The Frame Relationships Viewer


Whereas the class hierarchy viewer enables you to browse a KB following class-subclass and class-instance relationships, the frame relationships viewer provides a means of browsing the KB by following slot-value relationships. For example, in a KB of automobiles, you may have defined a Part slot, such that values of the Part slot for a particular car frame include a wheel frame and an engine frame. The Part slot values for the wheel frame may include a tire frame and a bearing frame, and so on. One can imagine constructing a graph showing the entire Part hierarchy starting at some car. This is exactly what the frame relationships viewer does. You can specify which slot-value relationship or relationships to follow (or just follow all of them), and one or more instances to start from, and a tree is drawn with the specified instances as roots. A frame B will be drawn as a child of frame A if B is a slot-value of one of the designated slots in A. Each edge is labelled with the appropriate slot name.

Following is an example of a relationships slot-value browse in a biochemistry KB, showing how a super-pathway is composed of its sub-pathways. The edges are labelled with the slot name, to distinguish slots in the case when you wish to follow more than one slot at a time.

An alternative way of browsing frame relationships is to look purely at classes: i.e. to determine which classes a value of a particular slot must be a member of. For example, if a slot in class A must be filled by an instance of class B, then class B is drawn as a child of class A. This type of browsing will be used if all the selected root frames are classes. We call this type of browse a slot-type browse, to distinguish it from the slot-value browse described above.

A variety of editing operations are available from this viewer. In addition to creating, deleting and renaming frames, slot-value relationships can be inserted and deleted by adding or removing the appropriate edges. This facility provides an intuitive mechanism for building up complex interrelationships between frames.

To invoke the frame relationships viewer, select one or more frames and the command Invoke Frame Relationships Viewer from the Application menu. Note that because you must initially select one or more frames to serve as roots of the relationships browse, it may help to browse the class hierarchy first, to bring the desired frames into the display where they can be clicked on. If you prefer not to browse the class hierarchy first, then after selecting the command, you will be prompted for a frame: just type in the name of the desired frame or frames in the text pane. A new application window containing the relationships view will pop up and become active. You must close this window before you can resume browsing the class hierarchy or performing any other commands in the class hierarchy viewer.

By default, all slots that contain frames as values are selected for browsing, but you may change this if you are interested in only one or a few slots.

If any of the selected roots are instance frames, then the browse will be a slot-value browse. Otherwise, if all selections are class frames, the browse will be a slot-type browse.

The same incremental browse facility is available for the relationships viewer as for the Class Hierarchy viewer. See the description on that page for more details. The command menus also contain many of the same commands as in the class hierarchy viewer command menus. Detailed command descriptions are provided below.

Application Commands

The commands Print Display, Copy to Kill Ring, and Help are as in the class hierarchy viewer. The one additional command, Close (Ctrl-q), closes the frame relationships viewer window and returns control to the hierarchy viewer window.

Knowledge Base Commands

At the time that this viewer is invoked, a KB should already be open and selected. Thus, only a subset of the commands from the class hierarchy Knowledge Base menu are available in this viewer: Save, Save As, and Revert to Saved, allow you to save the KB, to save the KB to a specified file, and to revert to the last saved version of the KB, respectively.

Frame Commands

The following commands all operate on one or more frames. There is some amount of duplication here: some of the editing commands can also be performed from the hierarchy viewer, whereas others can be performed from the frame-editing viewer. Nevertheless, it can be useful to have them all available in this context also.

View Commands

These commands pertain to setting up a relationships browse, and which frames are pictured on the display. They are generally analogous or equivalent to the View commands in the hierarchy viewer:

Preference Commands


Links

Return to the GKB-Editor Overview page.

Return to the beginning of the GKB User Manual.

Visit the Class Hierarchy Viewer page.

Visit the Frame-Editing Viewer page.


Suzanne M. Paley <paley@ai.sri.com>
Last modified: Wed May 29 15:51:36 1996