Marc-Antoine DupréAlexander PatronasErhard DinhoblKsenija IvekovicMartin Trenkwalder

Web Opinion Mining

RoadmapWhat is opinion mining and why?Objects, model and taskWords and phrasesSentiment classificationFeature-based opinion miningOpinion SpamTools on opinion mining

Questions:

What do users think about a specific product?

Which of our customers are unsatisfied? Why?

Which product is more popular among users?

Answer: Web Opinion Mining

Web Opinion MiningFacebook, blogs, … > opinionWikipedia > fact Opinions: underlying question

“ what do people in America think about Barack Obama?”

Mostly in deep webAI algorithm necessaryUseful: market intelligence (better ads)

Objects, ModelOpinion holder / object / opinionFeatures of object

F = {f1, f2, f3, …} fi ϵ F fi defined by words or phrases

W = {w1, w2, w3, …} Wi ϵ WO is some object (event, person,

product, …)

“Now the opinion holder is j and comments on a subset of features Sj of F of O. Now feature fk ϵ Sj is commented by j by a word or phrase from Wk to determine the feature and a positive, negative or neutral opinion on fk”

Task One document – one opinion from one

holder Opinion: positive, negative, neutral 3 levels:

Document - class determining Sentence (one opinion)

sentence type (objective or subjective) sentence class (neutral, positive, negative)

Feature – determining words and phrases

Words and PhrasesWords often context dependent („long“ –

long loading time – long battery runtime)

3 approaches to get wordlist:Manual approach Corpus-based approach Dictionary-based approach

Sentiment ClassificationClassify documents (e.g. reviews) based on

overall sentiments expressed by opinion holdersPositive, negative or neutral

Useful, but doesn’t find what reviewer liked or disliked!A negative sentiment on an object doesn’t

mean that opinion holder dislikes everything about object and opposite

Need to go to sentence level and the feature level

Feature-based Opinion Mining Objective: find what reviewers like and

dislikeFeatures and components

Three tasks:Extract object features that have been

commented on in each reviewDetermine whether opinions on the feature

are positive, negative or neutralGroup synonyms and produce summary

Different Review Formats

GREAT Camera., Jun 3, 2004 Reviewer: jprice174 from Atlanta, Ga.

I did a lot of research last year before I bought this camera... It kinda hurt to leave behind my beloved nikon 35mm SLR, but I was going to Italy, and I needed something smaller, and digital.

The pictures coming out of this camera are amazing. The 'auto' feature takes great pictures most of the time. And with digital, you're not wasting film if the picture doesn't come out. …

….

Extracting Object Features1. Part-of-speech tagging:

Features are noun and noun phrases

2. Frequent features generation Association mining to generate candidate

features Feature pruning

3. Infrequent feature generation Opinion words extraction Finding infrequent features using opinion words

Identifying Orientation of Opinion Sentence

Used dominant orientation of opinion words as sentence orientationIf positive opinion prevails, the opinion

sentence is regarded as a positive and vice versa

Feature-based Summary

GREAT Camera., Jun 3, 2004 Reviewer: jprice174 from Atlanta, Ga.

I did a lot of research last year before I bought this camera... It kinda hurt to leave behind my beloved nikon 35mm SLR, but I was going to Italy, and I needed something smaller, and digital.

The pictures coming out of this camera are amazing. The 'auto' feature takes great pictures most of the time. And with digital, you're not wasting film if the picture doesn't come out. …

….

Feature Based Summary:

Feature1: picturePositive: 12 The pictures coming out of this

camera are amazing. Overall this is a good camera with

a really good picture clarity.…Negative: 2 The pictures come out hazy if your

hands shake even for a moment during the entire process of taking a picture.

Focusing on a display rack about 20 feet away in a brightly lit room during day time, pictures produced by this camera were blurry and in a shade of orange.

Feature2: battery life…

Opinion Spam

Reviews contain rich user opinions on products and services, that possibly influence the purchase decisions of users

Generally three types of spam reviews:Untruthful opinionsReviews on brands onlyNon-Reviews

Tools for Sentiment Analysis [1/2]APIs

Evri – semantic search engine, very powerful API

OpenDover – Java based webservice

Blogosphere/TwittersphereRankSpeed – search by criteriasTwittratr – simple search tool (keyword

based)TwitterSentiment – project from Stanford

University, classifiers from machine learning algorithms, transparent

Tools for Sentiment Analysis [2/2]Newspaper

Newssift – sentiment search tool on newspapers (by Financial Times)

ApplicationsLingPipe – Java toolRadian6 – commercial social media

monitoring applicationRapidMiner – open-source machine learning

and data mining tool (Community Edition)

LIVE DEMO (evri)

Thank you for your attention!