Optimization of reliability allocation and testing schedule for software systems

To ensure an overall reliability of an integrated software system, software components of the system have to meet certain reliability requirements, subject to some testing schedule and resource constraints. The system testing activity can be formulated as a combinatorial optimization problem with known cost, reliability, effort and other attributes of the system components. In this paper, we consider the software component reliability allocation problem for a system with multiple applications. The failure rate of components used to build the applications are related to the testing cost through various types of reliability growth curves. We achieve closed-form solutions to problems where there is one single application in the system. Analytical solutions are not readily available when there are multiple applications; however, numerical solutions can be obtained using a nonlinear programming tool. To ease the specification of the optimization problem, we develop a GUI front-end to existing mathematical software. We present a systematic outline of the problem formulation and solution, and apply this to an example of a telecommunication software system.