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

  1. "A Tutorial on Hidden Markov Models and Selected Applications in Speech Recognition" (Rabiner, 1989)
  2. "Part-of-Speech Tagging Using Markov Models" (Church, 1988)
  3. "Bidirectional LSTM-CRF Models for Sequence Tagging" (Huang et al., 2015)

5. Online Resources

  1. Video Lectures

    • Stanford CS224N: Sequence Models and HMMs
    • NPTEL: Hidden Markov Models in NLP
    • Coursera: Sequence Models in NLP
  2. Interactive Tools

    • Online HMM POS Taggers
    • Sequence labeling visualizers
    • Markov chain simulators
  3. Code Repositories

    • Open-source HMM implementations (Python, Java)
    • Sequence labeling datasets
    • Tutorials for building POS taggers

6. Practical Exercises

  1. Basic Exercises

    • Implement a simple HMM POS tagger
    • Calculate emission and transition probabilities
    • Visualize state transitions in Markov chains
  2. Advanced Projects

    • Build a domain-adapted POS tagger
    • Compare HMMs with neural sequence models
    • Analyze tagging errors and confusion matrices
  3. 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
  1. "Speech and Language Processing" by Jurafsky & Martin (Chapters on HMMs and POS Tagging)
  2. "Foundations of Statistical Natural Language Processing" by Manning & Schütze
  3. "Pattern Recognition and Machine Learning" by Bishop (Markov models section)
Journals
  1. Computational Linguistics
  2. Natural Language Engineering
  3. Journal of Machine Learning Research