current trends and future directions Summary: Research on modality and negation focuses on [...]]]> Speaker: Roser Morante Senior researcher on the BIOGRAPH project led by Walter Daelemans.  CLiPS-Computational Linguistics research group University of Antwerp, Date: February 23, 2010 Time: 16:00 Where: Computer Science Faculty, Meeting room (batzar aretoa) .

Modality and negation in natural language processing: 

current trends and future directions

Summary:
Research on modality and negation focuses on finding subjective,
uncertain and counterfactual information in texts, be it in scientific
papers, product reviews, or opinions in blogs. This type of +research is
concerned with processing texts at the information level and aims at
deep text understanding.  Modality and negation are phenomena relevant
for all applications that are concerned with +some form of text
understanding, including text mining, sentiment analysis, recognizing
textual entailment, information extraction, text summarization, and
question answering. Hence, the adequate +modeling of these phenomena is
of crucial importance to the natural language processing (NLP) community
as a whole.

Whereas from a theoretical perspective, the study of modality has a long
tradition, only in the recent years have these topics attracted the
attention of NLP researchers. Mainly, the development of +sentiment
analysis techniques and the growing need of mining biomedical texts have
been the causes for the interest in these semantic aspects of language.
In this talk I will define modality and +negation from an NLP
perspective, I will motivate the need for processing these phenomena,
and I will summarize existing research on processing modality and
negation, touching on diverse aspects +ranging from task modelling to
feature visualization. Finally, I will speculate about future
developments in this research area.

ABSTRACT These two sessions cover some of the most important aspects of Computational Semantics and Pragmatics including: * Lexical Representations and Argument Structure * Parsing with constituency or dependency structure * Co-reference resolution [...]]]> Speaker: Rodolfo Delmonte, (Università Ca’ Foscari, Venice, Italy).
Date: January 17 and 18, 2011
Time: 16:00 – 19:30
Where: Computer Science Faculty

ABSTRACT
These two sessions cover some of the most important aspects of Computational Semantics and Pragmatics including:
* Lexical Representations and Argument Structure
* Parsing with constituency or dependency structure
* Co-reference resolution
* Underspecified arguments
* Argumentative structure, subjectivity, factuality and sentiment analysis
* Textual Entailment
The talks follow a linguistically motivated approach with the use of ontologies and similar resources to deal with co-reference or textual entailment tasks. The talks are accompanied by several applications and demonstrations.

SHORT BIO
Rodolfo Delmonte is Associate Professor of Computational Linguistics at the University of Venice where he is in charge of the corresponding course at BA, MA and Ph.D. level. Specialist in experimental phonetics and computational linguistics he presents his research work at major international conferences and publishes articles in international journals. He is referee for and publishes in Speech Communication, International Journal of Speech Technologies, Journal of Natural Language Engineering and international conferences every year. He has been invited speaker in a number of conferences, teacher at international schools, and invited professor in the last five years in Boulder, Colorado at the CLSR, in Besançon at the Centre Tesnière, in Dallas at UTD. Hot topics of his latest research include the following: Implicit entities and antecedents of omitted and underspecified arguments; Argumentative Analysis, Subjectivity, Factuality and Sentiment Analysis.

project.cgm.unive.it/delmonte.html

Linda Wiechetek, a researcher from the University of Tromsø (Norway) is visiting the Ixa Group in Donostia in the period April to July in 2010. Her visit is founded by the NILS mobility project.

Why Sami and Basque? Why do we [...]]]> Researchers working on Basque and Sami (Laponian) are collaborating on Automatic Language Processing.

Linda Wiechetek, a researcher from the University of Tromsø (Norway) is visiting the Ixa Group in Donostia in the period April to July in 2010. Her visit is founded by the NILS mobility project.

Why Sami and Basque? Why do we work with this unusual language pair?

Some of the reasons for that are:
1) Both are small languages,
2) With limited resources to face the use of language technology. (Sami is even lesser resourced than Basque now adays).
3) Sami and Basque morphologies are very rich and demand adequate tools such as our morphological transducers and syntactic disambiguation and analysis modules. Many of the better resourced languages with highly developed language Technology such as English, Spanish and French do not need such complex modules to create their basic tools.
4) There are clear syntactic parallels betwen Basque and Sami including the grammatical cases/postpositions causing morpho-syntactic ambiguity.

In this context we are collaborating on the following ways:
a) Use of semantic prototype features in Constraint Grammar for syntactic disambiguation.
b) Use of semantic features in Constraint Grammar for lexical/syntactic transfer in Machine Translation.
c) Use of information on verb-subcategorization for syntactic disambiguation.
d) Use of verb-subcategorization information in for lexical and syntactic transfer in Machine Translation.

The parser for Basque is not very accurate yet, not as accurate as English parsers. The Sami parser on the other hand gets good results in accuracy, but the use of valency is necessary for other tasks such as MT and QA.
With this collaboration between Basque and Sami researchers we aim to improve our NLP tools.

Besides of that, now Linda is able to speak some Basque, and we are learning some words in Sami.
That’s another way of collaboration

giellatekno.uit.no/background/giellatekno3.pdf

NLP systems for use in medical applications bring new problems not considered by classical methods. Broadly speaking medical texts have three genres: published papers, clinical reports, clinical notes.

Information Extraction (IE) and Questions Answering (AQ) are [...]]]> Speaker: Jon Patrick (University of Sydney)
Date: February 12, 2010
Time: 16:00
Where: Computer Science Faculty, room 3.17 .

NLP systems for use in medical applications bring new problems not considered by classical methods. Broadly speaking medical texts have three genres: published papers, clinical reports, clinical notes.

Information Extraction (IE) and Questions Answering (AQ) are the most common needs for NLP by clinical staf. Published papers are amenable to classical methods apart from needing coverage for many specialised terms. Clinical reports bring new problems due to the use of a specialised clinical terms, highly stylised content for scores, weights and measures and to a lesser degree a specialised grammatical structure. Clinical notes have these problems but many more, such as acronyms, neologisms, personal abbreviations, a high level of spelling errors due to mistyping and second language speakers, poor grammatical structure, multiple authors of the one document.

It is important to overcome these limitations in the text as they represent a large proportion of the content, up to 30%, and to reach the ultimate processing objective of achieving very high accuracy, say 95+% for information extraction, given that people’s lives depend on decisions made at the bedside using our tools.

We have designed a software architecture to tackle these problems whereby incrementally new knowledge discovered about the text is immediately fed back into the knowledge resources of the language processing system, so that it is continually improved at each phase of the processing.

www.hcsnet.edu.au/user/201