Experiences with Theme/UML for Architectural Design of a Multiagent System

In a recent R&D project, our research group developed an industrial AGV transportation system using a multiagent system (MAS). The software architecture of this system is modeled using several architectural views. In this paper, we study an alternative way of structuring of the architectural description using Theme/UML. Theme/UML is an aspect-oriented design approach that provides support for advanced separation of concerns. Our goal is twofold. (1) We structure the architectural description based on important architectural concerns (such as coordination and distribution), instead of the current structure based on different viewtypes (module, component, deployment). The goal is to investigate the advantages and trade-offs of separating concerns in architectural design of MASs. (2) Currently, Theme/UML provides only support for detailed design. We aim to evaluate whether Theme/UML can be applied to architectural design. The results of our experience are promising. The advantage of separating architectural concerns is that the resulting architectural description (1) is better aligned with the architectural concerns, and (2) facilitates the investigation of alternatives for those concerns. We illustrate this by changing the distribution schema of the AGV transportation system. A trade-off is that describing the concerns separately makes it more difficult to get an overall view on the system. Finally, the experiment shows that Theme/UML is not ready for architectural design. To improve support for architectural design of MASs, we propose several extensions to Theme/UML .