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SemPlan RdfLib Version 0.21

Excerpt: Oops. It seems that I forgot to update the build script to include the new mySQL classes for RdfLib, so I've released version 0.21 that does contain them! Direct downloads: binaries, source, docs, license

Carp Version 0.2

Excerpt: Hot on the heels of SemPlan RdfLib 0.2 is Carp 0.2, our Mono/.NET RDF API. As I mentioned earlier, we've refactored the two projects and pulled a lot of stuff out of Carp down into RdfLib. This leaves Carp leaner, but still as easy to use. Because of this, if you're using Carp and you want to upgrade RdfLib then you need to upgrade Carp too. Carp is now under the less restrictive MIT license too. The introduction of non-memory based triple stores in RdfLib has meant that we've had to rethink the way ResourceDescriptions work. There are some (slightly out of date) design notes on the wiki which help describe the problem. The summary is that because each ResourceDescription needs …

RDF queries using a relational triple store

Excerpt: While I was travelling in the States, I had the idea of writing a SQL stored procedure that would query a RDF triple store and return matching triple sets. The query would itself be specified as a triple set. For example, a simple query ("find the nodes with a name property that has the literal value of 'ian'") might look like this: ['?b', 'name', 'ian'] A more complex Friend of a Friend query ("find names of people that know a person that knows a person called 'ian'") might look like the triple set ['?a', 'knows', '?b'], ['?b', 'knows', '?c'], ['?c', 'name', 'ian'], ['?a', 'name', '?e'] When I talk about triple sets to describe RDF queries, I was inspired by the work of …

Semantic Web Ignored by AI Community?

Excerpt: An interesting thread on comp.ai started by Jorn Barger who asked why there has been almost no discussion of the Semantic Web project on the comp.ai newsgroup. Aren't businesses spending tons of money implementing XML data-standards, and don't they hire AI-grads for expertise on this? Or haven't AI grad-programs been adequately training students in these semantic skills?

PlaceTime URI Space

Excerpt: PlaceTime is a URI space that will define URIs for instants and intervals in time as well as points and regions in space. You'll be able to address a particular time or place or a combination of the two. The URIs themselves will be retrievable via HTTP and the RDF representations will contain enough information to provide conversion between different ways of measuring the same thing. For example, if you refer to a URI representing a date and time using the Gregorian calendar you'll be able to determine the same date and time in other ways of measuring time such as the Islamic calendar or the number of seconds since the UNIX epoch. You'll be able to determine coincident or nearby …

RDF test cases update

Excerpt: I tried testing the RDF to Triples stylesheet by hand, looking at the test cases and my own output. There are 540 triples produced by the test cases and whenever I tweaked my stylesheet to satisfy one set of output, I would break the stylesheet for another set. It felt like the "hitting the moles with a hammer" game. After a discussion with Dan Brickley I decided to bite the bullet and build a proper test harness, with SQL Server as a back end triple store, so that I can run intersection queries against the test case triples and my own. This involves some recursive processing with some scrappy C# classes and some SQL server development …

Update on RDF XSLT stylesheet

Excerpt: It's been a gruelling trek through the RDF XML syntax and test cases documentation but I feel near the end of the tunnel. The greatest problem I have faced is distinguishing between rdf:ID attributes on subjects, objects and predicates - on subjects and objects the ID relates to the resource, whereas on the predicate element the ID refers to a statement (arc) that is reified. Unfortunately you can't tell from within the context of an element whether it is a predicate or not, and because I was being clever in reusing templates I was processing the same element in as both a subject, object and predicate. This is the case where, for example, the predicate points to …

RDF to Triples XSLT stylesheet

Excerpt: I've almost completed an RDF XML syntax - to - triples stylesheet. This is based on the XML syntax document for RDF published by the W3C, which contains examples of syntax and corresponding triples. Although several XML to triples XSLT stylesheets have been produced in the past, this is the first (I believe) that supports collections and reification. The ability to extract triples from RDF is key to aggregating RDF and building graphs that span beyond a single document. The next stage should be to extract all the RDF and triples from the W3C published test cases (around 90? in all) and make sure that the stylesheet is 100% compatible. James Carlyle