Environmental Engineering Reference
In-Depth Information
Chapter 1
1.
R
ESILIENCE
C
ONCEPT
1.1.
I
NTRODUCTION
Resilience cannot be engineered simply by introducing more procedures,
safeguards, and barriers. Resilience engineering instead requires a continuous
monitoring of system performance, of how things are done. In this respect
resilience is tantamount to coping with complexity [1], and to the ability to
retain control.
A system is in control if it is able to minimize or eliminate unwanted
variability, either in its own performance, in the environment, or in both. The
link between loss of control and the occurrence of unexpected events is so
tight that a preponderance of the latter in practice is a signature of the former.
Unexpected events are therefore often seen as a consequence of lost control.
The loss of control is nevertheless not a necessary condition for unexpected
events to occur. They may be due to other factors, causes and developments
outside the boundaries of the system.
An unexpected event can also be a precipitating
factor for loss of control
and in this respect the relation to resilience is interesting. Knowing that control
has been lost is of less value than knowing when control is going to be lost,
i.e., when unexpected events are likely. In fact, according to the definition of
resilience, the fundamental characteristic of a resilient organization is that it
does not lose control of what it does, but is able to continue and rebound [2]
In order to be in control it is necessary to know what has happened (the
past), what happens (the present) and what may happen (the future), as well as
