Foundations¶
Operational Resilience Engineering builds on, and seeks to contribute to, several established bodies of research. It does not use the term resilience as a single settled concept.
Resilience engineering¶
A central foundation is the work of David D. Woods on resilience engineering. Woods distinguishes four important concepts that are often grouped under the single label resilience [Woo15]:
Rebound: returning toward an earlier condition after trauma or disruption.
Robustness: continuing to function despite disturbance.
Graceful extensibility: extending performance or adaptive capacity when surprise challenges established boundaries.
Sustained adaptability: maintaining the ability to adapt as conditions, demands, stakeholders, and constraints continue to change.
ORE adopts these distinctions as a starting point while developing a formal language for relating them to system states, performance boundaries, feasibility, intervention choices, and decision perspectives.
Graceful extensibility and brittleness¶
Woods characterizes graceful extensibility as the opposite of brittleness [Woo15, Woo18]. A brittle system can appear successful within familiar conditions but may collapse abruptly when demands or disturbances exceed its capacity to respond. Graceful extensibility concerns the capacity to stretch or bring additional adaptive resources to bear when those boundaries are approached.
This distinction is especially relevant to critical infrastructure systems, where reserve capacity, backup resources, coordination, and changes in operational strategy can determine whether a disruption becomes a sudden loss of service or a manageable change in operating mode.
Operations research¶
ORE also draws on operations research to make explicit the decision structures that are sometimes implicit in resilience discussions. These include decision and design spaces, constraints, feasibility, performance measures, uncertainty, and the relation between alternative interventions and operational outcomes.
ORE’s contribution¶
The intended contribution of ORE is not to replace established resilience engineering concepts. It is to develop a formal framework in which vulnerability, resilience, operational boundaries, feasible interventions, and interpretive perspectives can be specified and related.
References¶
David D. Woods. Four concepts for resilience and the implications for the future of resilience engineering. Reliability Engineering & System Safety, 141:5–9, 2015. doi:10.1016/j.ress.2015.03.018.
David D. Woods. The theory of graceful extensibility: basic rules that govern adaptive systems. Environment Systems and Decisions, 38(4):433–457, 2018. doi:10.1007/s10669-018-9708-3.