Systems modeling language: Difference between revisions

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[[File:Sysml diagrams collage.jpg|thumb|240px|Sysml diagrams collage]]

The '''Systems Modeling Language''' ('''SysML''')<ref>''Flexible Views for View-based Model-driven Development'' By Burger, Erik. KIT Scientific Publishing, Nov 14, 2014. Pg. 250.</ref> is a [[general-purpose modeling]] language for [[systems engineering]] applications. It supports the specification, [[analysis]], [[design]], [[verification and validation]] of a broad range of systems and [[System of systems|systems-of-systems]].

SysML was originally developed by an [[open source]] specification project, and includes an open source license for distribution and use.<ref name="faq">{{cite web|author=SysML Forum|title=SysML FAQ|url=http://www.sysmlforum.com/FAQ.htm|accessdate=2009-08-26}}</ref> SysML is defined as an extension of a subset of the [[Unified Modeling Language]] (UML) using [[profile (UML)|UML's profile mechanism]].

SysML was originally developed

by an [[open source]] specification project, and includes an open source license for distribution and use.<ref name="faq">{{cite web|author=SysML Forum|title=SysML FAQ|url=http://www.sysmlforum.com/FAQ.htm|accessdate=2009-08-26}}</ref> SysML is defined as an extension of a subset of the [[Unified Modeling Language]] (UML) using [[profile (UML)|UML's profile mechanism]].

== Overview ==

SysML offers systems engineers several noteworthy improvements over UML, which tends to be software-centric. These improvements include the following:<ref name="faq"/>

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SysML reuses seven of UML 2's fourteen diagrams, and adds two diagrams (requirement and parametric diagrams) for a total of nine diagram types. SysML also supports allocation tables, a tabular format that can be dynamically derived from SysML allocation relationships. A table which compares SysML and UML 2 diagrams is available in the SysML FAQ.<ref>{{cite web|url=http://www.sysmlforum.com/faq/|title=SysML Forum: SysML FAQ - What is SysML?, Why use SysML?, Who created SysML?|work=sysmlforum.com|accessdate=2014-12-04}}</ref>

The advantages of SysML over UML for systems engineering become obvious ifwhen you considerconsidering a concrete example, like modeling an automotive system. With SysML youone can use Requirement diagrams to efficiently capture functional, performance, and interface requirements, whereas with UML youone areis subject to the limitations of [[Useuse Casecase Diagramdiagram]]s to define high-level functional requirements. Likewise, with SysML youone can use Parametric diagrams to precisely define performance and quantitative constraints like maximum [[acceleration]], minimum [[curb weight]], and total [[air conditioning]] capacity. UML provides no straightforward mechanism to capture this sort of essential performance and quantitative information.

Concerning the rest of the automotive system, enhanced [[activity diagram]]s and [[State diagram#UML state diagram|state machine diagrams]] can be used to specify the [[embedded software]] control logic and information flows for the on-board automotive computers. Other SysML structural and behavioral diagrams can be used to model factories that build the automobiles, as well as the interfaces between the organizations that work in the factories.

== History ==

The SysML initiative originated in a January 2001 decision by the [[INCOSE|International Council on Systems Engineering]] (INCOSE) Model Driven Systems Design workgroup to customize the UML for systems engineering applications. Following this decision, INCOSE and the [[Object Management Group]] (OMG), which maintains the UML specification, jointly chartered the OMG Systems Engineering Domain Special Interest Group (SE DSIG) in July 2001. The SE DSIG, with support from INCOSE and the [[ISO 10303|ISO AP 233]] workgroup, developed the requirements for the modeling language, which were subsequently issued by the OMG parting in the ''UML for Systems Engineering Request for Proposal'' (UML for SE RFP; OMG document ad/03-03-41) in March 2003.<ref name="rfp">{{cite web|author=OMG SE DSIG|title=UML^TM for Systems Engineering RFP|url=http://syseng.omg.org/UML_for_SE_RFP.htm|accessdate=2006-06-29}}</ref>

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=== OMG SysML ===

After a series of competing SysML specification proposals, a SysML Merge Team was proposed to the OMG in April 2006.<ref>[http://www.omg.org/docs/ad/06-03-01.pdf OMG document ad/06-03-01]</ref> This proposal was voted upon and adopted by the OMG in July 2006 as OMG SysML, to differentiate it from the original open source specification from which it was derived. Because OMG SysML is derived from open source SysML, it also includes an open source license for distribution and use.

