UML & SysML modelling languages

UML or Unified Modeling Language is maintained as a standard by the OMG (Object Management Group - www.omg.org) since 1997.

As object-oriented programming languages became very popular in the 90s, various design techniques were released and became popular. However none covered the whole design process. In 1995 the "three amigos" i.e. Grady Booch, Ivar Jacobson, and James Rumbaugh, respectively authors of the Booch, OOSE (Object Oriented Software Engineering), and the OMT (Object Modeling Technique) modelling techniques, teamed up to combine techniques and notations under the "Unified Modeling Language" or UML. Two years later, UML became a standard design modelling language maintained by the Object Management Group standards body.

The current version of this standard is UML 2.4.1 (since 08/2011).

UML makes it possible to produce a visual and unified representation of a system's structural and behavioural characteristics through various elements such as activities, actors, processes, components, etc.

Hence UML can be used to help understand and manage complex concepts or architectures. UML is both suitable for simple or small projects with a few models or diagrams, and for complex and/or large projects through a complete set of models, e.g. requirements, use case, analysis, design, architecture, and database models.

UML 2.4 has 14 types of diagrams, divided into two categories as illustrated below:

Structural diagrams

• Class diagram
• Object diagram
• Package diagram
• Component diagram
• Deployment diagram
• Composite structure diagram
• Profile diagram

Behavioural diagrams

• Use case diagram
• Activity diagram
• Interaction diagrams: sequence, communication, interaction overview, and timing
• State Machine diagram