Project planning using a hierarchic non-linear planner

We describe work on a project aimed at producing an interactive program for the construction of project networks (e.g. for house building tasks). To do this we have developed a planner which can form plans epresented as a partiQlly ordered netwo k of actions. A formalism (TF) is given for describing a domain in a hierarchic fashion. The representation of plans and the planner (NONLIN) are fully explained. During this work, a general technique was developed for answering queries about Q situation when the informQtion about the world is stored as a partiQlly ordered network of alterations made to some initial situation. We give a general procedure for recognizing and correcting for interactions between actions in the network. This is based on an analysis of the goal structure of the problem. The work is compared to that of Sacerdoti (l975a) who pioneered the techniques of planning using plans represented as partially ordered networks of actions.