Analysis & Calculation

RAM Commander provides different ways of Fault Tree top gate probability calculation:

Calculation type	Description	How to start
Minimal Cut Sets Calculation	Default calculation mode. Quick, deals with large trees, but approximate. Allows qualitative MCS analysis, Importance/Sensitivity analysis and more.	"MCS Calculation" from the calculation menu - see the related paragraph later.
Monte-Carlo simulation	Suitable for trees with dynamic gates (Priority AND gate).	Calculation menu->Explore->Monte-Carlo Simulation
Simple calculation	Arithmetical calculation of the tree according to the logical laws, without considering identical events.	Calculation menu->Explore->Simple calculation
Bayes formula	Exact calculation of the tree using Bayes formula, suitable for small trees with low number of identical events (less than 15).	Calculation menu->Explore->Exact calculation-Bayes formula
BDD Calculation	Calculation with the help of Binary Decision Diagram Generation. Suitable for trees with only OR/AND logical gates (without K/N and NOT). More precise than MCS Calculation, but does not generate the MCS list.	Calculation menu->Explore->BDD Calculation

For all calculation types, basic event probabilities should be defined and calculated, using several event probability models (constant probability, unrepairable, repairable, latent etc.). See the "Basic Event Types" paragraph for more information about basic event probability models.

In addition to calculation of FTA top gate probability, you may calculate intermediary gate probabilities, perform Importance / Sensitivity Analysis , perform FALSE/TRUE Propagation, get Unavailability Curve and a lot of different FTA reports and graphs.