Loom Ontosaurus

The Ontosaurus is a Web Browser for Loom® knowledge bases. It provides a graphical hyperlinked interface to several of the knowledge bases. There is also an Ontosaurus interface for PowerLoom®.

A Javascript and frames capable browser is needed to use the system. We recommend Netscape version 2 or newer. Microsoft Internet Explorer version 3 seems to have some difficulty. Version 4 or newer should work.

Demo Version

A live demonstration version of the Ontosaurus browser is available for use. You will need to log in to the server. Use the name "tourist" with password "visit". This will allow browsing but no editing.

Please access Ontosaurus from this page rather than directly. (In other words don't bookmark the Ontosaurus browser itself. Use this page). The reason is that we occasionally need to move the location of the server, so a direct link will not be very useful.

We will attempt to have the server up as much as possible, but since this is work in progress, there may be periods where the server is not accessible. Please direct questions and comments to the maintainers.

About this Browser

This browser consists of three window panels as shown below. This document also contains hints for new users. For a quick start, begin by selecting theory AIRCRAFT, entering AIRCRAFT in the type in box and selecting "Find". Information and actions are also encoded using icons or other typographic conventions.




Bookmark Control

The Toolbar consists of buttons to perform various operations described below. The Reference and Content windows are designed to display contents of ontology. Links in both windows display their contents in the content window. This facilitates exploring various links associated with a word or concept in the reference window without the need to continuously go back and forth. The bookmark window holds user-selected references to Ontosaurus pages. The bookmarks window is managed by the buttons in the bookmark control window.


Depending on the user's access permissions and the existence of an edit lock, not all of the buttons may be visible.

Theory: Allows you to select a Context for interpreting the name in the input field.

Show: Displays an overview of the selected theory. This will include a section on undefined concepts and relations as well as a list of top level concepts in the theory. This page is displayed in the reference window.

Save..., Load...: Brings up a form for saving the current theory or loading a new theory. This form is displayed in the content window.

New...: Brings up a form for creating a new theory. The creation form is displayed in the reference window.

View...: Brings a page up in the reference window listing all of the source files that are visible from Ontosaurus. The source itself can be selected for viewing in the content window.

Hold Window: Moves the contents of the content (right) window into the reference (left) window. Since the reference window is used less frequently, this allows one to keep the page constant while continuing to browse.

Options...: Brings a page up in a new window showing various browser settings.

Browse Only, Make Changes: Radio buttons to establish and release edit locks on the knowledge base. Unless an edit lock is established by choosing "Make Changes", editting is not allowed and the editting and file loading related buttons and links are not displayed. These fields will only appear if the user has editting privileges.

Note that since only one user can make changes at any given time, choosing "Make Changes" blocks other edits. As a reminder, the background will be pink (in Netscape 3.0+). If someone else has an edit lock established, then the background will be yellow. This color coding does not update automatically, so it may not reflect the current state of Ontosaurus.

any, concept, relation, or instance. Selects the type of object entered in the type-in box. Any will match any kind of object in the selected theory.

Input Field (Type in Box): Input for entering the name of an object for browsing in the currently selected theory.

Find: Displays the object specified by the type menu and the type in box. This page is displayed in the reference window.

Edit: Brings up a form for editting the object specified by the type menu and the type in box. This form is displayed in the reference window.

New...: Brings up a form for creating a new object specified by the type menu. The type in box is ignored. This form is displayed in the reference window.

Match Allows the choice of matching style. The available styles are "Exactly", "Case Insensitive", "Substring", "Wildcard" and "Regular Expression".

To begin exploring select an appropriate theory, then select one of concept, relation, or instance. Finally enter a symbol in the input area of the toolbar and press Find to initiate a request to the server.

Bookmark Control

This is used to control bookmarks in the bookmark window together with the checkboxes that are in front of each bookmark itself.

Update: Update the contents of the bookmark window. All bookmarks that are currently marked by checkboxes are retained. Any bookmarks that are not checked are removed. This allows you to eliminate bookmarks that are no longer needed and keep the size of the bookmark window reasonable.

Reload: Refreshes the bookmark window.

Remove All: Removes all of the current bookmarks. The bookmark window will become empty.

Reset: Resets the bookmark window. This will cause all of the bookmarks to be checked. This provides a quick way of returning to the initial state of having all bookmarks checked and thus retained when the update button is pressed. This is useful if you change your mind about deleting bookmarks and want to start over (rather than checking individual bookmarks).

Meaning of Icons

Icon Meaning Active?
or Edit the object. Active
Clone (copy) the object into a new object. Active
Delete the object. A confirmation dialog will appear. Active
Clear the values in the object. A confirmation dialog will appear. Active
Create a new object of the specified type. Active
Add a link in the bookmark window referencing this page. Active
Bring up a query form for finding instances. Active
Bring up a dialog box with a menu for entering instances. Active
Copy the selected value above into the type-in box to the left. Active
Export the current object into a different theory. Active
Create a separate window showing the current translation tables. Active
, Save the object. If the second (darker) icon is used, then Ontosaurus believes that the object in question has not been changed since loading. Active
Information about the given topic or page section. Active
Print this message. Active
Bring up the Language Reference Manual. Active
Show the Loom home page. Active
Mark a single-valued relation. Information
Mark a multiple-valued relation. Information
, Marks read-only single and multiple-valued relations. Information
Marks a direct instance of a concept. Information
Marks an indirect instance of a concept. Information
? Marks an undefined concept or relation. Information
Active icons are buttons and will perform an action when selected. Information icons are used to convey information graphically and are not linked to any actions.

Other Browser Conventions

All symbols are quoted (preceded by a '). Types and role fillers in roman (normal) typeface are asserted by the user. Types and role fillers in italics are derived (inferred) by Loom. Types in bold face cannot be retracted. "Direct Types" are the most specific Loom types for an instance. "Asserted Types" are the result of user assertions. "Base Type" is a type specified as the base type when the instance was created. It cannot be retracted.


You can find the top level concepts in a particular theory by selecting that theory and pushing the "Find" button. You can also start a search from the top of the hierarchy by choosing "BUILT-IN-THEORY" and looking for the concept THING, but this is slow and will cause the browser to download over 200kb of data.

Navigating to an instance and choosing the "Find Similar Instances" link brings up a query-by-example form. This allows you to select particular relevant attributes of an instance to use in a query for finding other instances. In the second page of the query process, you can specify that a role should match any value by selecting the "exists" qualifier instead of the default "=" qualifier.

Ramesh Patil and Tom Russ

This Loom Web Browser was created at the University of Southern California's Information Sciences Institute. It is implemented using Netscape2 extensions to HTML2.0, namely, Frames and JavaScript. It uses the Lisp based HTTP server CL-HTTP DEVELOPED at the MIT AI Laboratory.

Plese send comments and suggestions to Tom Russ.

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