KRSL Plans Working Group - Plans and Activities

DRAFT: 20-Sep-96

The Plan Ontology Construction Group of ARPI is seeking to define a generic ontology of plans and activitiess. An earlier draft was arrived at following discussions in late 1994 and early 1995. The result of this work was the Draft KRSL-Plans ontology dated 2-Feb-95.

New work, involving a larger group, is now taking place to redefine this ontology and to seek a larger group consensus on its contents. The following definitions are the current draft of this ontology.

Level 1: Overall Framework

  1. A PLAN is a SPECIFICATION of ACTIVITY to meet one or more OBJECTIVES.
  2. A SPECIFICATION of ACTIVITY denotes or describes one or more ACTIVITIES.
  3. An ACTIVITY may change the STATES-OF-AFFAIRS.
  4. STATES-OF-AFFAIRS is something that can be evaluated as holding or not.
  5. An AGENT can perform ACTIVITIES and/or hold OBJECTIVES.
  6. An OBJECTIVE may have [one or more] EVALUATION-CRITERIA.

Level 1 Issues Remaining

Level 2: The Definition of Activity in the Context of Plans

  1. An EVALUATION-CRITERIA is an ASPECT of [one or more] STATES-OF-AFFAIRS or an ASPECT of [one or more] PLANS.
  2. An EVALUATION is a predicate (holds/does not hold) or a preference ranking on [one or more] EVALUATION-CRITERIA.
  3. An ACTIVITY takes place over a TIME INTERVAL identified by its two ends, the BEGIN TIME POINT and the END TIME POINT. The BEGIN TIME POINT is temporally before the END TIME POINT.
  4. An ACTIVITY-SPECIFICATION may have CONSTRAINTS associated with it [and its TIME-INTERVAL].
  5. An ACTIVITY-SPECIFICATION may be decomposed into one or more ACTIVITY-DECOMPOSITIONS.
  6. ACTIVITY-DECOMPOSITION: The specification of how an ACTIVITY is decomposed into one or more SUB-ACTIVITIES; this may include the specification of constraints on and between the SUB-ACTIVITIES [and their TIME-INTERVALs].
  7. SUB-ACTIVITY: Sub-activities are the constituent activities designated in any ACTIVITY-DECOMPOSITION.
  9. CONSTRAINTS can be stated with respect to none, one or more than one time point. They express things which are required to hold. They are evaluable with respect to a specific PLAN as holding or not holding.
    Such constraints may refer to world statements (conditions and effects), resource requirements and usage, authority requirements or provision, etc.

Level 2 Issues Remaining

Level 3: Aids to Specifying Activities

At this level, aids to enable the specification of activities and the constraints on activities are to be provided. These are likely to include: