双 宋黎明 李耀光 《机电工程》 CAS 北大核心 2024年第2期311-318,共8页
针对3RPUP_(c)-UPS并联机构运动学正解求解困难的问题,对新型3RPUPc-UPS并联机构的运动学特性进行了研究,并构建出位置正解求解模型,进而提出了一种基于粒子-人工蜂群算法(P-ABC)的并联机构运动学求解方法。首先,根据机构的拓扑特性,计... 针对3RPUP_(c)-UPS并联机构运动学正解求解困难的问题,对新型3RPUPc-UPS并联机构的运动学特性进行了研究,并构建出位置正解求解模型,进而提出了一种基于粒子-人工蜂群算法(P-ABC)的并联机构运动学求解方法。首先,根据机构的拓扑特性,计算得到了方位特征集、自由度和耦合度;然后,根据机构的几何特征,基于姿态变换矩阵和动平台投影方程,建立了机构的运动学逆解方程,并对比了MATLAB和SOLIDWORKDS的仿真结果,验证了逆解分析的正确性;最后,将运动学逆解方程转化为最小化求解问题,构建出了适合优化算法的运动学正解模型,并利用MATLAB的软件交互界面(GUI)功能,开发出用于计算并联机构运动学正解的软件,分别基于粒子群算法(PSO)、人工蜂群算法(ABC)和P-ABC算法,对该并联机构的运动学正解进行了计算。研究结果表明:P-ABC算法单次求解时间在0.5 s内,求解误差级别为10-20,相对于ABC算法,运行时间缩短了50.02%;而相对于POS算法,其求解精度提高了10个数量级。P-ABC算法能够用于求解该并联机构运动学正解,具有计算速度快、精度高的特点,可以为研究并联机构运动学正解提供新方法。 展开更多
关键词 机构学 并联机构 位置正解求解模型 方位特征集 粒子-人工蜂群算法 软件交互界面
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Polysurfacic Tori or Kideas Inspired by the Möbius Strip Topology
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作者 Emmanuel Cadier Anaxhaoza 《Advances in Pure Mathematics》 2023年第9期543-551,共9页
Polysurfacic tori or kideas are three-dimensional objects formed by rotating a regular polygon around a central axis. These toric shapes are referred to as “polysurfacic” because their characteristics, such as the n... Polysurfacic tori or kideas are three-dimensional objects formed by rotating a regular polygon around a central axis. These toric shapes are referred to as “polysurfacic” because their characteristics, such as the number of sides or surfaces separated by edges, can vary in a non-trivial manner depending on the degree of twisting during the revolution. We use the term “Kideas” to specifically denote these polysurfacic tori, and we represent the number of sides (referred to as “facets”) of the original polygon followed by a point, while the number of facets from which the torus is twisted during its revolution is indicated. We then explore the use of concave regular polygons to generate Kideas. We finally give acceleration for the algorithm for calculating the set of prime numbers. 展开更多
关键词 Heavenly Things Topology Euclidian Geometry möbius Strip Emmanuel’s Tori YiBoLong’s Tori Cadier’s Tori möbius Tori polysurfacic Tori Kideas The Keys KideaCross KideaStar Churros algorithm for Calculating the Set of prime Numbers p The Last Found Element of p
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CNOP-P-based parameter sensitivity for double-gyre variation in ROMS with simulated annealing algorithm 被引量:3
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作者 YUAN Shijin ZHANG Huazhen +1 位作者 LI Mi MU Bin 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2019年第3期957-967,共11页
Reducing the error of sensitive parameters by studying the parameters sensitivity can reduce the uncertainty of the model,while simulating double-gyre variation in Regional Ocean Modeling System(ROMS).Conditional Nonl... Reducing the error of sensitive parameters by studying the parameters sensitivity can reduce the uncertainty of the model,while simulating double-gyre variation in Regional Ocean Modeling System(ROMS).Conditional Nonlinear Optimal Perturbation related to Parameter(CNOP-P)is an effective method of studying the parameters