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<?php rcs_id('$Id: SemanticWeb.php,v 1.8 2004/04/18 01:11:51 rurban Exp $');
/**
* What to do on ?format=rdf What to do on ?format=owl
*
* Map relations on a wikipage to a RDF ressource to build a "Semantic Web"
* - a web ontology frontend compatible to OWL (web ontology language).
* http://www.w3.org/2001/sw/Activity
* Simple RDF ontologies contain facts and rules, expressed by RDF triples:
* Subject (page) -> Predicate (verb, relation) -> Object (links)
* OWL extents that to represent a typical OO framework.
* OO predicates:
* is_a, has_a, ...
* OWL predicates:
* subClassOf, restrictedBy, onProperty, intersectionOf, allValuesFrom, ...
* someValuesFrom, unionOf, equivalentClass, disjointWith, ...
* plus the custom vocabulary (ontology): canRun, canBite, smellsGood, ...
* OWL Subjects: Class, Restriction, ...
* OWL Properties: type, label, comment, ...
* DAML should also be supported.
*
* Purpose:
* - Another way to represent various KB models in various DL languages. (OWL/DAML/other DL)
* - Frontend to various KB model reasoners and representations.
* - Generation/update of static wiki pages based on external OWL/DL/KB (=> ModelTest/Categories)
* KB Blackboard and Visualization.
* - OWL generation based on static wiki pages (ModelTest?format=owl)
*
* Facts: (may be represented by special links on a page)
* - Each page must be representable with an unique URL.
* - Each fact must be representable with an unique RDF triple.
* - A class is represented by a category page.
* - To represent more expressive description logic, "enriched"
* links will not be enough (? variable symbolic objects).
*
* Rules: (may be represented by special content on a page)
* - Syntax: reasoner backend specific, or common or ?
*
* RDF Triple: (representing facts)
* Subject (page) -> Predicate (verb, relation) -> Object (links)
* Subject: a page
* Verb:
* Special link qualifiers represent RDF triples, based on RDF standard notation.
* See RDF standard DTD's on daml.org and w3.org, plus your custom predicates.
* (need your own DTD)
* Example: page [Ape] isa:Animal, ...
* Object: special links on a page.
* Class: WikiCategory
* Model: Basepage for a KB. (parametrizeable pages or copies of modified snapshots?)
*
* DL: Description Logic
* KB: Knowledge Base
*
* Discussion:
* Of course *real* expert systems ("reasoners") will help/must be used in
* optimization and maintainance of the SemanticWeb KB (Knowledge
* Base). Hooks will be tested to KM (an interactive KB playground),
* LISA (standard unifier), FaCT, RACER, ...
* Maybe also ZEBU (parser generator) is needed to convert the wiki KB
* syntax to the KB reasoner backend (LISA, KM, CLIPS, JESS, FaCT,
* ...) and forth.
* pOWL is a simple php backend with some very simple AI logic in PHP,
* though I strongly doubt the usefulness of reasoners not written in
* Common Lisp.
*
* SEAL (omntoweb.org) is similar to that, just on top of the Zope CMF.
* FaCT uses e.g. this KB DTD:
<!ELEMENT KNOWLEDGEBASE (DEFCONCEPT|DEFROLE|IMPLIESC|EQUALC|IMPLIESR|EQUALR|TRANSITIVE|FUNCTIONAL)*>
<!ELEMENT CONCEPT (PRIMITIVE|TOP|BOTTOM|AND|OR|NOT|SOME|ALL|ATMOST|ATLEAST)>
<!ELEMENT ROLE (PRIMROLE|INVROLE)>
... (facts and rules described in XML)
*
* Links:
* http://phpwiki.org/SemanticWeb,
* http://en.wikipedia.org/wiki/Knowledge_representation
* http://www.ontoweb.org/
* http://www.semwebcentral.org/ (OWL on top of GForge)
*
*
* Author: Reini Urban <rurban@x-ray.at>
*/
/*============================================================================*/
/*
Copyright 2004 Reini Urban
This file is part of PhpWiki.
PhpWiki is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
PhpWiki is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with PhpWiki; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/**
* RdfWriter - A class to represent a wikipage as RDF. Supports ?format=rdf
*
* RdfWriter
* - RssWriter
* - RecentChanges (RecentChanges?format=rss)
* channel: ... item: ...
*/
include_once('lib/RssWriter.php');
class RdfWriter extends RssWriter // in fact it should be rewritten to be other way round.
{
function RdfWriter () {
$this->XmlElement('rdf:RDF',
array('xmlns' => "http://purl.org/rss/1.0/",
'xmlns:rdf' => 'http://www.w3.org/1999/02/22-rdf-syntax-ns#'));
$this->_modules = array(
//Standards
'content' => "http://purl.org/rss/1.0/modules/content/",
'dc' => "http://purl.org/dc/elements/1.1/",
);
$this->_uris_seen = array();
$this->_items = array();
}
}
/**
* OwlWriter - A class to represent a set of wiki pages (a DL model) as OWL.
* Supports ?format=owl
*
* OwlWriter
* - RdfWriter
* - Reasoner
*/
class OwlWriter extends RdfWriter {
};
/**
* ModelWriter - Export a KB as set of wiki pages.
* Probably based on some convenient DL expression syntax. (deffact, defrule, ...)
*
* ModelWriter
* - OwlWriter
* - ReasonerBackend
*/
class ModelWriter extends OwlWriter {
};
/**
* ReasonerBackend - hooks to reasoner backends.
* via http as with DIG,
* or internally
*/
class ReasonerBackend {
function ReasonerBackend () {
;
}
/**
* transform to reasoner syntax
*/
function transformTo () {
;
}
/**
* transform from reasoner syntax
*/
function transformFrom () {
;
}
/**
* call the reasoner
*/
function invoke () {
;
}
};
class ReasonerBackend_LISA extends ReasonerBackend {
};
class ReasonerBackend_KM extends ReasonerBackend {
};
// (c-file-style: "gnu")
// Local Variables:
// mode: php
// tab-width: 8
// c-basic-offset: 4
// c-hanging-comment-ender-p: nil
// indent-tabs-mode: nil
// End:
?>
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