Lessons Learned using DAML-ONT for Markup

General KSL KB Development Overview

This accounting is a combination of input from a student doing markup for the DAML homework assignment, a programmer implementing translators, and two researchers (and their colleagues) running research projects using DAML-ONT. Note that multiple authors provided input on issues and when confusions were presented by people who had tried to read the appropriate documents, they have not been eliminated from the report even if the information may be present in some less obvious document.

A lot of the difficulties with the development of DAML-ONT ontologies arise not from the language itself but from the pragmatic issues of implementing a large ontology. When drawing concepts from large, heterogeneous ontologies and building ontologies with large sets of instances, it often becomes hard to keep track of the exact class, relation, and instance names resulting in misnamed objects. It is also difficult to manually keep track of constraints such as cardinality when many relations define these constraints and there is no automated method of verifying their mutual consistency. Therefore, it seems that there is a need for DAML-ONT editing and authoring tools in order for the language to truly become useful.

We were fortunate to have a general ontology editor (Ontolingua) supporting editing, browsing, and consistency checking, and automated translators (to and from the DAML-ONT specification) for the purposes of building and editing our ontology. We exploited Ontolingua's features of searching (via classes, relations, instances), input checking, and consistency checking. In this initial homework assignment, we did not use our more advanced Chimaera Ontology environment since we were focusing initially on simple ontology generation only. We will run the ontology through the current Chimaera diagnostics next since the person assigned to markup commented on the need for many of the features provided. The main needs sited were for analysis and diagnostics in combination with better search support. Additionally, the homework assignment has suggested some small modifications to Chimaera that would be useful in helping minimize some of the problems mentioned below by the person doing markup.

As a general preface to the problems below, it is obvious that it would be useful to leverage as much top-level ontology information as possible without redefining it for the purposes of a new ontology. So, for example, if you want to build an instance of a Publication, one should hope to have a predefined ontology with information relating to Publications, i.e. classes for the types (Journal Articles, Books, Proceedings) and appropriate relations (Has-Author, Has-Title, Has-Date-Of-Publication, etc...). However, the problem with top-level ontologies is that one wants to avoid redefining this information if it has already been defined, however when ontologies are developed independently by many different people, it often becomes hard to exactly match terms in a hypothesized ontology with their actual names. For example, one may be unable to find a relation for Has-Author if the equivalent relation were defined as Is-Authored-By. Humans can tell that these two terms are related if not equivalent but most editors would not provide this support. Small extensions to the merging suggestions found in Chimaera could be used to minimize this problem however. Additionally, classification methods found in reasoning systems such as description logics could also be used to identify relationships between terms.

Some pragmatic issues that we found to arise during the development of our DAML-ONT ontology in the homework assignment involved the following:

Suggested DAML-ONT Extensions/Modifications

Following are some issues that we encountered from our analysis of the language and the development of automated translators between DAML-ONT and our Ontolingua ontology development environment.

Suggested DAML-L Features

We are still in the very early stages of assessing DAML-ONT with respect to our other DAML project needs. The following are some preliminary comments regarding desired features for DAML-L. We anticipate updating this list as our needs crystallize.

  1. time limit: I couldn’t prove that a flight exists from San Jose to the North Pole in 5 minutes of search, therefore I assume there does not exist such a flight by (NAF 5min).
  2. context: I couldn’t prove that a flight exists from San Jose to the North Pole by searching (expedia, travelocity, UAL, AA, and Alaska Air), therefore I assume there does not exist such a flight by (NAF (expedia, travelocity, UAL, AA, and Alaska Air)).


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Last modified: Sunday, 03-Jul-2005 06:07:02 PDT