An overview on the obsolescence of physical assets for the defence facing the challenges of industry 4.0 and the new operating environments - Gonzalez-Prida, V.; Zamora, J.; Crespo Márquez, A.; Villar-Fidalgo, L.; De la Fuente, A.; Martínez-Galán, P.; Guillén, A. (Safety and Reliability - Safe Societies in a Changing World - Proceedings of the 28th International European Safety and Reliability Conference, ESREL 2018, 2018)