Agents & Intelligent Systems Dr Liz Black

What is an Agent? Software agents or physical agents (robots) The main point about agents is they are autonomous: capable of deciding for themselves what to do We want to delegate goals to the agent without having to worry about specifying how exactly those goals should be achieved Agent should work out for itself what to do in order to try to achieve its goals 2

Why do we need Agents? Because were lazy Because sometimes the problems we want to solve are so complex or unpredictable that we dont know how to write a precise program that solves them 3

Video Starring Douglas Adams and Tom Baker,

5

6

7

8

9

10

11 While(not home){ If no obstacle, move forward If obstacle, move left If far end of grid, move right }

12 While(not home){ If no obstacle, move forward If obstacle, move left If far end of grid, move right }

13 While(not home){ If no obstacle, move forward If obstacle, move left If far end of grid, move right }

14 While(not home){ If no obstacle, move forward If obstacle, move left If far end of grid, move right }

15 While(not home){ If no obstacle, move forward If obstacle, move left If far end of grid, move right }

16 While(not home){ If no obstacle, move forward If obstacle, move left If far end of grid, move right }

17

18 While(not home){ If no obstacle, move forward If obstacle, move left If far end of grid, move right }

19 While(not home){ If no obstacle, move forward If obstacle, move left If far end of grid, move right }

20 While(not home){ If no obstacle, move forward If obstacle, move left If far end of grid, move right }

21 While(not home){ If no obstacle, move forward If obstacle, move left If far end of grid, move right }

22 While(not home){ If no obstacle, move forward If obstacle, move left If far end of grid, move right } !

23

24 Goal: get home Knowledge: { Home is at C1 I am at C4 } A BC D E

25 A BC D E Goal: get home Knowledge: { Home is at C1 I am at C4 Obstacle at D3 No obstacle at B4, C4, D4, B3, C3 }

26 A BC D E Goal: get home Knowledge: { Home is at C1 I am at C3 Obstacle at D3 No obstacle at B4, C4, D4, B3, C3 }

27 A BC D E Goal: get home Knowledge: { Home is at C1 I am at C3 Obstacle at D3, B2, C2 No obstacle at B4, C4, D4, B3, C3, D2 }

28 A BC D E Goal: get home Knowledge: { Home is at C1 I am at B3 Obstacle at D3, B2, C2 No obstacle at B4, C4, D4, B3, C3, D2 }

29 A BC D E Goal: get home Knowledge: { Home is at C1 I am at B3 Obstacle at D3, B2, C2, A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4 }

30 A BC D E Goal: get home Knowledge: { Home is at C1 I am at C3 Obstacle at D3, B2, C2, A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4 }

31 A BC D E Goal: get home Knowledge: { Home is at C1 I am at C4 Obstacle at D3, B2, C2, A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4 }

32 A BC D E Goal: get home Knowledge: { Home is at C1 I am at D4 Obstacle at D3, B2, C2, A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4 }

33 A BC D E Goal: get home Knowledge: { Home is at C1 I am at D4 Obstacle at D3, B2, C2, A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4, E3, E4 }

34 A BC D E Goal: get home Knowledge: { Home is at C1 I am at E4 Obstacle at D3, B2, C2, A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4, E3,E4 }

35 A BC D E Goal: get home Knowledge: { Home is at C1 I am at E3 Obstacle at D3, B2, C2, A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4, E3,E4 }

36 A BC D E Goal: get home Knowledge: { Home is at C1 I am at E3 Obstacle at D3, B2, C2. A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4, E3,E4, E2 }

37 A BC D E Goal: get home Knowledge: { Home is at C1 I am at E2 Obstacle at D3, B2, C2, A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4, E3, E4, E2 }

38 A BC D E Goal: get home Knowledge: { Home is at C1 I am at E2 Obstacle at D3, B2, C2, A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4, E3, E4, E2, D1, E1 }

39 A BC D E Goal: get home Knowledge: { Home is at C1 I am at E1 Obstacle at D3, B2, C2, A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4, E3,E4, E2, D1, E1 }

40 A BC D E Goal: get home Knowledge: { Home is at C1 I am at D1 Obstacle at D3, B2, C2, A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4, E3, E4, E2, D1, E1 }

41 A BC D E Goal: get home Knowledge: { Home is at C1 I am at home Obstacle at D3, B2, C2, A2 No obstacle at B4, C4, D4, B3, C3, D2, A3, A4, E3,E4, E2, D1, E1 }

42 A BC D E

43 Can anybody help me? A BC D E

44 Maybe, Ive got a big pillow A BC D E

45 Please bring it to E2 A BC D E

46 Why should I? A BC D E

47 I will pay you £5 A BC D E

48 No way will I do it for less than £7 A BC D E

49 Ill give you £6 and thats my final offer A BC D E

50 Ok! A BC D E

51 A BC D E

52 A BC D E

53 A BC D E Im in position

54 A BC D E

55 A BC D E

56 A BC D E

57 A BC D E

58 A BC D E £6

59 A BC D E £6

60 A BC D E £6

61 While(not home){ If no obstacle, move forward If obstacle, move left If far end of grid, move right } ! What should we do when our actions dont have the effect we expect?

62 Goal: get home Knowledge: { Home is at C1 I am at C3 Obstacle at D3 No obstacle at B4, C4, D4, B3, C3 } How should we represent what we know about our environment?

63 Can anybod y help me? When do we need to get help from other agents?

64 Maybe, Ive got a big pillow How can agents communicate? What language should they use? How can they be sure they have the same shared meaning of words?

65 Im in positio n How do we know we can trust another agent?

66 Why should I? How can we get an agent to do something for us?

67 Ill give you £6 and thats my final offer Whats a good negotiation strategy?

Making decisions Deciding what to do becomes much more complicated when we have to take into account what someone else will do Game theory – used to study strategic decision making, takes into account the possible actions of others 68

69 Golden balls woman steals man steal s man splits woman splits Both split: share the money One steals and one splits: stealer gets all the money Both steal: neither gets any money

70 Golden balls woman steals man steal s man splits woman splits Both split: share the money One steals and one splits: stealer gets all the money Both steal: neither gets any money Dominant strategy A strategy S is dominant if no matter what the other does you can do no better than to play S

71 Golden balls woman steals man steal s man splits woman splits Both split: share the money One steals and one splits: stealer gets all the money Both steal: neither gets any money Assume the man splits. Whats the best thing that the woman can do?

72 Golden balls woman steals man steal s man splits woman splits Both split: share the money One steals and one splits: stealer gets all the money Both steal: neither gets any money Assume the man steals. Whats the best thing that the woman can do?

73 Golden balls woman steals man steal s man splits woman splits Both split: share the money One steals and one splits: stealer gets all the money Both steal: neither gets any money

Summary Agents are capable of deciding for themselves what to do to achieve their goals Useful because sometimes we dont know in advance the best way to achieve a goal, or we dont want to have to think about how to achieve a goal Often agents cant achieve their goals on their own but must cooperate with other agents 74