This document discusses sentiment analysis, which is the automated extraction of subjective content from text to determine sentiment such as positive or negative opinions. Sentiment analysis can analyze reviews, social media, blogs and forums to understand what people think about brands and products. It involves identifying subjective text, determining the sentiment expressed, and extracting opinion components such as aspects of products that are being discussed. There are challenges to sentiment analysis including dealing with different languages, domains, spam, and reliably identifying named entities.

1. What they think about my
brand/product ?!?!?
An Introduction to Sentiment Analysis
Jaganadh G
Project Lead NLP R&D
365Media Pvt. Ltd.
jaganadhg@gmail.com
National Seminar
on
Semantic Information Retrieval
National Institute of Technology
Tiruchirapally
30th Jan 2012
Jaganadh G What they think about my brand/product ?!?!?

2. About me !!
Software Engineer Specializing in Text Analytics Research
& Development
When free, teaches Python, Speaks about FOSS and
blogs at
http://jaganadhg.in
Working as Project Lead (NLP) 365Media Pvt. Ltd.
Coimbatore
I am a computational linguist / Linguist and Indologist,
Book reviewer
Maters Degree Holder in Sanskrit from University of
Kerala
Jaganadh G What they think about my brand/product ?!?!?

3. Introduction
Web Today
Jaganadh G What they think about my brand/product ?!?!?

4. Introduction
Sentiment
Picture Courtesy: http://webanalysis.blogspot.com/2011/09/sentiment-indicator-social-media-kpi.html
Jaganadh G What they think about my brand/product ?!?!?

5. Introduction
What other people think!!!
Jaganadh G What they think about my brand/product ?!?!?

6. Introduction
Friends and Family
Picture Courtesy: http://ianvaleza.com/mlm-secrets-warm-market-approach-strategies/
Jaganadh G What they think about my brand/product ?!?!?

7. Introduction
Survey
Picture Courtesy: http://www.oksociety.in/the-guest-for-legitmate-sites-for-paid-surveys/
Jaganadh G What they think about my brand/product ?!?!?

8. Introduction
Blogs, Forums, Social Network ....
Picture Courtesy: http://imfoundation.blogspot.com/p/im-forumsblogs.html
Picture Courtesy:http://www.my-social-network.org/
Jaganadh G What they think about my brand/product ?!?!?

9. Introduction
Issues with blogs and forums
Picture Courtesy: http://www.asunseenontv.com/4-fake-reviews/
Jaganadh G What they think about my brand/product ?!?!?

10. Introduction
Now : Sentiment Analysis
Jaganadh G What they think about my brand/product ?!?!?

11. What is Sentiment Analysis
Sentiment Analysis
Automated extraction of subjective content from digital text
and predicting the subjectivity such as positive or negative.
Jaganadh G What they think about my brand/product ?!?!?

12. Subjectivity
Subjectivity
Linguistic expression of somebody’s emotions, opinions,
sentiment .......
Picture Courtesy: http://www.asunseenontv.com/4-fake-reviews/
Jaganadh G What they think about my brand/product ?!?!?

13. Subjective Text Sources
Social Media
Picture Courtesy: http://www.alchemyuk.com/online marketing/social media marketing.php
Jaganadh G What they think about my brand/product ?!?!?

14. Example Review
Nokia Lumia 800
Review Courtesy:
http://www.techradar.com/reviews/phones/mobile-phones/nokia-lumia-800-1039101/user-review
Jaganadh G What they think about my brand/product ?!?!?

15. The Big Picture
Sentiment Analysis
Jaganadh G What they think about my brand/product ?!?!?

16. Basics of Sentiment Analysis
Components of Opinion
Jaganadh G What they think about my brand/product ?!?!?

17. Basics of Sentiment Analysis
Opinion Definition
Jaganadh G What they think about my brand/product ?!?!?

18. Components of Sentiment Analysis
Components
Jaganadh G What they think about my brand/product ?!?!?

19. Approaches
Approaches
Lexicon based
Supervised Learning
Unsupervised Learning
Keyword
Jaganadh G What they think about my brand/product ?!?!?

20. Issues and Challenges
Challenges
Picture Courtesy: http://inventionmachine.com/the-Sustainable-Innovation-Blog/bid/51703/Three-Key-
Challenges-to-Entering-New-Markets
Jaganadh G What they think about my brand/product ?!?!?

21. Issues and Challenges
Challenges
Language
Domain
Spam
Named Entity Identification
Reliable content
Jaganadh G What they think about my brand/product ?!?!?

22. Questions ??
Jaganadh G What they think about my brand/product ?!?!?

23. References
B. Pang, Lillian Lee Opinion Mining and Sentiment
Analysis, Now Publishers Inc, July 2008.
B. Pang, Lillian Lee, S Vaithyanathan Thumbs up?
sentiment classification using machine learning techniques,
2002.
Jaganadh G What they think about my brand/product ?!?!?

24. Finally
Jaganadh G What they think about my brand/product ?!?!?