Making Existing Reactive Systems Anticipatory

From the viewpoints of high safety and high security, any critical reactive system should be anticipatory, i.e., the system should be able to detect and predict accidents/attacks, take some actions to inform its users, and perform some operations to defend the system from possible accidents/attacks anticipatorily.However, most of existing reactive systems are not so, furthermore, it is impractical, but not impossible, to rebuild them to be anticipatory, because reimplementation of the whole of a system results in high cost. Therefore, it is desirable to extend an existing legacy reactive system with anticipatory ability without reimplementing the whole of the legacy system. This paper proposes a general methodology to realize such an extension. The novelty of the methodology is that it does not require reimplementation the whole legacy system, does not affect the system’s original functions, and can deal with various reactive systems by using the same process. By extending an existing reactive system anticipatory using our methodology, we can get a new generation system with high safety and high security. This paper also presents three case studies to show how to apply our methodology.