Modelling Location-Aware Access Control Constraints for Mobile Workflows with UML Activity Diagrams

In this paper an extension to activity diagrams from the Unified Modeling Language (UML) is proposed that supports the definition of several kinds of location constraints. A location constraint is a statement that says whether it is allowed to perform an activity within a mobile workflow at a particular location or not. They therefore constitute a special case of access control that is location-aware. We cover location constraints that are assigned at the design time of the workflow schema as well as constraints that a derived during the runtime of a workflow instance. Location constraints can help to tackle mobile-specific challenges that come along with the employment of mobile workflow systems, namely security issues and usability problems.