Upto techniques, Logic, Fault-tolerant computing, distributed calculi, Reliability, testing and fault tolerance of networks and computer systems, Theoretical Computer Science, labelled transition systems, upto techniques, Models and methods for concurrent and distributed computing (process algebras, bisimulation, transition nets, etc.), Bisimulation, Bisimulations, bisimulations, Obervational equivalences, Labelled transition systems, obervational equivalences, Distributed calculi, Fault tolerance, 004, Computational Theory and Mathematics, Distributed operating systems (Computers), Computer Science, fault tolerance, fault tolerence, Software