Fault Tree Analysis Applied to a tiny ― Computer Startup ― (2-3 people)
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Transcript of Fault Tree Analysis Applied to a tiny ― Computer Startup ― (2-3 people)
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Fault Tree Analysis
Applied to a tiny― Computer Startup ―
(2-3 people)
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Introduction
• Fault Tree Analysis
– “Tree”: A hierarchical structure ... – “Faults”: ... depicting all potential faults ...– “Analyse”: ... which we can use to analyse risks.
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Example(taken from IEC/FDIS 31010, p. 49)
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TerminologyTop event“a specified undesired event”
Base event“...until further analysis becomes unproductive.In a hardware system, this may be at the component failure level.”
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Chalkboard
Please pay attention and participate in the live example on the chalkboard.
Thank you!
Top event: server failureHuman errorsSoftware errorsHardware/Structural errors
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Usage
• Qualitative vs Quantitativebacktracking failure vs calculating probabilities
• Design Stage // Operating Phase // Posthumous
before implementing the system //while the system is running //
in order to understand past failures
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Application to Startup
Quantitative insights not terribly interesting...
Good way to assess Qualitative insights
– logically find vulnerabilities / weak spots(“disciplined approach, highly systematic”)
– Understand general system behaviour– Allow for all kinds of factors (system, human, ...)
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Application to Startup
Can use in design phase, during runtime and in order to understand past issues.
Most ‘limitations’ are related to quantitative probability analysis
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Application to Startup
Not a perfect method:Boolean model: possible to consider e.g. ‘low
performance’ instead of plain failure?
“Fault Tree is a static model; time interdependencies are not addressed.”
No built-in continuously recurring self-checks: danger of false sense of security(will this be reconsidered after system changes?)
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Conclusion
Risk identification – goodRisk analysis – very goodRisk evaluation – satisfactory
Feasible method in terms of skills & time
Combine / complement with other methods?(e.g. Make part of PDCA cycle, recheck regularly ...)
For other domains: nice additional feature, but not to use alone