Formal Visual Modelling of Human Agents in Service Oriented Systems

Abstract

When the level of granularity of services approaches that of business activities, humans become part of a serviceoriented system not just as users but as providers of services. A model of such a system has to take into account the characteristics of human actors as service providers. Conversely, in the world of agent-based systems, software components have been attributed with human properties such as reactivity, autonomy and proactivity. We believe that modelling techniques developed for software agents are a valid starting point for specifying human agents in service-oriented systems (HASOS). In particular, we extend UML use case and class diagrams by concepts of rolebased access control (RBAC) and use graph transformation (GT) rules to model changes to data as well as the dynamic (re-)assignment of roles played by human actors. From these models we can derive specifications of the services required systematically in terms of pre-and post-conditions as well as communication scenarios modelling their interactions. We use the formal framework provided by GT to formalize consistency relations between the different parts of these models. The technique will be demonstrated with the use of a pharmacy scenario.

Stochastic Modelling and Simulation of Dynamic Resource Allocation

“…While humans can be regarded as autonomous agents, our approach adds the element of dynamic reassignment of human agents to roles as well as the modelling of non-deterministic timing of actions. This relation is explored in more detail in a previous paper [4]. In summary, none of the approaches completely satisfies the requirements laid out in Section 1.…”