Monthly Archives: April 2009

RDF sequences … could they be more semantic?

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Although triples can in principle express anything (well anything computational), this does not mean they are particularly appropriate for everything1.

RDF sequences are one of the most basic structured types and I have always found the use of rdf:_1, rdf:_2 at best clunky.  In particular I don’t like the fact that the textual form embodies the meaning.

In the RDF schema, rdf:_1, rdf:_2, etc are all instances of the class rdfs:ContainerMembershipProperty and sub-properties of rdfs:member.  However, I was also looking to see if there was some (implicitly defined) property of each of them that said which index they represented.  For example:

<rdf:_3> <rdf:isSequenceNumber> “3”

This would mean that the fact that rdf:_3 corresponded to the third element in a sequence was expressed semantically by rdf:isSequenceNumber as well as lexically in the label “_3”.

Sadly I could find no mention of this or any alternative technique to give the rdf:_nnn properties explicit semantics 🙁

This is not just me being a purist,  having explicit semantics makes it possible to express queries such as gathering together contiguous pairs in a sequence:

<ex:a> ?r1 ?a.
<ex:a> ?r2 ?b.
?r1 <rdf:hasSequenceNumber> ?index.
?r2 <rdf:hasSequenceNumber> ?index + 1.

Without explicit semantics, this would need to be expressed using string concatenation to create the labels for the relations – yuck!

Have I missed something? Is there an alternative mechanism in the RDF world that is like this or better?

Mind you I don’t see what’s wrong with a[index] … but may be that is just too simple?

  1. see also previous posts on “It-ness and identity: FOAF, RDF and RDMS” and “digging ourselves back from the Semantic Web mire“[back]

tech talks: brains, time and no time

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Just scanning a few Google Tech Talks on YouTube.  I don’t visit it often, but followed a link from Rob Style‘s twitter.  I find the video’s a bit slow, so tend to flick through with the sound off, really wishing they had fast forward buttons like a DVD as quite hard to pull the little slider back and forth.

One talk was by Stuart Hameroff on A New Marriage of Brain and Computer.  He is the guy that works with Penrose on the possibility that quantum effects in microtubules may be the source of consciousness.  I notice that he used calculations for computational capacity based on traditional neuron-based models that are very similar to my own calculations some years ago in “the brain and the web” when I worked out that the memory and computational capacity of a single human brain is very similar to those of the entire web. Hameroff then went on to say that there are an order of magnitude more microtubules (sub-cellular structures, with many per neuron), so the traditional calculations do not hold!

Microtubules are fascinating things, they are like little mechano sets inside each cell.  It is these microtubules that during cell division stretch out straight the chromosomes, which are normally tangled up the nucleus.  Even stranger those fluid  movements of amoeba gradually pushing out pseudopodia, are actually made by mechanical structures composed of microtubules, only looking so organic because of the cell membrane – rather like a robot covered in latex.

pictire of amoeba

The main reason for going to the text talks was one by Steve Souders “Life’s Too Short – Write Fast Code” that has lots of tips for on speeding up web pages including allowing Javascript files to download in parallel.  I was particularly impressed by the quantification of costs of delays on web pages down to 100ms!

This is great.  Partly because of my long interest in time and delays in HCI. Partly because I want my own web scripts to be faster and I’ve already downloaded the Yahoo! YSlow plugin for FireFox that helps diagnose causes of slow pages.  And partly  because I get so frustrated waiting for things to happen, both on the web and on the desktop … and why oh why does it take a good minute to get a WiFi connection ….  and why doesn’t YouTube introduce better controls for skimming videos.

… and finally, because I’d already spent too much time skimming the tech talks, I looked at one last talk: David Levy, “No Time To Think” … how we are all so rushed that we have no time to really think about problems, not to mention life1.  At least that’s what I think it said, because I skimmed it rather fast.

  1. see also my own discussion of Slow Time[back]

French subvert democatic process to pass draconian internet laws

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Just saw on Rob @ dynamicorange, that the French have passed a law forcing ISPs to withdraw access based on accusations of IP infringement. Whether one agrees or disagrees  or even understands the issues involved, it appear this was forced through by a vote of 16 (out of 577) members of the French parliament at a time when the vote was not expected.  This reminds me of the notorious Shetland Times case back in the late 1990s, where the judgement  implied that simply, linking to another site infringed copyright and caused some sites to stop interlinking for fear of prosecution1, not to mention some early US patents that were granted because patent officers simply did not understand the technology and its implications2.

It would be nice to think that the UK had learnt from the Shetland case, but sadly not.  Earler this year the Government released its interim Digital Britain report. This starts well declaring “The success of our manufacturing and services industries will increasingly be defined by their ability to use and develop digital technologies“; however the sum total of its action plan to promote ‘Digital Content’ is to strengthen IP protection.  Whatever one’s views on copyright, file sharing etc., the fact that a digital economy is a global economy seems to have somehow been missed on the way; and this is the UK’s “action plan to secure the UK’s place at the forefront of innovation, investment and quality in the digital and communications industries”3.

  1. See “Copyright battles: The Shetlands” @ Ariadne and “Scottish Court Orders Online Newspaper to Remove Links to Competitor’s Web Site” @ Harvard’s Berkman Center for Internet & Society.[back]
  2. and for that matter, more recent cases like the ‘wish list’ patent[back]
  3. UK Department for Culture, Media and Sport Press Release 106/08 “Digital Britain – the future of communications” 17th October 2008[back]

movie: Lars and the Real Girl

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Last night we watched Lars and the Real Girl.  It was unusual for a US movie, which are great for the blockbuster and escapism, but rarely manage to deal with sensitive issues without feeling they have to be told  in epic scale.  Lars is set in a small town and shows a community and family dealing with psychological problems.  Quirky without being screwball, and full of touching moments, whilst not drawing back from the humour of the situation.

As well as the screenplay, the cinematography reminded me of British films, with that sense of really being there rather than in an over-polished Hollywood screen-set.

sun on the sea

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Today is raining and overcast, but the last two days utterly glorious.  Yesterday the sun on the sea took my breath away, the waves turned to quicksilver.