Tddc17 - Lab 2 Search
TDDC17 -‐ Lab 3 Part 2 Q5
P (Meltdown) = 0,02578 P(Meltdown | Ica weather) = 0.03472 b) Suppose that both warning sensors indicate failure. What is the risk of a meltdown in that case? Compare this result with the risk of a melt-‐down when there is an actual pump failure and water leak. What is the difference? The answers must be expressed as conditional probabilities of the observed variables, P(Meltdown|...). P(Meltdown | PumpFailureWarning, WaterLeakWarning) = 0,14535 P (Meltdown | PumpFailure, WaterLeak) = 0,2 c) The conditional probabilities for the stochastic variables are often estimated by repeated experiments or observations. Why is it sometimes very difficult to get accurate numbers for these? What conditional probabilites in the model of the plant do you think are difficult or impossible to estimate? a) What is the risk of melt-‐down in the power plant during a day if no observations have been made? What if there is icy weather?
It is hard to fully understand all possible factors that can effect or trigger an event and how they interact with each other. Observations are always a description of the past and is not always accurate in forecasting the future. E.g. Icy weather is not a thing you can measure and span over a wide range of weather conditions including combinations of precipitation, wind and temperature. d) Assume that the "IcyWeather" variable is changed
P (Meltdown) = 0,02578 P(Meltdown | Ica weather) = 0.03472 b) Suppose that both warning sensors indicate failure. What is the risk of a meltdown in that case? Compare this result with the risk of a melt-‐down when there is an actual pump failure and water leak. What is the difference? The answers must be expressed as conditional probabilities of the observed variables, P(Meltdown|...). P(Meltdown | PumpFailureWarning, WaterLeakWarning) = 0,14535 P (Meltdown | PumpFailure, WaterLeak) = 0,2 c) The conditional probabilities for the stochastic variables are often estimated by repeated experiments or observations. Why is it sometimes very difficult to get accurate numbers for these? What conditional probabilites in the model of the plant do you think are difficult or impossible to estimate? a) What is the risk of melt-‐down in the power plant during a day if no observations have been made? What if there is icy weather?
It is hard to fully understand all possible factors that can effect or trigger an event and how they interact with each other. Observations are always a description of the past and is not always accurate in forecasting the future. E.g. Icy weather is not a thing you can measure and span over a wide range of weather conditions including combinations of precipitation, wind and temperature. d) Assume that the "IcyWeather" variable is changed