OCL Plus:Processes and Events in Object-Centred Planning

An important area in AI Planning is the expressiveness of planning domain
specification languages such as PDDL, and their aptitude for modelling real
applications. This paper presents OCLplus, an extension of a hierarchical object
centred planning domain definition language, intended to support the representation
of domains with continuous change. The main extension in OCLplus provides
the capability of interconnection between the planners and the changes that are
caused by other objects of the world. To this extent, the concept of event and process
are introduced in the Hierarchical Task Network (HTN), object centred planning
framework in which a process is responsible for either continuous or discrete
changes, and an event is triggered if its precondition is met. We evaluate the use of
OCLplus and compare it with a similar language, PDDL+.