[1] While on sabbatical from Vassar College from 1999 to 2000, he collaborated with Nicola Guarino on OntoClean;[2] he was co-chair of the W3C Rule Interchange Format working group from 2005 to 2009.

[3] Welty is a graduate of Rensselaer Polytechnic Institute, (RPI) where he worked for the Free Software Foundation on version 16-18 of GNU Emacs as well as the formation of NYSERNet during the emergence of the Internet.

[8] During 1999-2000, while on sabbatical from Vassar College in Padova, Italy, he formed a productive collaboration with Nicola Guarino to develop OntoClean,[2] a notable and widely recognized contribution in Artificial Intelligence, specifically Ontologies.

[9] OntoClean was important as it was the first formal methodology for ontology engineering, applying scientific principles to a field whose practice was mostly art.

Welty was one of the developers of Watson, the IBM computer that defeated the best players on the American game show Jeopardy!.