It is now widely recognized that many important events in the life cycle of complex engineering systems cannot be foreseen in advance. From its origin in ecological systems, operating without the use of foresight, resilience theory prescribes presuming ignorance about the future, and designing systems to manage unexpected events in whatever form they may take. However, much confusion remains as to what constitutes a resilient system and the implications for engineering systems. Taking steps toward a synthesis across a fragmented body of research, this paper analyses 251 definitions in the resilience literature, aiming to clarify key distinctions in the resilience concept. Asking resilience of what, to what, and how, we first distinguish systems serving higher ends and systems that are ends in themselves, and, within these, performance variables to be minimized, preserved, or maximized. Second, we distinguish systems subject to adverse events, adverse change, turbulence, favorable events, favorable change, and variation. Finally, we distinguish systems capable of recovery, absorption, improvement, graceful degradation, minimal deterioration, and survival. Together, these distinctions outline a morphology of resilient systems and suggest answers to the principal design questions, which must be asked of any resilient engineering system.

中文翻译：

---

工程系统中的弹性概念化：文献分析

现在，人们普遍认识到，无法预先预见复杂工程系统生命周期中的许多重要事件。从其起源于生态系统开始，不使用预见性就可以运作的能力，复原力理论规定了对未来的无知，并设计了以任何形式处理突发事件的系统。但是，关于什么构成弹性系统及其对工程系统的影响，仍然存在很多困惑。为跨分散的研究领域进行综合，本文分析了弹性文献中的251个定义，旨在阐明弹性概念中的关键区别。询问什么，什么以及如何的弹性，我们首先要区分服务于高端的系统和本身就是终端的系统，并在其中区分要最小化，保留或最大化的性能变量。其次，我们区分遭受不利事件，不利变化，动荡，有利事件，有利变化和变化的系统。最后，我们区分能够恢复，吸收，改进，适度退化，最小程度的退化和生存的系统。这些区别共同概述了弹性系统的形态，并提出了对主要设计问题的答案，而对于任何弹性工程系统都必须提出这些设计问题。