salle A. Turing CE4
25 May 2012 - 14h00
A System Perspective on Processes and Their Interactions.
by Johannes Reich from SPA
Abstract: The starting point is a view of our social world as an open network of nondeterministic interactions between possibly deterministic systems. From an engineering perspective one essential question becomes how we can describe local parts of these networks without running into the unfulfillable requirement to describe the network as a whole.
Two different perspectives naturally arise: an interaction centric, providing the local borders and a process centric one, providing the executions. A process is being understood as a system which interacts with multiple other systems.
Based on a formal notion for finite systems, several issues are illustrated. Mutual interactions make system composition more complex than the usual simple box diagrams might suggest. The fact, that interactions as well as processes are just different views on the same network results in a unifying way to describe both, the interactions between systems as protocols in the sense of a causal relation between the input and output of different systems as well as the coordination of different interactions as processes in the sense of a causal relation between their input and output by similar means, namely different ways to restrict the transition relation of the resulting product automaton.
The close relationship between protocols in the above sense and extensive form games is illustrated and is a major justifier for the proposed approach.
An explanation is offered for the failure of scaling of distributed object models as well as the current approaches of componentization which solely rely on providing components only operational signatures instead of protocols.