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Simultaneous upscaling of two properties of reservoirs in one dimension using adaptive bandwidth in kernel function method
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作者 MOHAMMAD Reza Azad ABOLGHASEM Kamkar Rouhani +2 位作者 BEHZAD Tokhmechi MOHAMMAD Arashi EHSAN Baratnezhad 《Petroleum Exploration and Development》 2019年第4期746-752,共7页
Upscaling of primary geological models with huge cells, especially in porous media, is the first step in fluid flow simulation. Numerical methods are often used to solve the models. The upscaling method must preserve ... Upscaling of primary geological models with huge cells, especially in porous media, is the first step in fluid flow simulation. Numerical methods are often used to solve the models. The upscaling method must preserve the important properties of the spatial distribution of the reservoir properties. An grid upscaling method based on adaptive bandwidth in kernel function is proposed according to the spatial distribution of property. This type of upscaling reduces the number of cells, while preserves the main heterogeneity features of the original fine model. The key point of the paper is upscaling two reservoir properties simultaneously. For each reservoir feature, the amount of bandwidth or optimal threshold is calculated and the results of the upscaling are obtained. Then two approaches are used to upscaling two properties simultaneously based on maximum bandwidth and minimum bandwidth. In fact, we now have a finalized upscaled model for both reservoir properties for each approach in which not only the number of their cells, but also the locations of the cells are equal. The upscaling error of the minimum bandwidth approach is less than that of the maximum bandwidth approach. 展开更多
关键词 RESERVOIR properties SIMULTANEOUS upscaling primary MODEL simulation MODEL adaptive BANDWIDTH kernel function
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A KERNEL-TYPE ESTIMATOR OF A QUANTILE FUNCTION UNDER RANDOMLY TRUNCATED DATA 被引量:1
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作者 周勇 吴国富 李道纪 《Acta Mathematica Scientia》 SCIE CSCD 2006年第4期585-594,共10页
A kernel-type estimator of the quantile function Q(p) = inf{t:F(t) ≥ p}, 0 ≤ p ≤ 1, is proposed based on the kernel smoother when the data are subjected to random truncation. The Bahadur-type representations o... A kernel-type estimator of the quantile function Q(p) = inf{t:F(t) ≥ p}, 0 ≤ p ≤ 1, is proposed based on the kernel smoother when the data are subjected to random truncation. The Bahadur-type representations of the kernel smooth estimator are established, and from Bahadur representations the authors can show that this estimator is strongly consistent, asymptotically normal, and weakly convergent. 展开更多
关键词 Truncated data Product-limits quantile function kernel estimator Bahadur representation
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ASYMPTOTIC NORMALITY OF KERNEL ESTIMATES OF A DENSITY FUNCTION UNDER ASSOCIATION DEPENDENCE
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作者 林正炎 《Acta Mathematica Scientia》 SCIE CSCD 2003年第3期345-350,共6页
