1. Solving Problems by Searching 제 4 주 강의

2. Problem solving agent What to do by finding sequences of actions that lead to desirable states the current state (environment), applicable operations, nest states Find a sequence of states maximizing the performance measure

3. Problem solving Goal formulation Problem formulation :: the process of deciding what actions and states to consider Missionary-carnival problem, 청소하는 로봇, 교육하는 시스템 등에 적용 Sequence, solution

4. Formulating Problems Amounts of knowledge that an agent can have concerning its actions and the state that it is in  depends on the how the agent is connected to its environment through its percepts and actions

5. Knowledge and problem type Single-state problem ::: 에이전트는 세상 을 정확히 인지하고, 행위의 결과도 정확 히 안다. Multiple-state problem ::: 행위의 결과는 정확히 알지만, 세상 ( 환경 ) 을 인식하는 데 한계가 있다 ; 또는 행위의 결과를 정 확히 예측하지 못할 때 ; Murphy ’ s law

6. Knowledge and problem type (cont.) Contingency problem :::  Exact prediction is impossible  Solving this problem requires sensing during the execution phase;  Keep eyes open while walking or driving  Agents need to act before founding a guaranteed plan  Interleaving of search and execution

7. Knowledge and problem type (cont.) Exploration problem  No information about the effects of its actions  a strange country with no map  The agent must experiment, gradually discovering what its action and what sorts of states exists  Reinforcement learning

8. Well-defined problems and solutions Initial state operation Successor function new state goal test select a state  state space  path, solution, path cost (g)

9. Measuring problem-solving performance Effectiveness of a search  Does it find a solution ?  Is it a good solution ?  What is the search cost associated with the time and memory to find a solution ?

10. Example Problems The 8(16)-puzzle problems 5 4 6 1 8 7 3 2 1 2 3 8 4 7 6 5 

11. 문제 정의 (8 puzzle) Solving as search ::: Breadth first, Depth-first Heuristics 16 puzzle

12. 8 Queens problem Goal test ::: 8 queens on board, none attacked Path cost ::: zero States ::: any arrangement of 0 to 8 queens on board Operators ::: add a queen to any square Branch and Bound, Dynamic Programming AI techniques

13. Cryptarithmetic FORTY 29785 + TEN 850 -------- ------ SIXTY 31418 (F=2, O=9, R=7, etc.)

14. The vacuum world 복사하여 제공 후 설명 Robot arm problem 과 비교하여, 그림 3.7) 처럼 결과 나오게 상태도를 그린다 ( 숙제 )

15. Other toy problems Missionary and cannibals Water jug

16. Real world problems Route finding Travelling salesperson problem VLSI design Robot navigation Assembly sequencing