Systems Modeling Language
Encyclopedia
The Systems Modeling Language (SysML) 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 systems-of-systems
. SysML was originally developed by an open source
specification project, and includes an open source license for distribution and use. SysML is defined as an extension of a subset of the Unified Modeling Language
(UML) using UML's profile mechanism
.
SysML reuses seven of UML 2's thirteen diagrams, and adds two diagrams (requirements 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.
The advantages of SysML over UML for systems engineering become obvious if you consider a concrete example, such as modeling an automotive system. With SysML you can use Requirement diagrams to efficiently capture functional, performance and interface requirements, whereas with UML you are subject to the limitations of Use Case diagrams to define high-level functional requirements. Likewise, with SysML you can use Parametric diagrams to precisely define performance and quantitative constraints such as 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.
As for the rest of the automotive system, enhanced activity diagram
s and 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.
(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 AP 233
workgroup, developed the requirements for the modeling language, which were subsequently issued by the OMG as part of the UML for Systems Engineering Request for Proposal (UML for SE RFP; OMG document ad/03-03-41) in March 2003.
In 2003 Cris Kobryn
and Sanford Friedenthal organized and co-chaired the SysML Partners
, an informal association of industry leaders and tool vendors, which initiated an open source specification project to develop the SysML in response to the UML for Systems Engineering RFP. The SysML Partners distributed their first open source SysML specification drafts in 2004, and submitted SysML 1.0a to the OMG for technology adoption in November 2005.
The OMG SysML v. 1.0 specification was issued by the OMG as an Available Specification in September 2007. The current version of OMG SysML is v. 1.2, which was issued by the OMG in June 2010.
UML 2.0
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.
General-purpose modeling
General-purpose modeling is the systematic use of a general-purpose modeling language to represent the various facets of an object or a system...
language for systems engineering
Systems engineering
Systems engineering is an interdisciplinary field of engineering that focuses on how complex engineering projects should be designed and managed over the life cycle of the project. Issues such as logistics, the coordination of different teams, and automatic control of machinery become more...
applications. It supports the specification, analysis
Analysis
Analysis is the process of breaking a complex topic or substance into smaller parts to gain a better understanding of it. The technique has been applied in the study of mathematics and logic since before Aristotle , though analysis as a formal concept is a relatively recent development.The word is...
, design
Design
Design as a noun informally refers to a plan or convention for the construction of an object or a system while “to design” refers to making this plan...
, verification and validation
Verification and Validation
In software project management, software testing, and software engineering, verification and validation is the process of checking that a software system meets specifications and that it fulfills its intended purpose...
of a broad range of systems and systems-of-systems
System of systems
System of systems is a collection of task-oriented or dedicated systems that pool their resources and capabilities together to create a new, more complex system which offers more functionality and performance than simply the sum of the constituent systems...
. SysML was originally developed by an open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
specification project, and includes an open source license for distribution and use. SysML is defined as an extension of a subset of the Unified Modeling Language
Unified Modeling Language
Unified Modeling Language is a standardized general-purpose modeling language in the field of object-oriented software engineering. The standard is managed, and was created, by the Object Management Group...
(UML) using UML's profile mechanism
Profile (UML)
A profile in the Unified Modeling Language provides a generic extension mechanism for customizing UML models for particular domains and platforms...
.
Overview
SysML offers systems engineers several noteworthy improvements over UML, which tends to be software-centric. These improvements include the following:- SysML's semantics are more flexible and expressive. SysML reduces UML's software-centric restrictions and adds two new diagram types, requirement and parametric diagrams. The former can be used for requirements engineeringRequirements engineeringRequirements engineering is a systems and software engineering process which covers all of the activities involved in discovering, documenting and maintaining a set of requirements for a computer-based system...
; the latter can be used for performance analysisPerformance analysisIn software engineering, profiling is a form of dynamic program analysis that measures, for example, the usage of memory, the usage of particular instructions, or frequency and duration of function calls...
and quantitative analysisQuantitative analysisQuantitative analysis may refer to:* Quantitative analysis , an analysis technique applying mathematics stochastic calculus to finance...
. As a result of these enhancements, SysML is able to model a wide range of systems, which may include hardware, software, information, processes, personnel, and facilities. - SysML is a smaller language that is easier to learn and apply. Since SysML removes many of UML's software-centric constructs, the overall language is smaller as measured both in diagram types and total constructs.
- SysML allocation tables support common kinds of allocations. Whereas UML provides only limited support for tabular notations, SysML furnishes flexible allocation tables that will support requirements allocation, functional allocation, and structural allocation. This capability facilitates automated verification and validationVerification and ValidationIn software project management, software testing, and software engineering, verification and validation is the process of checking that a software system meets specifications and that it fulfills its intended purpose...
(V&V) and gap analysis. - SysML model management constructs support models, views, and viewpoints. These constructs extend UML's capabilities and are architecturally aligned with IEEE-Std-1471-2000 (IEEE Recommended Practice for Architectural Description of Software Intensive Systems).
SysML reuses seven of UML 2's thirteen diagrams, and adds two diagrams (requirements 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.
The advantages of SysML over UML for systems engineering become obvious if you consider a concrete example, such as modeling an automotive system. With SysML you can use Requirement diagrams to efficiently capture functional, performance and interface requirements, whereas with UML you are subject to the limitations of Use Case diagrams to define high-level functional requirements. Likewise, with SysML you can use Parametric diagrams to precisely define performance and quantitative constraints such as maximum acceleration
Acceleration
In physics, acceleration is the rate of change of velocity with time. In one dimension, acceleration is the rate at which something speeds up or slows down. However, since velocity is a vector, acceleration describes the rate of change of both the magnitude and the direction of velocity. ...
