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Peer-review analysis. Comprehensive exam Presentered by : Wenting Xiong Committees: Diane Litman Rebecca Hwa Jingtao Wang. Motivation. Goal
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Peer-review analysis Comprehensive exam Presentered by : Wenting Xiong Committees: Diane Litman Rebecca Hwa Jingtao Wang
Motivation • Goal Mine useful information in peers’ feedback and represent them in a intuitive and concise way • Tasks and related research topics • Identify review helpfulness NLP – Review analysis • Summarize reviewers’ comments NLP – Paraphrasing and Summarization • Sense-making of review comments interactive review exploration HCI – Visual text analytics
Part.1 NLP -- Review Analysis
Outline • Review helpfulness analysis • Sentiment analysis (opinion mining) Aspect detection Sentiment orientation Sentiment classification & extraction
1 Review helpfulness analysis • Automatic prediction • Learning techniques • Features utilities • The ground-truth • Analysis of perceived review helpfulness • Users’ bias when vote for helpfulness • Influence of the other reviews of the same product
1.1 -- Learning techniques • Problem formalization • Input: textual reviews • Output: helpfulness score • Learning Algorithms • Supervised learning – Regression • Product reviews (e.g. electronics) <Kim 2006>, <Zhang 2006>, <Liu 2007>,<Ghose 2010>, <O'Mahony 2010> • Trip reviews <Zhang 2006> • Movie reviews <Zhang 2006> • Unsupervised learning – Clustering • Book reviews <Tsur 2009> • Focus • Predict absolute scores VS. rankings • Identify most helpful <Liu 2007> vs. unhelpful <Tsur 2009>
1.1-- Feature utilities • Features used to model review helpfulness • Controversial results about the effectiveness of subjectivity features • term-based counts not useful <Kim, et. al, 2006>, category-based count shows positive words correlate with greater helpfulness <Ghose, et. al, 2010> • Data sparsity issues?
1.1 --The ground-truth • Various gold-standard of review helpfulness • Aggregated helpfulness votes Perceived helpfulness e.g. <Kim 2006> • Manual annotations of helpfulness Real helpfulness <Liu 2007> • Problems Percentage of helpful votes is not consistent with annotators judgments based on helpfulness specifications Error rate of preference pair < 0.5 <Liu 2007>
1 Review helpfulness analysis • Automatic prediction • Learning techniques • Features utilities • The ground-truth • Analysis of perceived review helpfulness • Biased voting of review helpfulness on Amazon.com • The perceived helpfulness is not only determined by the textual content
1.2 Analysis of perceived review helpfulness • Biased voting of review helpfulness on Amazon.com • Imbalanced vote • Winner Circle bias • Early bird bias <Liu 2007> • “x/y” does not capture the true helpfulness of reviews • The perceived helpfulness is not only determined by the textual content • Influence of the other reviews of the same product • Individual bias <Danescu-Niculescu-Mizil 2009>
1 Review helpfulness analysis • Summary • Effective features for identify review helpfulness • Perceived helpfulness VS. real helpfulness • Comments • New features • Introduce domain knowledge and information from other dimensions • Data sparsity problem • High-level features • Deep learning from low-level features • Other machine learning techniques • Theory-based generative models
Outline • Review helpfulness analysis • Sentiment analysis (opinion mining)
2 Sentient analysis (opinion mining) How people think about what? • Aspect detection • Sentiment orientation • Sentiment classification & extraction
2.1 Aspect detection • Frequency-based approach • Most frequent noun-phrase + sentiment-pivot expansion <Liu, 2004> • PMI (pointwise Mutual information) with meronymy discriminators + WordNet <Popescu 2005> • Generative approach • LDA, MG-LDA <Titov 2008>, sentence-level local-LDA <Brody 2010> • Multiple-aspect sentiment model <Titov 2008> • Content-attitude model <Sauper 2011>
2.2 Sentiment orientation • Aggregating from subjective terms • Manually constructed subjective lexicons • Bootstrapping with PMI • Adj & adv <Turney 2001> • opinion-bearing words <Liu 2004> • Graph-based approach • Relaxiation labeling <Popescu 2005> • Scoring <Brody 2010> • Domain adaptation • SCL algorithm <Blitzer 2007> • Through topic models • MAS -- aspect-independent + aspect-dependent <Titov 2008> • Content-attitude models -- predicted posterior of sentiment distribution <Sauper, 2011>
2.3 Sentiment classification and extraction • Classification • Binary <Turney 2001> • Finer-grained e.g. metric labeling <Pang 2005> • Data sparsity • Bag-of-Words vs. Bag-of-Opinions <Qu 2010> • Opinion-oriented extraction • Topic of interest • Pre-defined • Automatically learned • User-specified
2 Summary Comparing reviews’ helpfulness and sentiment • In terms of automatic prediction, both are metric inferring problem, that can be formalized as standard ML problems with same input X though different output Y • The learned knowledge about opinion topics and the associated sentiments would help model the general utility of reviews
Part.2 NLP -- Paraphrasing & Summarization
Outline • Paraphrasing Paraphrases are semantically equivalent with each other • Paraphrase recognition • Paraphrase generation • Summarization Shorter representation of the same semantic information of the input text • Informativeness computation • Extracted summarization of evaluative text
1.1 Paraphrase recognition • Discriminative approach • Various string similarity metrics • Different level of abstraction of textual strings <Malakasiotis 2009> Question: Any useful existing resourses for identifying equivalent semantic information? • Word-level: dictionary, WordNet • Phrase-level: ? • Sentence-level: ?
