by Nikola Beneš, Jan Křetínský, Kim Guldstrand Larsen, Mikael Moeller, Jiří Srba, A full version of the paper presented at conference LPAR 2012. January 2012, 23 pages.
FIMU-RS-2012-01. Available as Postscript, PDF.
Modal transition systems are a well-established specification formalism for a high-level modelling of component-based software systems. We present a novel extension of the formalism called modal transition systems with durations where time durations are modelled as controllable or uncontrollable intervals. We further equip the model with two kinds of quantitative aspects: each action has its own running cost per time unit, and actions may require several hardware components of different costs. We ask the question, given a fixed budget for the hardware components, what is the implementation with the cheapest long-run average reward. We give an algorithm for computing such optimal implementations via a reduction to a new extension of mean payoff games with time durations and analyse the complexity of the algorithm.
by Lasse Jacobsen, Morten Jacobsen, Mikael Moeller, Jiří Srba, A full version of the paper presented at EPEW`10. August 2010, 34 pages.
FIMU-RS-2010-09. Available as Postscript, PDF.
Many formal translations between time dependent models have been proposed over the years. While some of them produce timed bisimilar models, others preserve only reachability or (weak) trace equivalence. We suggest a general framework for arguing when a translation preserves Timed Computation Tree Logic (TCTL) or its safety fragment. The framework works at the level of timed transition systems, making it independent of the modeling formalisms and applicable to many of the translations published in the literature. Finally, we present a novel translation from extended Timed-Arc Petri Nets to Networks of Timed Automata and using the framework argue that it preserves the full TCTL. The translation has been implemented in the verification tool TAPAAL.