期刊文献+
共找到15篇文章
< 1 >
每页显示 20 50 100
数学维度空间和数学维度函数的发现 被引量:1
1
作者 楼明 《数学学习与研究》 2013年第3期112-114,共3页
本文根据维度空间公理建立数学维度空间,发现了数学维度空间和维度函数.
关键词 数学空间 函数
下载PDF
基于改进粒子群的二维模糊散度多阈值图像分割 被引量:7
2
作者 杨梦 雷博 +1 位作者 赵强 兰蓉 《计算机应用与软件》 北大核心 2020年第9期133-138,共6页
针对只利用灰度信息的图像分割算法精度低和未加优化的二维多阈值分割算法耗时长,以及粒子群算法易出现虚假收敛的问题,提出基于改进粒子群的二维模糊散度多阈值图像分割算法。考虑图像像素空间邻域信息,建立二维隶属度函数,进而推导出... 针对只利用灰度信息的图像分割算法精度低和未加优化的二维多阈值分割算法耗时长,以及粒子群算法易出现虚假收敛的问题,提出基于改进粒子群的二维模糊散度多阈值图像分割算法。考虑图像像素空间邻域信息,建立二维隶属度函数,进而推导出二维多阈值α型模糊散度作为选取最佳阈值的准则函数;用线性递减和线性递增函数分别对粒子群算法的自我认知和社会认知部分做改进;用改进粒子群算法优化求解二维多阈值α-型模糊散度的多组阈值。实验结果表明,该算法可以提高分割精度和改善分割性能。 展开更多
关键词 多阈值图像分割 隶属函数 模糊散 改进粒子群算法
下载PDF
二维广义模糊熵图像阈值分割法 被引量:10
3
作者 雷博 范九伦 《光子学报》 EI CAS CSCD 北大核心 2010年第10期1907-1914,共8页
针对一维广义模糊熵不能有效处理含噪图像的分割问题,在二维灰度直方图上定义了图像的二维隶属度函数,提出了二维广义模糊熵阈值分割法.该方法不仅考虑了图像的点灰度值,同时考虑了图像像素的邻域平均灰度值,能更好地利用图像中的信息.... 针对一维广义模糊熵不能有效处理含噪图像的分割问题,在二维灰度直方图上定义了图像的二维隶属度函数,提出了二维广义模糊熵阈值分割法.该方法不仅考虑了图像的点灰度值,同时考虑了图像像素的邻域平均灰度值,能更好地利用图像中的信息.为了提高二维广义模糊熵阈值法的运行速度、解决参量选取问题,结合粒子群优化搜索方法,设计了嵌套式的优化过程.实验表明,二维广义模糊熵阈值分割法对噪音图像有更好的适应性. 展开更多
关键词 图像分割 广义模糊熵 直方图 隶属函数
下载PDF
基于二维模糊熵的图像非监督变化检测 被引量:1
4
作者 孙文邦 陈贺新 +1 位作者 唐海燕 于光 《吉林大学学报(工学版)》 EI CAS CSCD 北大核心 2011年第5期1461-1467,共7页
针对图像变化检测,提出了一种基于二维模糊熵的方法。首先采用LMS方法寻找二维直方图的最佳分割方向;再根据最佳分割方向构建一种新的二维隶属度函数,并用其搜索差异图像二维模糊最大熵来确定最佳二维隶属度函数;最后按最佳二维隶属度... 针对图像变化检测,提出了一种基于二维模糊熵的方法。首先采用LMS方法寻找二维直方图的最佳分割方向;再根据最佳分割方向构建一种新的二维隶属度函数,并用其搜索差异图像二维模糊最大熵来确定最佳二维隶属度函数;最后按最佳二维隶属度函数检测差异图像中的变化区域。理论分析和实验结果表明,本文方法相对一般二维检测方法具有更好的检测性能。 展开更多
关键词 信息处理技术 变化检测 模糊熵 隶属函数
下载PDF
Mean Dimension for Non-autonomous Iterated Function Systems
5
作者 Meng Deyu Zhao Cao 《数学理论与应用》 2024年第3期119-129,共11页
In this paper we introduce the notions of mean dimension and metric mean dimension for non-autonomous iterated function systems(NAIFSs for short)on countably infinite alphabets which can be regarded as generalizations... In this paper we introduce the notions of mean dimension and metric mean dimension for non-autonomous iterated function systems(NAIFSs for short)on countably infinite alphabets which can be regarded as generalizations of the mean dimension and the Lindenstrauss metric mean dimension for non-autonomous iterated function systems.We also show the relationship between the mean topological dimension and the metric mean dimension. 展开更多
关键词 Non-autonomous iterated function system Mean dimension Metric mean dimension
下载PDF
基于模糊理论的开关柜状态评价研究
6
作者 颜彬皓 乐骁文 《自动化应用》 2023年第4期171-174,共4页
