The relevance of graphical functions in vehicular applications has increased significantly during the few last years. Modern cars are equipped with multiple displays used by different applications such as speedometer or navigation system. However, so far applications are restricted to using dedicated displays. In order to increase flexibility, the requirement of sharing displays between applications has emerged. Sharing displays leads to safety and security concerns since safety-critical applications as the dashboard warning lights share the same displays with uncritical or untrusted applications like the navigation system or third-party applications. To guarantee the safe and secure sharing of displays, we present a formal model for defining and controlling the access to display areas in this paper. We prove the validity of this model, and present a proof-of-concept implementation to demonstrate the feasibility of our concept.

In this paper, we present an object-oriented approach to the specification of discrete software controllers that are embedded in discrete-continuous (or hybrid) environments.The structure of the controller and its environment is specified using object notations extended to include continuous and hybrid objects.Control behavior is specified with state automata and pre/postconditions using the statechart notation and constructive Z-schemata.The behavior of the environment is specified '\\ith systems of differential equations using an object-oriented extension of Z for the specification of hybrid systems.We use a case study on control of a high-pressure steam boiler to illustrate how the environment structure can help to design the controller and how environment simulation can be used to derive control parameters.