Systems under attack-survivability rather than reliability: Concept, results, and applications

In this paper, we introduce the concept of system survivability under attack in analogy with system reliability. The problem is very important particularly nowadays when the world witnesses a large variety of intelligent threats including terrorism, rebellions, civil wars, pirating, and so on. We limit consideration to the discrete case. We define a component/system survivability to be the probability that the system/component continues functioning upon attack. We specify the differences between our suggested concept of system survivability and the traditional one of system reliability. Most often, the survivability follows a Bernoulli distribution for which the survival probability is derived based on the system configuration. We develop results for series, parallel, series-parallel, parallel-series and k-out-of-n systems. We also provide the expected number of attacks for each system configuration based on the particular attack strategy both for single and multiple attacks. We illustrate the process through a real application.