本文建立了开关柜分级状态评价模型,以开关柜设备为研究对象,按开关柜状态信息种类分类划分,状态评价指标权重计算采用层次分析法结合最优传递矩阵,将主观性和客观性相结合,使权重分配更合理,指标数据预处理采用模糊数学理论,设计了多... 本文建立了开关柜分级状态评价模型,以开关柜设备为研究对象,按开关柜状态信息种类分类划分,状态评价指标权重计算采用层次分析法结合最优传递矩阵,将主观性和客观性相结合,使权重分配更合理,指标数据预处理采用模糊数学理论,设计了多维隶属度函数,提出了基于模糊综合评价算法的状态评价模型,并通过实例进行运算,验证了算法的准确性,为设备状态检修开展提供更多依据。 展开更多
关键词 开关柜 状态评价 层次分析法 隶属函数 模糊综合评价
下载PDF
基于Epanechnikov混合模型的中心化模糊模型 被引量:2
7
作者 张钦礼 王士同 《计算机研究与发展》 EI CSCD 北大核心 2010年第5期940-947,共8页
基于Epanechnikov混合模型提出了一种新的模糊模型——具有多维隶属度函数的规则中心化模糊模型.它容易设计:任何一个Epanechnikov混合模型都唯一对应着一个规则中心化的模糊模型,Epanechnikov混合模型的条件期望输出是规则中心化的模... 基于Epanechnikov混合模型提出了一种新的模糊模型——具有多维隶属度函数的规则中心化模糊模型.它容易设计:任何一个Epanechnikov混合模型都唯一对应着一个规则中心化的模糊模型,Epanechnikov混合模型的条件期望输出是规则中心化的模糊模型的去模糊化输出;它具有高度的可解释性:其规则后件恰好是其输出在规则中心的一阶Taylor级数展开;它采用了多维隶属度函数,考虑了输入数据各个分量之间的相关性,更符合实际问题.对两个典型实例的仿真实验表明,由Epanechnikov混合模型设计的规则中心化的模糊模型比其他模糊模型速度快、精度高、鲁棒性好. 展开更多
关键词 Epanechnikov混合模型(EMM) 规则中心化的模糊模型 隶属函数 期望最大化算法 高斯混合模型
下载PDF
基于深度学习的网络流量快速预测方法
8
作者 许迎晨 《无线互联科技》 2024年第21期119-122,共4页
针对现行方法在网络流量快速预测中应用存在预测误差较高的问题,文章提出基于深度学习的网络流量快速预测方法。该方法利用相空间对收集的网络流量时间序列数据进行重构,描述网络流量数据非线性结构;利用维度变换函数将网络流量数据转... 针对现行方法在网络流量快速预测中应用存在预测误差较高的问题,文章提出基于深度学习的网络流量快速预测方法。该方法利用相空间对收集的网络流量时间序列数据进行重构,描述网络流量数据非线性结构;利用维度变换函数将网络流量数据转换为二维数据并通过提取数据自相似性特征,提取网络流量自相似性数据;利用深度学习对网络流量时间特征提取并通过特征融合预测未来时间点网络流量,实现基于深度学习的网络流量快速预测。实验证明,设计方法在网络流量快速预测场景中RMSE不超过0.01,MAE不超过0.1,可以实现对网络流量的精准快速预测。 展开更多
关键词 学习 网络流量 预测 相空间 变换函数 自相似性
下载PDF
Polar Functions for Fractional Brownian Motion
9
作者 肖益民 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第1期76-80,共5页
Let X (t)(t∈R^N) be a d-dimensional fractional Brownian motion. A contiunous function f:R^N→R^d is called a polar function of X(t)(t∈R^N) if P{ t∈R^N\{0},X(t)=t(t)}=0. In this paper, the characteristies of the cla... Let X (t)(t∈R^N) be a d-dimensional fractional Brownian motion. A contiunous function f:R^N→R^d is called a polar function of X(t)(t∈R^N) if P{ t∈R^N\{0},X(t)=t(t)}=0. In this paper, the characteristies of the class of polar functions are studied. Our theorem 1 improves the previous results of Graversen and Legall. Theorem2 solves a problem of Legall (1987) on Brownian motion. 展开更多
关键词 fractional Brownian motion polar function Lipschitz function class quasi-helix Hausdorff dimension
下载PDF
On Weighted Tent Space
10
作者 李兴民 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第2期78-83,共6页
In this paper, we introduce the A, weights into the tent space, many important results in the tent space are generalized. Also, new relations between the A, weights and Carleson measures are obtained.
