On the Use of CEP in Safety-critical Systems

Safety-critical systems have to continuously manage risks, in order to handle hazardous situations and still be able to fulfil their purpose. While being composed by a variety of software, as well as hardware components, it is necessary for each part of these systems, alone and as a whole, to exhibit a required set of characteristics, necessary to ensure the correct system functioning. Complex Event Processing (CEP) systems have been used in a diversity of applications and, while they focus on fast data gathering and processing as well as in providing intelligence to their users, there is incomplete information about how they are adequate to integrate safety-critical systems. In this paper we investigate if the mainstream off-the-shelf CEP systems are suitable for safety-critical applications. We describe the use of complex event processing engines in safety-critical systems and how some authors enhance those to better correspond to the critical system requirements. We demonstrate that, although dependability is well handled in most CEP systems, the same cannot be assumed about security and safety attributes.