在分析肠道微生物数据中,一般会对数据进行一定的转换,以使数据尽可能的服从正态分布。常用的方法有Centered Log-ratio (CLR)transformation和Cumulative Sum Scale (CSS)transformation等。这里介绍一下在R中如何进行CLR转换。 CLR转换的公式如下: clr.png g(x)是x的几何均数。 在进行微生物组数据转换时,第...
Can I use the CLR (centered log-ratio transformation) to prepare data for PCA? The 1st answer: The 2nd answer: 参考资料 clr {compositions} R Documentation [Package compositions version 2.0-5] Centered log ratio transform Description Compute the centered log ratio transform of a (dataset of) ...
在分析肠道微生物数据中，一般会对数据进行一定的转换，以使数据尽可能的服从正态分布。常用的方法有 Centered Log-ratio (CLR) transformation和 Cumulative Sum Scale (CSS) transformation等。这里介绍一下在R中如何进行CLR转换。 CLR 转换的公式如下：明白clr的基本原理，在R中的实现相对...
Centerd log-ratio (clr) transformation and robust principal component analysis of long-term NDVI data reveal vegetation activity linked to climate processes. Climate 2015; 3: 135-49.Faith, M. Centered Log-Ratio (clr) Transformation and Robust Principal Component Analysis of Long-Term NDVI Data ...
The logratio transformation aims to eliminate spurious correlations between components of compositional data. When applying this method to granulometric da... F Tauber - 《Mathematical Geology》 被引量: 43发表: 1999年 Multinomial logit PLS regression of compositional data And the model presents the ...
transformationFractalZarshuranThe aim of this study is to discriminate the geochemical anomalies in the Zarshuran district, NW Iran, using different geochemical methods and present a more useful method where anomalous areas better coincide with the geological features. For this methods of delineation,...
This study uses a centered log-ratio (clr) transformation approach and robust principal component analysis (PCA), on a long-term Normalized Difference Vegetation Index (NDVI) dataset to test its applicability in analyzing large multi-temporal data, and potential to recognize important trends and ...
The p53 gene (also known as TP53) may be the most common genetic target involved in the malignant transformation of human cells. Direct sequence analysis h... WM Koch,JA Brennan,M Zahurak,... - 《Jnci Journal of the National Cancer Institute》 被引量: 1850发表: 1996年 Correspondence Anal...
基于空间等价性的成分数据变换方法比较研究 A Comparative Study of Compositional Data Transformation Methods Based on Spatial Equivalence 单形空间的定和约束使得传统统计分析方法对成分数据失效,通常需要采用适当的变换方法将成分数据转化到欧氏空间后再进行统计分析.本文以非对称对数比变换,中心化对数比... 郭丽娟,...
convexmanifold.ThenwestudythesystemcapacityofMIMO-BICMsystemsthatuseLLRclipping.OurresultsshowthatstrongLLRclippingispossiblewithoutsignificantcapacityloss.WefinallyproposeanLLRtrans-formationschemewhichisnecessaryforapproachingcapacityincaseofstrongclipping.TheusefulnessofthisLLRtransformationisillustratedbynumerical...