Curiouser and Curiouser!

Curiouser and Curiouser! on rdf http://matt.blogs.it/ RSS feed for topic rdf Copyright 2006 Matt Mower Squib/0.1 self@mattmower.com self@mattmower.com en-gb liveTopics RSS, RDF and the Dublin Core Fri, 29 Nov 2002 08:55:46 +0000 liveTopics RSS2.0 feeds now use a vendor neutral XML namespace: <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> xmlns:rsstopics=<A href="http://purl.oclc.org/NET/rss-topics/">http://purl.oclc.org/NET/rss-topics/</A></BLOCKQUOTE> which is currently pointed at <A href="http://www.novissio.com/resources/rsstopics/">http://www.novissio.com/resources/rsstopics/</A> So each <item/> now comes with an <rsstopics:topic/> definition for every topic it is associated with.  These <topic> tags will soon be pointing back to their ToC entries and optionally to their definition within the XFML version of the weblog. I have taken a quick look at the work done on the RSS1.0 taxonomy module with defines an RDF syntax for specifying topics and advises the use of Dublin Core metadata for adding information.  I'll certainly be persuing the use of DC tags but does anyone think I should be trying to re-use the RDF module & syntax? http://matt.blogs.it/entries/00000905.html RDF primer released Fri, 31 Jan 2003 09:59:49 +0000 <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> <A href="http://www.steptwo.com.au/columntwo/archives/000480.html">RDF primer released</A>. On January 23, a working draft was released for a RDF Primer. (RDF standing for "Resource Description Framework".) To quote: This Primer is designed to provide the reader with the basic knowledge required to effectively use RDF. It introduces the... [<A href="http://www.steptwo.com.au/columntwo/">Column Two</A>]</BLOCKQUOTE> Got to get to grips with RDF one of these days. http://matt.blogs.it/entries/00001116.html Exploring topics in RSS2.0 Sat, 05 Apr 2003 10:38:33 +0100 I've been doing some thinking about how to encode topic information into RSS2.0 feeds.  As a simple test of the Radio callback facility I have <A href="http://matt.blogs.it/rss.xml">implemented</A> a very simplistic protocol.  Within each <item> is a tag <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> <topic id="topic_id" type="topic-type" source="url">topic name</topic></BLOCKQUOTE> for each topic associated with the item (post).  A concrete example (using the rsstopics namespace): <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> <rsstopics:topic rsstopics:id="the_state" rsstopics:source="http://matt.blogs.it/topics/topicsT.html#the_state" rsstopics:type="generic">the state</rsstopics:topic></BLOCKQUOTE> Whilst this does have the advantage that it's simple and direct it's also a bit silly to invent a new format for topic information when we have two standard culprits available already: <UL dir=ltr> <LI> <DIV><A href="http://www.w3.org/TR/rdf-primer/">Resource Description Framework (RDF)</A> </DIV> <LI> <DIV><A href="http://www.topicmaps.org/xtm/1.0/">XML Topic Maps (XTM)</A></DIV></LI></UL> RDF is a general format for describing resources.  A resource in RDF terms is anything which can be uniquely identified by a URI.  An RDF statement (utilizing <A href="http://dublincore.org/">Dublin Core</A> metadata) that asserts me as the owner of my weblog might look something like: <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> <rdf:Description rdf:about="http://matt.blogs.it">     <dc:Creator>Matt Mower</dc:Creator> </rdf:Description></BLOCKQUOTE> If you cut away the syntactic fluff what this says is: <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> Matt Mower is the Creator of <A href="http://matt.blogs.it/">http://matt.blogs.it</A></BLOCKQUOTE> Referring back to the problem at hand, describing what a post (expressed as an RSS item) is about we could come up with something like: <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> <item rdf:about="permalink">     <topic id="topic_id" type="topic-type" source="url">topic name</topic> </item></BLOCKQUOTE> Which is more or less exactly where we started -- using RDF hasn't altered the solution but it has added some framework around it (in this case adding rdf:about to signal the presence of RDF data within the item).  However we can go a step further.  A useful <A href="http://www.xml.com/pub/a/2001/05/02/semanticwebsite.html">article</A> by <A href="http://www.xml.com/pub/au/74">Eric van der Vlist</A> discusses this very subject and refers to the RSS1.0 taxonomy module. Somewhat counter to what you would expect <A href="http://backend.userland.com/rss">RSS2.0</A> does not follow on from <A href="http://www.purl.org/rss/1.0/">RSS1.0</A>, nor does RSS1.0 follow on from the popular RSS0.9x formats.  