Description of Research Projects

Main Research Projects I have been involved (brief description)

The XSB System

XSB is a research-oriented Logic Programming system incorporating Deductive Database and Non-Monotonic Reasoning capabilities. In addition to providing all the functionality of Prolog, XSB contains several features not usually found in Logic Programming systems, including:

A complete implementation of SLG resolution (a resolution strategy based on tabling) evaluating normal logic programs according to the well-founded semantics
A compiled HiLog implementation
A novel transformation technique called unification factoring that can improve program speed and clause indexing
Source code availability for portability and extensibility

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Syntactica

Syntactica is an innovative teaching tool designed to let its user explore natural language structure in an engaging, interactive way. More specifically, it allows its user to create grammars, view the structures that they assign to natural language expressions, and tranform those structures by movement, deletion, copying, etc.

Syntactica permits many aspects of syntactic theory to be explored. The rule and lexicon windows allow its user to assign and control the percolation of syntactic features. The TreeViewer window is used to perform a variety of formal operations on trees by simply pointing, clicking and using the Transforms panel. Syntactica also allows its user to control various constraints on operations, including an elementary version of Subjacency.

Together with Richard K. Larson, David S. Warren and Juliana Freire de Lima e Silva, the main designers and developers of Syntactica, we co-authored Syntactica's manual and published it under MIT Press (the not so ugly jacket of which is depicted on the left; the original design was much worse :-). The manual and accompanying software (for computers running NeXTStep), is available since January 1996 in bookstores.

A Windows 95 port of Syntactica is already available as a beta-version (see below) and an official Windows 95 version (with a manual again from MIT Press) is expected to appear in bookstores by the end of 1997.

For more information on the Syntactica manual, see the corresponding information on the MIT Press WWW server.

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Syntactica demo! [NeXTStep only]

Syntactica Win95 Beta-Test Program!

Semantica

Semantica (a follow on tool of Syntactica) is an innovative teaching tool designed to let its user explore natural language semantics in an engaging, interactive way. More specifically, it allows its user to create semantic theories (consisting of lexical and phrasal semantic rules), derive truth-conditions from that theory for natural language phrase markers, and test those truth-conditions against a pictorially represented universe of worlds and times.

Semantica permits many aspects of semantic theory to be explored. These include a wide variety of construction types such as predicates, proper nouns, demonstratives, quantifiers, tenses, and modal adverbs. Semantic theories can be built up step by step by students, with full control of their interpretive possibilities.

As with Syntactica, the same team of authors and O. Patricia Gomez wrote a book on Semantica (whose jacket is depicted on the left) that is about to be published by MIT Press. The application currently is available for machines running NeXTSTEP. A windows version of Semantica is also expected in the near future.

For more information on the Semactica manual, see the corresponding information on the MIT Press WWW server.

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Last modified: Wed Mar 17 22:07:07 MET 1999