GIPO [Graphical Interface for Planning with Objects]

1. GIPO [Graphical Interface for Planning with Objects] Demonstration case-tool for Knowledge Engineering to support Domain Independent Planning Ron Simpson - Lead Designer

2. Scope • Language Levels Supported • Classical Planning • Hierarchical [Classical] Planning • Planning with Durative Actions • Tool Elements • Domain Definition Editors • Task Definition Editors • Static Analysis • Dynamic Testing • Manual Task Stepping • Task Solution Generation • Integrated Planners • Third Party Planners • Export to PDDL

3. Planning With Objects • Plan execution involves changing the state of a subset of objects within the sphere of interest from an initial state to a desired goal state. • Domain Definition can be done by describing the possible changes in state that can be brought about to the different types of objects within the sphere of interest. • The object metaphor guides the domain designer in structuring the domain definition.

4. Domain Definition • Multiple methods • Follow Object Centric Method. • Define - Object Types - Predicates - Object States - Operators • Operator Induction • Define - Object Types - Predicates - Object States • Deduce Operators from known plan traces. • Supports Classical Mode and base operators within Hierarchical Mode. • Draw “Object Life Histories” • Draw stylised state transition diagrams defining the possible state transitions for each type of object and define the connections between the transition diagrams. • Use re-usable fragments of domains stored in library • Supports Classical and Durative action modes and base operators within Hierarchical mode.

5. Analysis • Static Analysis • Syntax Checked • Only legal domain specification will be produced when checks passed. • Semantics • State usage analysis reveals states that form dead-ends and states that cannot be generated. • Transparency analysis in hierarchical models guarantees that methods do achieve their post-conditions when their pre-conditions are met. • Dynamic Testing • Animators to help inspect plans produced by integrated planning engines. • Manual steppers to allow developer to check that domain definition does support known plans.

6. Object Centric View • Plans are strategies to bring about changes in the states of objects within the domain problem. • Objects have state and properties. • Actions bring changes of state and/or property values. • Properties are present in all states Tent Transition Descriptors State Descriptors

7. Hiking Domain – Example Transition Property Value Changing Satisfies next(x,y) nextStage(w,v) Constraint – Number Satisfies couple(x,y) Transition State Changing Tent Property : Location Value present in all identified states. Tent Person Car Person Properties: Location Stage Transition of Tent: Property Value Changing Location to Location

8. Transition Co-ordination Transitions Requires Object at State Break Association Forget Car Add Association Record car Transition Dependent on Source Both satisfy next(x,y) Transitions mutually dependent Both satisfy next(x,y)

9. Libraries of Generic Types • Object Life Histories share common structure that are re-usable. • Define Public interface i.e states and transitions that support merges. • Complexity of structures such as block stacks can be hidden in packages. • Users can save fragments of their own domains to the library

10. Richer Representations • Durative Actions • PDDL Level 5 equivalent • Processes. • Events. • Numeric Properties. • Supports • Domain Design using Life Histories. • Manual Plan stepping • No integrated planner at present time.

11. Testing • Static Analysis may Indicate problems otherwise Manual Stepping may reveal source of problem.

12. Benefits More intelligible. Faster More reliable Capable of being done by a wider user audience Programming Credits G. Elliot D. Liu R. Simpson W. Zhao