B:\datenbrei » foaf

Working as a Program Committee member

[GNU] — Thu, 21 Aug 2008 11:35:16 +0000

Back in May Uldis Bojars asked me if I would like to join the program committee for a series of workshops called “Social Data on the Web workshop (SDoW2008) co-located with the 7th International Semantic Web Conference (ISWC2008)”. As I am a great procrastinator and deadlines appear closed than they are I started reviewing two papers both found in the domain of tags and online presence.

I hope I get my stuff done this week, so stay tuned for more…

SIOC and Firefox: detect and identify

[GNU] — Fri, 18 Aug 2006 15:46:53 +0000

The number of site publishing SIOC data on the web ist constantly increasing. To help users make use of this data “Semantic Radar” has been developed and release by Uldis BojÄrs.

It is a browser extension (for Fireofx only by now) which inspects web pages for links to Semantic Web metadata and informs the user about their presence by showing an icon in browser’s status bar.

Originally developed to detect presence of SIOC metadata it has been extended to cover other types of data. Currently it supports SIOC, FOAF and DOAP metadata.
The current version of Semantic Radar also pings the Semantic Web Ping Service when metadata is detected. This allows a community based discovery of the semantic web data and a notification of a central ping service.

UPDATE: Fred also has a post on Semantic Radar…

Declarative Living: indicating the preferred contact channel

[GNU] — Tue, 01 Aug 2006 17:47:40 +0000

I have a first update to FOAF-EXT which is based on a comment by Richard Cyganiak, he suggested a more general way to indicate that something is my preferred way of contact/communication, a foafx:preferredMeansOfContact. So I have updated the FOAF EXTension ontology to have such a property, it is a boolean property and the suggested usage is to only use it with a value of true (to indicate that something is a preferredMeansOfContact).

Here is an example of its usage:


   
    
     true
     
     
     
   5554184@sipgate.de

This should be read as “this online account (actually a sip account at some sip provider) is my preferred way to contact me”.

Using preferredMeansOfContact does not involve subclassing foaf:OnlineAccount so it may be omitted by consumers which only understand FOAF, in contrast foafx:PreferredOnlineAccount may be skipped by such consumers which results in data loss.

no loopback from sioc:User to foaf:Person

[GNU] — Fri, 09 Jun 2006 06:49:05 +0000

Having a sioc:Post it points to it’s creator described as a sioc:User. Assuming a foaf:Person, it should describe that the Person owns a foaf:OnlineAccount – which is the sioc:User.
Since the sioc:User profile is “user”-centric (and sioc:User rdfs:subClassOf foaf:OnlineAccount), there should be a property that allows us to links back from a sioc:User to a foaf:Person to whom it belongs to.

Introducing a foaf:OnlineAccount foaf:accountOf foaf:Person


 a rdf:Property, owl:ObjectProperty;
:comment "Indicates an agent holds an account.";
:range ;
:domain ;
:isDefinedBy <http://xmlns.com/foaf/0.1/>;
owl:inverseOf ;
:label "account of";

See Also: SIOC for foafroll

SIOC enabling a community site

[GNU] — Mon, 22 May 2006 20:15:27 +0000

After installing the SIOC WordPress plugin this site is enabled to provide SIOC data for the site itself, users and all articles on B:\datenbrei. Many site on the internet don’t provide SIOC data, this is mainly due to the fact that SIOC development is still at an early stage. But what about Planets? Do they provide SIOC data? So let’s have a look at Planet RDF and how it may be enabled to provide SIOC data.

Planet RDF provides a foafroll, a RDF/XML representation of the feeds which get aggregated and their authors. This is a good starting point and actually a pretty complete description of the RDF community (at least of the blogging RDF community).

Taking a look at foafroll we find foaf:Agents and there blogs. This provided data will be convertet into SIOC Users in the first step.


