11th NASA/ESA Workshop on Product Data Exchange 2009

Allison Barnard Feeney, NISTDavid Price, Eurostep

Producing data exchange standards for 25 years - ~30 major information models for product data exchange◦ formally specified in EXPRESS ◦ standardized by ISO◦ in wide use in the manufacturing industry◦ supported by dozens of software tools

Production implementations in US aerospace, automotive and ship building companies have resulted in actual savings of $150M per year

STEP information models are of the high fidelity, high quality needed by US industry

Business requirements for IT have changed but STEP activities have not kept pace

EXPRESS and related implementation method standards work because people make them work, not because there is a consistent IT architecture behind them

STEP focus on data means its standards do not address other viewpoints that have become key to business process reengineering and systems integration over the past several years

The IT world has moved on◦ Web Services, Semantic Web, Ontologies, Reasoning◦ XML Schema, XSLT, RDF, OWL◦ Business Process/Rules Models, Topic Maps◦ UML, XMI, MDA, ODM, MOF, QVT, OCL

None are “domain models,” they are all IT OMG and W3C standards are more widespread

than EXPRESS; many more modelers and implementors understand them◦ Many good STEP models will not be widely used because

STEP only uses EXPRESS Bottom Line: The need for consensus information

models remains, but STEP must adapt to keep its models relevant

OMG’s Unified Modeling Language is “the standard” for software engineering◦ Model Driven Architecture analogous to STEP

Architecture◦ UML 2 is a family of languages with domain-specific

extensions (e.g. SysML)◦ MDA relies on models expressed in the Meta Object

Facility, and rendered in XML Metadata Interchange. W3C technologies for the Semantic Web

◦ Resource Description Framework (RDF) and the Web Ontology Language (OWL) are “the standard” for modelling semantics on the Web

Many in this room have been in agreement for the past 5 years that STEP must adapt

STEP projects have addressed this through mappings to XML Schema (Part 28) and UML (Part 25) ◦ These mappings were specified entirely in text and targeted

version 1 of XML Schema and UML Open-source projects have supported this migration

“exff.org,” EU F6 projects “MEXICO” and “Interop S-10”◦ Initial mappings to UML and OWL and prototype tools

published on exff.org in 2004 STEP PLCS and now AP233 projects are extending less

strongly typed models with OWL Reference Data

OMG has adopted the EXPRESS metamodel◦ EXPRESS is now an OMG language◦ OMG RTF underway now

Provides formal basis for mappings to UML and OWL that have existing OMG metamodels◦ EXPRESS schema exchange between MOF tools

via XMI◦ EXPRESS-based data exchange using XMI◦ OMG Model Driven Architecture languages

applied with EXPRESS schemas as input or output For example, a formal mapping between AP233 EXPRESS

and the OMG Systems Modeling Language (SysML) using OMG Query/View/Transform (QVT)

It is now possible to reproduce “the STEP architecture” in OMG’s MDA◦ MOF metamodel of EXPRESS defines the language◦ Use Object Constraint Language (OCL) for detailed

constraints◦ Use Query/View/Transform for mapping between

models and EXPRESS-X style transformations◦ EXPRESS schema exchange between MOF tools via

XMI◦ EXPRESS-based data exchange using XMI

We can also do a lot more◦ Ontologies using OMG Ontology Definition

Metamodel (ODM), Reasoning, Web services

The “bigger vision” should be an architecture where modelers use the languages that appropriate for the task◦ UML for software, OWL for ontologies, EXPRESS

for constrained data exchange◦ OMG’s MDA is a start in that direction

Standards and good open-source reference implementations in this area are required

SC4

AP

OMG

Schema

Implemented as

EXPRESS

published

Model of EXPRESS

Model DrivenArchitecture

Convert to

published published

Can process

UML

Web Services

ODMOntology

Can harveststandards from

Can use

SysML

Based on ActivityModels

Can map to/from

Formallydefines

XML Schema

STEP EXPRESSSchemas

Harvesting Process, Specs

& Tools

UML Profilefor EXPRESS

UML 2 Tool &Executable UML

STEP as UML

OWLReference

Data

ODM/OWL Reasoner

Data

Software Systems Integration

APIs & Services

OMG EXPRESS

ISO Future STEP Project

OMG Industry

Inter-relatedsuite of stds

Provide recommendations to OMG and ISO STEP on how to work together better, for example◦ Can ISO STEP adopt OMG MDA instead or in addition

to current modeling tools?◦ Can OMG MDA approach/tools learn any lessons from

ISO STEP modular architecture?◦ What in ISO STEP is worth harvesting into OMG?◦ ISO EXPRESS is now an approved OMG language,

should OMG take more advantage of that? End Goal

◦ Present recommendations for “Future STEP” to ISO STEP community in May – we hope that starts the process

StandardizedCore Ontologies

And Mapping

SOA

ROA

Reasoning

Data Exchange

Industry Extensions

EXPRESS/UML mapping◦ make UML class diagrams suitable for UML-based data

exchange◦ compatible with EXPRESS-based data exchange

AP EXPRESS to ODM OWL mapping◦ EXPRESS to OWL mapping as QVT may be RFC to ODM

specification UML Profile for EXPRESS stereotypes specification AP233/SysML mappings

Vanilla UML class diagrams from EXPRESS schema

AP-based OWL ontology from AP, RD and instance data

EXPRESS-as-UML class diagrams ◦ Using proposed UML Profile for EXPRESS diagram

notation EXPRESS schemas represented using MOF of

EXPRESS ◦ NIST implementation already exists but needs upgrade to

XMI 2 OMG XMI for data exchange using UML driven

from EXPRESS

Using an appropriate subset of AP233 as the example, the specification of:◦ AP233 as EXPRESS for data exchange◦ AP233 as UML Profile for EXPRESS◦ AP233 as vanilla UML for data exchange◦ AP233 as XML Schema for data exchange◦ AP233 as OWL for at least one scenario where

reasoning is possible◦ AP233-based Class diagrams for higher level

Systems Engineering Web services

AP233 ARMXML Schema

AP233 ARM API or Service

AP233 ARMEXPRESS

EXPRESS-basedcode generators

AP233 ARMUP4E XMI

UML 2 Tool

AP233 ARMUML 2 XMI

AP233 OWLRef Data

UML-basedcode generators

AP233 ARMOWL

Reasoner

Draft 1 of EXPRESS/UML mapping AP233 as UML provided to NIST for plug-fest,

transformation tools◦ Issue resolution underway

OMG RTF underway for EXPRESS Metamodel Held INCOSE and OMG mapping workshops

for SysML/AP233 common areas Participating in OMG Model Interchange team

to ensure XMI capable of data exchange Participated in NIST Ontology Summit 2009 –

Ontologies as Next Generation Standards

Process for enterprises to adapt STEP for software integration needs◦ Report to SC4 in May

Finalize mappings between STEP and OMG/W3C languages, models and data◦ June 2009 – publish working drafts for review◦ September 2009 – deliver specifications and

demonstration

How far should we “push” SC4 towards use of OMG MDA and related technologies?

Getting vendor buy-in◦ SysML vendors for AP233 export/import◦ EXPRESS vendors for OMG metamodel support

Testing new technologies ◦ XMI for data exchange◦ QVT for computer-interpretable mappings –

finding QVT tools to specify mapping is a problem Turns out we are “the pioneer” in this area for

publishing a standard transformation in an OMG standard

Transformation is key to MDA!