Process Modeling Using UML

The Unified Modeling Language (UML)1 is a visual, object-oriented, and multipurpose modeling language. Primarily designed for modeling software systems, it can also be used for business process modeling. Since the early 1970s, a large variety of languages for data and software modeling like entity-relationship diagrams [2], message sequence charts [5, 10], state charts [9], and so on, have been developed, each of them focusing on a different aspect of software structure or behavior. In the early 1990s, object-oriented design approaches gained increasing attention, for instance, in the work of James Rumbaugh (Object Modeling Technique or OMT [21]), Grady Booch [1], and Ivar Jacobson [12]. The UML emerged from the intention of Rumbaugh, Booch, and Jacobson to find a common framework for their approaches and notations. Furthermore, the language was also influenced by other object-oriented approaches like that of Coad and Yourdon [3]. The first version, UML 1.0 [20], was released in 1997 and accepted as a standard by the Object Management Group (OMG)2 the same year. The OMG, which took over the responsibility for the evolution of the UML from then on, is a consortium from both industry and academia and is also responsible for other wellknown initiatives like CORBA, MDA, and XMI. OMG specifications have to undergo a sophisticated adoption process before being agreed upon as a standard by the OMG members. Since many important tool builders and influential software companies are involved in the OMG, UML has quickly been accepted by the software industry, especially since version UML 1.3 appeared in 1999. When writing this book, the current UML version was UML 2.0 [18], a major revision of the language. UML is a conglomeration of various diagram types. Therefore, the challenge is to provide a uniform framework for all these heterogeneous diagram types and accounting for relationships between them. In UML, this is solved by a common meta-model that formally defines the abstract syntax of all diagram types. The