1.2 Paraphrase generation • Corpora • Monolingual vs. bilingual • Methods • Distributional-similarity based • Corpora based • Evaluation • Intrinsic evaluation vs. extrinsic evaluation
1.2 -- Corpora • Monolingual corpora • Parallel corpora • Translation candidates • Definitions of the same term • Comparable corpora • Summary of the same event • Documents on the same topic • Bilingual parallel corpora
1.1 -- Methods.1 • Distributional-similarity based methods • DIRT, paths frequently occur with same words at their ends • Using a single monolingual corpus • MI to measure association strength between slot and its arguments <Lin 2001> • Sentence-lattices, argument similarity of multiple slots on sentence-lattices • Using a comparable monolingual corpus • Hierarchical clustering for grouping similar sentences • MSA to induce lattices <Barzilay 2003>
1.2 -- Methods.2 • Corpora-based methods • Monolingual parallel corpus • Monolingual MT <Quirk 2004> • Merging partial parse trees FSA <Pang 2003> • Paraphrasing from definitions <Hashimoto 2011> • Monolingual comparable corpus • MSR paraphrase corpus <Dolan 2005> • Edit distance, Journalism convention • Sentence-lattices <Barzilay 2003> • Bilingual parallel corpus • Pivot approach <Callison-Burch 2005> <Zhao 2008> • Random-walk based HTP <Kok 2009>
1.2 -- Evaluation • Intrinsic evaluation • Responsiveness • Can access precision, but no recall • Standard test references <Callison-Burch 2008> • Manually aligned corpus • Lower bound precision & relative recall • Extrinsic evaluation • Alignment tasks in monolingual translation • Alignment error rate • Alignment precision, recall, F-measure <Dolan 2004> • Model-specific evaluation • FSA <Pang 2005>
2 Summarization Tasks in automatic summarization • Content selection • Information ordering • Automatic editing, information fusion Focus of this talk -- • Informativeness computation • Information selection (and generation) • Summarization evaluation
2.1 Computing informativeness • Semantic information (Topic identification) • Word-level • Frequency, TFIDF <Liu 2004>, Topic signature <Lin 2001>, PMI(w, topic) <Wang 2011>, external domain knowledge <Zhuang 2006> • Sentence-level • HMM content models <barzilay 2004> • Category classification + sentence clustering <Abu-Jbara 2011> • Summary-level • Sentiment-aspect match model + KL divergence <Lerman 2009> • Opinion-based sentiment scores for evaluative texts • Sentiment polarity, intensity, mismatch, diversity <Lerman 2009> • Discriminative approach to predict informativeness • Combine statistic, semantic, sentiment features in linear or log-linear models <wang 2011>
2.2 Information selection & generation • Extraction • Rank-based sentence selection • Aggregation of word informative weights (+ discourse features) <Carenini, 2006> <Wang, 2011> • Optimized by Maximal Marginal Relevance • Topic-based selection • HMM content model <Barzilay, 2004> • Languge-model based clustering of informative phrases <Liu, 2010> • Summarize citations based on category-cluster-setence <Abu-Jbara, 2011> • Structured evaluative summary • Aspect + overall rating <Hu, 2004> • Aspect + pos and cons <Zhuang, 2006> • Hierarchical aspects + sentiment phrasal expressions <Liu 2010> • Abstraction • Generate evaluative arguments based on aggregation of extracted information <Carenini, 2006> • Graph-based summarization using adjacently matrix to model dialogue structure <Wang, 2011>
2.3 Summarization evaluation • Pyramid (empirical) • Multiple human wrote gold-standards • SCU <Ani 2007> • ROUGE • Automatically compare with gold-standard • Consider correlation based on unigram, bigram, longest common subsequence <Lin 2004> • Fully automatic • Good summary should be similar to the input • KL divergence, JS divergence <Ani 2009> • User preference of sentiment summarizer
Paraphrasing and summarization -- Summary • Common theme • Semantic equivalence • Related to sentiment analysis in computing informativeness of reviews • Aspect-dependent sentiment orientation • Overall vs. distribution statistics • Aspect coverage • Compute through scoring or measuring probabilistic model's distribution divergence
Outline • Text visualization • Inner-set visualization for abstraction • Intra-set visualization for comparison • Interactive exploration • Design principles and examples
1 Text visualization • Inner-set visualization for abstraction • Semantic information • Sentiment information (opinions) • Intra-set visualization for comparison
1.1 Inner-set visualization techniques • Semantic information • Original text with highlighted keywords • Most detailed information • Topic-based representation • List of target entities (Jigsaw, <Stasko 2010>) • Haystack (Themail, <Viegas 2006>) • Tagcloud (OpinionSeer <Wu 2010>), TIARA <Liu 2009>, reviewSpotlight <Yatani, 2011>) • Vector-based representation • Dot in space (ThemeScapes <Wise 1995>)