Let {Xn, n≥1} be a strictly stationary sequence of random variables, which are either associated or negatively associated, f(.) be their common density. In this paper, the author shows a central limit theorem for a k... Let {Xn, n≥1} be a strictly stationary sequence of random variables, which are either associated or negatively associated, f(.) be their common density. In this paper, the author shows a central limit theorem for a kernel estimate of f(.) under certain regular conditions. 展开更多
关键词 Associated random variables negatively associated random variables kernel estimate of a density function central limit theorem
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The choosing of reproducing kernel particle shape function with mathematic proof
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作者 夏茂辉 李金 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第10期3067-3071,共5页
Many mechanical problems can be induced from differential equations with boundary conditions; there exist analytic and numerical methods for solving the differential equations. Usually it is not so easy to obtain anal... Many mechanical problems can be induced from differential equations with boundary conditions; there exist analytic and numerical methods for solving the differential equations. Usually it is not so easy to obtain analytic solutions. So it is necessary to give numerical solutions. The reproducing kernel particle (RKP) method is based on the Carlerkin Meshless method. According to the Sobolev space and Fourier transform, the RKP shape function is mathematically proved in this paper. 展开更多
关键词 point of interpolation PARTICLE reproducing kernel particle shape function
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加权高斯匹配滤波下激光复合成像三维重构
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作者 李丰 李燕 石彬彬 《激光杂志》 北大核心 2025年第1期251-256,共6页
激光复合成像三维重构是通过激光扫描和图像处理算法,实现对物体或场景的高精度三维重建。但在实际应用中,受到光照强度及噪声干扰,技术难以精准捕获像素点细节、纹理、亮度特征,导致重建的三维图像与实际存在一定偏差。为此,提出一种... 激光复合成像三维重构是通过激光扫描和图像处理算法,实现对物体或场景的高精度三维重建。但在实际应用中,受到光照强度及噪声干扰,技术难以精准捕获像素点细节、纹理、亮度特征,导致重建的三维图像与实际存在一定偏差。为此,提出一种加权高斯匹配滤波下激光复合成像三维重构方法。根据激光复合成像机理建立扫描方程,生成激光图像,利用邻域平均法平滑图像噪声,通过核函数、卷积运算匹配像素点对比度,采用马尔科夫随机场建立三维重构模型,经过距离保真、正则化运算,实现激光复合成像三维重构。实验结果表明,经加权高斯匹配滤波后,重构结果能够真实展现物体和场景三维立体图,且误差小、结构相似性高。 展开更多
关键词 加权高斯匹配滤波 激光复合成像 核函数 卷积核 空间距离
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Zeroes of the Bergman Kernels on Some New Hartogs Domains 被引量:5
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作者 WANG An ,LIU Yu-lan 《Chinese Quarterly Journal of Mathematics》 CSCD 2011年第3期325-334,共10页
We obtain the Bergman kernel for a new type of Hartogs domain.The corresponding LU Qi-Keng's problem is considered.
关键词 grouping circular domain Bergman kernel function LU Qi-Keng domain
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基于自适应最优组合核函数高斯过程回归的锂电池健康状态区间估计
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作者 刘迎迎 张孝远 +2 位作者 刘梦楠 孙俊章 张艳 《储能科学与技术》 北大核心 2025年第1期346-357,共12页