 FOAF Project
 
  
   FOAF Project

I would like to propose a mapping like this:

 
  FOAF Project

Next step is to set up a sioc:Usergroup containing all members (foaf:Agents) of the foafroll:

 
  Authors at PlanetRDF.com

Interpreting sioc:Site as “This is a Community” and not as “This is one Site of others of a Community” one must interpret Planet RDF as a Forum of the community/Site:


 PlanetRDF.com, part of the RDF Community
 
 



 The RDF Community
 Planet of the RDF Community

Note: Maybe it would make some sense to rename sioc:Site to sioc:Community? See also a SIOC-dev posting (or was it a chat with CaptSolo??).

I have not done some Jena-based code up until now. Before releasing it I would like to have some comments on the idea, maybe some improvements need to be incorporated…

A complete example of a SIOC-from-foafroll (handcrafted) and some coffee is available too.

Internationalized SPARQL queries

[GNU] — Wed, 26 Apr 2006 06:36:20 +0000

Looking throught some notes of the SPARQL Calendar Demo I encountered the problem of internationalization: My dataset (here) does contain myself as a FOAF Person with statements like:

  Christoph
  GÃ¶rn
  Goern

Using the SPARQL query that

Show me all people along with their names (if found), unique IDs (if found), and calendar URLs (if found) in my current RDF dataset.

results in:

1 ( ?who = http ://B4mad.Net/FOAF/goern.rdf#goern ) ( ?name = "Christoph Goern" )
   ( ?id = "0a9d600329b781dcdd710bf97c8ad16c44cf8dc9" ) ( ?cal = http ://b4mad.net/addressbook/geburtstage.rdf )
2 ( ?who = http ://B4mad.Net/FOAF/goern.rdf#goern> ) ( ?name = "Christoph Goern" )
   ( ?id = "0a9d600329b781dcdd710bf97c8ad16c44cf8dc9" ) ( ?cal = http ://b4mad.net/FOAF/goern-reisen.rdf )
3 ( ?who = http ://B4mad.Net/FOAF/goern.rdf#goern ) ( ?name = "Christoph GÃ¶rn"@de )
   ( ?id = "0a9d600329b781dcdd710bf97c8ad16c44cf8dc9" ) ( ?cal = http ://b4mad.net/addressbook/geburtstage.rdf )
4 ( ?who = http ://B4mad.Net/FOAF/goern.rdf#goern ) ( ?name = "Christoph GÃ¶rn"@de )
   ( ?id = "0a9d600329b781dcdd710bf97c8ad16c44cf8dc9" ) ( ?cal = http ://b4mad.net/FOAF/goern-reisen.rdf )

Too many of myself! Note to self: fix my body count.

To do so, the SPARQL query should filter out any foaf:name that has a unset xml:lang:

PREFIX foaf: 
PREFIX rdf: 
PREFIX ical: 
PREFIX rdfs: 
SELECT ?who ?name ?id ?cal
WHERE {
  ?who rdf:type foaf:Person .
  OPTIONAL { ?who foaf:name ?name }
  OPTIONAL { ?who rdfs:label ?name }
  OPTIONAL {
    { ?who foaf:mbox ?id }
      UNION
    { ?who foaf:mbox_sha1sum ?id }
  }
  OPTIONAL {
    ?who rdfs:seeAlso ?cal .
     ?cal rdf:type ical:Vcalendar
  } .
  FILTER ( langMatches( lang(?name), "" ) )
} ORDER BY ?name

Expressing my preferred method of contact initiation

[GNU] — Tue, 18 Oct 2005 19:56:18 +0000

Giving a business card to a person just meat usualy means that some kind of contact is going to be established in the future, by mail or phone or whatever the person will choose. Putting a FOAF file on the web basically solves the same task: giving the opportunity to contact. But how? Send Email? Use ICQ or AIM ?!

Within the FOAF Vocabulary there is no way to give the contacting Person a list of methods that I (as the FOAF providing Person) would like him to use to contact me. To answer the question “What is the best way to contact goern?” we need some extensions to FOAF that are able to document what recommendation I give on how to contact me: preferred online accounts.

The first extension I would like to suggest is to extend foaf:OnlineAccount to represent Email Online Accounts. The new OnlineEmailAccount is a subclass of foaf:OnlineAccount and has a mbox and mbox_sha1sum property in addition to the inherited properties. This extension will introduce redundant data becuase mbox and mbox_sha1sum is defined for a foaf:Person. TODO: link this four properties to be semantically the same.