RSS1.0 is, depending upon your point of view, a step forward or an aberation.  RSS1.0 uses a modular set of RDF based tags to describe items in the RSS feed.  One such module is the <A href="http://www.purl.org/rss/1.0/modules/taxonomy/">Taxonomy module</A> which is intended to allow classification of RSS channels & items. Using the taxonomy module you create something like: <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> <item rdf:about="permalink">     <taxo:topics>         <rdf:Bag>             <rdf:li resource="topic-uri-1"/>             <rdf:li resource="topic-uri-2"/>         </rdf:Bag>     </taxo:topics> </item></BLOCKQUOTE> Here the <topics> element contains a list (using the RDF defined Bag - or unorderer list - container element) of resources indicating topics that describe the item.  Each resource then has a <topic> element that describes the topic.  It  might look something like: <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> <taxo:topic rdf:about="http://matt.blogs.it/topics/topicsT.html#the_state">     <taxo:link>http://matt.blogs.it/topics/topicsT.html#the_state<taxo:link>     <rsstopics:type>generic</rsstopics:type>     <dc:title>The State</dc:title> </taxo:topic></BLOCKQUOTE> Although it's a jumble of RDF, the RSS1.0 taxonomy module, Dublic Core, and, a custom rsstopics schema this says exactly the same thing as the original: <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> <topic id="topic_id" type="topic-type" source="url">topic name</topic></BLOCKQUOTE> But do we have to deal with such an ugly mess?  Perhaps not.  Our original choices included the XML Topic Maps format.  This is a complete specification for exchanging topic information.  An example of a topic in XTM format might look something like: <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> <topic id="the_state">     <instanceOf>         <topicRef xlink:href="http://www.purl.org/rss-topics/rss-topics#generic">     </instanceOf>     <baseName>         <baseNameString>The State</baseNameString>     <occurence id="the-state-item">         <instanceOf>             <topicRef xlink:href="http://www.purl.org/rss-topics/rss-topics#story">         </instanceOf>         <resourceRef xlink:href="<permalink-uri>">     </occurence> </topic></BLOCKQUOTE> Again this encodes the same information, using a standard format and only one required namespace (that of XTM itself).  A URI such as <A href="http://www.purl.org/rss-topics/rss-topics#generic">http://www.purl.org/rss-topics/rss-topics#generic</A> points at a topic in another map (in this case a topic describing the topic-type generic). The use of XTM comes with a number of advantages with the main one being that there are an increasing number of tools available to process & manipulate it (for example, see <A href="http://www.topicmap.com/topicmap/tools.html">topicmap.com</A>).  However there also a number of problems with this representation when you attempt to embed it within another XML format such as RSS. <UL dir=ltr> <LI> <DIV>It's not clear whether an XTM fragment such as this is valid when used in this way</DIV> <LI> <DIV>Each time a topic is used we will be duplicating it's details, bloating the markup & potentially creating invalid entries</DIV> <LI> <DIV>The <occurence> relation within the <topic> element is technically redundant.  The enclosing <item> indicates the occurrence.  </DIV></LI></UL> One way to avoid these problems would be to embed the topics within the RSS <channel> definition and refer to them from each <item>.  However we still need a way to refer to the topic and XTM doesn't provide this.  If we had a good way to reference topics then we could either embed mini topic map within the RSS file, or just have the <topicmap> in an external file and point to it.  What could we use?  One possibility is RDF. Using a combination of RDF and XTM would mean something like: <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> <item rdf:about="<permalink-uri>">     <rsstopics:topic>http://www.example.org/myTopicMap.xtm#topic-id</rsstopics:topic>     </item></BLOCKQUOTE> or <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> <item rdf:about="<permalink-uri>">     <rsstopics:topic>#topic-id</rsstopics:topic>   </item></BLOCKQUOTE> In this example the item now refers to an XTM defined topic either elsewhere in the RSS feed (contained within a valid <topicmap> element) or within an external topic map.  The referenced <topic> element can further describe the topic (names, types and so on) using all the expressiveness of XTM.  It's also efficient since there is no duplicated information within the feed. I have described approaches using RDF, XTM and a hybrid of the two.  