1. Linked (meta)Data
Principles and Applications for BIM
Ana Roxin
EA7508, CNRS, Arts et Métiers, Univ. Bourgogne Franche-Comté (UBFC)
Contact: ana-maria.roxin@ubfc.fr
Monday, March the 26th 2018 Ana Roxin - Linked (meta)Data for BIM

2. Greatest challenge for BIM…
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Text extracted from an article by Mark Baldwin, BIMconnect.org
"We generally understand these concepts to refer to the same thing,
however in BIM we need to be much more specific."
"Different disciplines often use different terms to describe the same thing.
What an architect may call "insulation factor", a building services
engineer may call "U-value". While a product manufacturer may refer to
"thermal conductivity"".

3. Semantic Disambiguation
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"U-Value" of wall W12 ?
???
Metadata
"U-Value" of wall W12 ?
Interpret "U-Value" as being the same as "thermalConductivity as defined in IfcThermalMaterialProperties"
0,2
Btu/(hr·ft⋅F)
Building services engineer
ifc:thermalConductivity_IfcThermalMaterialProperties
http://www.buildingsmart-tech.org/ifcOWL/IFC2X3_Final#thermalConductivity_IfcThermalMaterialProperties
Identifier on the Web of the concept of "thermal
conductivity" as defined by IFC

4. What has been done until now
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IFC EXPRESS/STEP
Drawbacks for EXPRESS/STEP-based
formats:
• Queries are software-dependent
• Impossible to combine several IFC files
and query the collection
• Difficult to make links to other types of
data
• Not adapted for deducing new information
ifcOWL (IFC STEP translated into OWL)
Remaining problems:
• Still difficult understanding of IFC object
properties and relationships
• Complex access to the semantics of
building data
• Very little links to other vocabularies
• No leverage from constraints dictated by the
EXPRESS/STEP file format
The graph structure of
ifcOWL allows addressing
some limitations but not
in an optimal way !
Ana Roxin - Linked (meta)Data for BIM

5. What is "Linked (meta)Data" ?
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1st Resources have to
be identified with
IRIs
2nd Use HTTP to
access resources
3rd Resources must be
described with RDF-
based languages
4th RDF links must be
defined to concepts
in other schemas
Specify relations to concepts, properties as existing in different standard schemas…
Principles
Ana Roxin - Linked (meta)Data for BIM
Machine-processable description (OWL)
of the IfcBuilding concept, presented in
a human-readable format (HTML)
Web-scale identifier of the "IfcBuilding"
concept with respect to IFC2x3
Implementation example Comments
http://www.buildingsmart-tech.org/ifcOWL/ Direct links to all ifcOWL vocabularies
defined (e.g. IFC2x3, IFC4)
… these are missing from ifcOWL, namely because they are out of its scope !

6. Linking Schemas - Example
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ifcOWL BOT
ifcowl:IfcBuilding bot:Building
owl:equivalentClass
@prefix ifc: <http://www.buildingsmart-tech.org/ifcOWL/IFC2X3_Final#> .
@prefix bot: <https://w3id.org/bot#> .
…
…
ifc:IfcBuilding a owl:Class ;
owl:equivalentClass bot:Building;
…
@prefix bot: <https://w3id.org/bot#> .
@prefix ifc: <http://www.buildingsmart-
tech.org/ifcOWL/IFC2X3_Final#> .
…
…
bot:Building a owl:Class ;
owl:equivalentClass ifc:IfcBuilding;
…
Ana Roxin - Linked (meta)Data for BIM
http://www.buildingsmart-tech.org/ifcOWL/IFC2X3_Final https://github.com/w3c-lbd-cg/bot/blob/master/bot.ttl

