Category Archives: SemWeb

http://www.w3.org/2001/sw/
skos:broader http://danbri.org/words/?author=2/skos.rdf#c9 Web Technology

Computing Cloud

Databases, Hardware, SemWeb

Amazon is launching another Limited Beta, which seems to be the only way to launch anything these days.

This time they build on the S3 success, and add the next obvious component to the equation: Computing on demand, Amazon Elastic Compute Cloud (Amazon EC2).

As with S3, you get what you pay for and vice versa, no signup fees. S3 is used (and paid for separately) to store the computing images, and the EC2 additional pricing seems at first glance to be quite reasonable:

  • $0.10 per instance-hour consumed (or part of an hour consumed).
  • $0.20 per GB of data transferred outside of Amazon (i.e., Internet traffic).

The bandwidth cost might be an issue, but depending on what you want to compute, it might not a problem.

I could envision running some serious reasoning on a thing like this…

Planet Timeline

JavaScript, RSS, SPARQL

Following up on the other day’s post on SPARQL and the Simile Timeline, here is another way of putting items on a timeline.

I’ve created a SPARQL template for Planet Planet, you can see it in action on my personal planet.

The template makes (optional) use of identifying icons for each feed, which are configured in the Planet config.ini (don’t forget to add the SPARQL template to the template_files configuration option as well):

[http://www.wasab.dk/morten/blog/feed/rdf]
name = Binary Relations
timeline_icon = dull-red-circle.png

Once set up, the generated SPARQL results (example) can be run through the SPARQL Timeline Service (example).

Integrating the timeline into the default Planet HTML isn’t hard, I’ve created a tweaked version of examples/basic/index.html.tmpl from the latest nightly — see it in action.

Getting this running on a working Planet installation should be as simple as downloading the two templates to the right location, and updating the Planet configuration file (default dull-blue icons will be used if not specificed per feed).

Update: Note that the planet-sparql.srx file needs to be returned by the web server with an XML mime type, preferably application/sparql-results+xml. If you’re unable to configure your server to make it do that, try renaming the template and file to use .xml instead of .srx as the file extension — that should make it return with application/xml. Thanks to Edward Summers for pointing this out on the Planet developer list.

SPARQL and SIMILE Timeline

JavaScript, RDF/XML, Redland, RSS, SPARQL

Danny Ayers has been working on getting the SIMILE Timeline to eat SPARQL through the use of its JSON interface and some XSLT, he has notes on the ESW wiki.

While trying to get his work running here, I realized that the trip through XSLT to create JSON output really wasn’t necessary.

Instead, I’ve created a custom SPARQL event source parser, to load SPARQL results directly into the timeline. This way, the SPARQL results format generated by running the query doesn’t need a round trip into either JSON or the custom Timeline XML format.

The SPARQL Timeline demo works with any RSS 1.0 feed (try it with the one from Planet RDF) .

Update: Now also works with “raw” SPARQL results, try it with photos of laptops from The Gargonza Experiment (scroll to April of 2005). Expected variable bindings are date, title, description, and link, although the latter is optional and the first can be replaced by start.

Update: Now really works with “raw” SPARQL results. Due to javascript’s security model, only files on this server worked — until now. Also, a buglet regarding empty literal elements have been fixed.

(Almost) No More Comments

FOAF, Identity, WordPress

I haven’t been writing much here lately, but others have.

Or rather: They’ve tried.

Some time ago I turned off trackbacks and pingbacks completely, and changed the options for comments to require moderation before anything went online.

That hasn’t stopped the spammers though — I get at least ten mails about spam comments each day, and frankly that’s just not fun.

I should be upgrading to the lastest version of WordPress, as that includes the clever Akismet plugin for catching spam, which seems to work quite well on the other blogs I run. Also, I really should finish the plugin that leverages my social network through FOAF, that’d make for a really great combination, methinks.

Instead I’ve activated a plugin that turns off comments and pings within 30 days of the posting date.

I’m sorry for the inconvience for those who wish to comment on older posts — for now it has to be like that (but do send me a mail if you’d like to comment anyway).

Digital Camcorder Considerations

GPS/Geo, Hardware, Image Description

We want to get a digital camcorder.

There’s a wedding coming up, some travelling, later perhaps more interesting “subjects”, and then of course there’s the gadget dimension.

Among the criteria for selection are:

  • Relative ease of use: OK, I’m geeky, but devices with less than 85 keys are often impossible to figure out…
  • Dependability: We’re prepared to back up to HD and other media, but we still want to be able to trust the media.
  • Quality: The raw footage should be raw, not compressed. The images are more important than the sound.
  • Future proof: I know, not possible in this world, but it seems it’d be OK to go for HD?
  • Comfortable: Small and handy, likely to just be available and ready to go when needed.

Currently on the short list is the Sony HDR-HC3. Compared to its predecessor, the HC1, there are improvements as well as changes to the worse, but overall it seems it’s progress.

What to do?

ObSemWebAngle: Ideally, it should also include GPS integration and other ways of content description! ;-)