POS Tagging - Hidden Markov Model
Advanced Topics in Markov Models and POS Tagging
1. Markov Model Variants
- Hidden Markov Models (HMMs): Learn how HMMs are used for sequence labeling tasks like POS tagging.
- Higher-Order Markov Models: Explore trigram and n-gram models for capturing longer dependencies.
- Conditional Random Fields (CRFs): Study CRFs as an extension for structured prediction.
2. Sequence Labeling in NLP
- Compare HMMs, CRFs, and neural sequence models for POS tagging.
- Study applications in named entity recognition and chunking.
- Analyze challenges in tagging ambiguous and rare words.
3. Computational Implementation
- Algorithms for training and decoding (Viterbi, Forward-Backward).
- Efficient storage and computation for large tagsets.
- Handling data sparsity and smoothing techniques.
4. Research Papers
- "A Tutorial on Hidden Markov Models and Selected Applications in Speech Recognition" (Rabiner, 1989)
- "Part-of-Speech Tagging Using Markov Models" (Church, 1988)
- "Bidirectional LSTM-CRF Models for Sequence Tagging" (Huang et al., 2015)
5. Online Resources
Video Lectures
- Stanford CS224N: Sequence Models and HMMs
- NPTEL: Hidden Markov Models in NLP
- Coursera: Sequence Models in NLP
Interactive Tools
- Online HMM POS Taggers
- Sequence labeling visualizers
- Markov chain simulators
Code Repositories
- Open-source HMM implementations (Python, Java)
- Sequence labeling datasets
- Tutorials for building POS taggers
6. Practical Exercises
Basic Exercises
- Implement a simple HMM POS tagger
- Calculate emission and transition probabilities
- Visualize state transitions in Markov chains
Advanced Projects
- Build a domain-adapted POS tagger
- Compare HMMs with neural sequence models
- Analyze tagging errors and confusion matrices
Research Projects
- Study the impact of smoothing on tagging accuracy
- Explore multilingual POS tagging with HMMs
- Integrate morphological features into Markov models
7. Further Reading
Books
- "Speech and Language Processing" by Jurafsky & Martin (Chapters on HMMs and POS Tagging)
- "Foundations of Statistical Natural Language Processing" by Manning & Schütze
- "Pattern Recognition and Machine Learning" by Bishop (Markov models section)
Journals
- Computational Linguistics
- Natural Language Engineering
- Journal of Machine Learning Research