languagemodeling

000031 dan jurafsky what kinds of knowledge

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Unformatted text preview: I do not like green eggs and ham </s> Dan Jurafsky •  •  •  •  •  •  More examples: Berkeley Restaurant Project sentences can you tell me about any good cantonese restaurants close by mid priced thai food is what i’m looking for tell me about chez panisse can you give me a lis*ng of the kinds of food that are available i’m looking for a good place to eat breakfast when is caffe venezia open during the day Dan Jurafsky Raw bigram counts •  Out of 9222 sentences Dan Jurafsky Raw bigram probabili1es •  Normalize by unigrams: •  Result: Dan Jurafsky Bigram es1mates of sentence probabili1es P(<s> I want english food </s>) = P(I|<s>) × P(want|I) × P(english|want) × P(food|english) × P(</s>|food) = .000031 Dan Jurafsky What kinds of knowledge? •  •  •  •  •  •  •  P(english|want) = .0011 P(chinese|want) = .0065 P(to|want) = .66 P(eat | to) = .28 P(food | to) = 0 P(want | spend) = 0 P (i | <s>) = .25 Dan Jurafsky Prac1cal Issues •  We do everything in log space •  Avoid underflow •  (also adding is faster than mul*plying) p1 ! p2 ! p3 ! p4 = log p1 + log p2 + log p3 + log p4 Dan Jurafsky Language Modeling Toolkits •  SRILM •  h_p://www.speech.sri.com/projects/srilm/ Dan Jurafsky Google N ­Gram Release, August 2006 … Dan Jurafsky Google N ­Gram Release •  •  •  •  •  •  •  •  •  •  serve serve serve serve serve serve serve serve serve serve as as as as as as as as as as the the the the the the the the the the incoming 92! incubator 99! independent 794! index 223! indication 72! indicator 120! indicators 45! indispensable 111! indispensible 40! individual 234! http://googleresearch.blogspot.com/2006/08/all-our-n-gram-are-belong-to-you.html Dan Jurafsky Google Book N ­grams •  h_p://ngrams.googlelabs.com/ Language Modeling Es*ma*ng N ­gram Probabili*es Language Modeling Evalua*on and Perplexity Dan Jurafsky Evalua1on: How goo...
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This document was uploaded on 02/14/2014.

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