sensitivity,which represents a type of parameter error with maximum nonlinear development at the prediction time.Intelligent algorithms have been widely applied to solving Conditional Nonlinear Optimal Perturbation(CNOP).In the paper,we proposed an improved simulated annealing(SA)algorithm to solve CNOP-P to get the optimal parameters error,studied the sensitivity of the single parameter and the combination of multiple parameters and verified the effect of reducing the error of sensitive parameters on reducing the uncertainty of model simulation.Specifically,we firstly found the non-period oscillation of kinetic energy time series of double gyre variation,then extracted two transition periods,which are respectively from high energy to low energy and from low energy to high energy.For every transition period,three parameters,respectively wind amplitude(WD),viscosity coefficient(VC)and linear bottom drag coefficient(RDRG),were studied by CNOP-P solved with SA algorithm.Finally,for sensitive parameters,their effect on model simulation is verified.Experiments results showed that the sensitivity order is WD>VC>>RDRG,the effect of the combination of multiple sensitive parameters is greater than that of single parameter superposition and the reduction of error of sensitive parameters can effectively reduce model prediction error which confirmed the importance of sensitive parameters analysis. 展开更多
关键词 parameter sensitivity DOUBLE GYRE Regional Ocean modeling System(ROmS) CONDITIONAL Nonlinear Optimal perturbation(CNOp-p) simulated annealing(SA)algorithm
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Image Denoising Combining the P-M Model and the LLT Model 被引量:1
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作者 Qian Yang 《Journal of Computer and Communications》 2015年第10期22-30,共9页
In this paper, we present a noise removal technique by combining the P-M model with the LLT model. The combined technique takes full use of the advantage of both filters which is able to preserve edges and simultaneou... In this paper, we present a noise removal technique by combining the P-M model with the LLT model. The combined technique takes full use of the advantage of both filters which is able to preserve edges and simultaneously overcomes the staircase effect. We use a weighting function in our model, and compare this model with the P-M model as well as other fourth-order functional both in theory and numerical experiment. 展开更多
关键词 p-m model LLT model FOURTH-ORDER pDES COmBINATION Image DENOISING
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MODELLING OF P/M FORMING PROCESSES BY FEM
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作者 Wei, Yuanping Ruan, Xueyu(Department of Plasticity Technology,Shanghai Jiao Tong University, Shanghai 200030) 《中国有色金属学会会刊:英文版》 EI CSCD 1995年第3期66-70,共5页
MODELLINGOFP/MFORMINGPROCESSESBYFEM¥Wei,Yuanping;Ruan,Xueyu(DepartmentofPlasticityTechnology,ShanghaiJiaoTon... MODELLINGOFP/MFORMINGPROCESSESBYFEM¥Wei,Yuanping;Ruan,Xueyu(DepartmentofPlasticityTechnology,ShanghaiJiaoTongUniversity,Shang... 展开更多
关键词 modelLING p/m FORmING FEm YIELD CRITERIA CONSTITUTIVE
