About Me

I have graduated and will be joining the Allen Institute for Artificial Intelligence as a Research Scientist.

I was a Computer Science graduate student at Northwestern University. My advisor is Doug Downey. My research interests are Information Extraction, Machine Learning, NLP and Artificial Intelligence.

Check out our group homepage - WebSAIL.

Recently, I've worked on extracting key phrases from a large corpus of scholarly articles as part of the Semantic Scholar project at the Allen Institute for Artificial Intelligence. I've also worked on the Entity Linking problem, especially for entities in tables. Our group participated in the ERD'2014 competition in both the Short and Long text tracks.

I received my Bachelor's degree from NIT Allahabad, India in 2008. I worked at Yahoo! (Bangalore) for two years before joining Northwestern University in Fall 2010.

Doctoral Thesis (Proposed)

Learning Semantics of WikiTables


Key Phrase Extraction

The aim of this project is to extract key phrases for each paper in a large corpus of research articles. This work is now part of an online system "Semantic Scholar" at AI2. Check out an example here.

WebSAIL Wikifier

This project aims to link phrases in text to their referent entities in a Knowledge Base (Wikipedia). The problem is commonly known as Entity Linking which is a key task in populating facts in a knowledge base and enable a wide variety of applications. This is an on-going project -- we are exploring ways to improve the current state-of-the-art systems including using better features, models, data, and machine learning approaches.

TabEL is a system that applies entity linking methods to HTML tables found on the Web. See TabEL project page for more details.


This project extracted Wikipedia tables and used machine learning methods to enable table "search" and "join". WikiTables allows user to find and view columns from different tables side by side, and helps them discover interesting relationships by providing them unique views of table data. Check out the demo here.


Google Scholar

TabEL: Entity Linking in WebTables
Chandra Sekhar Bhagavatula, Thanapon Noraset and Doug Downey
[PDF ][BibTeX][Project Page]

Efficient Methods for Inferring Large Sprase Topic Hierarchies
Doug Downey, Chandra Sekhar Bhagavatula and Yi Yang
Association of Computer Linguistics (ACL) 2015
[PDF ][BibTeX][Project Page]

TextJoiner: On-demand Information Extraction with Multi-Pattern Queries
Chandra Sekhar Bhagavatula, Thanapon Noraset and Doug Downey
2014 workshop on Automated knowledge base construction, NIPS 2014
[PDF ][BibTeX][Project Page]

Adding High-Precision Links to Wikipedia
Thanapon Noraset, Chandra Sekhar Bhagavatula and Doug Downey
Empirical Methods in Natural Language Processing (EMNLP) 2014

WebSAIL Wikifier at ERD 2014
Thanapon Noraset, Chandra Sekhar Bhagavatula and Doug Downey
First international workshop on Entity recognition & disambiguation, SIGIR 2014

WebSAIL Wikifier: English Entity Linking at TAC 2013
Thanapon Noraset, Chandra Sekhar Bhagavatula, Yi Yang and Doug Downey
Text Analysis Conference (TAC)

Using Natural Language to Integrate, Evaluate, and Optimize Extracted Knowledge Bases
Doug Downey, Chandra Sekhar Bhagavatula and Alexander Yates
2013 workshop on Automated knowledge base construction, CIKM 2013

Methods for Exploring and Mining Tables on Wikipedia
Chandra Sekhar Bhagavatula, Thanapon Noraset, and Doug Downey
In Proceedings of the ACM SIGKDD Interactive Data Exploration and Analytics (IDEA). ACM, 2013
[PDF] [BibTeX] [Project Page]

Professional Experience

Professional Activity


Contact Info


Room No. 3-211
2133 Sheridan Road
Evanston, IL - 60201


"csb"+ "@u.northwestern.edu"