The ISO EXPRESS and Binary Data Project

January 2005

Agenda

• Background

• Survey of the state of the art

• Requirements

• Making the standard

Background : Need

• STEP and related standard information models are written using the ISO EXPRESS language

• There are standard implementation methods for Text and XML exchange of EXPRESS-driven data– There are also low level standard Java, C and C++ programming

language interfaces for EXPRESS-driven data called SDAI

• Based on experience in the STEP for Space TAS/NRF, Finite Element Analysis, Computational Fluid Dynamics and other fields, requirements for a more efficient exchange format have arisen

Background : VIVACE

• Value Improvement through a Virtual Aeronautical Collaborative Enterprise– VIVACE EU project started January 2004 for four

years– EXPRESS-driven Large Volume Binary Data

Representation is defined as a VIVACE deliverable• Mats Lindeblad is VIVACE task leader from Volvo Aero• David Price is VIVACE technical resource from Eurostep

Limited• Mats and David are proposed as the ISO SC4 Project Leader

and Editor

Background : STEP Meetings

• Mats set up initial discussions at ISO STEP in Poitiers, France October 2003

• Team has met at each of the three ISO STEP meetings in 2004– Ft. Lauderdale : First announced meeting set out plan

for Survey of technologies and requirements gathering

– Bath : Reviewed technologies and requirements, created features analysis matrix

– Seattle : Decided on HDF5 technology for first working draft and testing

Survey of State of the Art

• Searched for binary data representations to find candidate technologies

• Search found– ASN.1 : Abstract Syntax Notation 1– HDF5 : Hierarchical Data Format– XML/Binary

• Sun Fast Web Services• WAP Binary XML• Compact Binary XML

– CGNS : CFD General Notation System– SDAI implementation by LKSoft

Gathered Requirements

• At each of the ISO STEP meetings, requirements were gathered– 40-50 requirements have been identified

• Based on requirements, a matrix of features was derived– Lists features needed by the proposed standard along

with a simple priority• Measured HDF5 against those features and

reviewed results in October 2004 at Seattle ISO STEP meeting– Based on this and knowledge of other candidates,

those present decided HDF5 was the most suitable

HDF5 Technology

• HDF5 is more than simple compression, contained data has structure

“/” (root)

“/foo”

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Making the Standard

• The first working draft will be based on HDF5 per October 2004/Seattle decision

• Assume an ISO 10303-20s series part that is a “profile” of HDF5 for use with EXPRESS

• Plan should be for an open-source toolkit built on top of HDF5 that performs the EXPRESS/HDF5 mapping– Enforce EXPRESS base types, EXPRESS->HDF5 structure

mapper, the mapper may need to be configured– Should this be a Engineer Object Level API for STEP APs?

• A technical workshop is needed to create the working draft

• A New Work Item ballot (NWI) or Preliminary Work Item project (PWI) are required by the ISO SC4 STEP procedures

PWI on “EXPRESS and Binary Data”

• Evident industry need for complement to ISO10303-21/28Usage Domains:– Engineering Analysis, Manufacturing, Measurements and more

• Represent EXPRESS-compatible data in an efficient, binary form• No standardized mapping from EXPRESS to binary exists• Support from participants representing:

– Sweden, UK, US, Japan, Germany, France known• Financing:

– Project Lead and Editor 2004-2007 from EU 6th FP project “VIVACE”• Mats Lindeblad• David Price

• Proposed PWI for project within SC4/WG11– Proposed to target ISO 10303 Implementation Method– Planned Project Milestones => Next slide

WG11: EXPRESS and Binary Data

• Presentation and Discussion on Business Need for Standard• Review and Update of Gathered Requirements• Review of Potential Implementation Technologies from Survey

– Defined and prioritised an initial set of features for comparison• Planned Project Milestones:

– Jul 2004: PWI as SC4 Letter Ballot– Sep 2004: Release analysis of potential candidate technologies– Oct 2004 (Seattle SC4 meeting)

• Decide on scope & Candidate technologies to include in CD document– Feb 2004 Release of first Working Draft for review and testing– Mar 2005 (Lillehammer SC4 meeting)

• Hold walk through for ISO/SC4 community– Jun 2005: Release of CD document for ballot– Jul 2005 (Spain SC4 meeting) walkthrough and implementation reports– Fall 2005 (SC4 meeting): Hold CD ballot resolution work shop– Early 2006: Publish ISO TS document– … to be planned …– Nov 2007 : Published ISO International Standard of document(s)

Workshop needs• Produce a first working draft for implementors to do initial testing• Choose a subset of EXPRESS for prototyping

– Not required for initial prototyping• rules/functions• abstract entity• complex numbers

– Requirements• Entity and Attribute• Defined types of arrays• Enum• Select (some include both Entity and DT of array), • all simple datatypes• 3 level nested arrays of real• some redeclaration• Inverses• maybe derived and save results• lists are included

Workshop needs (2)

• Choose a subset of EXPRESS for prototyping (2)– Structured grids? Part 50 more complex but would be in AP209

E2– Configurability?

• For each Entity.attribute specify the encoding• Simple datatype - specify the encoding at a global level

– Transactions at the level of a “engineering or business object” level in the API

– AP209 testing• Keith Hunten needs a higher level interface for application

programmers that is even higher level than the AP209 schema• API is early bound to the schema, Keith would likely use C

Conclusion

• Sufficient industry interest and need exists for the EXPRESS/Binary data representation standard

• Good technology exists upon which to build a standard without inventing everything in ISO

• Anyone with similar needs/interests is invited to participate in the standard or in implementations