Logistic Distribution [F(x) = P(X \le x) = \frac{1}{1 + e^\frac{-(x - \mu)}{\gamma}} \ f(x) = F’(x) = \frac{e^\frac{-(x - \mu)}{\gamma}}{\gamma(1 + e^\frac{-(x - \mu)}{\gamma}) ^ 2}] where $\mu$...
SLM Chapter 5 Decision Trees
Idea Each node is a decision maker. It splits a set of data into several sub-sets according to some criterion, and passes each sub-group to its corresponding child node. A class label is given to ...
SLM Chapter 4 Naive Bayes
A generative learning model. Assumption Given a class label, each feature of a data point should be independently distributed. Specifically, for any data point $x_i=(x_i^{(1)}, x_i^{(2)},…, x_i^...
SLM Chapter 3 K-Nearest-Neighbor
A supervised learning model. Find the nearest K neighbors of a data point, assign according to majority vote. The value K needs to be fine-tuned Properties Needs a distance measure between tw...
SLM Chapter 2 Perceptron
Essentially a hyperplane that divides the space into two classes. Properties A linear and binary classifier. A discriminative (as apposed to generative) model. The hypothesis space is $\m...
SLM Chapter 1 Introduction
This is a series of learning notes that I made when reading the book Statistical Learning Methods（统计学习方法) by Li, Hang(李航). Elements of Statistical Learning Model A model $f$ is chosen from a hyp...
小骷髅（一篇同人文）
小骷髅独自坐在雪域的岸边，低头看水。尖锐的风已经使他的身体麻木，他大概感觉不到他的两条腿浸泡在温暖又平和的海水里。 水被小骷髅的腿搅动，开心得“喀啦啦”，“喀啦啦”地笑，裸露在空气里的年轻的骨头相互摩擦、挤压，发出的竟也是差不多的声音。 “孩子，你从哪里来？”只有半个人高的雪人一蹦一蹦地跳过来，蹲坐在小骷髅身边。 小骷髅撇了他一眼，轻轻...
中秋的传说
话说嫦娥偷吃了仙丹，即将奔月成仙。 月亮听说以后可高兴坏了，慌忙找人在自己肚子上盖了座气派的宫殿，还钻研了汉字，给它起了“广寒宫”这个有意思的名字。月亮又怕嫦娥一个人住在宫殿里太寂寞，于是托彗星送来一只兔子。 现在万事具备了，月亮便开始日夜期盼嫦娥的到来。他看起来一天比一天圆，一天比一天容光焕发。 终于到了约定好的日子，月亮迫不及待地想要迎接嫦娥：他把自己撑...