Hemodialysis Machine in Hybrid Event-B

The hemodialysis machine case study is examined in Hybrid Event-B (an extension of Event-B that includes provision for continuously varying behaviour as well as the usual discrete changes of state). A broadly component based strategy is adopted, using the multi-machine and coordination facilities of Hybrid Event-B. Since, like most medical procedures, hemodialysis is under overall human control, it is largely a sequential process, with some branching to deal with exceptional circumstances. This makes for a relatively uncomplicated modelling framework, provided a model of the operator is included in order to capture the handling of exceptions.