机器学习基石-03-3-learning with different Protocol

1.batch learning

batch of （email，spam）------>spam filter

batch of (patient,cancer)-------->cancer filter

batch of patient data-------->group of patients

batch learning：a very common protocol.

batch spam filter：predict with fixed g（固定的g）

2.online learning---which sequentially.

online learning不是固定的g（t）

PLA很容易就应用在online protocol；

reinforcement learning is often done online.因为强化学习也是sequentially。

online：hypothesis “improves” through receiving data instances sequentially.会不断地对g(t)进行修正

3.Active learning ----"learning by asking"

protocol等价于learning philosophy（学习哲学）

主动学习和之前的区别就在于，它会再回到前面的目标函数f上去“问”选定的xn对应的yn。

Active:improve hypothesis with fewer labels (hopefully) by asking questions.

多应用在labels标记很昂贵的情况下，比如珍贵药物标记。

总结：