I. Introduction
The design of a complex system is always a challenging task that involves different domain expertises. Usually, designers have to achieve four kinds of design requirements: functional requirements, technical requirements, cost restrictions and requirements on RAMS (Reliability, Availability, Maintainability and Safety) parameters. Ensuring a proper RAMS assessment during the design phase of a product is a fundamental topic that allows to achieve multiple advantages (e.g. compare multiple functional configurations; validate the design choices; achieve the required target; guarantee high availability and consequently ensure continuity of service; optimize the maintenance policy) [1] –[4]. One of the most critical design tasks involves the selection of components in terms of reliability requirements. This design phase represents a fundamental step to reduce probability of failures and maximize the system availability and system safety [5] –[8].