The OMG SysML v. 1.0 specification was issued by the OMG as an Available Specification in September 2007.<ref>{{cite web|url=http://www.omg.org/spec/SysML/1.0/PDF|title=SysML 1.0|work=omg.org|accessdate=2014-12-04}}</ref> The current version of OMG SysML is v1.4, which was issued by the OMG in September 2015.<ref>{{cite web|url = http://www.omg.org/spec/SysML/1.4/|title = SysML|work = omg.org|accessdate = 2015-02-18}}</ref>

== Diagrams ==

SysML includes 9 types of diagram, some of which are taken from [[Unified Modelling Language|UML]].

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* [[Parametric diagram]]

== Limitations and Criticismscriticisms ==

{{citation needed|reason=The entire Limitations and CriticismsRefimprove section is missing references.|date=August 2015}}

SysML takes time and effort to learn. It is intended to be a conventional language for conducting Model[[model-based Basedsystems System Engineeringengineering]] but it has some important limitations that reduce its efficiency and limit its acceptance. This limited usage is, in itself, a limitation, as the SysML language can be considered a hermetic language that non-initiated find sometimes difficult to exploit.

SysML has been criticized for being incomplete although there is little to stop a practitioner from adding their own content. In SysML, there is no provision for several diagrams and graphically-oriented tools that are commonly used in system engineering. Some of these diagrams can be built, for example, by extending the intended use of block definition diagrams but the results are not always adequate and often not in concordance with the rules of the SysML language. Missing elements include [[functional block diagram]], [[N2 chart]] , [[House of Quality]], [[Ishikawa diagram]] (fishbone), parameter diagram and others. The language is continually improving and other diagram types are being considered for addition in future updates, should they be deemed sufficiently useful for inclusion.

The diagrams generated by SysML are complicated and some are difficult to understand by people that are unfamiliar with the language. Some elements are slightly counter-intuitive and this could lead to confusion and errors. This is occasionally aggravated by SysML users believing SysML should be a widespread convention. This can be overcome by including explanatory notes and legends in SysML diagrams to ease their interpretation. As systemSystem-engineering diagrams are primarily intended for other members of an embedded team and; people outside the team that, more often than not, are not system engineers and are less likely to know SysML. This can be overcome by including explanatory notes and legends in SysML diagrams to ease their interpretation.

When drawn in a software tool, the diagrams that respect the rules of SysML often include redundant pieces of model information that can impair their interpretation.

== Tools ==

There are several modeling tool vendors already offering SysML support, or are in the process of updating their tools to comply with the OMG SysML specification. Lists of tool vendors who support, or have announced support of, SysML or OMG SysML can be found on the SysML Forum<ref>{{cite web|url=http://www.SysMLforum.com|title=SysML Forum: What is SysML? - What You Need to Know|work=sysmlforum.com|accessdate=2014-12-04}}</ref> or SysML<ref>{{cite web|url=http://www.omgsysml.org|title=OMG SysML|work=omgsysml.org|accessdate=2014-12-04}}</ref> websites, respectively.

=== Model Exchangeexchange ===

As an [[Object Management Group|OMG]] [[Unified Modeling Language|UML 2.0]] [[profile (UML)|profile]], SysML models are designed to be exchanged using the [[XML Metadata Interchange]] (XMI) standard. In addition, architectural alignment work is underway to support the [[ISO 10303]] (also known as STEP, the Standard for the Exchange of Product model data) AP-233 standard for exchanging and sharing information between [[systems engineering]] software applications and tools.

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* [[SoaML]]

* [[Energy Systems Language]]

* [[Object Process Methodology]]

* [[Universal Systems Language]]

== Further readingReferences ==

{{reflist|30em}}

== Further reading ==

* {{cite book

| first= Laurent

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| url = http://www.jot.fm/issues/issue_2007_07/article5.pdf

| title = An Overview of the Systems Modeling Language for Products and Systems Development

| publisher = Journal of Object Technology, vol. 6, no. 6, July–August 2007, pp. 149-177

}}

* {{cite book

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| isbn=978-0-12-800202-5

|edition=Third}}

==References and notes==

''Notes''

{{Reflist|group=note}}

''Citations''

{{reflist|30em}}

== External links ==