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Next: Fetching a Package Up: Cassandra's Plans Previous: A Plan to

Disarming a Bomb

This is the plan shown in Figure 6 and Figure 7 and discussed inSection 4.1.1. Note that both moving steps and both dunking steps are always possible, but each is only necessary in one outcome of the uncertainty. A fail-safe plan (see Section 6.2) is therefore possible.

Initial:       When [UNK0S: O2] (CONTAINS PACKAGE-2 BOMB)
               When [UNK0S: O1] (CONTAINS PACKAGE-1 BOMB)
               (AND (AT PACKAGE-1 RUG) (AT PACKAGE-2 RUG))

Step  1 (5): (X-RAY PACKAGE-2)
               (KNOW-IF (CONTAINS PACKAGE-2 BOMB))

Step  2 (3): (X-RAY PACKAGE-1)
               (KNOW-IF (CONTAINS PACKAGE-1 BOMB))

Step  3 (2): (DECIDE UNK0S)
               (and (CONTAINS PACKAGE-2 BOMB)
                    T                ) => [UNK0S: O2]
               (and (CONTAINS PACKAGE-1 BOMB)
                    T                ) => [UNK0S: O1]
                  1 -> (KNOW-IF (CONTAINS PACKAGE-2 BOMB))
                  2 -> (KNOW-IF (CONTAINS PACKAGE-1 BOMB))

Step  4 (7): (MOVE RUG TOILET PACKAGE-1)          YES: [UNK0S: O1]
               (AND (NOT (AT PACKAGE-1 RUG)) (AT PACKAGE-1 TOILET))
                  0 -> (AT PACKAGE-1 RUG)

Step  5 (6): (MOVE RUG TOILET PACKAGE-2)          YES: [UNK0S: O2]
               (AND (NOT (AT PACKAGE-2 RUG)) (AT PACKAGE-2 TOILET))
                  0 -> (AT PACKAGE-2 RUG)

Step  6 (4): (DUNK PACKAGE-2)                     YES: [UNK0S: O2]
               (WET PACKAGE-2)
                  5 -> (AT PACKAGE-2 TOILET)
               (DISARMED BOMB)
                  0 -> (CONTAINS PACKAGE-2 BOMB)  NO : [UNK0S: O1]

Step  7 (1): (DUNK PACKAGE-1)                     YES: [UNK0S: O1]
               (WET PACKAGE-1)
                  4 -> (AT PACKAGE-1 TOILET)
               (DISARMED BOMB)
                  0 -> (CONTAINS PACKAGE-1 BOMB)  NO : [UNK0S: O2]

Goal:        (DISARMED BOMB)

             GOAL                                 YES: [UNK0S: O2]
                  6 -> (DISARMED BOMB)            NO : [UNK0S: O1]

             GOAL                                 YES: [UNK0S: O1]
                  7 -> (DISARMED BOMB)            NO : [UNK0S: O2]

Complete!


next up previous
Next: Fetching a Package Up: Cassandra's Plans Previous: A Plan to

Louise Pryor <louisep@aisb.ed.ac.uk>;
Last modified: Mon Mar 18 18:29:11 1996