WIF:Semantics

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Expressing Semantics with WIF

This page contains proposals and discussions about how to express semantic information with WIF. From a first investigation, RDFa seems to be a good solution. Actually we studied a subset of RDFa able to express the most relevant information we are interested in.

In particular we propose to use tags LINK, SPAN, META, A, and attributes property, rev, content and type. A very brief explanation about how they can be used is reported below.

Note: whenever we define a property, it is always referenced to the current document (and so, the property domain is the subject of the document).

Datatype properties tags

<span>  : to mark an inline value, defining the corresponding property with the special attribute property.

For example the following piece of text: 

<< ... you can contact me at john@doe.com <mailto:john@doe.com>  ... >>

can be marked up as follows: 

<< ... you can contact me at <span property=”email”>john@doe.com</span>	... >>


<meta> : to define properties which won't be rendered in the document (hidden in the final presentation). They will be inserted in the HEAD section of a page. A different encoding for the previous fragment can be: 

<head>
<meta property=”email” content=”john@doe.com <mailto:john@doe.com> ”/>
</head>

The attribute content can be used to represent the property value in a machine-parsable way. For example, the date 6th October 2006 can be represented as content=”2006-10-06”.

Both these solutions can be instanciated in (or extracted from) Semantic Media Wiki, as a datatype property (email): 

 [[email: <http://creativecommons.org/licenses/by-nc/2.5/> =john@doe.com]]

ObjectType properties tags

<a> : to define inline objectProperties, that is semantic relations embedded in the document content.

The following piece of text, which defines a relation between the document (property domain) and its license (property range),: 

<< ... this document is licensed under a Creative Commons Non-Commercial License ... >>

can be marked up as follows, by using the rel attribute: 

<< ... this document is licensed under a <a type="relation" rel=”has_license” 
href=”http://creativecommons.org/licenses/by-nc/2.5/ <http://creativecommons.org/licenses/by-nc/2.5/> ”>
Creative Commons Non-Commercial License
</a> ... >>

The attribute type can be used to define the link type giving some extra information. Apart from the previous example (such a link is a relation), we need to express "simple" or "interwiki" links ot whatever users need.


<link>: to express the same (or richer) information without embedding it in the text.

The same property of the example can be expressed as follows: 

<HEAD>
   <link rel=”has_license” href=”http://creativecommons.org/licenses/by-nc/2.5/”/> <http://creativecommons.org/licenses/by-nc/2.5/> 
</HEAD>

The rev attribute can be used to define inverse properties.

Both these solutions can be instanciated in (or extracted from) Semantic Media Wiki, as a relation ("has_licence"): 

[[has_license::http://creativecommons.org/licenses/by-nc/2.5/]] <http://creativecommons.org/licenses/by-nc/2.5/>
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