The Cardiac Pacemaker

Abstract

Building high quality and zero defects medical software-based devices is a critical task, and formal modelling techniques can effectively help to achieve this target at the certain level. Formal modelling of a high-confidence medical device, such as that is too much error prone in operating, is an international Grand Challenge in the area of Verified Software. Modelling a cardiac pacemaker is one of the proposed challenges, and we consider the complete description of pacemaker’s functionalities using an incremental proof-based approach. To assess the effectiveness of our proposed development methodology and associated techniques and tools, we select this case study. This chapter presents the development of a cardiac pacemaker using our proposed development life-cycle methodology from requirement analysis to automatic code generation. In this development, we use formal verification to verify the correctness of the requirements for a simple and closed-loop model, model checking to verify the correctness of the system behaviours, real-time animator to check the system behaviours according to the domain experts (i.e. medical experts), and finally the code generation tool EB2ALL for generating the codes into several programming languages. The refinement charts are used to handle the complexity of the system, where it helps to organise the code structure according to the different operating modes. Formal models are expressed in the Event-B modelling language, which integrates conditions (called proof obligations) for checking their internal consistency with respect to the invariants and safety properties. The generated proof obligations of models are proved by the Rodin tool and desired behaviour of the system is validated by the ProB tool and real-time animator according to the medical experts.