Repairable as an alternative to robust

To be sure of achieving a goal in the face of an uncertain future, individuals and organizations pursue plans that can cope with mistakes and unexpected events. One way of doing so is to choose a robust plan: one that is able to absorb any one setback and thereby achieve the goal with certainty. A different strategy is to choose a repairable plan: one that can be easily modified in the face of setbacks such that the goal is achieved, even though the original plan might have failed without modification.

In this project we develop a theory of systems that achieve resilience by being repairable instead of robust. Our approach is to minimize the typical cost of a workaround, averaged over all possible failure modes. We deduce design principles for easily repairable systems and show that repairability is a superior strategy whenever the number of failure modes is high.

Adopting a paradigm of repairability will increase the resilience of technologies and infrastructure to natural and man-made disasters when the next type of failure mode is hard to predict. This includes communication grids, transport networks and technologies for exploring space. It also suggests alternative strategies for sustainability in the face of environmental change.