Guest lecture by Jan Peleska

Jan Peleska from the University in Bremen will give a talk in the elite program’s special lecture series. The title of the talk is “An Introduction to SysML” and it will take place virtually as an online meeting at 4PM on July 1st 2021.


The System Modeling Language SysML is one of the most widely used wide-spectrum formalisms for model-based systems engineering (MBSE). It has been elaborated as a profile of the Unified Modeling Language UML, with emphasis on systems modelling. Just like UML, it has been standardised by the Object Management Group OMG. We briefly introduce the SysML 1.6 components for modelling

  • Structure (Blocks, Ports, Connectors, Flows and associated Block Definition Diagrams and Internal Block Diagrams)
  • Behaviour (State Machines, Activities, Interactions, Use Cases)

When compared to other (formal or semi-formal) modelling languages, SysML has some unique selling points:

  • Requirements are “first-class citizens” of the SysML language: they are represented by specific language elements, and they can be associated with other model elements for the purpose of requirements tracing.
  • Physical laws can be specified in re-usable model libraries by means of so-called constraint blocks.
  • For a concrete system, the laws can be imported, and their formal parameters may be bound to concrete system parameters.
  • The standardised XML-based internal representation of SysML models and its meta models (so-called XMI-format) allows for effective model-based code generation.

Despite these unique selling points, SysML has been criticised to be fairly complex to handle in practise. We explain the main reasons behind this criticism: the syntax may be regarded as too rich, and the static and behavioural semantics are quite complex, since they have to be traced back to UML via the profile mechanism. Moreover, graphical notation is not as well-supported by existing modelling tools as textual programming with today’s IDEs like Eclipse, MS Developer, or Xcode. This criticism has led to the (not yet fully standardised) definition of SysML v2, whose highlights will be briefly sketched to conclude the talk.

Since the size of the SysML is really enormous, we can sketch many aspects of this language only briefly in this overview talk. However, detailed references to the literature will be given.