lecture 6: hidden variables and expectation-maximization

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Machine Learning for Language Technology Lecture 6: Hidden Variables and Expecta6on Maximiza6on (EM) Marina San6ni Department of Linguis6cs and Philology Uppsala University, Uppsala, Sweden Autumn 2014 Acknowledgement: Thanks to Prof. Joakim Nivre for course design and materials

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Maximum Likelihood Estimation, Hidden and Latent Variables, Expectation-Maximization, EM for Naive Bayes

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Page 1: Lecture 6: Hidden Variables and Expectation-Maximization

Machine  Learning  for  Language  Technology    Lecture  6:  Hidden  Variables  and  Expecta6on  Maximiza6on  (EM)  

Marina  San6ni  Department  of  Linguis6cs  and  Philology  Uppsala  University,  Uppsala,  Sweden  

 Autumn  2014  

 Acknowledgement:  Thanks  to  Prof.  Joakim  Nivre  for  course  design  and  materials  

Page 2: Lecture 6: Hidden Variables and Expectation-Maximization

Repe66on:  Baysian  Approach  to  Classifica6on  

Page 3: Lecture 6: Hidden Variables and Expectation-Maximization

MLE  

Page 4: Lecture 6: Hidden Variables and Expectation-Maximization

Hidden  and  Latent  Variables  

Page 5: Lecture 6: Hidden Variables and Expectation-Maximization

Expecta6on-­‐Maximaza6on  (1)  

Page 6: Lecture 6: Hidden Variables and Expectation-Maximization

Expecta6on-­‐Maximaza6on  (2)  

Page 7: Lecture 6: Hidden Variables and Expectation-Maximization

Expecta6on-­‐Maximiza6on  (3)  

Page 8: Lecture 6: Hidden Variables and Expectation-Maximization

Expecta6on-­‐Maximiza6on  (4)  

Page 9: Lecture 6: Hidden Variables and Expectation-Maximization

Naive  Bayes  Revised    

•  Equa6ons  are  ok  

Page 10: Lecture 6: Hidden Variables and Expectation-Maximization

EM  for  Naive  Bayes  

Page 11: Lecture 6: Hidden Variables and Expectation-Maximization

A  Simple  Example  

Page 12: Lecture 6: Hidden Variables and Expectation-Maximization

Supervised  Learning  

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Unsupervised  Learning  

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First  Guess  

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First  E-­‐Step  

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First  M-­‐Step  

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Second  E-­‐Step  

Page 18: Lecture 6: Hidden Variables and Expectation-Maximization

Second  M-­‐Step  

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Third  E-­‐Step  

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Third  M-­‐Step  

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Fourth  E-­‐Step  

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Fourth  M-­‐Step  -­‐  Convergence  

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Uses  of  EM  

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The  end