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Rated Aspect Summarization of Short Comments. Yue Lu, ChengXiang Zhai, and Neel Sundaresan Presented by: Sapan Shah. 1. Web 2.0 Opinions Everywhere. Novotel. iPhone. Sushi Kame. Overall Rating. ……. 2. Seller’s Feedback on eBay. 23,385 Feedback received.
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Rated Aspect Summarization of Short Comments Yue Lu,ChengXiang Zhai, and Neel Sundaresan Presented by: Sapan Shah 1
Web 2.0 Opinions Everywhere Novotel iPhone Sushi Kame Overall Rating …… 2
Seller’s Feedback on eBay 23,385 Feedback received Very fast shipping and awesome price!!! 3
Need More Specific Aspects! Fast shipping Is this seller rated high/low mainly because of service? Good service Which seller provides fast shipping? 4
Rated Aspect Summarization 23,385 Feedback received Representative Phrase Aspect Aspect Rating 5 Support Information Challenges: • How to identify coherent aspects? with user interest? • How to accurately rate each aspect? • How to get meaningful phrases supporting the ratings? 5
Related Work • Review summarization • Unsupervised feature extraction + opinion polarity identification:[Hu&Liu 04], OPINE [Popescu&Etzioni 05], … • Supervised aspect extraction: [Zhuang et al] … • Sentiment classification • Binary classification:[Turney02] [Pang&Lee02] [Kim&Hovy04] [Cui et al06] … • Rating classification: [Pang&Lee05] [Snyder&Barzilay07] … • Hidden aspect discovery • [Hofmann99] [Blei et al03] [Zhai et al04] [Li&McCallum06] [Titov&McDonald08]… 6
Overall Approach Step2: Aspect Rating Prediction Step3: Extract Representative Phrases Step1: Aspect Discovery and Clustering 7 7
Preprocessing of Short Comments Source Modifier (opinion) Head Term (feature) 1 fast shipping awesome price 2 great business honest seller Very fast shipping and awesome price!!! Comment 1 Great business, honest seller Comment 2 Shallow parsing 8
Step1: Aspect Discovery & Clustering Step2: Aspect Rating Prediction Step3: Extract Representative Phrases Step1: Aspect Discovery and Clustering 9 9
Method(1) Head Term Clustering Source Modifier Head Term 1 fast shipping honest seller 2 fast shipping quick delivery reliable seller Clustering: e.g. k-means Modifiers Head Term • fast:100 speedy:80 slow:50 … Shipping • fast:120 speedy:85 slow:70 … Delivery • honest:80 reliable:60 … Seller Support = Cluster Size 10
Method(2) Unstructured PLSA Source Modifier Head Term 1 fast shipping honest seller 2 fast shipping quick delivery reliable seller d1 d2 w dk Topic model = unigram language model = multinomial distribution [Hofmann 99] shiping 0.3 delivery 0.2 1 email 0.25comm. 0.22 2 … service 0.32exchange 0.2 k 11
Method(2) Unstructured PLSA Source Modifier Head Term 1 fast shipping honest seller 2 fast shipping quick delivery reliable seller ? ? d1 ? ? d2 w ? ? dk Topic model = unigram language model = multinomial distribution [Hofmann 99] shiping delivery 1 Estimation: e.g. EM with MLE email comm. 2 … service exchange k 12
Method(3) Structured PLSA Source Modifier Head Term Modifier Head Term 1 fast Shipping fast shipping:180 honest Seller delivery: 80 2 fast delivery slow shipping: 70 quick delivery delivery: 30 reliable seller response: 10 d1 d2 w dk ? shiping delivery ? 1 email comm. ? 2 ? … ? ? service exchange k 13
Method(2) (3): Topics Aspects d1 d2 w dk Aspects Topics shiping 0.3 delivery 0.2 1 email 0.25comm. 0.22 2 … service 0.32exchange 0.2 k Support = Topic Coverage 14
Method(2) (3): Adding Prior to PLSA d1 d2 w dk Dirichlet Prior Topics shiping ? delivery ? shiping delivery a1 1 email ?comm. ? email comm. 2 a2 … service ?exchange ? k Estimation: e.g. EM with Maximum A Posteriori (MAP) instead of MLE 15
Step2: Aspect Rating Prediction Step2: Aspect Rating Prediction Step3: Extract Representative Phrases Step1: Aspect Discovery and Clustering 16 16
Method(1) Local Prediction Source Modifier Head Term 1 fast shipping great product 2 slow delivery poorly packaged fine product … … … What if? Aspects slow Shipping Product Shipping Packaging Product 17
