Week 9: Decision Theory for Engineers Flashcards
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Compare routine vs. make-or-break decisions.
Routine:
- small impact
- reversible
- short term
- standard decision process
Make-or-break:
- high impact
- irreversible
- long term
- variety of decision processes
What is an unstructured decision process?
Do nothing
Guess
Flip a coin
What are qualitative structured decision processes?
Pros and cons list
Multi Criteria Decision Analysis (MCDA)
Analytical Hierarchy Process (AHP)
Delphi method
Fuzzy logic
What are quantitative structured decision processes?
Mathematical models
Statistical tools and trend analysis
Hypothesis testing, Monte Carlo, Markov Chains, …
Risk is a combination of …
The events and the consequences of these events, and the associated uncertainties.
Risk can be described by (A, C, C*, U, P, K).
What do each of these terms stand for?
C = consequences of the activity, A
C* = prediction of C
U = uncertainty about what value C will take
P = probability of specific events and consequences, given the background information, K
What are the 3 steps of the Risk Management Process?
Planning
Risk assessment
Risk treatment
Time allocation: 1/3 each
What is the Planning step of the risk management process?
Problem definition, information gathering, organisation of work.
Select analysis method.
What is the RIsk assessment step of the risk management process?
Identification of initiating events.
Cause and consequence analysis.
Risk picture.
What is the risk treatment step of the risk management process?
Compare alternatives, identification and assessment of measures.
Management review and judgement. Decision.
What are the three risk analysis methods?
Simplified risk analysis
Standard risk analysis
Model-based risk analysis
Describe simplified risk analysis
Qualitative
Informal procedure that establishes risk picture using brainstorming sessions and group discussions.
Describe standard risk analysis.
Qualitative or quantitative.
Formalised procedure. Recognised risk analysis methods are used (HAZOP, coarse risk analysis)
Risk matrices.
Coarse risk analysis.
What is model-based risk analysis?
Quantitative
Event tree analysis, fault tree analysis to calculate risk.
What is a Fault Tree Analysis (FTA)?
System analysis technique used to determine root causes and probability of occurrence of a specific undesired event.
Deductive.
What are Cut Sets (CS)?
Set of events that together cause the top undesired event to occur.
What are some uses of FTA?
Foundation design for critical buildings
Tunnel construction safety
Construction site safety
Construction assessment
Construction equipment reliability
Compare a reactive vs. proactive FTA.
Reactive:
- performed after an accident has occurred.
- used as an accident investigation method.
Proactive:
- performed during system development to influence design by predicting and preventing future problems
- used as a risk analysis method.
What is an Event Tree Analysis (ETA).
Inductive procedure that shows all possible outcomes resulting from an accidental event. Takes into account installed safety barriers, additional events and factors.
Outline the ETA process.
dont need to remember this he said
- Define the system
- Identify accidental scenarios
- Identify initiating events
- Identify pivotal events
- Build ETD
- Obtain failure event probabilities
- Identify outcome risk
- Evaluate outcome risk
- Recommend corrective action
- Document ETA
What are Markov Chains?
Markov Chains are used to compute probabilities of events occurring by viewing them as states transitioning into other states, and back into the same state as before.
Where are Markov Chains?
- Predicting traffic flows
- Communications networks load
- Genetic issues
- Cruise control systems in vehicles
- etc.
What are regular Markov chains?
Markov chain is regular if transition matrix is regular.
Matrix is regular if some power of the matrix has only positive entries.
What is an absorbing Markov State?
Absorbing if once the state is entered it is impossible to leave.
