Problem 4: Determine the minimal cut sets of the following fault tree using top-down and bottom- up Boolean operations (Consider Remove Safety Fence and the light is poor also as a basic events). Fall into the Mine Shaft and Die Fall into the Mine Shaft by Accident Depth and Condition in the Shaft Safety Fence Fault Walk to the Shaft by Mistake Not Safety Fence Remove Safety Fence Safety Fence is Broken Don't Know There is a Shaft Didn't see the Shaft Not Familiar with the Area Forget There is a Shaft Absent Minded No Safety Sign The Light is Poor Problem 4: Determine the minimal cut sets of the following fault tree using top-down and bottom- up Boolean operations (Consider Remove Safety Fence and the light is poor also as a basic events). Fall into the Mine Shaft and Die Fall into the Mine Shaft by Accident Depth and Condition in the Shaft Safety Fence Fault Walk to the Shaft by Mistake Not Safety Fence Remove Safety Fence Safety Fence is Broken Don't Know There is a Shaft Didn't see the Shaft Not Familiar with the Area Forget There is a Shaft Absent Minded No Safety Sign The Light is Poor