SysML Partners: Creators of the SysML

Who created SysML?

The Systems Modeling Language (SysML) was created by the SysML Partners, an informal association of Systems Engineering experts and software modeling tool experts that was organized by Cris Kobryn in 2003 to create a profile (dialect) of the Unified Modeling Language (UML) that could be used for Systems Engineering applications.

Since Kobryn had previously successfully led the UML 1.x and UML 2.0 language design teams, two INCOSE leaders (David Oliver and Sanford Friedenthal) asked Kobryn to lead their effort to respond to the Object Management Group's UML for Systems Engineering RFP issued in March 2003. As Chair of the SysML Partners Kobryn coined the language name "SysML" (short for "Systems Modeling Language"), designed the original SysML logo, organized the SysML core language design team as an open source specification project, and served as Chief Editor of the SysML specifications.

David Oliver, Co-Chair of the INCOSE Model Driven Design Working Group and INCOSE Fellow, was a seminal contributor to the SysML Partners throughout the project. (See Acknowledgement in Memoriam below.) Sandy Friedenthal, chair of the OMG Systems Engineering Special Interest Group, served as Deputy Chair of the SysML Partners during the start of the project. Other key contributors to the SysML open source project included, but were not not limited, to Chris Sibbald (Teleogic), Thomas Wiegert (Motorola), and Brian Willard (Northrop Grumman).

A Brief History of SysML

The SysML Partners submitted SysML Specification v. 0.9 to the OMG for review 10 Jan. 2005 (OMG document ad/05-01-03). After considering constructive feedback from the OMG, INCOSE, and the general public, the SysML Partners submitted their SysML Specification v. 1.0a for OMG technology adoption on 14 Nov. 2005 (OMG document ad/05-11-05).

After more than one-and-a-half years of contentious OMG technology and political processes the OMG formally adopted the OMG SysML 1.0 specification (OMG document ptc/06-05-04) in July 2006. Subsequently, the SD Times awarded the SysML Partners with its "SD Times 100" award for industry leadership in the “Modeling” category award in 2007

There has been no major revision of OMG SysML 1.x since it was formally adopted by the OMG in July 2006. The OMG has only adopted minor revisions to the OMG SysML 1.x specification since 2006, and the most recent minor revision is OMG SysML 1.4 (2005).

SysML Language Design Principles

The following fundamental design principles guided the development of the SysML open source specification:
Parsimony: SysML is based on a subset of UML that economically satisfies the basic requirements of the systems engineering community as defined in the UML for SE RFP. Additional constructs and diagram types are added to this UML subset only as needed to address derived system engineering requirements discovered during the language specification process. This disciplined application of Occam’s razor results in a more concise, yet more semantically expressive language which is easier to learn, implement and apply.
Reuse: SysML strictly reuses UML constructs wherever practical, and when modifications to UML are required, they are done in a manner that strives to minimize changes to the underlying language. Consequently, SysML is intended to be straightforward for UML vendors to implement. • Modularity: The principle of strong cohesion and loose coupling is applied to organize normative and non-normative language constructs into stereotype extension and model library packages.
Layering: Layering is used to organize the SysML profile in two ways. First, since SysML is defined as strict UML Profile, all SysML packages may be considered an extension layer of the underlying UML metamodel. Second, a SysML language constructs are organized into two levels of compliance, Basic and Advanced, which constitutes an additional layering.
Partitioning: Partitioning is used to organize conceptual areas within the same layer. SysML’s package structure, which is explained in the following section, partitions the SysML profile into packages that correspond to the language’s major diagram types. This partitioning is largely isomorphic with UML’s package structure, and is intended to facilitate reuse and implementation.
Extensibility: SysML supports the same extension mechanisms furnished by UML (metaclasses, stereotypes, model libraries), so that the language can be further extended for specific systems engineering domains, such as automotive, aerospace, manufacturing and communications.
Interoperability: SysML is aligned with the semantics of the ISO AP-233 data interchange standard to support interoperability among engineering tools, and inherits the XMI interchange from UML.

Reference: SysML Specification v. 1.0a, Section 6.1 Design Principles [14 Nov. 2005]

SysML Language Design Technical Approach

The following summarizes the technical approach followed by the SysML language designers in defining SysML as a dialect (profile) of UML 2:
  • Parsimoniously extend UML constructs only as needed: Sparingly add new constructs to UML 2 only as needed to support Systems Engineering requirements as specified by the OMG's UML for Systems Engineering RFP;
  • Reduce UML constructs not needed: Explicitly eliminate software-centric UML constructs not needed by SysML so that the SysML dialect will be simpler and less complex than the UML parent language, and therefore easier to learn and apply;
  • Support SysML + UML mixed language usage: Ensure that SysML constructs can be synergistically combined with UML 2 constructs in a model shared by Systems Engineers and Software Engineers, where the former use SysML and the latter use UML. The synergistic combination of SysML and UML should maximize requirements traceability and minimize semantic overlap between the two languages.
Google Groups
Subscribe to SysML Forum
Visit this group

SysML Partners

The main contributors to the SysML v. 1.0a specification follow:

Other SysML contributors

Other SysML contributors that include, but are not limited to, SysML Partners' SysML Specification v. 0.9 copyright holders:

SysML 1.0 & OMG Adoption

The SysML Partners completed their SysML v. 1.0a open source specification draft and submitted it to the OMG in November 2005. A series of competing specification proposals was followed by a "SysML Merge Team" proposal submission to the OMG in April 2006, which the OMG adopted as OMG SysML™ in July 2006.

Industry Recognition

  • 2006: The International Council on Systems Engineering (INCOSE) presented Cris Kobryn, Chair of the SysML Partners, with its Outstanding Service Award for his contributions to the development of the SysML.
  • 2007: The Software Development Times' (SD Times's) editors named the SysML Partners as a winner in the "Modeling Category" of the SD Times 100, which recognizes the leaders and innovators of the software development industry.

Acknowledgement in Memoriam
The seeds of what eventually grew into the SysML Partners open source specification project began with collaborations between David W. Oliver (1932-2011) and Cris Kobryn starting in 2001. During that time Oliver was an INCOSE Fellow who served as Co-Chair of the INCOSE Model Driven Design Working Group, and Kobryn was consumed with leading the UML2 Partners visual modeling language design team.

Kobryn was impressed by Oliver's vision and passion for a UML for Systems Engineering profile (UML dialect) backed by his Systems Engineering expertise. Both Oliver and Kobryn realized early that UML software components and Systems Engineering hardware components were more similar than dissimilar. Convinced that the two kinds of components could be unified syntactically and semantically, Kobryn subsequently directed his UML2 Partners specification team to reduce gratuitous software-centric aspects of the UML 2.0 specification draft so that it could potentially serve as a syntactic and semantic foundation for a future UML for Systems Engineering profile.

Without Oliver's passion and vision, which inspired this tedious but essential UML 2.0 foundation re-work, it is unlikely that the SysML open source specification project could have been completed in a timely manner.
Systems Modeling Language and SysML are not usable as trademarks (see SysML open source project Legal Notices). Unified Modeling Language, UML and OMG SysML are trademarks of the Object Management Group. All other product and service names mentioned are the trademarks of their respective companies.