Comparing two approaches to modelling decentralised manufacturing control systems with UML capsules

In this paper, we describe two orthogonal methodologies for building decentralised manufacturing control systems. The fundamental building block of these control systems is the UML capsule stereotype that can be used to design object-oriented software systems that are open, agile, have the capacity to manage real-time tasks and so can provide varying degrees of ´intelligence´ within a 21^st century manufacturing environment. We also evaluate the merits of these two viewpoints using a discrete-event simulation experimental test bed.