Transcript Diapositiva 1 - Caesar Systems
Beyond data models
(what we can do with RDF alone)
David Leal [email protected]
Traditional data exchange
• Blobs
– Encapsulate the data that defines the shape – Encapsulate the data that is the specification of the part.
– Encapulate the data that is the specification of the analysis.
• The data inside the blob and the data outside the blob are separate – what is inside can be specified in a contract.
• It is “data push” –
I tell you what you need to know.
The blob can be an e-mail attachment – it can be downloaded by FTP.
This is what the EXPRESS data model + part 21 / 28 file methodology achieves.
What this is good for
• Command driven processes – I tell you what to do, and what you need to know to do it.
• Processes where the data within the blob can be easily defined – Shape information is a success story – it has a well defined scope – Engineering analysis has not taken off – the scope is fuzzy and much larger • Processes where the blob has a particular destination system – CAD, CAE, CAM, PDM, LCA
You need to know the type of destination system is before selecting the type of the blob. This is why standards define different types of blob – ISO 10303-203, ISO 10303-210, etc. for product data – ELCD XML for life cycle data
• A user publishes data on the Web – the user makes his or her own decision about what data are published – Somebody else can use the data, if they want to.
• A user chooses standard vocabularies to publish data as statements – Vocabularies can be used together as required • “Somebody” seeking information can follow links between one set of published data and another – Just like the ordinary Web, but the statements are semantically precise – and the “somebody” can be a computer application
• It is “data pull” -
you go and get what you want This is what the provides.
Tracking back materials information
@prefix item:
@prefix model:
@prefix alcom:
item:98-12345 part:toDesign model:ABC456_v3 ; part:madeFromBatch alcom:PQR-12345-06 .
URI of an individual part URI of a vocabulary about parts URI of a design URI of a batch of material
Tracking back materials information
@prefix item:
@prefix model:
@prefix alcoa:
item:98-12345 part:toDesign model:ABC456_v3 ; part:madeFromBatch alcom:PQR-12345-06 .
dereference to get the next formula
Tracking back materials information
item:98-1234 part:toDesign model:ABC456_v3 ; part:madeFromBatch alcom:PQR-12345-06 .
alcom:PQR-12345-06 mat:materialProductType mil5:XYZ2048-asSheet ; mat:manufacturingProcess alcom:LineA-2006-02-13 .
a classification with respect to a materials standard the actual manufacturing process a standard vocabulary for manufacturing processes
Tracking back materials information
item:98-1234 part:toDesign model:ABC456_v3 ; part:madeFromBatch alcom:PQR-12345-06 .
alcom:PQR-12345-06 mat:materialProductType mil5:XYZ2048-asSheet ; mat:manufacturingProcess alcom:LineA-2006-02-13 .
dereference again to get the next formula
Tracking back materials information
alcom:PQR-12345-06 mat:materialProductType mil5:XYZ2048-asSheet ; mat:manufacturingProcess alcom:LineA-2006-02-13 . facility that performed the process
alcom:LineA-2006-02-13 mat:performedBy alcom:LineA ; act:startTime [ iso8601:utc “2006-02-12T09:00” ] ; act:endTime [ iso8601:utc “2006-02-12T17:00” ] .
more manufacturing vocabulary vocabulary for time generic work flow vocabulary dereference again to get the next formula
Tracking back materials information
alcom:PQR-12345-06 mat:materialProductType mil5:XYZ2048-asSheet ; mat:manufacturingProcess alcom:LineA-2006-02-13 ;
tabont:isMentionedIn alcom:specimen-67890/formula.n3 . alcom:specimen-67890 part:madeFromBatch alcom:PQR-12345-06 ; part:toDesign test:SpecimenTypeXYZ .
another use of the ISO product vocabulary a standard specimen type dereference again to get the next formula
Tracking back materials information
alcom:PQR-12345-06 mat:materialProductType mil5:XYZ2048-asSheet ; mat:manufacturingProcess alcom:LineA-2006-02-13 ; tabont:isMentionedIn alcom:specimen-67890/formula.n3 .
alcom:specimen-67890 part:madeFromBatch alcom:PQR-12345-06 ; part:toDesign test:SpecimenTypeXYZ ; tabont:isMentionedIn alcom:Test-67890/formula.n3 .
dereference again to get the next formula
Tracking back materials information
alcom:specimen-67890 part:madeFromBatch alcom:PQR-12345-06 ; part:toDesign test:SpecimenTypeXYZ ; tabont:isMentionedIn alcom:Test-67890/formula.n3 .
alcom:Test-67890 obs:onSpecimen alcom:specimen-67890 ; act:toProcedure test:MaterialTestTypePQR ; obs:givesResult alcom:Result-67890 .
more generic workflow vocabulary a generic measurement and observations vocabulary dereference again to get the next formula a standard test method
Tracking back materials information
alcom:Test-67890 obs:onSpecimen alcom:specimen-67890 ; act:toProcedure test:MaterialTestTypePQR ; obs:givesResult alcom:Result-67890 .
alcom:Result-67890 { alcom:specimen-67890 mat:compressiveYieldStress [ iso:MPA “201.3” ] }
a statement with provenance and finally dereference again to get the result of a real test
Many vocabularies are used to record the data
personnel they are developed independently but used together observations inventory workflow product design units material test material handbook GIS manufacture electrical networks maintain life cycle assessment earth sciences
Data models
• Data models are good – they specify exactly what data should be supplied for a particular activity – they have constraints to ensure that the data is complete and correct • But – different activities need different data – different activities have different ideas about what “complete” means • So – There are lots of similar but overlapping data models • A data model does not enable you to publish data on the Web
Vocabularies/ontologies
• Vocabularies/ontologies are good – precise statements can be made about things – different vocabularies can be used together to say what you want • But – there is no constraint on what is said – you may not say all that needs to be said • So – vocabularies are not enough to specify the data flow between activities – replacing data models with vocabularies + rules is a research activity • Vocabularies work with the emerging Semantic Web technology
What next
• Use the past 20 years work on data models to create vocabularies – cannot be generated automatically from UML, EXPRESS or XML schemas – people have to read the words – real work • All standards developments have this problems – data models in UML, EXPRESS or XML Schema • product data - EXPRESS • electrical networks - UML • GIS - UML • building and construction - UML • materials information – XML and EXPRESS • earth sciences – XML • life cycle assessment – XML (ELCD XML schema from ISO 14048)