8 Tactics to Combat Imbalanced Classes in Your Machine Learning Dataset by Jason Brownlee on August 19, 2015 in Machine Learning Process Has this happened to you? You are working on your dataset. You create a classification model and get 90% accuracy…

How to handle Imbalanced Classification Problems in machine learning? from:https://www.analyticsvidhya.com/blog/2017/03/imbalanced-classification-problem/ Introduction If you have spent some time in machine learning and data science, you would have d…

原文:Learning from Imbalanced Classes 数据不平衡是一个非常经典的问题,数据挖掘.计算广告.NLP等工作经常遇到.该文总结了可能有效的方法,值得参考: Do nothing. Sometimes you get lucky and nothing needs to be done. You can train on the so-called natural (or stratified) distribution and sometimes it works w…

Learning from Imbalanced Classes AUGUST 25TH, 2016 If you’re fresh from a machine learning course, chances are most of the datasets you used were fairly easy. Among other things, when you built classifiers, the example classes werebalanced, meaning t…

https://www.svds.com/learning-imbalanced-classes/ 下采样即 从大类负类中随机取一部分,跟正类(小类)个数相同,优点就是降低了内存大小,速度快! http://www.tuicool.com/articles/r2ee2ie Learn more about SMOTE, see the original 2002 paper titled “ SMOTE: Synthetic Minority Over-sampling Technique “.…

上篇文章提到了误差分析以及设定误差度量值的重要性.那就是设定某个实数来评估学习算法并衡量它的表现.有了算法的评估和误差度量值,有一件重要的事情要注意,就是使用一个合适的误差度量值,有时会对学习算法造成非常微妙的影响.这类问题就是偏斜类(skewed classes)的问题.什么意思呢.以癌症分类为例,我们拥有内科病人的特征变量,并希望知道他们是否患有癌症,这就像恶性与良性肿瘤的分类问题.假设y=1表示患者患有癌症,假设y=0表示没有得癌症,然后训练逻辑回归模型.假设用测试集检验了这个分类模型,并…

推荐一篇英文的博客: 8 Tactics to Combat Imbalanced Classes in Your Machine Learning Dataset 1.不平衡数据集带来的影响 一个不平衡的两类数据集,使用准确率(accuracy)作为模型评价指标,最后得到的准确率很高,感觉结果很棒大功告成了,但再看看混淆矩阵(confusion matrix)或者少数类(样本数量少的这一类)的召回率(recall),你的心可能就拔凉拔凉的.你可能会发现少数类的样本几乎完全分错,即模型将样本基本…

最近在学深度学习相关的东西,在网上搜集到了一些不错的资料,现在汇总一下: Free Online Books  by Yoshua Bengio, Ian Goodfellow and Aaron Courville Neural Networks and Deep Learning42 by Michael Nielsen Deep Learning27 by Microsoft Research Deep Learning Tutorial23 by LISA lab, University…

##机器学习(Machine Learning)&深度学习(Deep Learning)资料(Chapter 2)---#####注:机器学习资料[篇目一](https://github.com/ty4z2008/Qix/blob/master/dl.md)共500条,[篇目二](https://github.com/ty4z2008/Qix/blob/master/dl2.md)开始更新------#####希望转载的朋友**一定要保留原文链接**,因为这个项目还在继续也在不定期更新．希望看到…

Kernel PCA 原理和演示 主成份(Principal Component Analysis)分析是降维(Dimension Reduction)的重要手段.每一个主成分都是数据在某一个方向上的投影,在不同的方向上这些数据方差Variance的大小由其特征值(eigenvalue)决定.一般我们会选取最大的几个特征值所在的特征向量(eigenvector),这些方向上的信息丰富,一般认为包含了更多我们所感兴趣的信息.当然,这里面有较强的假设:(1)特征根的大小决定了我们感兴趣信息的多少.即…