DATE: Thu, April 21, 2016
TIME: 1:30 pm
PLACE: SITE 5084
TITLE: Semantic Annotation on the Linked Data Cloud - Experiments and Evaluation
PRESENTER: Michel Gagnon
Ecole Polytechnique de Montreal
ABSTRACT:

Semantic annotation, the process of identifying key-phrases in texts and linking them to some concepts from a knowledge base, is an important basis for developing semantic information retrieval technologies. Despite the recent emergence of semantic annotation systems, very few comparative studies have been published on their performance.
In this talk, I will present two works that result from a collaboration between Prof. Amal Zouaq, from University of Ottawa, and the WeST lab, at Polytechnique Montrl. I will first present a semantic annotator that is based on the principle of collective disambiguation. I will then present an evaluation of the performance of existing systems over three tasks: full semantic annotation, named entity recognition, and keyword detection. The evaluation is achieved in two steps: we first compute precision and recall on several corpora, and we then build a statistical model, using logistic regression, to a) identify significant performance differences and b) provide some estimate of the expected performance of semantic annotators on similar but unknown corpora.

BIO: Michel Gagnon is a professor at the Computer Engineering Department of Polytechnique Montreal since 2002. Previously, he worked as a team leader at Machina Sapiens inc., a company which at that time was a leader in the development of grammar checkers, and as a professor at the Univerdade Federal do Parana, in Brazil. He received his Ph.D. degree in computer science in 1993 from the Universitde Montreal. Since then, he has been working on natural language processing, with a special attention to semantics. Since 2002, his research activities also include the semantic web, e-learning and security, with a particular interest in the knowledge extraction from texts.