Method(2) Global Prediction Shipping Shipping fast 0.2 timely 0.2 quick 0.2… … slow 0.01 fast , timely, quick, fast, slow, quickly, fast, great, bad Aspects Source Modifier Head Term 1 fast shipping Shipping great product Product Shipping 2 slow delivery Packging poorly Packaged Shipping Shipping fine product Product slow 0.4 bad 0.2… …quick 0.02fast 0.01 slow , bad, fast, poor, slowly, unbearable, quick, poor … … … What if? slow shipping Language Model 18
Method(1)(2): Rating Aggregation Aspect Aspect Rating quick shipping AVG Fast delivery 2.33 stars Shipping slow shipping well packaged AVG poor packaging 1.67 stars Packaging badly wrapped 19
Step3: Representative Phrases Step2: Aspect Rating Prediction Step3: Extract Representative Phrases Step1: Aspect Discovery and Clustering 20 20
Step3: Top K Frequent Phrases Step 1 Step 2 Step 3 Fast shipping Timely delivery Quickly arrived quick shipping Fast delivery Shipping slow delivery bad shipping Slow shipment Bad shipping Slow delivery (50) Support = Phrase Freq. 21
Experiments: eBay Data Set Statistics Mean STD # of comments/seller 57,055 62,395 # of phrases/comment 1.5533 0.0442 overall rating (positive %) 97.9 0.95 28 eBay sellers with high feedback scores for the past year Positive rating 1 Neutral rating 0 Negative rating 0 22
Experiments: Evaluate Step 1 Step1: Aspect Discovery & Clustering Gold standard: human labeled clusters Questions: • Is phrase structure useful? • Is topic modeling effective? 23
Eval Step 1: Aspect Coverage Aspect Coverage measures the percentage of covered aspects Unstructured PLSA Structured PLSA k-means Aspect Coverage 24 Top K Clusters
Eval Step 1: Clustering Accuracy Method Clustering Accuracy K-means 0.36 Unstructured PLSA 0.32 Structured PLSA 0.52 Seller1 Seller2 Seller3 AVG Annot1-2 0.6610 0.5484 0.6515 0.6203 Annot1-3 0.7846 0.6806 0.7143 0.7265 Annot2-3 0.7414 0.6667 0.6154 0.6745 AVG 0.7290 0.6319 0.6604 0.6738 Clustering Accuracy measures the cluster coherence Still much room for improvement! Human Agreement Low Agreement; Varies a lot 25
Experiments: Evaluate Step 2 Step2: Aspect Rating Prediction Questions: • Local prediction v.s. Global prediction? • How does aspect clustering affect this? 26
Detailed Seller Ratings as Gold std Gold standard: user DSR ratings DSR criteria as priors of aspects 27
Eval Step 2: Correlation Step 1 Step 2 Kendal’s tau Pearson Baseline 0.2892 0.3162 K-means Local 0.1106 (-62%) 0.1735 (-45%) K-means Global 0.1225 (-58%) -0.0250 (-108%) Unstr. PLSA Local 0.2815 0.4158 Unstr. PLSA Global 0.4958 (+76%) 0.5781 (+39%) Str. PLSA Local 0.1905 0.4517 Str. PLSA Global 0.4167 (+119%) 0.6118 (+35%) Correlationmeasures the effectiveness of ranking the four DSRs for a given seller 28
Eval Step 2: Ranking Loss Step 1 Step 2 AVG of 3 DSR Baseline 0.2363 K-means Local 0.2170 (-8%) K-means Global 0.6307 (+167%) Unstr. PLSA Local 0.1977 (-16%) Unstr. PLSA Global 0.2101(-11%) Str. PLSA Local 0.1909 (-19%) Str. PLSA Global 0.1534 (-35%) Ranking Loss measures the distance between the true and predicted ratings (smallerbetter) Local Pred: more robust Global Pred: more accurate 29
Experiments: Evaluate Step 3 Step3: Representative Phrases Questions: • How do previous steps affect the phrase quality? 30
Eval Step 3: Human Labeling DSR Rating 1 Rating 0 Item as Described Communication Shipping time Shipping and Handling Charges Rating 1: Rating 0: Fast delivery Prompt email Slow shipping … Excessive postage As promised … 31
Eval Step 3: Measures & Results Step 1 Step 2 Prec. Recall K-means Local 0.3055 0.3510 K-means Global 0.2635 0.2923 Unstr. PLSA Local 0.4127 0.4605 Unstr. PLSA Global 0.4008 0.4435 Str. PLSA Local 0.5925 0.6379 Str. PLSA Global 0.5611 0.5952 Information Retrieval measures: Human generated phrases “relevant document“ Computer generated phrases “retrieved document". 32
Summary • Novel problem • Rated Aspect Summarization • General Methods • Three steps • Effective on eBay Feedback Comments • Future Work • Evaluate on other data • Three steps One optimization framework 33
Thank you! 34