Seth Ladd's Blog

Henry has discovered SWOOP , a small ontology editor from MindSwap . This reminds me to point out a very nice feature of SWOOP, one that Protege does not have out of the box. SWOOP , through its integration with Pellet , is able to not only compute classifications but also able to tell you *why* your ontology is inconsistent. This, to me, is a huge step towards being able to use ontologies in "every day" problems. The use case here is: You are collecting information from many many different sources. You have an ontology that defines your view of the world. It's possible that all the different information sources will present to you conflicting information. Your ontology defines what is consistent, so therefore it should be able to tell you when you have information that is *inconsistent*. SWOOP does a pretty good job at giving you the feedback to find the source of the inconsistency. An example output is: Inconsistent ontology Reason: Individual ErrorBoat has m...

Found RDF - Connecting Software and People - Google Video via a post to swig mailing mail . The video is quite compressed, but you can view the original slides and high quality video from the original blog post by the author. The video does a good job of grounding RDF into some real world problem domains with real world tools such as NetBeans (the author works for Sun). To funny bit is, as I started to watch the video, I was impressed by the cool soundtrack it had. I thought, "Wow, this guy went all out and put in a cool trance soundtrack the match with the cutting edge, futuristic feel of the semantic web." Then I realized I had an internet radio station playing in the background. Time for a remix of the RDF presentation video? :)

Temporal relations from Henry Story on 2006-03-23 (semantic-web@w3.org from March 2006) is a post to the swig mailing list dealing with time in RDF. The proposal in the email attempts to use N3's ability to declare metadata about graphs, in order to say when the graph was fetched. For instance: { :Oven :temp "22"^^t:celsius . } :fetched [ :at "2006-03-23T10:00:00Z"^^xsd:dateTime; ] . Of course, the problem here is there's no formal RDF semantics for this, as there's no formal way to write triples about a graph. This is an N3 thing. I would guess the closest thing in RDF would be reification. This is similar to how I've been thinking about the problem, which is marking the time the triples were retrieved from the source. The email, though, points out that it is difficult to merge those graphs together, as you'll end up with many values for an Oven's :temp. Once merged, how do you query for a particular temp at a particular time? Ano...

Instance Store is a > Java application for performing efficient and scalable Description Logic (DL) reasoning over individuals What does this mean? It's an attempt to build a system that can reason (using OWL, for instance) across a large set of instances. Apparently it stores individuals in a RDBMS, such as MySQL or Oracle. It then connects that store to a reasoner, such as Racer or FaCT++. I haven't tried it yet, but I will soon, so I'm storing this here for future reference. Would be interesting to see if plugging this directly into Oracle 10g's RDF store provides any benefits. I should note that a quick glance at the code indicates that it hasn't been touched in about two years.

The J2EE Best Practice seminar put on by Symantec is giving attendees a free copy of Expert Spring MVC and Web Flow. That's pretty exciting, but what about a free trip to London for the authors? :)

Expert Spring MVC and Web Flow is off for a second printing. I have no idea how many were printed in the first place, but this is good news none the less. A big mahalo to everyone who purchased a copy. All of the typos and errors identified will be fixed.

ConsVISor is a nice web service that can check an OWL ontology (with individuals) for consistency. It displays any errors with easy to read non-technical-jargon sentences. I've been trying to find a workflow where I can test a set of individuals against an ontology to see where the inconsistencies are, and this tool is the best so far for reporting any problems. FaCT++, via Protege, doesn't seem to provide any error messages. It does fail, though (correctly). Can't figure out how to get it to tell me what and where the problem is. Pellet, via their online demo, seems to work. However, the error messages are cryptic and seemingly misleading. I'm assuming they are correct, however they would never lead the lay-person to the real problem. Anyone else using OWL for consistency checking across individuals? What tool are you using? Can it provide useful error messages?