Each has advantages and disadvantages although I believe the hybrid makes the best use of both formats. I'd welcome comments and or opinions from interested parties. http://matt.blogs.it/entries/00001353.html You'd think with a name like OWL I'd be able to come up with a pun... Tue, 08 Apr 2003 21:47:00 +0100 <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> Roger Costello and David Jacobs have published a <A href="http://www.xfront.com/owl-quick-intro/sld001.htm">quick introduction</A> to the <A href="http://www.w3.org/TR/owl-ref/">OWL Web Ontology Language</A> (OWL) which is a semantic layer that sits above the <A href="http://www.w3.org/TR/rdf-primer/">Resource Description Framework</A> (RDF). [Posted on <A href="http://lists.xml.org/archives/xml-dev/">xml-dev</A>]</BLOCKQUOTE> I doubt this introduction will make converts of anyone, OWL just isn't that easy to grok, but the applications it presents are credible ones.  I think the problem for skeptics is that they (a) have seen it all before, and, (b) are suspicious of things that they can't directly grapple with, and, OWL & RDF are not for the fainthearted. The fact that RDF is not widely considered to be a success is not surprising to me.  It looks complicated and it's not immediately obvious what you do with it - it's just metadata after all.  I believe that OWL or, more precisely, useful OWL ontologies, are what will make RDF successful.  It's OWL that tells applications what they can (and cannot) do with RDF metadata. That's it's power. Two key things need to happen now: <UL> <LI>The creation of applications that help developers to create robust and useful ontologies. <LI>The creation of libraries for embedding RDF+OWL into applications (as ubiqitous as XML parser libraries are today).</LI></UL> If these two pieces of the puzzle can be assembled then I think we will see a raft of components built that utilize ontologies to perform their functions.  These components will be made into JavaBeans, .NET assemblies, published as web services, whatever.  Users will consume those services and never need to know that OWL or RDF are involved. However until those tools arrive I believe the only course left to you (unless you're trying to build them yourself) is to be pragmatic and keep a weather eye open.  As <A href="http://www.scripting.com/">Dave Winer</A> <A href="http://joi.ito.com/archives/2003/04/06/rss_and_rdf_fun.html">commented</A> recently about RDF: "I am not against it, as long as it doesn't interfere with what I want to do." http://matt.blogs.it/entries/00001372.html I mean, do people want fire that can be fitted nasally? Tue, 15 Apr 2003 12:17:48 +0100 I've been having an agreeable chat with, among others, <A href="http://dannyayers.com/">Danny Ayers</A> about <A href="http://www.purl.org/NET/ENT/1.0/">ENT</A>, <A href="http://www.w3.org/TR/rdf-primer">RDF</A>, and ThreadsML.  Danny expressed some concerns about the dangers of re-inventing wheels.  I share his concern although our viewpoints are perhaps a little different. I want to share part of one my messages: <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> My view is that RDF is a great way of doing things as long as it is wrapped with 1st rate tool support and matched with applications that warrant it. So far as I can tell both of those are near to non-existant right now and RDF remains primarily the domain of "those people who are interested in RDF and think it is a good idea," with a few exceptions. Back when Paolo and I were tossing this idea around we carefully thought over "are we re-inventing RDF" and came to the answer: "no." ENT is, by comparison, pretty simple/limited compared to RDF. But right now I think simplicity is more valuable thanpower. We are still in the early stages of building the semantic web and, really, the applications we have don't *need* RDF's power right now. We think ENT is "just good enough" to launch a raft of exciting applications. I fully expect though, that those applications will grow too big for ENT and simple "hard-wired" standards like it. But this demand will, perhaps, lead to an awakening about RDF. It's time will have come because there will be applications that justify it's complexity & the perceived benefits of those applications will be enough to overcome the inertia involved in getting started with it. And, hopefully, by that time the RDF folks will have delivered much more solidly on the tools front ;) In short my belief is that simple, focused, standards now will pave the way for the adoption of more powerful standards later. Also, as I have stated before, I don't think that RDF will really hit a home run until OWL is ready for