A Visual Programming Tool for Designing Planning Problems for Semantic Web Service Composition

This chapter is concerned with the issue of knowledge representation for AI Planning problems, especially those related to Semantic Web Service composition. It discusses current approaches in encoding planning problems using the PDDL formal language and it presents ViTAPlan, a user-friendly visual tool for planning. The tool is built on top of HAPRC, a rule-configurable planning system, which automatically adapts to each problem, in order to achieve best performance. Apart from HAPRC, ViTAPlan can be interfaced with any other planning system that supports the PDDL language. More than just being a user friendly environment for executing the underlying planner, the tool serves as a unified planning environment for encoding a new problem, solving it, visualizing the solution and monitoring its execution on a simulation of the problem’s world. The tool consists of various sub-systems, each one accompanied by a graphical interface, which collaborate with each other and assist the user, either a knowledge engineer, a domain expert, an academic or even an end-user in industry, to carry out complex planning tasks, such as composing complex Semantic Web Services from simple ones, in order to achieve complex tasks. The key feature of ViTAPlan is a visual programming module that enables the user to encode new planning problems just by using visual elements and simple mouse operations. The visual tool performs a validity check on the visual program created by the user 1 and then compiles it to PDDL files that are ready to be used by any planning system. Finally, the planning system will solve the planning problem and then export the plan in an appropriate Web Service composition language to a Web Service execution monitoring system or just publish it in a UDDI registry.