YAPPR: Yet Another Probabilistic Plan Recognizer

Yappr (yet another probabilistic plan recognizer) is a plan recognition system, written in Lisp.

YAPPR was designed by SIFTers and Dr. Christopher W. Geib of the University of Edinbugh. This team has deployed Yappr as part of both the Poirot system from the Integrated Learning program, and the SDPR network security system for the SRS program. Yappr represents a breakthrough in the complexity of probabilistic plan recognizers, allowing this technology to be applied to much broader applications. Technical details about Yappr are available in a paper presented at ICAPS 2008.

Yappr is freely available for non-commercial use. Please contact us for a license and to acquire the code.