1.1 Inner-set visualization techniques • Sentiment information • Value-based visual representation • Bar -- Opinion polarity and intensity <Liu 2005> • Histogram -- Rating distribution <Carenini 2006> • Double-square -- Frequency, polarity, intensity <Oelke 2009> • Thumbnail table -- opinion report for people in groups <Oelke 2009> Comment: • Requires NLP techniques for opinion mining and sentiment analysis • e.g. Intelligence support for identify salient information for exploration (Aspect that opinions are most (dis)consisitant) <Carenini 2006>
1 Text visualization • Inner-set visualization for abstraction • Semantic information • Sentiment information (opinions) • Intra-set visualization for comparison • Dimensionality of comparison • Via layout or visualizing metadata as axis
1.2 Intra-set visualization techniques • Dimensionality of exploration • 1D: layout or metadata • 2D: layout or/and metadata • 3D & 3D+: layout or/and metadata
1.2 Intra-set visualization -- 1D Exploration • Side-by-side • Compare single product reviews feature-by-feature <Liu 2005> • Connect interesting events of different period of times (Continuum, <Andre 2007>) • Explore the connection of entities across documents (Jigsaw, <Stasko 2010>) • Grid-layout of data in groups • Faceted metadata for image browsing <Yee 2003> • Facetbox for presenting filtering by facet-data <Lee 2009> • Exploring term-based language patterns across document <Don 2007> • Timeline -- temporal features • Themail <Viegas 2006>, Contitunn <Andre 2007> Tiara <Liu 2009>, TwitInfo <Marcus 2011> etc.
1.2 Intra-set visualization -- 2D Exploration • Aspect-based opinion analysis across multiple targets • Paired <Liu 2005> • Matrix <Orlke 2009> • Scatter plot of targets with metadata as axis • Discover the entity-coverage in documents (Jigsaw <Stasko 2010>) • Visual DL search result with categorical and hierarchical axes <Shneiderman 2000> • 2D graph (layout) • Exploring relationships between entities and documents (Jigsaw <Stasko 2010>) • *Diagram of social network (TIARA <Liu 2009>) • Spatial representation in 2D space • Triangle scatter-plot of opinions (OpinionSeer <Wu 2010>) • *Opinion space <Faridani 2010> • Circled correlation map of review aspects <Orlke 2009>
1.3 Intra-set visualization -- 3D Exploration • 3D-spacial representation • ThemeScapes <Wise 1995> • Theme strength as elevation (terrain map) • Combine multiple visualization of metadata variables • OpinionSeer <Wu 2010> • Radial visualization with co-centric rings + stacked graph + triangle scatter plot • TIARA <Liu 2010> • Stacked topic-models (Wordcloud) over timeline Pos • Discover unperceivable interactions among multiple factors Cons • Concise but hard to interpret • Interaction is more complex and hard to design
2 Interactive exploration Design principles and examples • Data on-demand and in-depth exploration From the data perspective • Overview then detailed view From the interaction perspective • zoom-in and zoom-out for exploration • Hierarchic filtering for search and browse • Detail information as tooltip in explanatory visualization • Support exploration of multiple interest • View switching for interest-specific visualization techniques • Query-based content browsing • Pivot action for navigating between related items • Context preserving • Overview + detailed view • Support local interactions (hierarchically structured data) • A view of selection history of browsing
Visual text analytics -- summary To conclude • Text visualization construct the semantic mapping between the text and visual variables • Visualize metadata together with textual information for comparison and exploration • Interaction design should follow human's intuition of data exploration • Data characteristics • Inherited connection between data and metadata
Visual text analytics -- Connection between NLP and HCI • NLP help visual analytic in extracting the target information and organize them in a desired way • Visual analytic provide exploratory tool for text analysis and opinion mining • Poses challenges to NLP in terms of both new corpora and interesting problems
Conclusion In terms of my own research interest • Review analysis • How to model the real helpfulness of peer-reviews • Paraphrasing and summarization • How to identify common themes and aggregate comments from different reviewers • Visual text analytic • How to create informative representation of reviews • And design intuitive interactive-exploration for students or teachers to mind useful information Challenges and contributions • Theory-based high level information of usefulness • Summary-style paraphrasing • Visualize connection between opinions with detailed semantic information in context