ldac 2015 - towards an industry-wide ifcowl: choices and issues
TRANSCRIPT
Towards an industry-wide ifcOWL: choices and issues
Pieter Pauwels, Ghent UniversityMaría Poveda-Villalón, UPM
3rd workshop on Linked Data in Architecture and Construction – 17 July 2015 - Eindhoven
• Diverse suggestions in academic research to make IFC available as an OWL ontology to allow the usage of semantic web technologies
Schevers and Drogemuller, 2005 Beetz et al., 2009
• General purpose initiative to convert EXPRESS schemas and STEP file to OWL ontology, not focused on IFC
Krima et al., 2009 (OntoSTEP) Barbau et al., 2012 (OntoSTEP)
• From 2012 onwards, increasing uptake in research and developments=> many different ifcOWL structures floating around
• Need for formalisation and standardisation=> combine efforts and proceed in a more formalised, standard fashion=> role of standardisation bodies: W3C, BuildingSMART
• BuildingSMART Technical Summit March 2015 (London) and October 2015 (Singapore)
we owe our past and present - 2005-2015
1. Short intro to ifcOWL Pieter and Walter + comparison with Nam’s work
2. Scope: the extended ifcOWL3. Deciding on ifcOWL open issues
FOCUS for this presentation
outline
SHORT INTRO TO IFCOWL (W&P)
DOWNSTREAM
EXTENDED IFCOWL
FILE-BASED CONVERSION RELYING ON THE IFCOWL ONTOLOGY
Image courtesy: Nam Vu Hoang, Aalto University
conversion procedure / approach Nam
conversion procedure EXPRESS schema to OWLIFC
Schema
Simple data type
Defined data type
Aggregation data typeSET data type --------
LIST & ARRAY data type --------
Constructed data typeSELECT data type --------
ENUMERATION data type --------
Entity data typeAttributes --------
Derive attrWHERE rules
FunctionsRules
ifcOWLOntology
owl:class + owl:DatatypeProperty restriction
owl:class
owl:class-------- owl:ObjectProperty restriction on ifc:hasSet-------- indirect subclass of ifc:List
owl:class-------- owl:unionOf ( owl:classes )-------- one of ( owl:NamedIndividuals )
owl:class-------- object properties
----
what is included in ifcOWL extended?
Image courtesy: Nam Vu Hoang, Aalto UniversityEXTENDED IFCOWL
Totally okay with ‘compartmentalization’ or ‘layers’If it helps industry
differences (1)
Image courtesy: Nam Vu Hoang, Aalto University
OWL DL focus only==> everything in there, should be enoughLeads to property renaming==> 1 domain / range for each property
Wrap XSD types
Subclasses of simple datatypes or other defined datatypes
| Can easily be changed|||||||
Step 2. Simple data types
ifc:REALrdf:type owl:Class ;rdfs:subClassOf[
rdf:type owl:Restriction ;owl:allValuesFrom xsd:double ;owl:onProperty ifc:has_double
] .
ifc:has_doublerdf:type owl:DatatypeProperty ;rdf:type owl:FunctionalProperty ;rdfs:label "has_double" ;rdfs:domain[
rdf:type owl:Class ;owl:unionOf ( ifc:REAL )
] ;rdfs:range xsd:double .
OWL
Step 3. Defined data typesIFC
Schema
Simple data type
Defined data type
ifcOWLOntology
owl:class + owl:DatatypeProperty restriction
owl:class
TYPE IfcAreaDensityMeasure = REAL;END_TYPE;
ifc:IfcAreaDensityMeasurerdf:type owl:Class ;rdfs:subClassOf ifc:REAL .
EXPRESS
OWL
differences (2)
Image courtesy: Nam Vu Hoang, Aalto University
MANY OPTIONS HERE – LARGE IMPACT, as all geometric data (90% of IFC) is in lists ==> huge impact on triple count
No policy here => we focused only on EXPRESS to OWL
RDF instances is a whole alternative area. If the Extended OWL Ontology is followed, one should have enough and naming should not matter too much.
SCOPE: THE EXTENDED IFCOWL VERSION
Image courtesy: Nam Vu Hoang, Aalto University
current status
ifcOWL Walter
ifcOWL Pieter
= identic. =
~ equiv. ~
Image courtesy: Nam Vu Hoang, Aalto University
targeted status
ifcOWL - e Walter
ifcOWL - e Pieter
= identic. =
= identic. =
ifcOWL - si Walter
ifcOWL - si Pieter
ifcOWL - st Walter
ifcOWL - st Pieter
= identic. =
= identic. =
= identic. =
= identic. =
importimport
Minimal aim for LDAC2015
DECIDING ON IFCOWL OPEN ISSUES
issue 1 - ontology name and provenance
issue 2 - URI naming convention for object properties
Name_of_IfcRootName_of_IfcOrganization …Degree
issue 2 – alternative 1
Name
Name_of_IfcRootName_of_IfcOrganization …Degree
issue 2 – alternative 2
Name
Name_of_IfcRootName_of_IfcOrganization …Degree_of_IfcBSplineCurve
Degree
STANDARD / SIMPLE
EXTENDED (FULL)
issue 2 – alternative 3
Name_of_IfcRootName_of_IfcOrganization …Degree_of_IfcBSplineCurve
issue 3 - URI naming convention for individuals in Enumerations
=> Similar to object property renaming, except for the domain and range restrictions=> Alternatives: use all short names (ENUM individuals belong to multiple classes) or use all long names ([]_of_[]) (ENUM individuals belong to one class only)
RECAP / CONCLUSIONS
Parallels in the extended ifcOWL (1)
Image courtesy: Nam Vu Hoang, Aalto University
OWL DL
Wrap XSD types
Subclasses of simple datatypes or other defined datatypes
| ||||||
OWL DL
1
Can we follow the subproperty proposal?
Parallels in the extended ifcOWL (2)
Image courtesy: Nam Vu Hoang, Aalto University
MANY OPTIONS HERE – LARGE IMPACT, as all geometric data (90% of IFC) is in lists ==> huge impact on triple count
Beyond development of an extended ifcOWL
Image courtesy: Nam Vu Hoang, Aalto University
explore options for compartmentalisation
ifcOWL - e Walter
ifcOWL - e Pieter
= identic. =
= identic. =
ifcOWL - si Walter
ifcOWL - si Pieter
ifcOWL - st Walter
ifcOWL - st Pieter
= identic. =
= identic. =
= identic. =
= identic. =
importimport
Minimal aim for LDAC2015
