One of the most cited definitions of interdependency is the one by Rinaldi et al. who define interdependency as a
This definition is adopted on the Commission's staff working document on a new approach to the EPCIP :
The degree of interdependency does not need to be equal in both directions. For example, the Energy Sector depends on a functioning Water Sector for successful day-to-day operations, just as the Water Sector needs energy to effectively manage water and wastewater systems .
An older definition was:
Empirical analysis of Critical infrastructure incidents and events by Van Eeten et al. shows that interdependencies (= the mutual Dependency) hardly occur; and when they occur the effect is at a lower (weaker) dependency level.
- Steven M. Rinaldi, James P. Peerenboom, Terrence K. Kelly, Identifying, Understanding and Analysing Critical Infrastructure Interdependencies, IEEE Control Systems Magazine, December 2001, p.14.
- Staff Working Document on a new approach to the European Programme for Critical Infrastructure Protection - Making European Critical Infrastructures more secure, SWD(2013) 318 final, Brussels, 28.8.2013
- DHS Risk Lexicon 2010 Edition, September 2010
- Critical Infrastructure Protection and Resilience Toolkit (Glossary), US Department of Homeland Security
- http://www.kritis.bund.de/SharedDocs/Downloads/Kritis/EN/Baseline%20Protection%20Concept.pdf Protection of Critical Infrastructures – Baseline Protection Concept: Recommendation for Companies, BMI.
- Unpublished working glossary of UP KRITIS and BSI, 2014