Refinement for Transition Systems with Responses

Motivated by the response pattern for property specifications and applications within flexible workflow management systems, we report upon an initial study of modal and mixed transition systems in which the must transitions are interpreted as must eventually, and in which implementations can contain may behaviors that are resolved at run-time. We propose Transition Systems with Responses (TSRs) as a suitable model for this study. We prove that TSRs correspond to a restricted class of mixed transition systems, which we refer to as the action-deterministic mixed transition systems. We show that TSRs allow for a natural definition of deadlocked and accepting states. We then transfer the standard definition of refinement for mixed transition systems to TSRs and prove that refinement does not preserve deadlock freedom. This leads to the proposal of safe refinements, which are those that preserve deadlock freedom. We exemplify the use of TSRs and (safe) refinements on a small medication workflow.Comment: In Proceedings FIT 2012, arXiv:1207.348

Distributed Dynamic Condition Response Structures

We present distributed dynamic condition response structures as a declarative process model in-spired by the workflow language employed by our industrial partner and conservatively generalizing labelled event structures. The model adds to event structures the possibility to 1) finitely specify re-peated, possibly infinite behavior, 2) finitely specify fine-grained acceptance conditions for (possibly infinite) runs based on the notion of responses and 3) distribute events via roles. We give a graph-ical notation inspired by related work by van der Aalst et al and formalize the execution semantics as a labelled transition system. Exploration of the relationship between dynamic condition response structures and traditional models for concurrency, application to more complex scenarios, and further extensions of the model is left to future work.

Experience Report: Constraint-Based Modelling and Simulation of Railway Emergency Response Plans

AbstractWe report on experiences from a case study applying a constraint-based process-modelling and -simulation tool, dcrgraphs.net, to the modelling and rehearsal of railway emergency response plans with domain experts. The case study confirmed the approach as a viable means for domain experts to analyse and rehearse emergency response plans, through the activities of formally modelling the plan and subsequently rehearsing it by simulating that model collaboratively. In particular, the constraint-based modelling notation resulted in a flexible model giving rehearsal participants freedom to explore different ways to proceed, including ways not necessarily anticipated in the paper-based emergency response plans. The case study was undertaken as part of a short research, ProSec, project funded by the Danish Defence Agency, with the aim of applying and developing methods for collaborative mapping of emergency and security processes in the danish public transport sector and their dependency on ICT