锂电池健康状态(state of health, SOH)的退化过程在一定程度上是一个非平稳随机过程,使得当前多数点估计机器学习方法在实际应用中受到限制。基于贝叶斯理论的高斯过程回归(Gaussian process regression,GPR),因可输出估计结果的不确定... 锂电池健康状态(state of health, SOH)的退化过程在一定程度上是一个非平稳随机过程,使得当前多数点估计机器学习方法在实际应用中受到限制。基于贝叶斯理论的高斯过程回归(Gaussian process regression,GPR),因可输出估计结果的不确定性,近年来在锂电池SOH区间估计中得到广泛应用。然而,GPR的性能很大程度上取决于其核函数的选择,当前研究多凭借经验选用固定单一核函数,无法适应不同的数据集。为此,本文提出一种基于自适应最优组合核函数GPR的锂电池SOH区间估计方法。该方法首先从电池充放电数据中提取出多个健康因子(health factor, HF),并采用皮尔森相关系数法优选出6个与SOH高度相关的健康因子作为模型的输入。然后,在当前常用的7个核函数集合上,通过两两随机组合构造新的组合核函数,并利用交叉验证自适应优选出最优组合核函数。采用3个不同数据集对所提方法进行了验证,结果表明:本文方法具有出色的SOH区间估计性能。在3个公开数据集上,平均区间宽度指标在0.0509以内,平均区间分数大于-0.0004,均方根误差小于0.0181。 展开更多
关键词 锂电池 健康状态 高斯过程回归 区间估计 组合核函数
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基于各向异性混合核函数高斯过程回归的RC柱概率抗剪承载力模型
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作者 李启明 张鹏飞 +1 位作者 喻泽成 余波 《工程科学与技术》 北大核心 2025年第1期287-295,共9页
针对钢筋混凝土(RC)柱抗剪承载力传统预测模型的非线性逼近能力不足且无法合理描述不确定性所存在的缺陷,提出一种基于各向异性混合核函数高斯过程回归的RC柱概率抗剪承载力预测模型。首先,基于核函数相加性和自动相关性,构造出一种新... 针对钢筋混凝土(RC)柱抗剪承载力传统预测模型的非线性逼近能力不足且无法合理描述不确定性所存在的缺陷,提出一种基于各向异性混合核函数高斯过程回归的RC柱概率抗剪承载力预测模型。首先,基于核函数相加性和自动相关性,构造出一种新型的各向异性混合核函数;然后,结合高斯过程回归原理和各向异性混合核函数,建立了RC柱的概率抗剪承载力模型;进而采用极大似然估计法,确定了RC柱概率抗剪承载力模型的超参数;最后,基于91组剪切破坏RC柱的试验数据,通过与传统核函数形式和传统模型进行对比分析,验证了该模型的有效性。结果表明:与传统核函数相比,各向异性混合核函数的确定性预测指标均方根误差R_(MSE)和平均绝对误差M_(AE)分别降低约16%和19%,概率性预测值指标负对数预测密度N_(LPD)和平均标准化对数损失M_(SLL)分别降低约15%和23%;与传统机器学习模型相比,本文模型的均方根误差R_(MSE)和平均绝对误差M_(AE)分别降低约38%和39%;根据所提出的概率模型能够建立概率密度函数曲线和置信区间,从而合理描述抗剪承载力的不确定性并校准分析传统模型的预测精度。 展开更多
关键词 钢筋混凝土柱 各向异性混合核函数 高斯过程回归 概率抗剪承载力模型 不确定性
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中国城镇居民收入分布演进特征——基于非参数Kernel密度估计方法和省域区域视角 被引量:14
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作者 陈立中 《财贸研究》 CSSCI 2010年第6期8-13,共6页
基于城镇居民人均可支配收入分组数据,运用非参数Kernel密度估计方法和MonteCarlo模拟技术,估计了1987—2008城镇居民收入分布及其演进特征。结果发现:(1)从全国城镇居民收入分布演进特征看,城镇居民收入不平等呈扩大趋势,基尼系数由0.1... 基于城镇居民人均可支配收入分组数据,运用非参数Kernel密度估计方法和MonteCarlo模拟技术,估计了1987—2008城镇居民收入分布及其演进特征。结果发现:(1)从全国城镇居民收入分布演进特征看,城镇居民收入不平等呈扩大趋势,基尼系数由0.17上升到0.33,增长近一倍,但没有观察到普遍和持久的两极分化现象(双峰分布);(2)在12个代表性省(区、直辖市)中,以经济发展模式(经济增长—收入分配)分类,广东属于平等发达型,湖南、四川、宁夏和广西属于不平等落后型,急需调整和转变增长方式;(3)从区域经济发展特征看,东部地区和东北地区收入增长较快,但收入不平等现象十分严重,中部地区和西部地区收入增长相对较慢,不平等现象相对轻微。 展开更多
关键词 收入分布 分组数据 非参数kernel密度估计方法 MONTE Carlo模拟技术
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基于Copula函数的框支剪力墙基础隔震结构地震易损性分析
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作者 孙倩龙 何沛祥 《合肥工业大学学报(自然科学版)》 北大核心 2025年第2期267-273,共7页
针对经典构件地震易损性分析方法的不足,文章将Copula函数引入到构件地震易损性分析中,提出一种基于Copula函数的构件地震易损性分析方法。在地震易损性分析框架的基础上,通过引入非参数核密度估计和Copula函数建立地震动强度和构件地... 针对经典构件地震易损性分析方法的不足,文章将Copula函数引入到构件地震易损性分析中,提出一种基于Copula函数的构件地震易损性分析方法。在地震易损性分析框架的基础上,通过引入非参数核密度估计和Copula函数建立地震动强度和构件地震需求的联合概率分布函数,使地震易损性分析无需人为假定易损性函数分布形式。以某框支剪力墙基础隔震结构为工程背景,基于Copula函数的地震易损性分析方法建立结构各构件的易损性曲线,并与常用构件易损性分析方法的计算结果进行比较,验证了该方法的可行性。研究结果表明,该方法有助于优化框支剪力墙隔震结构易损性曲线的建模过程,为地震易损性研究提供新的思路和方法。 展开更多
关键词 框支剪力墙 基础隔震 地震易损性 COPULA函数 核密度估计
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APPLICATION OF HOLOMORPHIC INVARIANTS IN REPRODUCING KERNEL
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作者 潘利双 王安 《Acta Mathematica Scientia》 SCIE CSCD 2017年第2期355-367,共13页
We use holomorphic invariants to calculate the Bergman kernel for generalized quasi-homogeneous Reinhardt-Hartogs domains. In addition, we present a complete orthonormal basis for the Bergman space on bounded Reinhard... We use holomorphic invariants to calculate the Bergman kernel for generalized quasi-homogeneous Reinhardt-Hartogs domains. In addition, we present a complete orthonormal basis for the Bergman space on bounded Reinhardt-Hartogs domains. 展开更多
