Question 2:
Make sure the door in never left open.
Sequences:
Sequence_A : Open_A, Wait xTime , ~Open_A (open A, wait, close A)
Sequence_B : Open_B, Wait xTime , ~Open_B (open B, wait, close
Test one button at a time with priority.
States:
A1 : Button A1 pressed
A2 : Button A2 pressed
B1 : Button B1 pressed
B2 : Button B2 pressed
Open_A : Door A open
Open_B : Door B open
Rules (in order of priority):
B2 -> Sequence_B
A2 -> Sequence_A
A1 -> Sequence_A
B1 -> Sequence_B
Open_A -> ~Open_A
Open_B -> ~Open_B
Question 7:
The propositional satisfiability (PSAT) problem is the basic problem for which efficient algorithms in the classical sense do not exist. It is a special type of constraint satisfaction problem.
Given a set C of clauses over a set P of propositional variables
– a propositional variable can be assigned true or false
– a literal is a variable or its negation
– a clause is a disjunction of literals
• Is there a truth assignment for P that satisfies all clauses in C?
• SAT is NP-complete
Constraint satisfaction is the process finding a solution to a set of constraints. Such constraints express allowed values for variables, and a solution is therefore an evaluation of these variable that satisfies all constraints.
The finite domain contains a set of variables whose values can only be taken from the domain, and a set of constraints, each constraint specifying the allowed values for a group of variables.
Mathematical problems where one must find states or objects that satisfy a number of constraints or criteria.
Typically solved using a form of search. The most used techniques are variants of backtracking, constraint propagation, and local search.