prime-time. </BLOCKQUOTE> http://matt.blogs.it/entries/00001390.html Ungrokked RSS-Data Wed, 08 Oct 2003 13:25:54 +0100 <div style="margin-left: 40px;"><a href="http://www.docuverse.com/blog/donpark/2003/10/07.html#a959">RSS-Data</a>. </div> What I like about <a href="http://radio.weblogs.com/0113297/2003/10/01.html">Jeremy Allaire's RSS-Data proposal</a>: <ol style="margin-left: 40px;"> <li>Reduced need to change RSS schema, binding, and parser to support new payloads. </li><li>Possibility of reusing XML-RPC code and SOAP code. </li><li>Arguably faster to parse. In my experience, element-rich XML documents are faster to parse than attribute-rich XML documents. But this is not important given readily available processing power at the consuming end.</li></ol> What I dislike: <ol style="margin-left: 40px;"> <li>Ugly and harder to read although not as bad as RDF. </li><li>Increased need to change RSS application to support new payloads. </li><li>Contextually inconsistent and verbose. <name> <name>value</name>  <name> <name>name</name>  <value>value</value> </name> </name> </li></ol> With RSS-Data, developer's attention will shift from RSS parsers to RSS application frameworks capable of supporting new payload types and routing mechanics via plugins. Despite <a href="http://www.kuro5hin.org/story/2003/10/7/172247/665">irksome cosmetic downsides</a> of RSS-Data, I like that. Only problem is that one can make the same arguments for RDF which makes me a hypocrite. No news there, but I find it ironic to see RDF folks attacking RSS-Data. <div style="margin-left: 40px;"> [<a href="http://www.docuverse.com/blog/donpark/">Don Park's Daily Habit</a>] </div> Hmm... .I tried to read Jeremy's posts on RSS-Data but found there was too much stuff in the way of understanding the basic proposal.  What seems to be suggested is a generic framework for transporting data in an RSS item which isn't terribly astounding so I guess there must be something more exciting going on to raise all this fuss. Is there an RSS-Data in a Nutshell post to be had? http://matt.blogs.it/entries/00001660.html UpComing events Thu, 26 Feb 2004 09:25:29 +0000 <blockquote><a href="http://matt.blogs.it/2004/02/25.html#a1345">One event standard - please!</a>. <IMG src="http://matt.blogs.it/images/head5.jpg" align=right border=0>Here's Matt Mower's thoughts on adding ESF events to the When category of the <A href="http://w4.evectors.it/itEntDirectory/topic?topic=k-collector">k-collector</A>. I'm gonna rely upon Matt and Paolo to grok all this stuff. I just hope they're making sure: <UL> <LI>that all these events standards can work together</LI> <LI>that they've gone back and checked out the earlier standardization efforts that happened in the blogosphere (I seem to remember an rdf schema from <A href="http://dannyayers.com/">Danny Ayers</A>)</LI> <LI>that they're talking to Andrew Baio of UpComing.org.</LI></UL> Schedule and Calendar aggregation is key to the overall <A href="http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=%22digital+lifestyle+aggregator%22">digital lifestyle aggregation</A> scenario.[<a href="http://blogs.it/0100198/">Marc's Voice</a>]</blockquote> I think we're likely to support ESF straight away because: <ul> <li>it's there</li> <li>it's simple</li> <li>it's RSS2.0</li> </ul> I notice that there is also an <a href="http://web.resource.org/rss/1.0/modules/event/">events module</a> for RSS1.0. Does anyone use it? Based upon Marc's suggest I have taken a look at UpComing.org however it doesn't seem to support event metadata in it's feeds yet. Clearly we're interested in what such services will do in this area. http://matt.blogs.it/entries/00001929.html A cracking good read Fri, 17 Jun 2005 23:53:52 +0100 Today I picked up a copy of <a href="http://www.amazon.co.uk/exec/obidos/ASIN/0262531410/qid=1119048812/sr=8-1/ref=sr_8_xs_ap_i1_xgl/202-9212189-3436646">Statistical Language Learning</a> by Eugene Charniak. It seems like quite a thorough treatment of natural language processing using hidden markov models and probabilistic context free grammars. I'm also half way through Thomas Passin's <a href="http://www.amazon.co.uk/exec/obidos/ASIN/1932394206/qid%3D1119048989/202-9212189-3436646">Explorers Guide to the Semantic Web</a> which is a very useful guide to the current state of the art in RDF w.r.t. agents, searching, logic, and ontology. I'm especially motivated by the relevance to the cognitive psychology reading I did on judgement, reasoning, and decision making this year. Off the back of that I'm tinkering with a simple agent programming environment, written in Ruby, which I might release if it amounts to anything interesting. http://matt.blogs.it/entries/00002672.html