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Applying Semantic Web Technology to the Life Cycle

Support of Complex Engineering Assets

David Price and Rob Bodingtondavid.price@eurostep.com

ISWC 2004

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Agenda

• What is Product Life Cycle Support?• Implementing PLCS• The Requirements and Approach for Reference

Data• Future use of full Semantic Web capabilities• Sources of Reference Data• Pilot Project• Conclusions

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What is PLCS?

• ISO 10303-239 Product Life Cycle Support, part of STEP– Information model for system integration and data exchange

• PLCS scope is “support” of complex assets (e.g. ships)– Configuration Management : As-Designed, As-Realized, As-

Maintained

– Support Engineering : Support Required (activities, tasks, resources)

– Resource Management : Spares, Who/what/when

– Maintenance and Feedback : Failures, Replacements, …

• Life cycle measured in decades– 80-90 percent of the cost of a ship to UK MoD is after delivery

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What is STEP?

• Formally, ISO 10303 Product data representation and exchange– Written in ISO EXPRESS, an OO-style language roughly

equivalent to UML Static Class Diagrams

• Commonly called STEP – Standard for the exchange of Product Model Data

• Not something new, first STEP parts reached International Standard status in 1994

• STEP scope is vast and varied– under development for 15+ years– Ship Moulded Forms, Printed Circuit Boards, Finite

Element Analysis, Systems Engineering, …

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The Approach to the PLCS standards

• In ISO, standardize flexible information model– ability to classify using external classes is built into the model

– 200 PLCS information model concepts require Reference Data

• Outside ISO, standardize user guides and Reference Data– OASIS PLCS Technical Committee formed for this purpose

• US DoD, UK MoD, BAE Systems, DNV, Norwegian Defence, FMV, Boeing, LockheedMartin, Saab, Rolls Royce, Pennant, Eurostep, and LSC Group are members

• Enable non-standard Reference Data extensions– Enables further tailoring and contracting for PLCS-based

exchange between partners

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PLCS Requirements

ISO Information Model OASIS Reference Data

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Linked Reference DataLibraries

XML exchangedocument

MMS

translateto PLCS

translatefrom PLCS

classification

HUMS

Health and UsageMonitoring Systemon board a ship

MaintenanceManagement System

Basic PLCS Implementation Scenario

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What to do about Reference Data?

• UK MoD contracted Eurostep to do a survey of candidates for Reference Data

• Definition of Reference Data– The semantics required to complete an information model for

use in data exchange scenarios

• Goal– Determine best approach for PLCS Reference Data

• Scenario– Automating failure reporting using PLCS-based data exchange

• Technical Assumptions– Exchange based on PLCS EXPRESS->XML Schema

– Enable inclusion and reference to Reference Data

– Standard Reference Data is extended in implementing organization

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RD requirements arising …

• Define RD and relationship to PLCS information model

• Need class hierarchy, properties and the associated documentation

• Easy browsing and operational use on Web and in internal applications

• Formally relate organization-specific extensions to standard RD

• Integrate extensions into standard RD over time, as appropriate

• Enable Net-Centric implementation

• Support for very large Reference Data Libraries

• Support XML-based exchange

• Support Reference Data to be embedded, exchanged or referenced

• Support addition of business rules and constraints

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Recommendations

• After reviewing OASIS, OMG, W3C and ISO standards, decided OWL was best fit for requirements and community

• Also recommended RD developers use a specific set of tools to minimize risk– Stanford University Protégé with OWL plug-in

– Pre-loaded a template containing PLCS schema, high level RDL, etc. for RD developers

• Approach approved by OASIS PLCS TC in March 2004

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Why this approach?

• OWL satisfies RD modeling requirements– Class, multiple inheritance, properties, datatypes,

instances, reuse of models• EXPRESS modelers understand base concepts already

• OWL satisfies the IT requirements– Has an XML syntax, Web enabled, can map to RDBMS

• Aligns with ISO standards having potentially reusable Reference Data– ISO 15926 Oil and Gas data warehouse standard

• Other factors– Industry and academic support and open-source tools

available– Large community with no STEP knowledge know OWL

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PLCS Ontologies When Deployed

plcs-express

plcs-dc plcs-dcterms

MoD-rdl-extensions

plcs-refdata

plcs-rdl

Dublin Core Elements and

Terms(read-only)

PLCS EXPRESS as OWL

(read-only)

Reference Data for PLCS Editors

Reference Data for PLCS Users

(read-only)

Reference Data for Organization

Editors

XML exchange document

classification

subClassOf

subClassOfimport

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The EXPRESS/RD OWL Relation

PLCS Schema Classes

RD ClassessubClassOf

PLCS Schema Classes

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Benefits to OWL approach

• For business processes and rules, reasoners and related technology have potential use

