Timed Communicating Object Z

This paper describes a timed, multithreaded object modeling notation for specifying real-time, concurrent, and reactive systems. The notation Timed Communicating Object Z (TCOZ) builds on Object-Z's strengths in modeling complex data and algorithms, and on Timed CSP's strengths in modeling process control and real-time interactions. TCOZ is novel in that it includes timing primitives, properly separates process control and data/algorithm issues and supports the modeling of true multi-threaded concurrency. TCOZ is particularly well suited for specifying complex systems whose components have their own thread of control. The expressiveness of the notation is demonstrated by a case study in specifying a multi-lift system that operates in real-time.