Section 5-1 to 5-4.md

5.1 Application for spelling correction

用到：最小编辑距离, 候选集

（pronunciation candidate set, spelling candidate set）

5.2 Noisy Channel Intuition

噪声信道的可信度：贝叶斯规则的最大概率估计
几种纠正方法：删除，替换，插入,交换
mispelling tests set

5.3 Real-Word Spelling errors

candidate set and its sequence to maximize the P(W)

5.4 State of the Art Systems

commensurate
1.改进的概率假设：词语概率非条件独立
2.factors that could influence p(mispelling | word)
source word, target word
3.
除了channel model和language model,还有其它的model
概率分布计算的模型