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基于L-M算法的铝合金铸造过程界面换热系数的反问题模型
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作者 王一帆 温治 +1 位作者 豆瑞锋 于博 《热加工工艺》 北大核心 2024年第9期122-129,共8页
铝合金铸造过程铸件-铸模之间的界面换热系数的变化非常复杂,且预测非常困难。本文基于L-M(Levenberg-Marquardt)算法建立了铝合金铸造过程传热反问题模型,通过反问题分析获得铝合金铸造过程中铸件-铸模界面换热系数。通过将铸件-铸模... 铝合金铸造过程铸件-铸模之间的界面换热系数的变化非常复杂,且预测非常困难。本文基于L-M(Levenberg-Marquardt)算法建立了铝合金铸造过程传热反问题模型,通过反问题分析获得铝合金铸造过程中铸件-铸模界面换热系数。通过将铸件-铸模界面换热系数反演值与标准值进行比较,验证传热反问题模型的准确性。在此基础上,分析了铸模上测点位置(与铸件-铸模界面距离、相邻测点间距)和温度测量误差对铸件-铸模界面换热系数反演值的影响规律,并给出了最优的测点布置方案和温度测量误差要求。通过铝合金铸造实验,用该反问题模型能求解出铝合金凝固过程中的铸件-铸模界面换热系数。 展开更多
关键词 铸造 反传热模型 LEVENBERG-mARQUARDT算法 界面换热系数 凝固
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A New Generalized Weibull-Exponential Frailty Model
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作者 Ashok Shanubhogue Ankit R. Sinojiya 《Open Journal of Statistics》 2017年第1期84-91,共8页
We have proposed a new generalized Weibull-exponential frailty model which is a general case of classical frailty model suggested by [1] and [2]. In classical frailty model, modeling of hazard rate is considered where... We have proposed a new generalized Weibull-exponential frailty model which is a general case of classical frailty model suggested by [1] and [2]. In classical frailty model, modeling of hazard rate is considered whereas, in this paper, direct modeling of conditional survival function given the frailty is considered. Simulation study is carried out using E-M algorithm using MATLAB programme. Further we implemented the suggested model on a real life data. As an illustration, we have fitted the model to the data given in [3] which examines the strength of isolated carbon fiber under tensile aload. 展开更多
关键词 FRAILTY proportional HAZARD E-m algorithm LIKELIHOOD Ratio Test GOODNESS of FIT of the model
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LIMITING BEHAVIOR OF RECURSIVE M-ESTIMATORS IN MULTIVARIATE LINEAR REGRESSION MODELS AND THEIR ASYMPTOTIC EFFICIENCIES
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作者 缪柏其 吴月华 刘东海 《Acta Mathematica Scientia》 SCIE CSCD 2010年第1期319-329,共11页
Recursive algorithms are very useful for computing M-estimators of regression coefficients and scatter parameters. In this article, it is shown that for a nondecreasing ul (t), under some mild conditions the recursi... Recursive algorithms are very useful for computing M-estimators of regression coefficients and scatter parameters. In this article, it is shown that for a nondecreasing ul (t), under some mild conditions the recursive M-estimators of regression coefficients and scatter parameters are strongly consistent and the recursive M-estimator of the regression coefficients is also asymptotically normal distributed. Furthermore, optimal recursive M-estimators, asymptotic efficiencies of recursive M-estimators and asymptotic relative efficiencies between recursive M-estimators of regression coefficients are studied. 展开更多
关键词 asymptotic efficiency asymptotic normality asymptotic relative efficiency least absolute deviation least squares m-ESTImATION multivariate linear optimal estimator reeursive algorithm regression coefficients robust estimation regression model
