Deriving Safety Properties for Home Network System Based on Goal-Oriented Hazard Analysis Model

The home network system (HNS, for short) is comprised of networked home appliances, which achieves various value-added services for home users. Assuring safety of the HNS and the services is a crucial issue. However, safety properties to be verified against the HNS have been given in an ad-hoc manner. This paper presents a systematic method that can derive the verifiable safety properties from a given HNS model and hazard contexts. Specifically, we first define a hazard analysis model for the HNS consisting of four levels of abstractions. We then conduct a Goal-oriented analysis to specify logical relations between the adjacent abstraction levels. The analysis yields cause-and-effect chains from the abstract hazard contexts to the concrete attributes and operations of HNS objects (appliances, services, environment). Finally, the safety properties and their responsible operations are derived from the complete model, which give the strong rationale of the safety of the HNS.