ARC2 and Triplify

I have been using Triplify to publish the MySQL world example database as linked data (see results here). I also tried out ARC2 to start messing about with PHP and SPARQL. Unfortunately the two don't currently play nicely together because ARC2's parsers don't like Triplify's N3 output. Fortunately we can use a back-door via CURL and SPARQL to work some magic.

function fetchURLAndStore($arc2store, $into, $url) {    
  $buffer = curl_exec($curl_handle);
  $q = 'INSERT INTO <' . $into . '> { ' . $buffer . ' }'


Gender Research and the Semantic Web

I enjoyed this interview with researcher Corinna Bath on Semantic Web Company's site. Her work touches on areas in my own research. This line in particular stood out for me: "Knowledge is always historically and culturally situated". Semweb triplets are so atomised that they are devoid of a context from narrative (both surrounding temporal/time & heteroglossia). However, the choice of ontology that the triplet is expressed still carries the context. Yes, the decision on the data for a particular object in a subject-predicate-object relationship is culturally dependent - but the boundaries for what the object can be are set by the ontology. The mere existence of a triplet also infers that it has some value - and that notion of value is culturally situated. The semweb allows for alternative viewpoints and for data to be expressed in whatever ontology fits the worldview you subscribe to. There is no central data-source and no central dictator of ontology. In this environment some ontologies and data-sources will become dominant. In the world of direct-linking RDF (LDI e.g. DBPedia) there will be a mainstream discourse that is powerful. However, this does not exclude alternatives. A pragmatic information consumer accepts that the information author holds certain views and adjusts. The "adjusting" applies as equally to alternative voices as it does to the mainstream hegemony. This is at the heart of the critical consumer/critical thinking or, in simpler terms, surfing with the BS filters set to high. Creative writing authors are encouraged to find their voice; the parallel for semweb information producers is to produce information in the worldview in which they can produce the most accurate information with the least amount of data. The flipside, and something I'm keenly aware of as a graphic designer, is that there must be some utility to the audience. That is, you write using your voice with an audience in mind because your voice is wasted if your intended audience will not understand or accept it. An utterance attempts to convince an audience of the truth of the utterance. This applies even to data triplets on the semweb - except that a semweb triplet is like storytelling with three word flash fiction (e.g. priest->death->saturday). My hope is that future semweb interfaces allow for the synthesis of data from multiple sources/ontologies and that indirect-linking is further developed. Indirect-linking allows for information discovery off the direct-link beaten track. This would allow users more control over what they see - hopefully allowing users tools that assist recontextualising data from the expressed worldview into the user's own reality.


Beta: Rule of Twos

Via Stylegala comes a post by Lois Knight on Typography Essentials. I have been toying with a rule-of-thumb for simplifying web-typography. It's not what I'd call fully tested yet, but it has been working well enough with the students that I've had try it. Here it is:

The rule of twos: No more than two type faces, two colours, two point sizes, two line-spacings and two weights.

Of course you should break this rule, but when you don't have the time, energy or inspiration such rules of thumb can be useful. Oh, it's still in beta so send me your feedback.


Links for Group Presentation

Faceted Browser examples
Tabulator example Links for my research group presentation. Some examples of web methods for browsing the semantic web.


Tabulator Firefox extension

I've just started using the Tabulator Firefox extension for browsing the SemWeb. I found that it needed a few tweaks to make it play super-duper nicely.

  • If you have the Piggybank (and Solvent) Firefox extensions then disable these.

Use about:config in the address bar of firefox and change these keys:

  • signed.applets.codebase_principal_support = true (search using the word signed or codebase)
  • network.http.accept.default : add application/rdf+xml to the head of the comma-separated list. (search using the word accept)

Now DBPedia "resource/" links will correctly resolve to using Tabulator, while "page/" links will use DBPedia's own browser. Try it out below:


Ontological Expressiveness and FOAF

This post on Danbri's Blog highlights an interesting issue in ontological design. Just how specific and expressive do we make an ontology?

TBL has espoused designs that have the "Least Power" which makes them easier to design, implement and use. The sucess of HTTP is a great case in point. As a parallel, in graphic design we have a famous quote about beauty being taking everything out until you can't take anything else out. It's a pretty good philosophy, but like least approached it requires a knowledge of exactly how much is enough and how much is too much. That requires a deep knowledge of how the ontology will be used.

In FOAF, the a single relationship type foaf:knows exists. And most mapping tools I've seen assume a bi-directionality in foaf links - that is if one person lists another as a friend then a back-link is assumed whether or not it actually exists.

Do we want more specificy in foaf relationship types? Perhaps a fuller suite of uni-directional relationship types? In these early stages I'm not sure it's so important to get so specific. Once we get more of foaf:knows relationships then some way to classify these would become more important. For example, Facebook allows an optional level of extra specificity in describing relationship types - that is often necessary given the numbers of friends some people collect in Facebook social networks.

There is some work in this area already: A vocabulary for describing relationships between people

From another perspective, if an enumerated type over a typical dataset forms clusters approaching a single member - and that enumerated type is not meant to be a candidate key and the enumerated label is not naturally a singleton then the enumerated type is probably too specific. (an example of a natural singleton enumeration would be motherof or fatherof.)

And "typical" is the key here. Ultimately it becomes the specialist vs generalist tension that only really gets resolved via de-facto usage.


SemWeb links of the Week

My Top 3 SemWeb links for the week:
  • DBpedia - community based effort to extract structured data from Wikipedia.
  • Freebase - Community organised ontologies and ontologies with an open api for apps to access
  • Revyu - Review and rate anything