(22nd-August-2020)
• The following knowledge base formalizes the part of the communication network we are interested in:
• send_signal_lg_sc ←ok_sc_lg ∧alive_sc.
• send_signal_hg_sc ←ok_sc_hg ∧alive_sc.
• get_signal_s1 ←send_signal_hg_sc ∧ok_s1_ant.
• get_signal_s2 ←send_signal_hg_sc ∧ok_s2_ant.
• send_signal_s1 ←get_signal_s1 ∧ok_s1_trans.
• send_signal_s2 ←get_signal_s2 ∧ok_s2_trans.
• get_signal_gc ←send_signal_s1 ∧ok_a1.
• get_signal_gc ←send_signal_s2 ∧ok_a2.
• get_signal_gc ←send_signal_lg_sc ∧ok_a3 ∧no_dist.
• Ground control is worried, because it has not received a signal from the spacecraft (no_signal_gc). It knows for sure that all ground antennae are okay (i.e., ok_a1, ok_a2, and ok_a3) and satellite s1's transmitter is ok (ok_s1_trans). It is not sure about the state of the spacecraft, its transmitters, the satellites' antennae, s2's transmitter, and atmospheric disturbances.
• Specify a set of assumables and an integrity constraint that model the situation.
• Using the assumables and the integrity constraints from part (a), what is the set of minimal conflicts?
• What is the consistency-based diagnosis for the given situation? In other words, what are the possible combinations of violated assumptions that could account for why the control center cannot receive a signal from the spacecraft?
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