The EPISTLE Reference Data Libraryan ontology for the .ppt

1、The EPISTLE Reference Data Library an ontology for the Process Industry,David Leal, CAESAR Systems Limited,GbR mbH http:/,EPISTLE - major sponsors and members,EPISTLE,EPISTLE: European Process Industry STEP Technical Liaison Executive,STEP : STandard for the Exchange of Product data (ISO 10303),GbR

2、mbH http:/,What sort of thing is it?,Need one place to store the meaning and map between different terminology,Acknowledgements to POSC/CAESAR,GbR mbH http:/,Our starting point,STEP - ISO 10303 STandard for the Exchange of Product data shape FEA (Finite Element Analysis) PDM (Product Data Management

3、) special models forshipbuilding, plant spatial layout, electrical design engineering semantics - what things or relationships are real world vs designs/classes/specifications Parts Libraries - ISO 13584 families of standard parts a methodology for unique part identification some use of set theory,?

4、,Complicated, ad-hoc information models - result of a learning process,begun in 1984,not web,GbR mbH http:/,ISO 15926,Life cycle data for process plants including floating, flying, and with wheels simple basic model extended by class libraries (i.e. ontologies) STEP technology - EXPRESS Entity/Relat

5、ionship language - similar to UML (static class diagram) simple exchange file representation API - bindings to C, C+, Java XML representation - horrible Consequences hard wired information model - voted on by ISO, and not easily extensible extension by standard instances held in external files (clas

6、s libraries) - also standardised by ISO - externally maintained registry with continuous revision,ERDL,GbR mbH http:/,A thermowell,Acknowledgements to POSC/CAESAR,GbR mbH http:/,Thermowell (Dry Well) POC (01.01.08),Functional Parts,Physical Parts,Subclasses,Properties,Thermowell,Estimated Dry Weight

7、,Measured Dry Weight,Thermowell stem,Thermowell Process Connection,Internal thread,Thermowell Instrument Connection,Thermowell insertion length,Thermowell standout length,Thermowell lag length,Thermowell total length,Thermowell internal bore,Welded (Weld-in) Thermowell,Flanged Thermowell,Screwed The

8、rmowell,Van Stone Thermowell,Tapered Stem Thermowell,Stepped Stem Thermowell,Socket Weld Thermowell,Welded Flange Thermowell,Solid Forged Flanged Thermowell,Straight Stem Thermowell,NORSOK I-001 Rev. 3 T01 Thermowell,ISA S20T2501 Thermowell,GbR mbH http:/,Thermowell Stem (Dry Well) POC (01.01.08),Ph

9、ysical Wholes,Properties,Properties,Subclasses,Thermowell stem larger outside diameter,Thermowell stem tip outside diameter,Upper limit thermowell stem outside diameter,Thermowell stem tip thickness,Thermowell,NORSOK I-001 Rev. 3 T01 Thermowell stem,NORSOK I-001 Rev. 3 T01 Thermowell,Thermowell inte

10、rnal bore,Wake / natural frequency ratio,ISA S20T2501 Thermowell Stem,ISA S20T2501 Thermowell,Thermowell stem outside diameter at support,Thermowell Stem,Tapered Thermowell Stem,Stepped Thermowell Stem,Straight Thermowell Stem,GbR mbH http:/,Part type and materials,crankshaft,V6 crankshaft,Rover 75

11、crankshaft,Rover 75 crankshaft rev1.2,GbR mbH http:/,ECM and ERDL (ISO 15926) Structure,Physical Object Classes,GbR mbH http:/,ERDL - size of the problem,basic concepts 200 core classes 2000 first release of standard classes 20000 - more to come commodity classes 1 million for big owner-operator man

12、ufactured items ?,product/artifact, activity, state, composition, connection,thermowell, pump, pipe, flange, raised face flange,ISAS20T2501 thermowell,A design/specification is a class.,GbR mbH http:/,ERDL - how to define the classes,basic concepts 200 core classes 2000 first release of standard cla

13、sses 20000 commodity classes 1 million for big owner-operator manufactured items ?,information modellers - theoreticians with an industry background,teams of domain experts - initial tutorials from the information modellers heat transfer team, piping team, rotating equipment team, etc.,further work

