MOCUS
To determine cut sets or path sets, MOCUS first assigns a unique identifier (ID) to each fault tree gate and event. Because MOCUS proceeds from the top event downward, it assigns the initial ID to the top event. MOCUS then replaces intermediate events and gates as follows:
• If the list contains an ID for an OR gate, then multiple lists are created by replacing that ID with the IDs of each of its inputs.
• If the list contains an ID for an AND gate, then the list is enlarged by appending to that ID the IDs of each of its inputs.
To obtain minimal cut sets or path sets, MOCUS removes supersets, which are cut sets that include other cut sets.
A repeated event is an event that affects multiple portions of a tree. When a repeated event occurs, it occurs simultaneously everywhere it is inserted in the tree. If the tree contains repeated events, MOCUS uses the same ID for all occurrences of these events.