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基于L-M优化算法的BP神经网络的作物需水量预测模型 被引量:50
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作者 张兵 袁寿其 +2 位作者 成立 袁建平 从小青 《农业工程学报》 EI CAS CSCD 北大核心 2004年第6期73-76,共4页
应用L-M优化算法BP神经网络,通过多维气象数据(太阳辐射、空气温度、湿度)与作物需水量的相关分析,来确定网络的拓扑结构,建立作物需水量的人工神经网络模型。用美国田纳西州大学高原实验室所测的100d气象数据为输入、作物需水量为输出... 应用L-M优化算法BP神经网络,通过多维气象数据(太阳辐射、空气温度、湿度)与作物需水量的相关分析,来确定网络的拓扑结构,建立作物需水量的人工神经网络模型。用美国田纳西州大学高原实验室所测的100d气象数据为输入、作物需水量为输出来训练建立好的BP神经网络,仿真表明该神经网络能很好地解决需水量多影响因素之间的不确定性和非线性,模型的预测精度较高,同时通过一组非样本天气环境参数和作物需水量来验证该神经网络,也得到了较好的预测结果,能够满足灌溉的精度要求。 展开更多
关键词 Bp神经网络 作物需水量 L—m优化算法 预测模型
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光伏电池建模及MPPT控制策略 被引量:141
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作者 杨永恒 周克亮 《电工技术学报》 EI CSCD 北大核心 2011年第S1期229-234,共6页
提出了一种求取光伏电池模型等效电阻的方法,并利用Matlab的S-函数构建了光伏电池的仿真模型。在对光伏系统常用的扰动观测法和电导增量法这两种MPPT算法进行了深入地分析和比较的基础上,针对扰动观测法的不足,提出了一种改进扰动观测M... 提出了一种求取光伏电池模型等效电阻的方法,并利用Matlab的S-函数构建了光伏电池的仿真模型。在对光伏系统常用的扰动观测法和电导增量法这两种MPPT算法进行了深入地分析和比较的基础上,针对扰动观测法的不足,提出了一种改进扰动观测MPPT方案。最后,通过仿真和实验对这三种MPPT算法进行了测试和比较。结果表明,所建立的光伏电池模型能够较好地模拟实际光伏模块的特性,且调试简单,便于数字实现;所提出的改进扰动观测MPPT算法在一定程度上弥补了传统方法的不足,与理论分析一致。 展开更多
关键词 光伏建模 S-函数 mppT 扰动观测法 电导增量法
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利用改进的P-M模型抑制声呐图像散斑噪声 被引量:7
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作者 郭海涛 方金 王泽洋 《仪器仪表学报》 EI CAS CSCD 北大核心 2014年第1期82-87,共6页
提出一种基于改进的P-M模型的声呐图像散斑噪声抑制方法。改进的P-M模型中,当图像梯度模值在小波阈值范围之内时,扩散函数为经典P-M模型中扩散函数与指数函数的加权之和。应用改进的P-M模型抑制海底小目标声呐图像的散斑噪声,并与用经典... 提出一种基于改进的P-M模型的声呐图像散斑噪声抑制方法。改进的P-M模型中,当图像梯度模值在小波阈值范围之内时,扩散函数为经典P-M模型中扩散函数与指数函数的加权之和。应用改进的P-M模型抑制海底小目标声呐图像的散斑噪声,并与用经典P-M模型、中值滤波、Wiener滤波处理后的结果比较。在散斑噪声抑制方面,改进的P-M模型较经典P-M模型效果好,较中值滤波、Wiener滤波有优势;在图像边缘保持方面,改进的模型优于经典P-M模型、中值滤波、Wiener滤波。实验表明,经改进的P-M模型抑制散斑噪声后的图像的峰值信噪比超过26 dB,边缘保持度超过98%。 展开更多
关键词 声呐图像 散斑噪声 pm模型 扩散函数
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岩石非线性弹性的实验研究及其P-M模型的理论解释 被引量:14
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作者 包雪阳 施行觉 《岩石力学与工程学报》 EI CAS CSCD 北大核心 2004年第20期3397-3404,共8页
岩石介质由于自身的不均匀性如微孔隙和微裂纹的普遍存在,可以认为是非线性弹性介质,它的重要特征之一就是应力-应变曲线的滞回现象。对不同的岩石样品在MTS伺服压力机上进行了一系列的循环加、卸载实验,得到了不同岩石的应力-应变的滞... 岩石介质由于自身的不均匀性如微孔隙和微裂纹的普遍存在,可以认为是非线性弹性介质,它的重要特征之一就是应力-应变曲线的滞回现象。对不同的岩石样品在MTS伺服压力机上进行了一系列的循环加、卸载实验,得到了不同岩石的应力-应变的滞回曲线。Preisach-Mayergoyz模型(简称P-M模型)是一种从微观概率分布入手研究滞回现象的理论。在简要阐述了该模型的基本原理后,研究了微观模型参数变化对宏观力学性质(如应力-应变曲线和动静态弹性模量等)的影响,结合一组实验数据推算出岩石样品的模型参数,利用这些参数得出其他组的理论曲线,发现理论曲线与实验得到的应力-应变曲线、弹性模量曲线基本吻合。这证明P-M模型在模拟岩石中的微孔隙和微裂纹在低应力状态下对岩石力学性质的影响时是一种有效的方法。最后,对模型的适用范围和改进办法进行了讨论。 展开更多
关键词 岩石力学 非线性弹性 滞回现象 p-m模型 微孔隙和微裂纹
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实现自适应边缘增强的P-M模型 被引量:2
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作者 崔文超 邓小炼 《计算机工程与应用》 CSCD 北大核心 2010年第32期180-181,共2页
P-M模型利用扩散偏微分方程进行图像平滑,通过随梯度自适应变化的扩散系数实现去除噪声的同时保护图像边缘特征,为进一步提高图像视觉效果,希望在图像边缘附近进行逆扩散以增强边缘特征,为此提出了实现自适应边缘增强的P-M模型。该改进... P-M模型利用扩散偏微分方程进行图像平滑,通过随梯度自适应变化的扩散系数实现去除噪声的同时保护图像边缘特征,为进一步提高图像视觉效果,希望在图像边缘附近进行逆扩散以增强边缘特征,为此提出了实现自适应边缘增强的P-M模型。该改进模型中的边缘增强作用基于shock滤波器逆扩散方程,通过设置随梯度自适应变化的逆扩散系数而实现。实验结果表明,相比经典P-M模型,改进模型能使去噪后的图像有更好的主观视觉效果,同时峰值信噪比也更高。 展开更多
关键词 图像去噪 p-m模型 shock滤波器 自适应边缘增强
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