[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: RE: A Few Thoughts on an Ontology as a Self Organizing Sys
Hi, I've read your post on this really interesting subject... But let me ask a question: what's the point of using self-evolving taxonomy? Search engine? Thesaurus? Something else? We kind of disagree b/c there is no "real" point of doing that. Between creating an ontology for a blog for a search engine and creating a taxonomy for a subset of Biology the work does not seem the same... Besides, remember Goedel's theorem which says (if I remember right) that a system can't prove both its completeness and its closure (if it's the right English term). It does limit things isn't it? So my guess would be: 1/ define why and where we would need that? (a zeitgeist a la Google?) 2/ think about it :=) 3/ implement a solution (yes I know easier to say than doing) Hope to have helped thinking about this subject. nicolas -----Message d'origine----- De : Cox, Bruce [mailto:Bruce.Cox@U...] Envoye : lundi 29 septembre 2003 05:13 A : Roger L. Costello; xml-dev@l... Objet : RE: A Few Thoughts on an Ontology as a Self Organizing System Some equally fuzzy remarks: 1. As I understand it, for structure to appear in a complex system, the system components have to exhibit some kind of individual behavior, as chemicals in a test tube where, based on complex, spontaneous chemical interactions over time, the system can become more organized rather than less; somewhat like the emergence of heavy elements (more complex nuclei etc.) and solar systems during the evolution of the cosmos from primordial gas. I can see the analogy in the Web as a whole, where humans are involved, or perhaps where servers are active without premeditated coordination. In a system that consists only of vocabularies, where is the activity from which structure emerges? The addition, subtraction, and change that you describe is imposed from the outside, not from within the elements; elements have only static properties that don't change without external intervention. I don't suggest that life is required, but some sort of internal activation (like electromotive forces or human passion) seems to be. 2. Are such systems of vocabularies in a domain sufficiently large and homogenous to exhibit the statistical properties of complex systems? I don't know. On the Web there may be large enough populations of homogenous objects in a domain to exhibit such behaviors, rather than their vocabularies. To continue a typical ontology example, there may be enough different bottles of wine in the world, or even types of wine, but I wonder if a collection of vocabularies would be sufficient. If you combined all the vocabularies from all the domains? (But what would be the point of doing that?) 3. Those who maintain taxonomies can testify to the forces acting on the domain that create the need for change in the taxonomy. Ask (Chemical | Physics | Biological) Abstracts how and why they update their indexing vocabularies. At some point in time, the number of papers that mention a specific topic, and the demand for access to papers on that topic, rise to the point that indexers take note, and then revise the vocabulary to include terms for the topic. This does not indicate that some new topic has appeared, only that it has gotten enough attention to justify the effort of revising the taxonomy. The point in time when the topic first appeared in papers is uncertain because 1) the pre-revision taxonomy did not "know" it was there and 2) it will have been discussed informally long before appearing in a refereed paper. A specific revision is not an emerging behavior of a taxonomy, no matter how complex, but an outside influence, forcing change on what normally has a great deal of inertia associated with it. Stability (inertia) is necessary for the success of a taxonomy, but not sufficient. 4. If you want to model the evolution of an ontology, you may want to start with the population in the domain who evolved its vocabulary in the usual human manner. A taxonomy is a subset of that general vocabulary, where each term is assigned scoped and documented meanings with the consensus of the population. Are taxonomies a property that emerges from the behavior of the experts in a domain? Are ontologies (assigning specific terms from a taxonomy to specific objects [is that right?]) a kind of second-order property that emerges from the behavior of a subset of experts in a domain? If the population of a domain is large enough, it may be that it would qualify as a complex system, but is the subset of experts who make ontologies large enough? 5. None of this solves the problem of the cost of maintaining an ontology, which I presume is the motivation for automating it. No matter the answers to any of the above questions, none of them will render the process automatic, as far as I can see. Expanding a taxonomy requires judgment based on a sense of the market and its needs. Assigning terms to objects requires an understanding of the object and the terms that transcends a coincidental lack of common character strings. It will require the attention of humans, the commitment of at least one institution, and investment from at least the population of the domain (using it and paying for it), to maintain an ontology. Even if complex systems analysis is applicable, I understand that it is a statistical science, which does not in general apply to individual events but to a population of such events, so I doubt it could be used to automate the revision of an ontology. Bruce B. Cox SA4XMLT USPTO/OCIO/AETS 703-306-2606 -----Original Message----- From: Roger L. Costello [mailto:costello@m...] Sent: Friday, September 26, 2003 4:57 PM To: xml-dev@l... Subject: A Few Thoughts on an Ontology as a Self Organizing System Hi Folks, This is a continuation of the discussion that we had last week on complex systems. I have a couple of somewhat fuzzy ideas that I would like to throw out. My objective is to stimulate the flow of ideas, and perhaps bring clarity to my ideas. Mike Champion made an interesting statement last week while discussing semantics: > But how about the messy real world most of us must operate in, where > there is an intent to deceive (spammers, virus writers, software > companies with patents on common sense, politicians starting wars [or > questioning the definition of "is"], ad nauseum)? How about in pop > culture contexts where meanings of words are changed literally for the > fun of it? That got me to thinking. Suppose that we define the collection of all XML tags that are used within a domain as a "system". Let me refer to each individual tag as a "part" of the system. The system is dynamically expanding and shrinking, i.e., parts (tags) are being introduced/withdrawn all the time. There are both fixed and changing interactions in the system, i.e., some parent/child, sibling, semantic relationships are fixed, others change. What we have is a complex system. I could continue on with this description and talk about system properties, emergent properties, attractors, etc. However, since the topic is semantics, I would like to focus on the use of ontologies in such a system. Ontology languages such as RDF Schema and OWL provide the ability to *statically* capture semantic relationships. However, as Mike points out, semantics is a continually evolving thing. As a system evolves, so must the ontology evolve. In fact, an ontology must be part of the system. "The essence of self-organization is that system structure often appears without explicit pressure or involvement from outside the system."[1] To manage evolving semantics a system must self-organize as semantics evolve. In other words, an ontology must be a constantly evolving entity. How can we create an ontology that evolves? Here is a thought: express semantic relationships in an XSLT document! An XSLT stylesheet has an interesting property of being able to output a modified version of itself, i.e., the output of the stylesheet is another, modified, stylesheet. The output stylesheet may contain template rules that have been modified to reflect changing semantics, and additional template rules that contain new semantic relationships. Honestly, I am not sure how one would express semantic relationships in a stylesheet. For example, how would you express that a SLR is a type of Camera, or aperture is synonymous with f-stop? Well, that's it. As you can see my ideas are rather fuzzy, but perhaps they will stimulate your thoughts. /Roger [1] Self-Organizing Systems FAQ for Usenet newsgroup comp.theory.self-org-sys ----------------------------------------------------------------- The xml-dev list is sponsored by XML.org <http://www.xml.org>, an initiative of OASIS <http://www.oasis-open.org> The list archives are at http://lists.xml.org/archives/xml-dev/ To subscribe or unsubscribe from this list use the subscription manager: <http://lists.xml.org/ob/adm.pl>
|
PURCHASE STYLUS STUDIO ONLINE TODAY!Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced! Download The World's Best XML IDE!Accelerate XML development with our award-winning XML IDE - Download a free trial today! Subscribe in XML format
|