Combining HTN-DL Planning and CBR to compound Semantic Web Services

Semantic Web Services (SWS) are distributed and reusable software components that are described using standard formal languages like SWDL or OWL-S. SWS can be automatically discovered, invoked and combined. Complex applications can be built combining different Web Services and therefore, it is important to provide assisting tools to help in the composition process [6]. Planning techniques can be used to find the flow of services that accomplish a specific task. Several approaches have been tried in software component composition [4], but all of them have a common requirement: the domain must be completely formalized, and this is very difficult in real domains. Case Based Planning (CB Planning) [2] tries to solve this deficiency using cases that represent past experiences, i.e., plans that were used to solve previous problems. On the other hand, HTN-DL planning [5] is a very new approach that combines the power of hierarchical planning with the inference capabilities of Description Logics. In my thesis I propose to combine CB Planning and HTN-DL to obtain a hierarchical planner that utilizes the best of both worlds.