Threads STRIPS style plans into parallel and interleaves plan "threads", as described in my PhD thesis, "A New Heuristic-Based model of Goal Recognition Without Libraries", 2015.
Makes use of JavaFF planning framework, which must be on classpath. See https://github.com/dpattiso/javaff
The following paper outlines the idea of planthreader, but is frankly isn't very representative of the final algorithm. Instead, cite the final PhD thesis.
@incollection{strathprints49736,
booktitle = {Proceedings of the 28th Workshop of the UK Special Interest Group on Planning and Scheduling},
editor = {Simone Fratini and Alfonso Gerevini and Derek Long and Alessandro Saetti},
month = {December},
title = {Extracting plans from plans},
author = {D. Pattison and D. Long},
year = {2010},
pages = {149 -- 156},
url = {https://strathprints.strath.ac.uk/49736/},
@phdthesis{phdthesis,
author = {David Pattison},
title = {A New Heuristic Based Model of Goal Recognition Without Libraries},
school = {University of Strathclyde},
year = 2015
}