Machine Learning : Introduction
定义 Old Field of study that gives computers the ability to learn without being explicitly programmed —— Arthur Samuel (1959) Mordern A computer program is said to learn from experience E with respect to some class of tasks T and performance measure P, if its performance at tasks in T, as measured by P, improves with experience E —— Tom Mitchell (1998) 算法分类 监督学习(Supervised Learning) 特点:”Right answers given” 即有训练集(training set),包含输入和期望的输出 回归 (Regression) Predict continous valued output 分类 (Classification) Discreted valued output(判断是或不是) 非监督学习(Unsupervised Learning) 即没有训练集,譬如典型的根据相似度进行分类,但并不知道某一类是什么 其他还有增强学习(Reinforcement Learning), 推荐系统(Recommender Systems)