7. Taking dependencies into account

7.1 General considerations on addiction

The preceding developments assume that the BDF blocks evolve independently of each other. However, in reality, this assumption is often not respected, due to the limited number of maintenance teams, the existence of common cause failures (leading to the simultaneous failure of several blocks), sequential aspects (the order of occurrence of failures changes what happens at system level), etc. On the other hand, the extent of these dependencies may be limited to a few blocks, or concern many blocks. On the other hand, the extent of these dependencies may be limited to a few blocks, or concern many blocks. They may even affect all blocks, as we have seen with reliability calculations.

When dependencies are confined to a...