Improving the Dependability of Sensornets

Wireless Sensor Networks (WSNs) are being developed and deployed in a wide range of Cyber-Physical systems, some of which must be dependable, e.g. in assisted living facilities where their failure could lead to an accident. In this paper, it is shown that the state of the art approaches do not meet the needs of dependability that these applications require. The main reason is an issue is the unpredictable physical environment in which they operate. Currently there is little emphasis on how these systems behave when failures occur, instead authors emphasise average case performance. Consequently there is little understanding of how and why systems fail and the possible consequences e.g. a system hazard. In this paper simulated tests are used at run-time to check key dependability properties of the system. The results of these tests are used to plan maintenance, thus ensuring available and reliable operation, and determining when the system is at risk of subjecting people to unacceptable hazards such that appropriate steps can be taken. Our approach has been show to perform with 15% less time at risk than the current state-of-the art.