1 Introduction and Rationale

This document proposes a representation for objectives This representation is based on discussions with CHECKMATE, and was developed for use in IFD-4. More specifically, its development is part of the ISI work in developing INSPECT (INtelligent System for air campaign Plans evaluation based on ExpeCT). INSPECT is a knowledge-based system developed using ISI's EXPECT framework. The system checks the consistency of air campaign plans with respect to several criteria. INSPECT provides consistency checking for operational plans developed (or modified) using ACPT. For a detailed description of INSPECT, see [Valente et al., 1996].

The representation proposed in this document has as its main focus providing a richer and more structured representation for air campaign plan objectives than the one that is present in ACPT at the moment, specifically as needed by INSPECT and the other IFD-4 systems. However, since it has been submitted to a detailed validation process with the experts in CHECKMATE, it may be used by other groups within the initiative. It must be noted, however, that the work presented here is still in progress, and this document should not be seen as final or officially approved.

In addition to a representation for objectives, this document proposes a library of objectives. More precisely, the elements of this library are templates for the specification of the central part of the objectives, namely their action (or activity) descriptions. The templates make use of the structure defined in the proposed representation for objectives. They can provide a basis for a structured objectives editor in ACPT, that enforces to some extent the correctness of the specification of objectives. They also provide a set of coherent (and hopefully sufficient) elements to construct objectives, and thus it is complementary to current work in the initiative about plan ontologies and air campaign planning ontologies. Specifically, the work presented in this document can be used as an input to an ontology of the air campaign planning domain.

Both grammar and library have been built using a ``bottom-up'' process. We departed from a set of prototypical examples of objectives proposed by CHECKMATE. We abstracted an initial set of elements and some common patterns in that set, and then refined these by interviewing CHECKMATE experts. The coverage of the library is mostly limited to force application objectives -- a consequence of the set of examples we departed from. However, this coverage can be extended if necessary in the future.

The representation of objectives and the library of objetive templates propose here is an intermediary solution between providing the ACPT user with a set of predefined examples of objectives and leaving the user free to write whatever seems to work. CHECKMATE has expressed preference for the approach adopted here.

Acknowledgements

Knowledge acquisition was a critical task in building this grammar, and demanded much effort from the experts. Many thanks to all Checkmate members who interacted with us, and most especially to Colonel Plebanek, who allowed us to have this interaction, Major Cardenas, for coordinating the knowledge acquisition sessions, and to the Checkmate members we used as experts and worked with closely: Major Allison (``Coach''), Major Cardenas, Major Cunico, and Major Jackson (``J.J.''). Special thanks to Major Alred (``Yogi''), who was the major expert in the construction of this representation. Their support to our work and their patience in answering our questions has been vital to this effort. We hope they like the results.