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FOAF spec revised - addtion of foaf:focus, a skos extension linking topical and factual information

From: Dan Brickley <danbri@danbri.org>
Date: Mon, 9 Aug 2010 14:17:01 +0200
Message-ID: <AANLkTinSiEtwAjsk8dpjO4xE9CNqWocTZ1DSU=A_pzrJ@mail.gmail.com>
To: SKOS <public-esw-thes@w3.org>
Hi SKOS folks

http://xmlns.com/foaf/spec/
http://xmlns.com/foaf/spec/20100809.html#term_focus

Just to let you know, there's a revision of the FOAF specification
today. It includes a new term, foaf:focus that links a skos:Concept to
the thing that the concept stands for.

This notion has been discussed many times here over the years,
sometimes as "skos:it", but never made it into W3C's REC-track SKOS
spec. FOAF has long contained a cluster of topic-oriented properties
(topic/page, primaryTopic), and in FOAF we have a long-standing
concern with describing the areas of interest and expertise for people
and other agents (eg. organizations, groups, projects). The addition
of foaf:topic is intended as a modest and pragmatic bridge between
SKOS-based descriptions of topics, and other more entity-centric RDF
descriptions. When a SKOS Concept stands for a person or agent, FOAF
and its extensions are directly applicable; however we expect
foaf:focus to also be used with places, events and other identifiable
entities that are covered both by SKOS vocabularies as well as by
factual datasets like wikipedia/dbpedia and Freebase.

Other relevant changes: the overview of FOAF at the top of the spec
now more clearly separates two informal sub-sets of FOAF terms: "Core
FOAF" terms and "Social Web" terms. The distinction is made with
regard to whether a term is useful in describing someone or something
who lived before the Web / internet. Only the more universal
characteristics of groups, people etc are considered 'core FOAF';
things like 'homepage', 'openid', 'weblog' are in the "Social Web"
layer. Previously, we mistakenly gave the impression that FOAF was
only for describing modern-day online accounts; hopefully the new
formulation more accurately conveys an interest in capturing
historical information too. There have also been some other textual
changes that attempt to indicate more clearly what we're attempting
with FOAF - essentially the combination of social and informational
networks.

Re the "Core" subset, brief excerpt: "Core - These classes and
properties form the core of FOAF. They describe characteristics of
people and social groups that are independent of time and technology;
as such they can be used to describe basic information about people in
present day, historical, cultural heritage and digital library
contexts. In addition to various characteristics of people, FOAF
defines classes for Project, Organization and Group as other kinds of
agent."

Also, various older terms (used in early demonstrations and
prototypes, plus some spelling variations) are now marked 'archaic',
both in human and machine-readable documentation.

Feedback on the current design and description are welcome, either
here or on the foaf-dev list. My hope is that with foaf:focus we can
begin today gathering real-world implentation experience and data that
could inform any future revisions to SKOS itself. If W3C were to
eventually charter and complete an effort to update SKOS with matching
functionality to foaf:focus, we would of course update FOAF
accordingly to indicate the new mechanism. In the meantime, foaf:focus
is available for use, experimentation and collaboration. I hope it
proves useful when linking topically structured and factually based
RDF information.

cheers,

Dan

ps. one thing the spec currently lacks is an example of the new
property. I'm waiting on this point, as several people are working on
related datasets, and I hope soon we'll have real-world examples to
illustrate foaf:focus's usage.
Received on Monday, 9 August 2010 12:17:33 GMT

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