ARTIFICIAL INTELLIGENCE [INTELLIGENT AGENTS PARADIGM] Professor Janis Grundspenkis Riga Technical University Faculty of Computer Science and Information Technology Institute of Applied Computer Systems Department of Systems Theory and Design APPLICATION OF RESOLUTION IN EXPERT SYSTEMS

User Interface KB Logical Sentences (necessarily true) Inference Engine Resolution Working Memory Application of Resolution in Expert Systems RESOLUTION (continued)

Application of Resolution in Expert Systems RESOLUTION (continued) Problem’s description 1.Anyone who is lucky wins the lottery. 2.Anyone who wins the lottery is happy. 3.At least one who is happy studies at the university. 4.Anyone who studies at the university can pass all his examinations. 5.Anyone who pass all his examinations graduates from the university.

Application of Resolution in Expert Systems RESOLUTION (continued) Logical Sentences 1.  X(lucky(X)  win(X, lottery)) 2.  X(win(X, lottery)  happy(X)) 3.  X(happy(X)  study(X)) 4.  X  Y(study(X)  pass(X, Y)) 5.  X  Y(pass(X, Y)  graduate(X))

Application of Resolution in Expert Systems RESOLUTION (continued) Facts 6. lucky(george) 7. pass(george, ml&ai)

Q: Does George graduate from the university? S1:  lucky(X)  win(X, lottery) S2:  win(X, lottery)  happy(X) S3:  happy(george)  study(george) S4:  study(X)  pass(X, Y) S5:  pass(X, Y)  graduate(X) S6: lucky(george) S7: pass(george, ml&ai) S8:  graduate(X) Application of Resolution in Expert Systems RESOLUTION (continued) User Interface KB Inference Engine Resolution Working Memory

S1 S2 S3 S4 S5  lucky(X)  win(X, lottery)  win(X, lottery)  happy(X) { }  lucky(X)  happy(X) S6 S7 S8 Application of Resolution in Expert Systems RESOLUTION (continued) User Interface KBInference Engine Resolution Working Memory

S1 S2 S3 S4 S5  lucky(X)  happy(X)  happy(george)  study(george) { george/X }  lucky(george)  study(george) S6 S7 S8  lucky(X)  happy(X) Application of Resolution in Expert Systems RESOLUTION (continued) User Interface KBInference Engine Resolution Working Memory

S1 S2 S3 S4 S5  lucky(george)  study(george)  study(X)  pass(X, Y) { george/X }  lucky(george)  pass(george, Y) S6 S7 S8  lucky(X)  happy(X)  lucky(george)  study(george) Application of Resolution in Expert Systems RESOLUTION (continued) User Interface KBInference Engine Resolution Working Memory

S1 S2 S3 S4 S5  lucky(george)  pass(george, Y)  pass(X, Y)  graduate(X) { george/X }  lucky(george)  graduate(george) S6 S7 S8  lucky(X)  happy(X)  lucky(george)  study(george)  lucky(george)  pass(george, Y) Application of Resolution in Expert Systems RESOLUTION (continued) User Interface KBInference Engine Resolution Working Memory

S1 S2 S3 S4 S5  lucky(george)  graduate(george) lucky(george) { } graduate(george) S6 S7 S8  lucky(X)  happy(X)  lucky(george)  study(george)  lucky(george)  pass(george, Y)  lucky(george)  graduate(george) User Interface KB Application of Resolution in Expert Systems RESOLUTION (continued) Inference Engine Resolution Working Memory

Application of Resolution in Expert Systems S1 S2 S3 S4 S5 graduate(george)  graduate(george) { } Contradiction! S6 S7 S8  lucky(X)  happy(X)  lucky(george)  study(george)  lucky(george)  pass(george, Y)  lucky(george)  graduate(george) graduate(george) RESOLUTION (continued) Inference Engine Resolution Working Memory User Interface KB

Conclusion: George graduates from the university S1 S2 S3 S4 S5 Application of Resolution in Expert Systems RESOLUTION (continued) User Interface KB Inference Engine Resolution Working Memory