The second extension is a subclass of foaf:OnlineAccount and is called PreferredOnlineAccount. It has no additional properties and is only used to denote an online account of any kind (Chat or Email) as a preferred online account. Example usage may be found in an earlier posting on this topic.

As a first draf I have put together something I called FOAFX – FOAF Extensions this can also be found on schemaweb

I’ll be very happy to receive any feedback on the idea, extensions and draft.

From Foaf to WITW

[GNU] — Thu, 06 Oct 2005 19:13:44 +0000

This evening I hacked arround some Jave/Jena/ARQ/XMPP based stuff. My main goal was to have a bot accessable via XMPP Chat or Groupchat that is capable of answering simple questions. Right now it can show me depictions of a Person bild von somenick and figure out where someone is wo ist nick. The wo-ist-service depends on Norman Walsh WITW Service. The link between a nick and the depiction of a person is obviously foaf:nick, using Sparql retrieving this information from the Jena Model was not that hard. The link between a nick and WITW is a foaf:onlineAccount with a foaf:accountServiceHomepage of http://norman.walsh.name/2005/02/witw/is/ Retrieving all such foaf:onlineAccount for a given foaf:nick reveals if the person has an account for the WITW and what his userid is at WITW. Having this data I simply http.get the XML from …/witw/is/…

Accessing WITW via HTTP, onlineAccount and depiction information from the Jena Model has been seperated into so called Data Access Objects (DAO) which return Value Objects (VO) containing the actual data.

XMPP communication starts retrieving information and sends back the content of Value Objects to (at the moment) a Multi User Chat (MUC) at #b4mad@conference.jabber.ccc.de

That’s it… source code for this can be found… happy for any feedback! Thanks to ldodds and AndyS for the support. The jabber id of the bot is gnu-0000-000-a@b4mad.info

UPDATE 2005-10-07: I you want to enable your FOAF File to contain the required information for the WITW service add something like

to your foaf:Person .

X-FOAF in Mail.app

[GNU] — Fri, 10 Dec 2004 15:44:28 +0000

Ok, here are the usual references: The idea and the mac-related implementation. But what’s next? A fancy plugin for Mail.app to open up foaf-explorer or rules that highlight all mails from people with X-FOAF headers? Or maybe a plugin that tries to pick up the gpg keys of people to grow my gpg keyring automatically to fully encrypt the next mail to the sender which just got in my mailbox with an X-FOAF: ?

via Planet RDF – Link auf FOAF file in jeder Mail

[GNU] — Tue, 23 Nov 2004 10:47:29 +0000

Via Planet RDF kam die Idee, dass
“you can include an email header X-FOAF: http://example.org/foaf.rdf that indicates the location of your FOAF file.” Super Sache das, nur wie sag ich es meiner MacOSX Mail.app??

FOAF-Galway must be a success

[GNU] — Tue, 07 Sep 2004 16:07:24 +0000

FOAF-Galway has produced some very interessting papers and a huge like collection…

foaf and semantic visits

[GNU] — Wed, 07 Jul 2004 08:43:08 +0000

So I added the two wonderful plugins by mortenf: 1) Semantic Visits and 2) FOAF Output. But the foaf.rdf generation is still broken…

FOAF – Ich kenne wen den du auch kennst…

[GNU] — Thu, 11 Sep 2003 11:30:59 +0000

Heute habe ich endlich mal mein FOAF file updated, es ist jetzt also brandneu, und genuegt den neusten Konventionen.

Aber, wieso braucht der Internet-Mensch eigentlich ein solches file? Man weiss es noch nicht, es ist eine Idee im “semantic web”, und ich denke das es ein gutes Tool ist die Menschen und Gruppen zu visualisieren.

Starten kann man gut mit dem FOAF-a-matic Tool von Leigh Dodds. Damit hat man alle Basiseintraege die man haben sollte. Zwei weitere gute Tools sind die FOAF Tools und die FOAF people map. Letzteres erfordert ein SVG Plugin.

Wo findet man nun mein FOAF file?! Entweder direkt im erdGeschoss oder schoen visualisiert.