Esame students 15062020 solution

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Name:___________________ I.D.: __________________ METODI COMPUTAZIONALI PER LA SICUREZZA E L’ANALISI DI RISCHIO I: Final Exam (15/05/2020) Note: 1. Make sure to write your name and I.D. Number 2. The exam consists of 2 problems 3. Exam time is 40 minutes (20 minutes for Mobility Engineerig) Good Luck! Problem 1. (20 minutes) [both courses Mobility Engineering and Reliability Engineering](15 points) A locomotive is a multi-unit engine that provides the motive power for a train and which, in this exemple, consists of seven components 𝐸!~𝐸". The functional logic of the locomotive is indicated in the diagram of the Figure below. The components have an identical failure probability 𝑝=10#$. (15 points) Questions: 2A) Draw a fault tree for the failure of the system (7) 2B) List the minimal cut sets (5) 2C) Find the probability of the top event (3) Problem 2. (Only for and Reliability Engineering) (15 points) According to the historical records of the quality control section of a pump manufacturing company, there is a 30% chance of failure of the pump within 5 years. The company monitors the noise of the pumps during first 5 years of operation, the following facts from the monitoring experiment are known: • On pumps that have failed, 95% of them had the operating noise greater than 80 dB. • On pumps that have NOT failed, 25% of them had the operating noise greater than 80 dB. Question: You test a specific pump and realize that its operating noise is greater than 80 dB. What is the chance that it will fail? (15) (Hint: identify the events, then use Bayesian updating to calculate the Pr (failure| noise exceeds 80 dB)) E2 E3 E1 E4 E5 E6 E7