Introduction to Natural Language Processing (600.465)HMM Parameter Estimation: the Baum-Welch Algorithm

HMM: The Tasks

A Variant of EM

Setting

Initialization

Data Structures

The Algorithm Part I

The Algorithm Part II

Baum-Welch: Tips & Tricks

Example

Example: Initialization

Fill in alpha, beta

Counts & Reestimation

HMM: Final Remarks