7. bSDD
Human knowledge
Why we need to go further ?
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ifc:thermalConductivity_IfcThermalMaterialProperties
a owl:ObjectProperty , owl:FunctionalProperty ;
rdfs:domain ifc:IfcThermalMaterialProperties ;
rdfs:label "ThermalConductivity" ;
rdfs:range ifc:IfcThermalConductivityMeasure .
ifcowl
bsdd:insulation_factor bsdd:u_valve bsdd:thermal_conductivity
owl:equivalentProperty
Several vocabularies/schemas/models (defined with Semantic Web
languages) exist. There is no need to re-define them:
- just add links towards them and
- verify they are correctly accessed and interpreted.
Only missing and needed concepts should be defined.
Ana Roxin - Linked (meta)Data for BIM
IFD (ISO 12006-3)
ifd:Property
ifd:ObjectProperty
ifd:MeasureProperty ifd:Measure
ifd:hasMeasure
rdfs:subClassOf
rdfs:subClassOf
ifd:Unit
ifd:hasUnit
NASA QUDT Units Ontology
unit: http://www.qudt.org/qudt/owl/1.0.0/unit/
qudt: http://www.qudt.org/qudt/owl/1.0.0/qudt/Properties.html#
quantity: http://www.qudt.org/qudt/owl/1.0.0/quantity/index.html#
unit:BtuFootPerSquareFootHourDegreeFahrenheit
qudt:quantityKind
quantity:ThermalConductivity

8. Initiatives
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French
ifcWoD – IFC adapted fro LD
(presented at bSI Rotterdam)
LD Perspective for BIM
(presented at bSI Jeju)
ifcViews - Extract IFC elements as defined
in an MVD (presented at bSI Jeju)
Linked Data implementation of the Unified
Code of Units and Measures (UCUM)
(Maxime Lefrançois)
Aligning classifications – Classifications
WG (presented earlier by Y. Cotherel)
Regulations checking – CSTB
(presented tomorrow RR1 session)
International
Simplifying ifcOWL structure
(presented at ECPPM with P. Pauwels)
Querying and reasoning over
large scale building datasets –
benchmark
MVD whitepaper
(presented at bSI Barcelona with M. Weise)
Towards a modular ifcOWL (presented at
FOMI by P. Pauwels and W. Terkaj)
The BOT and its applications for HVAC
managers (presented at bSI London by Mads H.
Rasmussen)
The W3C Linked Building Data CG
(2017 workshop was in Dijon)
2016
2018
2016
2017

9. Example application: querying
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Building
envelope ?
More about this use case in the presentation of
Mads Holten Rasmussen
Tuesday March the 27th, Session 4 (BR4), 16h30

10. Ana Roxin - Linked (meta)Data for BIM
Example application: IFC↔COBie
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IFC
COBie
How to
combine
them ?
IFC and COBie schemas
are represented through
autonomous ontologies
Mapping rules exist in
the form of COBieMVD
ifcOWL
COBie
OWL
COBieMVD
Issue: Idea: Application:
Can be transformed into
"links" from one schema
to the other
Retrieve COBie data originally
described using IFC (and vice
versa)

11. Ana Roxin - Linked (meta)Data for BIM
Example application: Regulations
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Building data
Regulations
How to
combine
them ?
Transform existing
regulations into logical
rules (IF -> THEN)
Apply these constraints
on top of existing
building data
Issue: Idea: Implementation:
The building data is
classified / categorized
accordingly
Definition of a high-level vocabulary
(regulations ontology) +
Description of existing French
regulations (e.g. fire protection) based
on this vocabulary.

12. "Communicating Matter for BIM"
ongoing ANR financed project
(2017-2020)
N° ANR-17-CE10-0014-03
Ana Roxin - Linked (meta)Data for BIM
Example application: Concrete
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Placing tags directly into
concrete
Add metadata to the
small pieces of data
gathered with the tags
Issues: Idea: Application:
Directly integrate them
into an IFC file
(building snippet)
How to get information about
the building’s concrete
elements?
How to have a real-time
snippet of a building's state ?
We envision applications for:
• Concrete manufacturing
• Construction site
supervision
• Structural health monitoring

13. Conclusion
Linked Data is Linked Metadata
• 4 principles for linking existing schema definitions
• The original data is not modified when augmented with metadata
It is a lightweight, scalable and fast approach, that allows :
• Specifying to a machine how data should be interpreted
• Integrating, querying and reasoning over data annotated with such metadata
• Justifying inferences or deductions made
Linked (meta)Data is a way of defining a building's "digital twin"
• Thus a computer can approximate the meaning of the data it handles
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14. Thank you for your attention.
Contact: ana-maria.roxin@ubfc.fr
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