**Acknowledgements**

protection, was published a year later. This methodology focuses both on the prevention of emergencies and the mitigation of its consequences. The same year saw the publication of the Resilience Measurement Index: An Indicator of Critical Infrastructure Resilience study [42], whose main objective is to measure the ability of a critical infrastructure to reduce the magni-

In 2013, the European Commission published a working document on a new approach to the European Programme for Critical Infrastructure Protection: Making European Critical Infrastructures more secure [43]. This document clearly emphasized the importance of resilience and interdependencies in a critical infrastructure as well as the need to develop tools

In addition, the issue of measuring critical infrastructure resilience has long been explored by the Swiss Federal Institute of Technology in Zurich (Eidgenössische Technische Hochschule Zürich). The institute presents the results of its risk and resilience research in the form of scientific reports, with the issue of resilience measurement addressed in detail in the SKI Focus Report 8: Measuring Resilience [44] and the SKI Focus Report 9: Measuring Critical

There are also several major international projects dealing with critical infrastructure resilience assessment at present, including SMART RESILIENCE: Smart Resilience Indicators for Smart Critical Infrastructures, IMPROVER: Improved Risk Evaluation and Implementation of Resilience Concepts to Critical Infrastructure, RESILIENS: Realizing European Resilience for Critical Infrastructure, or RESILIENCE 2015: Dynamic Resilience Evaluation of Interrelated

In 2016, a comprehensive approach based on the results of leading research projects was published in the Guidelines for Critical Infrastructures Resilience Evaluation document [35]. This approach has its basis in the evaluation of individual indicators constituting resilience, the resulting composite indicator being a function of indicators in technical (i.e., prevention, absorption, adaptation, and recovery), personal, organizational, and cooperative dimensions. Additional significant approaches to evaluate resilience have been presented, for example, in an interim report of the project RESILIENS D2.2: Qualitative, Semi-Quantitative and Quantitative Methods and Measures for Resilience Assessment and Enhancement [34]. The second part of the document presents a critical infrastructure resilience assessment tool (CI-RAT), which has been developed as part of this project and is based on a semi-quantitative methodology for CI resilience assessment, and on a CI resilience management concept.

The chapter entitled "Failures in a Critical Infrastructure System" presents a comprehensive overview of a critical infrastructure system, which may be regarded as the basis for ensuring the functional continuity of society from both the economic and social perspectives. The introductory part of the chapter is designed as a historical framework, defining critical infrastructures in relation to legislative, normative, and institutional processes involved in addressing

tude and/or duration of impacts from disruptive events.

and methods for their assessment.

88 System of System Failures

Infrastructure Resilience [45].

Critical Infrastructure Subsystems.

**5. Conclusion**

The chapter has been elaborated within the project of the Ministry of the Interior of the Czech Republic filed under VI20152019049 and entitled "Dynamic Resilience Evaluation of Interrelated Critical Infrastructure Subsystems."