关键词 Generalized quasi-homogeneous domain Bergman kernel function holomorphic invariant
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Quantifyingα-diversity as a continuous function of location——a case study of a temperate forest
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作者 Peijian Shi Brady K.Quinn +2 位作者 Long Chen Jie Gao Julian Schrader 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第6期1683-1691,共9页
α-diversity describes species diversity at local scales.The Simpson’s and Shannon-Wiener indices are widely used to characterizeα-diversity based on species abundances within a fixed study site(e.g.,a quadrat or pl... α-diversity describes species diversity at local scales.The Simpson’s and Shannon-Wiener indices are widely used to characterizeα-diversity based on species abundances within a fixed study site(e.g.,a quadrat or plot).Although such indices provide overall diversity estimates that can be analyzed,their values are not spatially continuous nor applicable in theory to any point within the study region,and thus they cannot be treated as spatial covariates for analyses of other variables.Herein,we extended the Simpson’s and Shannon-Wiener indices to create point estimates ofα-diversity for any location based on spatially explicit species occurrences within different bandwidths(i.e.,radii,with the location of interest as the center).For an arbitrary point in the study region,species occurrences within the circle plotting the bandwidth were weighted according to their distance from the center using a tri-cube kernel function,with occurrences closer to the center having greater weight than more distant ones.These novel kernel-basedα-diversity indices were tested using a tree dataset from a 400 m×400 m study region comprising a 200 m×200 m core region surrounded by a 100-m width buffer zone.Our newly extendedα-diversity indices did not disagree qualitatively with the traditional indices,and the former were slightly lower than the latter by<2%at medium and large band widths.The present work demonstrates the feasibility of using kernel-basedα-diversity indices to estimate diversity at any location in the study region and allows them to be used as quantifiable spatial covariates or predictors for other dependent variables of interest in future ecological studies.Spatially continuousα-diversity indices are useful to compare and monitor species trends in space and time,which is valuable for conservation practitioners. 展开更多
关键词 Distance-based weighting Diversity continuum kernel function Shannon-Wiener index Simpson’s index Tri-cube kernel
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The Bergman Kernels on WIII
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作者 LUKe-ping ZHAOXiao-xia 《Chinese Quarterly Journal of Mathematics》 CSCD 2004年第1期24-29,共6页
