How to diagnose a KB

In this section, you will learn the basics of diagnosing an ontology using Chimaera.

Select "Deselect all" from the "View" menu.

There should now be no frames highlighted on the display. You are ready to run diagnosis commands.

Select "Analyze-all-KB" in the "Analysis" menu.

Chimaera runs all diagnosis commands that are available to it and displays the results in a separate window. You can view a copy of the diagnosis of this tutorial KB here. Scroll through and see what diagnosis tools are offered.

You can also run diagnosis commands individually from the "Analysis" menu. The diagnosis will be faster and possibly easier to browse if you run only the diagnoses that you are interested in.

Following is an abbreviated view of output of a few different analysis commands and a brief description of the diagnosis performed.

Missing Term Definitions

Presents an analysis of the current KB showing all of the frames that are missing from the KB. These missing frames are references to terms that have no apparent definition in the KB. For example, if the KB says (Mother-of Sally Mary), but there is no frame definition of Mary in the KB, then Mary will be identified as a missing frame.

The following view shows 2 of the 37 missing term definitions in Kb-Merge.

Class Graph Cycles

Presents an analysis of the current KB showing all of the taxonomy cycles. For example, in the view of the Kb-Merge diagnosis shown below, the KB says

(direct-superclasses cruise-missile missile) (direct-superclasses missile cruise-missile)

The latter superclass relation should probably be removed.

Missing Documentation Strings

Presents an analysis of the current KB showing all terms that have missing documentation strings. As shown below for KB-Merge, 2 of the 240 terms that are missing documentation strings in KB-Merge are Afv and Air-Defense-Gun.

Relations/functions Missing Type Constraints

Presents an analysis of the current KB showing all of the relations and functions (including slots and facets) for which there are any arguments that either have no type constraint or for which the type constraint is trivially Thing.

As you can see below, KB-Merge has a few relations and functions that are missing domain and range constraints.

Classes with Redundant Direct Superclasses

Presents an analysis of the current KB showing all of the classes that have redundant direct superclasses. This analysis does not identify errors, but rather identifies areas of possible confusion or bad style in the KB.

For example, in the view of the Kb-Merge diagnosis shown below, the KB says

(direct-superclasses Warplane Weapon) (direct-superclasses Warplane Convential-Weapon) (direct-superclasses Conventional-Weapon Weapon)

The third superclass relation should probably be removed.

In the next section, you will learn how to save your new KB.