内容主要出自吴恩达机器学习网课

机器学习

Grew out of in AI

New capabilitiy for computers 计算机开发的新功能

部分应用

Data mining 数据挖掘

Applications cant program by hand 人无法手写的程序

Self-customizing programs 私人定制程序

Understanding human learning(brain,real AI) 理解人类学习与大脑

定义

Arthur Samuel (1959)：Machine Learning: Field ofstudy that gives computers the ability to learnwithout being explicitly programmed.

在没有明确设置的情况下，使计算机具有学习能力的研究领域

Tom Mitchell（1998）：Well-posed Learning Problem：A computer program is said to learn from experience E with respect to some task T and some performance measure P，if its performance on T，as measured by P，improves with experience E.

一个适当的学习问题定义如下：计算机程序从经验 E （程序与自己下上万次跳棋）中学习，解决某一任务 T （玩跳棋），进行某一性能度量 P （与新对手玩跳棋时赢的概率），通过 P 测定在 T 上的表现因经验 E 而提高。

问题

假设你的邮箱正在观察你将哪些邮件标记为垃圾邮件，并基于此学习如何更好的过滤邮件，那么在这里任务 T 是什么？

A. Classifying emails as spam or not spam.

B. Watching you label email as spam or not spam.

C. The number(or fraction) of eamils correctly classified as spam/not spam.

D. None of the above–this is not a machine learning problem

A 是任务T B是经验E C是度量P D雀氏一眼错啊

机器学习算法

最常用的监督学习与无监督学习

监督学习(Supervised learning)

无监督学习(Unsupervised learning)

Others

Reinforcement learning 强化学习
recommendersystems 推荐系统