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Opinion Digger: An Unsupervised Opinion Miner from Unstructured Product
ReviewsSamaneh Moghaddam, Martin Ester
CopyRight@luzhonghao
Lab for Internet Software TechnologiesLab for Internet Software Technologies
Abstract
• Propose an unsupervised method for aspect extraction from unstructured reviews using known aspects.
• Introduce an unsupervised method for aspect rating(on a scale from 1 to 5)based on the rating guideline.
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Lab for Internet Software TechnologiesLab for Internet Software Technologies
Problem Definition
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Known aspects
Output aspects
Lab for Internet Software TechnologiesLab for Internet Software Technologies
Aspect Extraction
• Finding frequent noun phrases
• Mining opinion patterns
• Filtering out non-aspects
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Lab for Internet Software TechnologiesLab for Internet Software Technologies
Finding Frequent Noun Phrases
• Hypothesis:those nouns that are frequent noun phrases as a set of potential aspects
• Apply Apriori algorithm to find all multi-part noun phrases which are frequent.(support value=1%)
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Lab for Internet Software TechnologiesLab for Internet Software Technologies
Mining Opinion Patterns
• Finds matching phrases for each of the known aspects.It searches for each known aspect in the reviews and finds its nearest adj. in that sentence segment as corresponding sentiment.
• Saved the matching phrase and picks the POS tags of all words as a pattern.
• After mining all POS patterns, use GSP(Generalized Sequential Pattern) to find frequent patterns(sup=1%)
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Lab for Internet Software TechnologiesLab for Internet Software Technologies
Filtering out non-aspects
• Pnum: whitch is the number of opinion patterns that are matched at least once by the potential aspect.
• If pnum < 2: eliminate the aspect
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Lab for Internet Software TechnologiesLab for Internet Software Technologies
Compute Aspect Rating
• For each aspect,extracts the nearest adj. as its sentiment.
• For each sentiment of the every aspect of a product,search in the WordNet synonymy graph to find two rated synonyms from the rating guideline .(can see them from the website Epinion.com)
• Compute the rating of each sentment8
Lab for Internet Software TechnologiesLab for Internet Software Technologies
Sentiment rating space
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Lab for Internet Software TechnologiesLab for Internet Software Technologies
Compute each sentiment
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Lab for Internet Software TechnologiesLab for Internet Software Technologies
Experimental results
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Lab for Internet Software TechnologiesLab for Internet Software Technologies
Evaluation of Aspect Extraction
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Lab for Internet Software TechnologiesLab for Internet Software Technologies
Thank you!
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