Category Archives: General

URIs have a namespace part and a local part, right?

Posted on February 8, 2016 by Richard Cyganiak

This is a technical post on the way URIs break down into “namespace parts” and “local parts” in RDF. It was prompted by this comment in a recent discussion: In a URI, the namespace part ends with the last slash … Continue reading →

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Multiple itemtypes in Microdata

Posted on August 2, 2011 by Richard Cyganiak

There’s a lot of discussion recently around HTML5’s microdata proposal, and how it relates to W3C’s earlier RDFa standard that is currently being updated for HTML5. Microdata solves many of the use cases of RDFa in a much simpler way. … Continue reading →

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Creating an RDF vocabulary: Lessons learned

Posted on March 7, 2011 by Richard Cyganiak

With tools like Neologism and OpenVocab, creating an RDF vocabulary is easy. But if your goal is re-use within a wider community, you will face many questions that are not so easy to answer: How much work is it going … Continue reading →

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Blank nodes considered harmful

Posted on March 2, 2011 by Richard Cyganiak

Well, they are not always harmful. But most of the time. I’ll get to that in a minute. On the semantic-web@w3.org list, W3C’s Sandro Hawke has a lucid and concise summary of the problems with blank nodes in RDF. It’s … Continue reading →

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Top 100 most popular RDF namespace prefixes

Posted on February 15, 2011 by Richard Cyganiak

I run prefix.cc, a website for RDF developers where anyone can register and look up the expansion URIs for namespace prefixes such as foaf, dc, qb or void. The site tracks which prefixes gets looked up most often. This allows … Continue reading →

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Maintenance

Posted on October 28, 2010 by Richard Cyganiak

This weblog has become quiet. These days, most of my word count goes into mailing lists, Twitter, and way too much personal email. Over here on the blog, cobwebs are gathering and some signs of bitrot have become evident. So … Continue reading →

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prefix.cc, MkII

Posted on January 11, 2010 by Richard Cyganiak

prefix.cc is a website I’ve made last February to ease a very common task in the life of RDF developers and SPARQL users: looking up namespace URIs. A short summary of what the site can do for you is available … Continue reading →

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What’s in a name? And the Linked Data Police

Posted on November 21, 2009 by Richard Cyganiak

So I wrote a rather angry private email to Erik Wilde a few days ago, complaining about his use of the term “linked data” for a site that doesn’t follow the linked data practices. Erik decided to publish my email … Continue reading →

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Linked data at the New York Times: Exciting, but buggy

Posted on October 30, 2009 by Richard Cyganiak

Update: Evan Sandhaus reports that all the issues mentioned below will be fixed. Great! Yesterday at the International Semantic Web Conference, Evan Sandhaus of the New York Times unveiled data.nytimes.com, a site that publishes linked data for some parts of … Continue reading →

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Multiple Java versions on OS X, and their paths

Posted on August 18, 2009 by Richard Cyganiak

Java version management on OS X is a wee bit complicated. Here’s what I understand. All different versions of Java are installed into the directory: /System/Library/Frameworks/JavaVM.framework/Versions/ For example, the JDK home directory for 1.4.2 would be Versions/1.4.2/Home/. There are three … Continue reading →

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