The Tawny-OWL library provides a fully-programmatic environment for ontology building; it enables the use of a rich set of tools for ontology development, by recasting development as a form of programming. It is built in Clojure - a modern Lisp dialect, and is backed by the OWL API. Used simply, it has a similar syntax to OWL Manchester syntax, but it provides arbitrary extensibility and abstraction. It builds on existing facilities for Clojure, which provides a rich and modern programming tool chain, for versioning, distributed development, build, testing and continuous integration. In this paper, we describe the library, this environment and the its potential implications for the ontology development process.

  • Phillip Lord

Plain English Summary

In this paper, I describe some new software, called Tawny-OWL, that addresses the issue of building ontologies. An ontology is a formal hierarchy, which can be used to describe different parts of the world, including biology which is my main interest.

Building ontologies in any form is hard, but many ontologies are repetitive, having many similar terms. Current ontology building tools tend to require a significant amount of manual intervention. Rather than look to creating new tools, Tawny-OWL is a library written in full programming language, which helps to redefine the problem of ontology building to one of programming. Instead of building new ontology tools, the hope is that Tawny-OWL will enable ontology builders to just use existing tools that are designed for general purpose programming. As there are many more people involved in general programming, many tools already exist and are very advanced.

This is the first paper on the topic, although it has been discussed before here.

This paper was written for the OWLED workshop in 2013.


Reviews are posted here with the kind permission of the reviewers. Reviewers are identified or remain anonymous (also to myself) at their option. Copyright of the review remains with the reviewer and is not subject to the overall blog license. Reviews may not relate to the latest version of this paper.

Review 1

The given paper is a solid presentation of a system for supporting the development of ontologies – and therefore not really a scientific/research paper.

It describes Tawny OWL in a sufficiently comprehensive and detailed fashion to understand both the rationale behind as well as the functioning of that system. The text itself is well written and also well structured. Further, the combination of the descriptive text in conjunction with the given (code) examples make the different functionality highlights of Tawny OWL very easy to grasp and appraise.

As another big plus of this paper, I see the availability of all source code which supports the fact that the system is indeed actually available – instead of being just another description of a “hidden” research system.

The possibility to integrate Tawny OWL in a common (programming) environment, the abstraction level support, the modularity and the testing “framework” along with its straightforward syntax make it indeed very appealing and sophisticated.

But the just said comes with a little warning: My above judgment (especially the last comment) are highly biased by the fact that I am also a software developer. And thus I do not know how much the above would apply to non-programmers as well.

And along with the above warning, I actually see a (more global) problem with the proposed approach to ontology development: The mentioned “waterfall methodologies” are still most often used for creating ontologies (at least in the field of biomedical ontologies) and thus I wonder how much programmatic approaches, as implemented by Tawny OWL, will be adapted in the future. Or in which way they might get somehow integrated in those methodologies.

Review 2

This review is by Bijan Parsia.

This paper presents a toolkit for OWL manipulation based on Clojure. The library is interesting enough, although hardly innovative. The paper definitely oversells it while neglecting details of interest (e.g., size, facilities, etc.). It also neglects relevant related work, Thea-OWL, InfixOWL, even KRSS, KIF, SXML, etc.

I would like to seem some discussion of the challenges of making an effect DSL for OWL esp. when you incorporate higher abstractions. For example, how do I check that a generative function for a set of axioms will always generate an OWL DL ontology? (That seems to be the biggest programming language theoretic challenge.)

Some of the dicussion is rather cavalier as well, e.g.,

“Alternatively, the ContentCVS system does support oine concurrent mod-ication. It uses the notion of structural equivalence for comparison and resolution of conflicts[4]; the authors argue that an ontology is a set of axioms. However, as the named suggests, their versioning system mirrors the capabilitiesof CVS { a client-server based system, which is now considered archaic.”

I mean, the interesting part of ContentCVS is the diffing algorithm (note that there’s a growing literature on diff in OWL). This paper focuses on the inessential aspect (i.e., really riffing off the name) and ignores the essential (i.e., what does diff mean). Worse, to the degree that it does focus on that, it only focuses on the set like nature of OWL according to the structural spec. The challenges of diffing OWL (e.g., if I delete an axiom have I actually deleted it) are ignored.

Finally, the structural specification defines an API for OWL. It would be nice to see a comparison and/or critique.


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