14、by domain experts conversion of existing standards - using standard procedures,uptake of methodology by industry,GbR mbH http:/,Key concepts,product/artefact product life segment/activity product at instant/state,A distribution of matter through space and time, that is regarded as the whole life of

15、an object by some business process,A product for a particular period of time.,A product at an instant in time.,start with real world things:,then sets/classes of real world things;,then classes of class, etc.,GbR mbH http:/,ERDL Scope,piping valves rotating equipment heat exchangers electrical machi

16、nery electrical distribution instruments connections activities (for plant design, operation, maintenance) civil/structural documents (for plant design, operation, maintenance) properties (for classes defined above) units,core classes in each area,GbR mbH http:/,Some experiences,keep the hierarchy f

17、lat - without two many intermediate layer not a strict hierarchy, but a directed graph intermediate abstractions are woolly people argue about them endlessly,product,rotating equipment,pump,expander,Is this really needed? Does it have a precise definition?,GbR mbH http:/,Use of classification of cla

18、ss,Makes woolly classes less visible but still there - power set,product,pump,expander,rotating equipment class,indicates the responsible team of domain experts,GbR mbH http:/,Use of classification of class,Filtering for drill down,product,thermowell,instrument class,generic class,ISAS20T2501,instru

19、ment class,standard class,ISA class,J. Bloggs model XYZ,manufacturer class,J. Bloggs class,GbR mbH http:/,Rules for the development of class libraries,Stick to classes with precise definitions write the text definitions as you go Do not add collector classes to structure the class library Use classi

20、fication of class to provide structure Some classes can be defined by set theory and property contraints. It is not practical to do this for all classes. Text definition of the form:A xxx is a that .,GbR mbH http:/,Intersection of classes,cast part,engine part,cast engine part,A complete definition

21、of cast engine part without words!,GbR mbH http:/,Intersection of classes,cast part,engine part,Two subset relationships are not a complete definition!,cylinder block,GbR mbH http:/,Class hierarchy,thing,physical object,product / artefact,product for a period of time,product at an instant in time,th

22、ermowell,flanged thermowell,screwed thermowell,welded thermowell,GbR mbH http:/,Recording real world objects,The part with serial number 98/1234 is an instance of screwed thermowell The part with serial number 98/1234 is an instance of product, classified as a screwed thermowell, 98/1234 ,98/1234 ,X

23、ML equivalent to the EXPRESS implementation,GbR mbH http:/,Dictionary,thing,class of physical object,class of product / artefact,class of product for a period of time,class of product at an instant in time,class,screwed thermowell is one of these,GbR mbH http:/,Recording classes,Screwed thermowell i

24、s an instance of class of product Relationship to the class Product is implicit., Screwed thermowell, Thermowell,XML equivalent to the EXPRESS implementation,GbR mbH http:/,Relationships and constraints,GbR mbH http:/,Individual and class models,product,composition,* part,* whole,class of product,cl

25、ass of composition,* part,* whole,my_thermowell my_thermowell_stem,my_thermowell_stem is part of my_thermowell,thermowell thermowell_stem,thermowell_stem is part of thermowell,GbR mbH http:/,ScadaOnWeb,variables,positions,states/times,semantics,gigabytes of structured data,extract and download subse

26、ts,Define semantics of process monitoring data with respect to web ontologies,GbR mbH http:/,Next steps for EPISTLE,Exploit the current standards EXPRESS tools are mature, and scalable (but expensive) But Ontologies need publication and management Why develop EXPRESS based tools for ontology publica

27、tion and management, when there is a much bigger community out there Currently class libraries held as files corresponding to the ISO 15926 EXPRESS schema tools support import/export from a simple EXCEL spreadsheet class library development uses EXCEL Future domain class libraries published as an on

28、tology on the web retain use of EXCEL by domain experts ISO 15926 basic concepts as a web ontology,?,WonderWeb ScadaOnWeb,GbR mbH http:/,Conclusions,Large body of work - searching for a formal representation on the web Generic tools needed for access and maintenance merging libraries are particular problem Multi-layer structure need a consistent format for all levels no sharp distinction between data and meta-data (a design is a class),www.epistle.ws www.posccaesar.org www.uspi.nl,for more information,