(page 455). When an alarm is observed, a decision is made whether or not to shut down the reactor.

Shutting down the reactor has a cost cs associated with it (independent of whether the core was overheating), whereas not shutting down an overheated core incurs a cost cm that is much higher than cs.

(a) Draw the decision network to model this decision problem for the original system (i.e., with only one sensor).

(b) Specify the tables for all new factors that must be defined (you should use the parameters cs and cm where appropriate in the tables). Assume that utility is the negative of cost.

(c) Show how variable elimination can be used to find the optimal decision.

For each variable eliminated, show which variable is eliminated, how it is eliminated (through summing or maximization), which factors are removed, what factor is created, and what variables this factor is over (similar to Example 12.22 (page 546)). You are not required to give the tables.