In this paper, we compute the Bergman kernel function on WIII.and RIII(q) denote the Cartan domain of the third class. Because domain WIII is neither homogeneous domain nor Reinhardt domain, we will use a new way to s... In this paper, we compute the Bergman kernel function on WIII.and RIII(q) denote the Cartan domain of the third class. Because domain WIII is neither homogeneous domain nor Reinhardt domain, we will use a new way to solve this problem. First, we give a holomorphic automorphism group, such that for any Zo, there exists an element of this group, which maps (W, Zo) into (W,O). Second, introduce the concept of semi-Reinhardt and discuss the complete orthonormal system of this domain. 展开更多
关键词 Bergman kernel function holomorphic automorphism group complete or-thonormal system
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基于FSS-kernel BSS方法的机械故障诊断 被引量:2
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作者 杨彦龙 程伟 常洪振 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2012年第11期1557-1561,共5页
机械设备发生故障时,故障特征的提取是很重要的.为了从观测信号中分离出不同的故障特征源信号,并根据分离信号准确地进行故障诊断,从观测信号样本出发,提出了基于有限支持样本核函数的盲源分离(FSS-kernel BSS)方法.此方法利用有限的观... 机械设备发生故障时,故障特征的提取是很重要的.为了从观测信号中分离出不同的故障特征源信号,并根据分离信号准确地进行故障诊断,从观测信号样本出发,提出了基于有限支持样本核函数的盲源分离(FSS-kernel BSS)方法.此方法利用有限的观测样本估计信号的概率分布,得到了评价函数,具有很好的自适应能力.仿真试验结果表明:此方法能成功地分离超、亚高斯混合信号,与其他盲源分离方法相比,此方法具有更好的分离性能.将该方法用于转子不平衡和支座松动的复合故障信号的盲分离,分离出了各复合故障的主要频谱.分离结果表明:此方法应用于机械设备复合故障诊断中是可行的. 展开更多
关键词 故障诊断 盲源分离 有限支持样本 核函数
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基于kernel K-means算法的城市交通客流量分析 被引量:3
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作者 闫明月 《物流技术》 北大核心 2013年第9期158-160,213,共4页
基于核函数这种基于统计学习理论的方法,介绍了kernel K-means算法的基本原理与步骤,与传统的K-means算法进行了对比分析,无论是运算速度还是算法有效性,kernel K-means算法都优于传统的K-means算法,并应用于实际的城市交通客流量数据... 基于核函数这种基于统计学习理论的方法,介绍了kernel K-means算法的基本原理与步骤,与传统的K-means算法进行了对比分析,无论是运算速度还是算法有效性,kernel K-means算法都优于传统的K-means算法,并应用于实际的城市交通客流量数据分析实验,结果验证了方法的有效性,为城市交通规律分析、城市规划与交通政策的制定提供了依据。 展开更多
关键词 传统K-means算法 kernel K-MEANS算法 核函数 城市交通 客流量
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CALCULATION FOR KERNEL OF INTERVAL GREY NUMBER BASED ON BARYCENTER APPROACH
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作者 曾波 刘思峰 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2013年第2期216-220,共5页
The kernel of interval grey number is most likely the real number,which can be used to represent whitenization value of interval grey number.A novel method for calculating kernel of interval grey number is constructed... The kernel of interval grey number is most likely the real number,which can be used to represent whitenization value of interval grey number.A novel method for calculating kernel of interval grey number is constructed based on the geometric barycenter of whitenization weight function in the two-dimensional coordinate plane,and the calculation of kernel is converted to the calculation of barycenter in geometric figures.The method fully considers the effect of all information contained in whitenization weight function on the calculation result of kernel,and is the extension and perfection of the existing methods in the scope of application. 展开更多
关键词 grey theory interval grey number kernel whitenization weight function barycenter approach
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基于CNN-SVM的输送带纵向撕裂检测方法研究 被引量:1
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作者 张释如 余文瑾 王锐 《煤炭技术》 CAS 2024年第7期201-204,共4页
