Visions of Aestia

My music CD was released to manufacturing today. Should be on sale any day now.

At least it’s out before Christmas proper, though it may be difficult to get copies in time for the holidays.

Coming Soon! - Latest News

I heard rumours about this the last year or two; unfortunately the loss of Stephen Biggs (Dr. Franklin) caused a script rewrite.

Looks like the new script has finally been approved and filming can begin!

OK, let’s say you’ve decided to take the plunge and switch from plain XML to the distributed kind you get with RDF. How are you going to get there?

Step 0: Make sure your XML parser understands namespaces. You’re going to be needing them.

The first refactoring should be pretty easy. You need to replace any existing ID values in your XML with RDF-specific IDs.
Let’s look at an example snippet:

<customer id="12">
<name>John Smith</name>
</customer>
<order id="17">
<customer id="12" />
<product id="45" />
</order>

Probably this XML comes from a database somewhere. Doesn’t really matter. The thing to recognise here is that the “id” attribute is actually being used as both an anchor and a reference.

Pass one, we replace the anchors.

<customer rdf:ID="customer#12">
<name>John Smith</name>
</customer>
<order rdf:ID="order#17">
<customer id="12" />
<product id="45" />
</order>

Remember, RDF just uses the ID value as a unique key. It doesn’t have to point to a real document.

In pass two, we replace the references.

<customer rdf:ID="customer#12">
<name>John Smith</name>
</customer>
<order rdf:ID="order#17">
<customer rdf:resource="customer#12" />
<product rdf:resource="product#45" />
</order>

We also have to update any existing XML parsing we do to use the new attribute values instead of the old ones, but that should be straightfoward.

UPDATE: Fixed broken example tags. Yeesh - and the characters WordPress ate.
UPDATE (27-Dec-2004): Fixed embarrassing typo in response to Dave’s comment below.

Once you understand that RDF is really just a distributed form of XML (see RDF/OWL == XML/XSLT, part 1 if needed), you’ll probably want to start taking advantage of it. Unfortunately, most of the existing tools seem to be written by AI specialists.

Dumb RDF is the kind most of us actually want to write. We don’t want to bother about transitive properties, triples, or inductive logic. All we really want is the ability to split our XML blocks across multiple files and magically piece it together. The other stuff is cool, but utterly irrelevant to most of us at this stage.

Examples of Dumb RDF includes Dublin Core (for tagging documents), FOAF (for tagging people), and RSS (for tagging syndicated content). All these examples involve some fairly simple XML that doesn’t require any special knowledge. Notice how popular these formats are.

Smart RDF is where we get into topic maps, ontologies, triples, and other complicated areas. This is where the AI people add all sorts of tags to constrain relationships, definitions, and carefully-defined vocabularies. Smart RDF can deduce that my father’s brother’s only brother’s daughter is my sister, is female, and has only one paternal uncle.

Dumb RDF is just data. Everybody can undertand it and generate it. This is where most of us will always want to be. But Smart RDF is where the active practitioners are. That’s why it seems so complicated and unapproachable.

You know what? That division is just fine, because RDF is distributed. You and I can go off and write Dumb RDF, W3C implementors can write Smart RDF, and we never have to know about each other. An RDF parser that stumbles across Smart RDF will suddenly get smarter and be able to answer more questions, but it still works if it sticks to Dumb RDF.

Animal Planet is going to be airing a segment on dragons. On the one hand, as an avid role-player, I certainly applaud any documentary that approaches one of my favorite creatures.

http://animal.discovery.com/convergence/dragons/dragons.html

On the other hand, I can’t help but worry about the general state of science programming on television. This feels very much like all those pseudo-documentaries about mummies and UFOs that get constant air time. No real substantial debate, mostly speculation, and constant repetition of key themes with little or no rigourous review of challenge.

In other words, pseudo-science instead of real science. Sure, “Scientific American Presents” and “Nova” present real science, but you’ll notice they get little traction against the huge volumes of rubbish being pumped out. Not a good trend at all.