backward machine transliteration by learning phonetic similarity
DESCRIPTION
Backward Machine Transliteration by Learning Phonetic Similarity. Advisor : Dr. Hsu Presenter : Chien Shing Chen Author: Wei-Hao Lin and Hsin-His Chen. PRESENTED AT SIXTH CONFERENCE ON NATURAL LANGUAGE LEARNING, TAIPEI, TAIWAN,2002. Outline. Motivation Objective Introduction - PowerPoint PPT PresentationTRANSCRIPT
Intelligent Database Systems Lab
國立雲林科技大學National Yunlin University of Science and Technology
Advisor : Dr. Hsu
Presenter : Chien Shing Chen
Author: Wei-Hao Lin and Hsin-His Chen
Backward Machine Transliteration by Learning Phonetic Similarity
PRESENTED AT SIXTH CONFERENCE ON NATURAL LANGUAGE LEARNING, TAIPEI, TAIWAN,2002
Intelligent Database Systems Lab
N.Y.U.S.T.
I. M.Outline
Motivation Objective Introduction Grapheme-to-Phoneme(音素 ,音位 ) Transformation Similarity Measurement Learning Phonetic Similarity Experimental Result Conclusions Personal Opinion
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I. M.Motivation
a similarity-based framework to model the task of backward transliteration
a learning algorithm to automatically acquire phonetic similarities from a corpus
Backward transliteration: from a transliteration to original language, like “ 本拉登” =>Bin Laden
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I. M.Objective
Backward machine transliteration by learning phonetic similarity
雨果 (Yu-guo) => Hugo
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I. M.Introduction
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I. M.Introduction
IPA : International Phonetic Alphabet( 國際音標 )Yu-guo =>h j u g oU
Hugo =>v k uo
Similarity Measurement
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I. M.Introduction
CMU pronunciation dictionary 0.6 版ftp://ftp.cs.cmu.edu/project/fgdata/dict
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I. M.Similarity Measurement-alignment
Set is the alphabet set of two strings S1 and S2. ,where ‘_’ stands for space.
Space can be inserted into S1’ and S2’
S1’ and S2’ are aligned
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I. M.Similarity Measurement-score
<English,Chinese> <Hugo, Yu3-guo3>
the phoneme pair (v k uo, h j u g oU)
={h, j, u, v, g, k, oU, uo, _}
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I. M.Similarity Measurement-score
={h, j, u, v, g, k, oU, uo, _}
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I. M.Similarity Measurement-Dynamic
Dynamic programming to trade off :alignment
similarity scoring matrix M
OPTIMALS1 (j h u g oU)
S2 (v k uo)
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I. M.Dynamic programming-Dynamic
Set T is a n+1 by m+1 table where n is the length S1, m is the length of S2.
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I. M.Learning Phonetic Similarity
develop a learning algorithm to remove the efforts of assigning scores in the matrix
capture the subtle difference
How to prepare a training corpus, followed by the learning algorithm.
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I. M.Learning Phonetic Similarity
Positive pairs: original words and the transliterated words are matched
Negative pairs: mismatch the original words and the transliterated words
Ei: original English
Ci: transliterated Chinese
Corpus with n pairs
克林頓
本拉登
魯賓遜
Clinton
Bin Laden
Robinson n positive pairn (n-1) negative pair
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I. M.Learning Algorithm
Treat each training sample as a linear equation
m is the size of the phoneme sets, m=9
wi,j is the row i and the column j of the scoring matrix
xi,j is a binary value indicating the presence of wi,j in the alignmenty is the similarity score.
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I. M.Learning Algorithm
Linear equation in the corpus can be conveniently represented in the matrix form,
, R is the number of pairs in the corpus
i stands for the ith sample pair in the corpus
•wi,j is the scoring matrix•xi,j is a binary value•y is the similarity score
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I. M.Learning Algorithm
The criterion is the sum-of-squared error minimized.
The classical solution is to take the pseudo inverse of , i.e. ,to obtain the w that minimizes the SSE , i.e.
adopt the Widrow-Hoff rule to solve
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I. M.Learning Algorithm
k stands for the kth row in the matrix X
i for the number of iterations
is the learning rate
is the momentum coefficient.
is empirically set as
as
follows,
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N.Y.U.S.T.
I. M.Learning Algorithm
The w(i) is updated iteratively until the learned w appears to overfit.
The iterations to ensure the w will converge to a vector satisfying
Update w(i) immediately after encountering a new training sample instead of accumulating all errors of training samples
The other speed-up technique is the momentum used to damp the oscillations. .
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I. M.Experiments
.corpus is consisted of 1574 pairs of <English,Chinese> names
313 have no entries in the pronouncing dictionary.
97 phonemes used to represent these names, in which 59 and 51 phonemes are used for Chinese and English names.
Rank is the position of the correct original word in a list of candidate words sorted.
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I. M.Experiments
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I. M.Experiments
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I. M.Conclusions
Without any phonological analysis, the learning algorithm can acquire those similarities without human intervention.
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I. M.Personal Opinion
Drawbackobtain the score matrix depend on a few empirically rule
Is the experiment tie in with the testing samples ?
ApplicationA different method to compute the similarity between words.
Future WorkThe Widrow-Hoff rule may estimate the parameter to substitute for attempting intervention blinded.
Combine sound speech recognize with this method to output a new objectivity method