针对传统基于机器学习的输送带纵向检测方法中,特征提取过分依赖于人工设计的缺陷,采用卷积神经网络(CNN)对输送带纵向撕裂特征自动进行提取。但CNN中自带的Softmax分类器不能较好地解决非线性问题,而支持向量机(SVM)能利用核函数将向... 针对传统基于机器学习的输送带纵向检测方法中,特征提取过分依赖于人工设计的缺陷,采用卷积神经网络(CNN)对输送带纵向撕裂特征自动进行提取。但CNN中自带的Softmax分类器不能较好地解决非线性问题,而支持向量机(SVM)能利用核函数将向量映射到高维空间,将线性不可分的问题在高维空间线性可分,有效解决非线性问题,因此采用SVM代替CNN自带的Softmax分类器,提出一种基于CNN-SVM的输送带纵向撕裂检测方法。此外,在CNN中引入批量归一化(BN)、Dropout处理和SE注意力机制进行改进。实验结果表明,基于CNN-SVM的输送带纵向撕裂检测方法准确率可达到99.46%,有效提高了输送带纵向撕裂的检测准确率。 展开更多
关键词 纵向撕裂检测 特征提取 卷积神经网络 支持向量机 核函数
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一个含离散型分式核的Hilbert型不等式
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作者 有名辉 董飞 杨必成 《兰州理工大学学报》 CAS 北大核心 2024年第3期151-155,共5页
引入若干正参数,新构建了一个分式型的离散形态的核函数,并借助于权系数的方法,建立了一个二重Hilbert型级数不等式,并证明此不等式的常数因子是最佳取值.另外,根据余割函数的有理分式展开形式,给出最佳常数因子的余割函数表示形式.通... 引入若干正参数,新构建了一个分式型的离散形态的核函数,并借助于权系数的方法,建立了一个二重Hilbert型级数不等式,并证明此不等式的常数因子是最佳取值.另外,根据余割函数的有理分式展开形式,给出最佳常数因子的余割函数表示形式.通过对参数赋予一些特殊数值,得到了一些已有结果,并且给出了一些新的含特殊核函数的Hilbert型不等式. 展开更多
关键词 HILBERT型不等式 分式型核函数 有理分式展开 余割函数
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Mercer Kernel Based Fuzzy Clustering Self-Adaptive Algorithm
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作者 李侃 刘玉树 《Journal of Beijing Institute of Technology》 EI CAS 2004年第4期351-354,共4页
A novel mercer kernel based fuzzy clustering self-adaptive algorithm is presented. The mercer kernel method is introduced to the fuzzy c-means clustering. It may map implicitly the input data into the high-dimensional... A novel mercer kernel based fuzzy clustering self-adaptive algorithm is presented. The mercer kernel method is introduced to the fuzzy c-means clustering. It may map implicitly the input data into the high-dimensional feature space through the nonlinear transformation. Among other fuzzy c-means and its variants, the number of clusters is first determined. A self-adaptive algorithm is proposed. The number of clusters, which is not given in advance, can be gotten automatically by a validity measure function. Finally, experiments are given to show better performance with the method of kernel based fuzzy c-means self-adaptive algorithm. 展开更多
关键词 fuzzy c-means mercer kernel feature space validity measure function
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Functional Equivalence and Translation of English Long Sentences
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作者 胡明爽 《海外英语》 2018年第9期141-142,共2页
Since English long possess a lot of modifiers and their syntax structures are complicated, it is difficult for the Chinese readers to understand them, not to mention translating them. The paper adopts Nida's theor... Since English long possess a lot of modifiers and their syntax structures are complicated, it is difficult for the Chinese readers to understand them, not to mention translating them. The paper adopts Nida's theory of functional equivalence as the guideline in the process of translation, since it bears the merit of facilitating the communication of information. In terms of concrete methods, the long sentence should be decomposed into kernel sentences and reconstructed according to the expression of the standard Chinese language. Only by doing that, the translation version can be faithful, correct and elegant. 展开更多
关键词 functional equivalence kernel sentences reconstructuring TRANSLATION long sentences
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