04/2013 - today
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10/2010 - 04/2013
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2009 - 10/2010
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2009 - 2010
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2008 - 2010
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OWLlink:
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Work on the W3C Member Submissions OWLlink. I specified the
functional binding
and the
S-Expression binding
in collaboration with
the company Derivo, colleagues from the university of Ulm, and DOCOMO Euro Labs.
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My Common Lisp open source framework
OntoLisp
provides the native reference
implementation of OWLlink.
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2008 - 2009
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BOEMIE:
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A project funded by the European Commission
on semantic multi-media interpretation and ontology bootstrapping.
My ontology query language
"nRQL" was extended with abductive query answering capabilities to provide the reasoning backbone of the
semantic interpretation engine.
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2007 - 2009
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2007 - 2010
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2001 - 2006 (PhD Work)
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DLMAPS (Description Logic Maps):
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An experimental,
prototypical description logic-based geographic information system,
featuring a high-performance deductive query answering engine. The
framework supports hybrid (spatial and logical) representations and is
capable of processing ontology-based spatio-thematic queries.
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The Racer query
language nRQL is an instantiation of this generic query engine
framework.
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Similar systems have
appeared, e.g. "Pellet Spatial" ™ by Clark & Parsia,
and standards such as GeoSPARQL are emerging.
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2004
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2003 - 2010
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nRQL (new Racer Query Language):
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An influential
Description Logic and OWL query language for the RacerPro reasoner.
The generic query engine underlying nRQL explored the idea of
representation- and application-specific entailment relationships
(nowadays called "entailment regimes" in SPARQL), offering
expressive means such as classical negation and negation as failure,
universal quantification, subqueries, user-defined procedural
extensions, etc. Many of these expressive means have been adopted for
standards such as SPARQL in the meantime.
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nRQL was the first
practical, fully working description logic "ABox" query engine with
a heuristic cost-based query optimizer. The optimizer uses selectivity
heuristics for re-ordering of subgoals in conjunctive queries,
hence generating effective query evaluation plans by rewriting queries.
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The optimizer was fully
operational and documented in RacerPro in 2004. More
details about the optimizer can by found in my thesis from 2007,
together with a comprehensive evaluation of the effectiveness of the
various optimization techniques using the LUBM benchmark. Some of these
optimization techniques have been applied to SPARQL by other researchers in the meantime, for example, see
this paper by Stocker et al.,
or
this paper by Glimm et al.
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In 2004, nRQL became the first
OWL query engine that could answer the queries from the (nowadays standard) "Lehigh University Benchmark (LUBM)" completely.
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Here is a (non-exclusive) list of researchers who have used nRQL in their projects:
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11
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2004 - 2010
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1997 - 1998 (Diploma Thesis)
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1995 - 1996 (Project Work)
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GenEd:
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A description
logic-based graphical editor for designing visual formalisms (e.g. Petri Nets).
The editor is capable of recognizing spatial constellations described by spatial
concepts in a description logic ontology.
Enjoy our QuickTime video ;-)
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