18.

(a) Explain why NASA may want to use abduction rather than consistency-based diagnosis for the domain of Exercise 17.

(b) Suppose that an atmospheric disturbance dist could produce static or no signal in the low-bandwidth signal. To receive the static, antenna a3 and the spacecraft’s lowbandwidth transmitter sc_lg must be working. If a3 or sc_lg are not working or sc is dead, there is no signal. What rules and assumables must be added to the knowledge base of Exercise 17 so that we can explain the possible observations no_signal_gc, get_signal_gc, or static_gc? You may ignore the high-bandwidth links. You may invent any symbols you need.