Posts Tagged: linked data

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9
May 11

Installing 4Store on MacOSX

Having got on fairly well with installing swiftOWLIM, I thought it would be a good idea to have a go with 4Store.

  1. Download the disk image.
  2. Open the disk image and copy the app to your Applications.
  3. Run the app.
  4. A terminal window will open which has the 4Store command-line tools in it’s path.
  5. Create a database (instructions): I went with the basic command. 
    4s-backend-setup mystorename
  6. Load some data (instructions): here I wanted to load multiples so used the command: 
    4s-import mystorename `ls /path/to/ntriples/*.nt`

    Some few minutes later (really not very long at all), my 18 million triples were loaded at a rate of something like 55,000 triples per second!

  7. Set up a SPARQL endpoint (instructions). 4Store has an internal soft limit on SPARQL queries to protect you from expensive ?s ?p ?o queries and other expensive query types. This defaults to 1000, but I wanted to alter that so I could run some queries which I knew were going to be inefficient due to the structure of the data I am working with. As this is my dev machine, I decided to just turn the soft limit off for all SPARQL endpoints that I create. Therefore I created a config file in /etc/4store.conf 
    sudo vi /etc/4store.conf
[default]
    soft-limit = 0 #disable soft limit.

    Then started the SPARQL http server endpoint on my chosen port.

    4s-httpd -p 8000 mystorename
  8. All done. and running expensive queries that return pretty fast.

This has to be the easiest setup of a triple store yet.

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8
Oct 10

Remove the dust sheets

It’s high time I removed the dust sheets from this blog and tried to discipline myself to actually write something.  To be honest I think I should try to stop thinking in sentences of 140 characters or less.  Twitter has probably clouded my ability to think thoughts longer than a text box with a countdown.

So, change is afoot again. If there is one thing that Talis (my employer) isn’t, it’s static.  The Talis strapline ‘Shared Innovation’ is exactly what we do on a daily basis.  I am currently shifting my role from a purely library focus, dealing with library customers in the library world to dealing with anyone who wants to work with semantically formed data published on the web of data.

How is this different from libraries?  Well, to some extent it is no different.  We are talking about standardising the publishing of data in machine readable form, whereas Library’s deal with information published and catalogued in a fairly standard human readable way.  One of the reasons that it is so easy to find things in a library (no really!) is because there are standard ways to represent, through classification, where the main topic of a book sits, and therefore which books it should be next to on the shelf.

Thus it is with Linked Data and the semantic web, except here the field is so new that we are still evolving the ways to say things about things, and ways to find what other people are saying about things. I plan to explore some of this stuff in later posts.

So, over the coming months, in my consultancy role, I will be getting the opportunity to meet other people who are getting started with the idea of linked data, and sharing with you some of the first steps experiences that I too have been through.

Now, how many of those sentences are longer than 140 characters?