Modelling user tasks with the Unified Modelling Language

This paper discusses the extension of the Unified Modelling Language (UML) for modelling tasks and user groups. The term task is used widely, to include collaborative and multi-user tasks and without reference to some specific theory of user task lfuowledge or behaviour. The paper presents the proposed extension to the UML, focusing on the concepts involved and the abstract syntax for the notation introduced, comparing it to related formalisms and other extensions to the UML