Categories
RDF Writing

RDF and Grounding

I was so caught up in the Pie/Echo/Atom stuff yesterday that I missed Jon Udell’s discussion about my book. He wrote:

To get a better picture of how the CVM works, I read Shelley Powers’ very well-written new book, Practical RDF. I read it online, actually. Very cool to be able to do that. (Tank, I need a pilot program for a B-212 helicopter.) My eyelids fluttered for a while, and when I opened them again it was Chapter 10: Querying RDF: RDF as Data that emerged as pivotal.

Working through the chapter he finds:

This is cool. RDF triples are relations, and here we see that they’re amenable to relational processing. I can grok that.

Well, that made my morning. To hear others say they liked the book is a goodness, but when someone works through one of the chapters, and details an ‘Aha!’ moment, well, that’s what a writer lives for.

Jon also has some tough questions on grounding. What I should do is get with Simon St. Laurent and write an article on namespaces – the Meaning of it All – he from the tree structure, me from the graph point of view.

Categories
RDF

New IsaViz version out

One of the tools/utilities I covered in the book was Emmanuel Pietriga’s IsaViz, a nifty graphical tool for working with RDF models.

Emmanuel just sent me an email to let me know that a whole new version is out. This new version supports the latest last call working drafts for the RDF specification and also uses GSS – an RDF-based style language for rendering RDF models. It would be interesting to see the possibilities of this vocabulary’s use in other products.

IsaViz installs easily and is very easy to use, with a nice interface

Categories
RDF

PIE/Echo/Atom-seeing the light?

Thanks to some tweaks suggested by Aaron Swartz, the Pie/Echo/Atom folks are exploring the possibility of formating the syndication format in RDF/XML.

As I’ve said in comments – this is a very good thing. It unifies RSS 1.0 and RSS 2.0 beautifully and justifies having yet another syndication effort. Discussion on this continues at the syndication feed email list.

Good job Aaron, Sam, others in the group.

Categories
RDF

Edd Dumbill: I like RDF Dammit!

Recovered from the Wayback Machine.

Edd Dumbill has a new essay on why he continues to support RDF. Much of it has been heard before, but I like what he had to say on RDF being failure-friendly:

Processing RDF is therefore a matter of poking around in this graph. Once a program has read in some RDF, it has a ball of spaghetti on its hands. You may like to think of RDF in the same way as a hashtable data structure – you can stick whatever you want in there, in whatever order you want. With XML, you expect to get a tree with its elements in a predictable order. If an expected element is missing, then it tends to render your whole XML document invalid with respect to the schema you are using. If an element you don’t expect to be there is present, then again your document becomes invalid. With RDF, you have no particular expectations; if the particular strand of spaghetti you’re looking for isn’t there, the rest of the ball remains. If there are new strands you don’t expect, you won’t even notice their presence if you don’t go looking for them.

All too true. That’s another reason I like to use RDF/XML for all my applications – it’s dead simple to process, and doesn’t require specialized vocabulary handling to process all that vocabulary dependent dead-tree structures of vanilla XML.

I wonder at the timing of Edd’s essay? Do we think it has anything to do with the recent conversation about namespaces, when you consider the following:

My “find the title” processor can still deal with your description just fine, as all it cares about is the dc:title property. All RDF processors are automatically future compatible, and all RDF descriptions are automatically backwards compatible. This is a huge benefit over traditional XML processing.

This is the main reason I was strongly behind the use of RDF for RSS. Everyone wants to extend and play with RSS for their own purposes, and RDF gives them the chance to do that without breaking everybody else’s software.

Yes, yes, yes!

I’ve said that I’m not a greek chorus for RDF – too much of that at times – but I also have little tolerance for people trying to re-invent sophisticated features in an XML vocabularly like RSS 2.0 that are included free of charge with the RDF/XML version of RSS, RSS 1.0. With all RDF/XML vocabularies when it comes to that.

Gah! Go bang your head against the wall if you like pain.

Categories
RDF

Jon Udell on RSS and namespaces

Recovered from the Wayback Machine.

I love being nothing more than a whiteboard at times….

Jon Udell writes today:

What we have now is ‘entity escape and stuff in description’ and I doubt anyone will argue that’s good. Like Dan, I don’t know which of the other two options is best. I do know, however, that I can easily shred an XML document with XPath and XSLT, pick out subsets – whether or not they’re namespace-qualified – and do useful things with them. I don’t believe that doing that, without first settling on a higher-order semantic model, is a bad idea. Far from it. It’s abundantly clear to me that we’ve wasted years, that we must do that experiment ASAP, and that it will yield new killer applications. No agreement on the higher-order model need be reached as a precondition. If some higher-order model is going to ultimately prevail, then a lot of existing data will have to get converted into it. Would you rather convert ‘entity-escaped-and-stuffed-in-the-description’ data, which is all we have now, or XML data that you can at least shred and manipulate? That choice seems transparently clear to me.

Finally, a plea to all concerned. Let’s stop punishing RSS syndication for its success by asking it to carry the whole burden of XML usage in the semantic Web.

I wasn’t aware that any of us were asking RSS to carry the burden of the semantic web – I’ve long said that RSS is a simple syndication format, and that we should stop trying to stuff the world into it because extraneous data is outside the syndication business domain.

Having said this, I have no problems with the RSS folk, or the Pie/Echo/Atom folk, working on namespace issues and wish them the best. However, I don’t think we, who use and prefer RDF/XML have to wait for them. Or break a working model just to play with the boys who would prefer to play by themselves.

I understand where Dan Brickley is coming from, and it sounds like communication has again moved from the weblog to private emails, without the messiness of us all that don’t ‘go with the flow’ getting in the way. However, Dan has not come back to me with how we’re going to handle context.

Dan? I’m here. Let’s chat.

If you can get XML namespaces to work and don’t have to use encoded blobs of text to work around limitations with RSS, great. But I won’t see the RDF model broken to get there.