Risiko COPY COPY Flashcards
What is risk?
Risk = combination of consequences and associated uncertainties
What are the risk concept and its denotation
(C, U) = Consequences with respect to something of value
OR
(A, C, U) = Consequences with respect to something of value, given the event A
What is the general risk description and what is Risk described by?
Risk description = (A’, C’, P, SoK, K)
Risk is described by = (C’, Q, K) and (A’ C’, Q, K)
What do the different variables mean?
A’ = Specified events
C’ = Specified consequences
Q = Uncertainty measure describing uncertainties related to A’ and C’. Commonly represented by (P, Sok).
P = Probability
SoK = Strength of knowledge
K = Knowledge that Q and (A’, C’) are based on.
Describe some common risk metrics
E[C’] = Expected value
Ef[C] = Average value of return if one runs a project an infinite (or large) amount of times.
VaR = Value at Risk
PLL = Potential loss of lives in a period of one year
FAR = Fatal accident rate. Expected number of fatalities per 100 million exposed hours.
What are the formulas for PLL and FAR?
PLL = n * IR
n = number of equally exposed individuals
IR = probability that a specific person is killed in a year
FAR = Fatalities pr. exposed hour * 100 million
OR
FAR = (PLL / Number of exposed hours) * 100 million
Define a frequentist probability
Pf(A) = Number of times A would occur when repeating situations over and over nearing infinite.
Define subjective/knowledge-based probability
A probability expresses a person’s uncertainty or degree of belief that an event will occur. The person compares the uncertainty or belief related to event A.
What is a crucial assumption related to the underlying value in frequentist probabilities?
The value needs to be estimated as the underlying true value is generally not known.
Define Resilience
The ability of a system to sustain or restore its basic functionality following an event (risk source).
Define Vulnerability
Vulnerability is essentially risk conditioned on the occurrence of an event A.
What is the description of vulnerability?
Vulnerability = (C, U|A)
What is the connection between Resilience and Vulnerability?
Resilience reflect an aspect of vulnerability by focusing on the systems ability to recover after an event A.
Define Reliability
A system’s ability to work as intended
In what way is safety the antonym of risk?
High safety = Low Risk
Low Safety = High Risk
What does the term “Safe and secure” mean in practice?
The term “Safe and Secure” means that the risk is acceptable/tolerable