, minimum curb weight
Curb weight
Curb weight or kerb weight is the total weight of a vehicle with standard equipment, all necessary operating consumables , a full tank of fuel, while not loaded with either passengers or cargo.This definition may differ from definitions used by governmental regulatory agencies or other...
, and total air conditioning
Air conditioning
An air conditioner is a home appliance, system, or mechanism designed to dehumidify and extract heat from an area. The cooling is done using a simple refrigeration cycle...
capacity. UML provides no straightforward mechanism to capture this sort of essential performance and quantitative information.
As for the rest of the automotive system, enhanced activity diagram
Activity diagram
Activity diagrams are graphical representations of workflows of stepwise activities and actions with support for choice, iteration and concurrency. In the Unified Modeling Language, activity diagrams can be used to describe the business and operational step-by-step workflows of components in a system...
s and state machine diagrams can be used to specify the embedded software
Embedded software
Embedded software is computer software that plays an integral role in the electronics it is supplied with.Embedded software's principal role is not Information technology , but rather the interaction with the physical world. It's written for machines that are not, first and foremost, computers...
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 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 GroupObject Management Group
Object Management Group is a consortium, originally aimed at setting standards for distributed object-oriented systems, and is now focused on modeling and model-based standards.- Overview :...
(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 AP 233
ISO 10303
ISO 10303 is an ISO standard for the computer-interpretable representation and exchange of product manufacturing information. Its official title is: Automation systems and integration — Product data representation and exchange...
workgroup, developed the requirements for the modeling language, which were subsequently issued by the OMG as part of the UML for Systems Engineering Request for Proposal (UML for SE RFP; OMG document ad/03-03-41) in March 2003.
In 2003 Cris Kobryn
Cris Kobryn
Cris Kobryn is an American technologist, system architect and entrepreneur who specializes in advanced software and systems development.-Biography:...
and Sanford Friedenthal organized and co-chaired the SysML Partners
SysML Partners
SysML Partners is a consortium of software tool vendors and industry leaders organized in 2003 to create the Systems Modeling Language , a dialect of UML customized for systems engineering...
, an informal association of industry leaders and tool vendors, which initiated an open source specification project to develop the SysML in response to the UML for Systems Engineering RFP. The SysML Partners distributed their first open source SysML specification drafts in 2004, and submitted SysML 1.0a to the OMG for technology adoption in November 2005.
OMG SysML
After a series of competing SysML specification proposals, a SysML Merge Team was proposed to the OMG in April 2006. 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. The current version of OMG SysML is v. 1.2, which was issued by the OMG in June 2010.
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 or OMG SysML websites, respectively.Model Exchange
As an OMGObject Management Group
Object Management Group is a consortium, originally aimed at setting standards for distributed object-oriented systems, and is now focused on modeling and model-based standards.- Overview :...
UML 2.0
Unified Modeling Language
Unified Modeling Language is a standardized general-purpose modeling language in the field of object-oriented software engineering. The standard is managed, and was created, by the Object Management Group...
profile
Profile (UML)
A profile in the Unified Modeling Language provides a generic extension mechanism for customizing UML models for particular domains and platforms...
, SysML models are designed to be exchanged using the XML Metadata Interchange
XML Metadata Interchange
The XML Metadata Interchange is an Object Management Group standard for exchanging metadata information via Extensible Markup Language .It can be used for any metadata whose metamodel can be expressed in Meta-Object Facility ....
(XMI) standard. In addition, architectural alignment work is underway to support the ISO 10303
ISO 10303
ISO 10303 is an ISO standard for the computer-interpretable representation and exchange of product manufacturing information. Its official title is: Automation systems and integration — Product data representation and exchange...
(also known as STEP, the Standard for the Exchange of Product model data) AP-233 standard for exchanging and sharing information between systems engineering
Systems engineering
Systems engineering is an interdisciplinary field of engineering that focuses on how complex engineering projects should be designed and managed over the life cycle of the project. Issues such as logistics, the coordination of different teams, and automatic control of machinery become more...
software applications and tools.
See also
- Energy Systems LanguageEnergy Systems LanguageThe Energy Systems Language , also referred to as Energese, Energy Circuit Language and Generic Systems Symbols, was developed by the ecologist Howard T. Odum and colleagues in the 1950s during studies of the tropical forests funded by the United States Atomic Energy Commission...
- Universal Systems LanguageUniversal Systems LanguageUnlike traditional languages, the Universal Systems Language is based on a preventative instead of a curative paradigm. Based on systems theory, to a great extent derived from lessons learned from the Apollo onboard flight software effort, USL has evolved over several decades and taken on multiple...
- PapyrusPapyrus (software)Papyrus is an Open Source UML 2 tool based on Eclipse and licensed under the EPL. It can either be used as a standalone tool or as an Eclipse plugin. Papyrus provides support for Domain Specific Languages and SysML.-UML2:...
- MagicDraw
External links
- SysML Open Source Specification Project Provides information related to SysML open source specifications, FAQ, mailing lists, and open source licenses.
- OMG SysML Website Furnishes information related to the OMG SysML specification, SysML tutorial, papers, and tool vendor information.
- SysML Forum A web community dedicated to SysML, contains information related to SysML modeling tools, training, tutorials, specifications, publications, mailing lists and blogs.
- TOPCASED Website Set of eclipse-based open source model editors, transformation and formal verification tools. Modeling languages include SysML. Development sponsored by European aerospace manufacturers.
- Visio Stencil and Template for SysML 1.0
- Article "EE Times article on SysML (May 8, 2006)"
- SE^2 MBSE Challenge team: Telescope Modeling
- SysML User Group on LinkedIn
- Paper System Modelling Language explained (PDF format)