• While PLCS data exchange isn’t “Semantic Web”, approach lays the foundation for future PLCS Semantic Web applications

• Makes PLCS Reference Data usable by non-PLCS applications– The STEP Systems Engineering community standard, ISO

10303-233, planning to adopt this approach and reuse PLCS Reference Data

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Onboard LocationManagement System

distance = 8000km

distance = 16000km

Shore-based Maintenance Planning System

MPS

Ship data

Report to shipyardfor engine maintenance

Onboard LocationManagement System

Future use case: Automated planning

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Engineering Data Interoperability

STEP, EXPRESS

MDA,UML

OWL,CL

Software Modeling/Engineering Interoperability Region

Semantic Integration and KnowledgeInteroperability Region

Data Exchange/Integration Interoperability Region

ConceptsPropertiesRelationships

Harry Frisch

ISO 15926?ISO ?

OMG ODM?

OMG ODM

ISO 10303-25

Still looking for the “Killer” App or Demo

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Sources of Reference Data

• UK MoD, NATO and other standards– Codifications of tasks, skills, etc.

• ISO 15926-2 Oil and Gas data warehouse projects (also called EPISTLE Core Model)– 4D ontology-based model submitted to IEEE Standard

Upper Ontology Working Group, written in EXPRESS

– Equipment types and some activity types (20K classes undergoing ISO standardization at the moment)

– ISO 15926 community is investigating OWL as standard form of their reference data

• Expecting 100K+ classes in multiple servers for full PLCS implementation

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Issue : Ontology Management

• This use case is not based in the “World Wild Web”– Ontologies are engineering artefacts used in complex systems

– Some Ontologies are International and/or Industry Standards

– Software “diff” for versioning not sufficient for this community

– Protégé Server “anyone can change anything” not sufficient for this community

• Change Management and Configuration Control of Ontologies (at least Class level) is required– This discipline is well understood in the engineering domain

• Issues raised, proposals made, solutions approved, etc.

– We lack Ontology tools for this at the moment and so are forced to use lots of separate OWL files and CVS – it’s not pretty

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Issue : Ontology Subset or View

• Using organizations contract for complex assets and software to manage them– The Reference Data required needs to be stated in the

contract

– Typical contract will not require all the Reference Data

• Organizations need to specify a subset or view defining the Reference Data for the contract– Investigating Protégé PROMPT Plug-in but also

investigating a Class-of-Class approach

– Have tried to avoid Class of Class as then the RD is no longer DL

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Pilots progress since the paper …

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UK MoD RDL Server prototype

ProtégéOWL files

MySQLDatabase

PLCS RDL Web Server

Webservices

OWL APIOWL XML

QueriesWeb

server

Webbrowser

FMVModel Server

AP233Demo

RDL Classbrowser

TCP/IP --- LAN / Internet backbone

PLCS Clients

MySQLDatabase

MOD RDL Web Server

Webservices

OWL APIOWL XML

QueriesWeb

serverImplement OWLRDL Database

Defined RDL content usingProtégé

Define APIAs web services

Web clientsPLCS applications

Define queries

RD extensions (TBD)

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PLCS applications using the RDL Server: FMV model server

• FMV Model Server is a STEP-based PLM capability for Web-enabled collaboration– Implements a significant portion of PLCS

• Pilot project extended Model Server to use RD– Accesses RDL Server to allow dynamic classification of:

• Activities, Parts, Documents

– We could do this as Model Server is an extension of a Eurostep product called Share-A-space

• Business benefits– Dynamically configurable PLM/PLCS application

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When creating an Item, click green

plus-sign to add new Classes from the

RDL Server.

When creating an Item, click green

plus-sign to add new Classes from the

RDL Server.

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Select Classes from RDL Server to use in Model

Server

Select Classes from RDL Server to use in Model

Server

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The classes are now selectable in the

listbox.Model Server has cached a copy.

Choose one.

The classes are now selectable in the

listbox.Model Server has cached a copy.

Choose one.

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The Item is classified.Mouse-over Class and its definition

appears.

The Item is classified.Mouse-over Class and its definition

appears.

In a way, Model Server is allowed engineers to annotate their PLM data for SW

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Typical RDL Web Service QueryQuery: What Classes are

allowed when classifying an Identification assignment applied to a Product as

realized?

Answer: Serial identification code

and Name. But not Activity

identification code or Part number

Restriction works for simple case,may need rules later (SWRL?)

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Conclusion

• The flexibility defined in the PLCS approach allows it to be used across a wide domain– However, that flexibility means PLCS implementation

depends on Reference Data

• OWL provides very good capabilities for defining, reusing, publishing and relating information models and reference data– By being Web-enabled, RDLs can be linked and distributed

– OWL also enables the future use of knowledge/logic applications as part of PLCS implementations