Week 4 - Dependability Analysis and Evaluation

Question 1

Hazard

Answer 1

A state or set of conditions, together with environmental conditions, will lead to an accident

Question 2

Hazard level?

Answer 2

The combination of hazard severity and likelihood of occurrence

Question 3

Reliability

Answer 3

The probability of the system to deliver correct services over a specified time period under given conditions

Question 4

Failure rate

Answer 4

The expected number of failures of a certain device over a given time frame.

Question 5

What is the difference between a series and a parallel system?

Answer 5

In a series system, if one component fails the whole system fails. In a parallel system one component failing does not result in a system failure

Question 6

Given a reliability block diagram, what is a cut set?

Answer 6

The combinations of elements in which simultaneous failure would lead to a system failure.

Question 7

Given a reliability block diagram, what is a tie set?

Answer 7

The combinations of elements in which simultaneous operation would lead to a correctly working system.