In addition it is useful to architect and design systems to reduce and manage complexity . The following principles support designing a system that “ performs its intended functions in the manner intended ” and is as resilient as possible 33 , 34 :
1 Absorption The system can absorb the impact of a disruption . 2 Physical Redundancy There are two or more independent redundant components .
3 Functional Redundancy
4 Layered Defense ( Defense in depth )
There are two or more ways to perform a task .
There are two or more independent approaches address a single vulnerability .
5 |
Human in the Loop |
There should be a human as part of the system where human thinking is required . |
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The premise is that humans are better at dealing with unprecedented situations . |
6 |
Reduce Complexity |
A system should be no more complex than necessary by reducing the number of |
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complex components ( including humans ) and interfaces . |
7 Reorganization Principle
A system , either organizational or technical , should be capable of changing its entire architecture , or structure , in the face of a threat .
8 |
Repairability |
A system should have the capability of being brought up to partial or full |
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functionality over a specified period of time and in a specified environment . |
9 Localized Capacity ( Modularity )
The functionality of a system should be distributed through various nodes of that system so that if a single node is damaged or destroyed , the remaining nodes will continue to function .
10 |
Loose Coupling |
The system should have the capability to limit the ability of failures to propagate |
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from one component to the next in a system of many components . |
11 |
Drift correction |
If the system is drifting towards failure this is detected and measures can be taken |
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to avoid the threat , or it can be diminished through corrective action . |
12 |
Neutral state |
Humans delay taking action when there is an opportunity to survey the situation and |
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make a more reasoned judgement . |
13 Inter-node interaction
14 Reduce Hidden Interactions
Every node , or element , of a system should be capable of communicating , cooperating , and collaborating with every other node .
Efforts should be made to assure that potentially harmful interactions between nodes of the system should be reduced .
Table 4-1 : Resilience implementation principles
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30 July 2022