TY  - CHAP
ID  - eprints2575
EP  - 190
T2  - Proceedings of the 7th International Conference on the Quantitative Evaluation of Systems (QEST)
Y1  - 2010/09//
TI  - Hybrid semantics for PEPA
AV  - none
UR  - http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5600389&isnumber=5600366
SN  - 978-1-4244-8082-1
PB  - IEEE
A1  - Bortolussi, Luca
A1  - Galpin, Vashti
A1  - Hillston, Jane
A1  - Tribastone, Mirco
N2  - In order to circumvent the problem of state-space explosion of large-scale Markovian models, the stochastic process algebra PEPA has been given a fluid semantics based on ordinary differential equations, treating all entities as continuous. However, low numbers of instances and/or relatively slow dynamics may make such approximation too coarse for some parts of the system. To deal with such situations, we propose an hybrid semantics lying between these two extremes, treating parts of the system as discrete and stochastic and others as continuous and deterministic. The underlying mathematical object for the quantitative evaluation is a stochastic hybrid automaton. A case study of a client/server system with breakdowns and repairs is used to discuss the accuracy and the cost of this hybrid analysis.
SP  - 181
ER  -