关键词 tent space A weights Carleson measure
下载PDF
Spin-Orbit Scattering Effects on Hall Conductivity in a Layered Disordered Electron System
11
作者 王勇刚 杨永宏 《Journal of Southeast University(English Edition)》 EI CAS 2002年第2期191-196,共6页
Spin-orbit scattering effects in a layered quasi-2D disordered electron system have been investigated by the diagrammatic techniques in perturbation theory. The expression of Cooperon (propagator in particle-particle ... Spin-orbit scattering effects in a layered quasi-2D disordered electron system have been investigated by the diagrammatic techniques in perturbation theory. The expression of Cooperon (propagator in particle-particle channel) is obtained as the function of interlayer coupling. The analytical result for the quantum correction to Hall conductivity has been obtained as functions of elastic, inelastic and spin-orbit scattering times. It is shown that the strong and weak couplings correspond, respectively, to the 3D and 2D situations. The Hall coefficient is shown to vanish. The relevant dimensional crossover behavior from 3D to 2D with decreasing the interlayer coupling has been discussed, and the condition for the crossover has been obtained. The present theory is expected to apply for the electronic transport in tunneling superlattices. 展开更多
关键词 layered system WEAK-LOCALIZATION Hall conductivity spin-orbit scattering
下载PDF
Pricing American Options using the Malliavin Calculus
12
作者 Mohamed KHARRAT 《Journal of Mathematics and System Science》 2013年第11期556-559,共4页
In this paper we elaborate a general expression of the conditional expectation related to pricing problem of the American options using the Malliavin derivative (without localization). This work is a generalization ... In this paper we elaborate a general expression of the conditional expectation related to pricing problem of the American options using the Malliavin derivative (without localization). This work is a generalization of paper of Bally et al. (2005) [ 1 ] for the one dimensional case. Basing on the density function of the asset price, Bally and al. used the Malliavin calculus to evaluate the conditional expectation related to pricing American option problem, but in our work we use the Malliavin derivative to resolve the previous problem. 展开更多
关键词 Conditional expectation Malliavin derivative American option.
下载PDF
THE FUNCTIONAL DIMENSION OF SOME CLASSES OF SPACES
13
作者 LIUSHANGPING LIBINGREN 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2005年第1期67-74,共8页
The functional dimension of countable Hilbert spaces has been discussed by some authors. They showed that every countable Hilbert space with finite functional dimension is nuclear. In this paper the authors do further... The functional dimension of countable Hilbert spaces has been discussed by some authors. They showed that every countable Hilbert space with finite functional dimension is nuclear. In this paper the authors do further research on the functional dimension, and obtain the following results: (1) They construct a countable Hilbert space, which is nuclear, but its functional dimension is infinite. (2) The functional dimension of a Banach space is finite if and only if this space is finite dimensional. (3)Let B be a Banach space, B* be its dual, and denote the weak * topology of B* by σ(B*, B). Then the functional dimension of (B*, σ(B*, B)) is 1. By the third result, a class of topological linear spaces with finite functional dimension is presented. 展开更多
关键词 Functional dimension Countable Hilbert space Topological linear space
原文传递
Construction of homogeneous loading functions for elastoplastic damage models for concrete 被引量:2
14
作者 ZHANG Ji LI Jie 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第3期490-500,共11页
Over the past 2 decades,tight restriction has been imposed on strength criteria of concrete by the combination of plasticity and damage in one theory.The present study aims at constructing plastic/damage loading funct... Over the past 2 decades,tight restriction has been imposed on strength criteria of concrete by the combination of plasticity and damage in one theory.The present study aims at constructing plastic/damage loading functions for elastoplastic damage models for concrete that can perform more satisfactorily in 3D stress states.Numerous strength criteria of concrete are reorganized according to their simplest representations as Cartesian,cylindrical,mixed cylindrical-Cartesian,and other forms,and the homogeneity of loading functions discussed.It is found that under certain supplementary conditions from physical meanings,an unambiguous definition of the cohesion in a strength criterion,which is demanded in an elastoplastic damage model,is usually available in an explicit or implicit form,and in each case the loading function is still homogeneous.To apply and validate the presented theory,we construct the respective homogeneous damage and plastic loading functions and implant them into some widely used elastoplastic damage models for concrete,and their performances in triaxial compression prove to have improved significantly. 展开更多
关键词 CONCRETE strength theory DAMAGE PLASTICITY loading function
原文传递
Method for extracting geometrical characteristics of joint probability density based on contour lines
15
作者 Shengli Chen Zhiqiang Wu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2022年第2期130-140,I0004,共12页
This paper presents a method for extracting geometrical features of the joint probability density function(PDF)of two-dimensional systems based on its contour lines,with particular interests given to the number and po... This paper presents a method for extracting geometrical features of the joint probability density function(PDF)of two-dimensional systems based on its contour lines,with particular interests given to the number and position of peaks and craters.In order to detect those two types of structures,a series of horizontal planes are applied to truncate the joint PDF with contour lines generated.Starting with the analysis of contour lines in a single plane,shape characteristics of the peak and the crater can be reflected on the contour lines in the aspects of gradient direction and inclusion relationship.Aided by the properties of PDF,the information about gradient direction and inclusion relationship of contour lines can be obtained simultaneously if the contour tree is built.According to the contour tree,the contour lines can be classified as two groups.Then the corresponding relation between contour lines in different planes is discussed.Based on the corresponding relation,clustering analysis about contour lines belonging to the same group but having different heights is performed.Two sets of contour lines are finally obtained as the simplest expression of geometrical characteristics of a joint PDF.They can be used to obtain the number and position of each peak and crater.Three oscillators of different types are chosen to test this method,which shows that this method can pave the way for numerical calculation about the stochastic P-bifurcation of multi-dimensional systems. 展开更多
关键词 Joint probability density function PEAK CRATER Contour lines Stochastic P-bifurcation
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部