Download Jos Uiterwijk - Van der Waals

Games as a Test Bed for Developing
AI Applications (in Physics)
Brains vs Computers
Symposium of the “van der Waals” study association
December 10, 2013
Jos Uiterwijk
Department of Knowledge Engineering
Maastricht University
1/36
Overview
• Computer chess and computer games
• The role of computer games in Artificial
Intelligence
• Brute force?
• The impact of knowledge and heuristics
• New developments
• AI and Physics
• Conclusions
Jos Uiterwijk
2/36
Some history
• Start of computer
chess
• The Turk
• It was all fake!
Jos Uiterwijk
3/36
Origin of the AI
• Starts around 1950
• Chess as the
drosophila
melanogaster of AI
• 2 pioneers:
– Alan Turing
– Claude Shannon
Jos Uiterwijk
4/36
Why is chess of interest for AI?
1. Rules are simple, but the strategy is complex
2. Domain is fixed, by which programs are easily
comparable, both with other programs and with
humans. By the nature of a game it is easy to test
if a new technique is “better”.
3. Games are typical for human intelligence
(Goethe: chess is the touchstone of the intellect).
This explains the interest from psychology.
Jos Uiterwijk
5/36
Alan Turing (1912-1954)
• Worked in Bletchley
Park during World
War II
• Decoding the German
Enigma codes: The
Bombe
• Was the first who
seriously posed the
question: Can
machines think?
Jos Uiterwijk
6/36
Alan Turing: Turing test
Jos Uiterwijk
7/36
Alan Turing
• Used the computer in his “spare time” for
chess programming.
• Was the first who wrote a chess program
Jos Uiterwijk
8/36
Claude Shannon (1916-2001)
• Was also concerned with
computer chess
• Built chess endgame
machines
• Wrote the “bible” of
chess programming:
Programming a computer
for playing chess (1950)
Jos Uiterwijk
9/36
Claude Shannon
• Shannon was
brilliant in many
domains, both
theoretically and
practically: he built
among others a
juggling robot
• By the way, he also
could juggle
himself quite good!
Jos Uiterwijk
10/36
State of the Art in computer chess
• Nowaday computers are stronger
than human world champions
• Mile stone: Kasparov losing from
chess machine Deep Blue in 1997
• Kramnik loses from the “simple”
desk top program Deep Fritz in 2006
Jos Uiterwijk
11/36
Adriaan de Groot (1914-2006)
• Professor in
psychology
• Studies on “chess
thinking”
• PhD thesis (1946) Het
Denken van den
Schaker, translated
(1965) as Thought and
Choice in Chess
Jos Uiterwijk
12/36
Brute force
• For many board games just used brute
computer power was initially used (i.e., as
many calculations as possible): dumb but
fast. This is called the brute-force approach
• Later the question arose: can the brain still
beat the machine by clever use of
knowledge? The knowledge-based approach
Jos Uiterwijk
13/36
Knowledge
• Facts
• Heuristics
(rules of thumb)
Jos Uiterwijk
14/36
Facts (1)
• The “mutilated chess board” problems:
Can I put domino stones (of 2 x 1 size) in such a way
on the board that all squares are covered?
?
?
The 4x4 problem
Jos Uiterwijk
15/36
Facts (2)
The 8x8 problem
Jos Uiterwijk
16/36
Facts (3)
The 20x20 problem
Jos Uiterwijk
17/36
Heuristics (1)
• The knight jump puzzle:
Can you find a route on the chess board starting at a
given location such that all squares are traveled
exactly once?
• Heuristic (rule of thumb):
First visit the corners, then the edges, etc., gradually
going to the centre
• Does this heuristic work?
Jos Uiterwijk
18/36
Heuristics (2)
• The knight
jump puzzle on
the 8x8 board
45
32
11
16
43
34
10
17
44
33
12
15
42
35
31
46
59
56
61
52
13
2
18
9
62
53
58
55
36
41
47
30
57
60
51
64
3
24
8
19
50
63
54
25
40
37
29
48
21
6
27
38
23
4
20
7
28
49
22
5
26
39
Jos Uiterwijk
14
19/36
Heuristics (3)
• However: a heuristic is
fallible:
20 11 6
18
5 16 19 12 7
• The 5x5 knight jump
puzzle
Jos Uiterwijk
10 21
?
17 2
15 4 23 8 13
22 9 14 3 24
20/36
Chosing the right representation
• Another knight jump problem
start
goal
What is the shortest route to switch the white and black knights?
Jos Uiterwijk
21/36
Solution
• Step 1: number the squares:
10
8 9
5 6
1 2 3
Jos Uiterwijk
7
4
22/36
• Step 2: draw the neighbour diagram for
knight jumps (which squares are reachable
in one jump?)
from:
1
we get:
10
8
5
2
9
6
3
7
4
3
10 6 1 8 7 2 9 4 5
Jos Uiterwijk
23/36
• Step 3:
Draw the start situation
B
WW B
and the goal situation
W
B BW
Jos Uiterwijk
24/36
• Step 4:
Recognise that this is just a
railcar switching problem!
Jos Uiterwijk
25/36
• Step 5: solution now is simple:
B
WW B
12 steps
B
WW B
B
14 steps
B
6 steps
B WW
B
WW
8 steps
=====
W
B BW
40 steps
Jos Uiterwijk
26/36
State of the art for other
computer games
• Many other games have been or are target
of AI research.
• Many have been solved, which means that
the computer has an optimal strategy
against any resistance.
• Others are played above human level
• Some are still difficult
Jos Uiterwijk
27/36
Reversi
• Until recently, strong humans refused to play
against computers
• Reason: computers are too strong
• (recently the human world champion
nevertheless played a match; he lost 8-0!)
Jos Uiterwijk
28/36
Connect-Four, Domineering, Checkers
• Standard boards are completely solved
• The Checkers program CHINOOK even
gained the official World Champion title
Jos Uiterwijk
29/36
Go
• Until recently, strong humans refused to play
against computers.
• Reason: humans are too strong!
• This is, since 10 years, rapidly changing though
(Monte Carlo simulations work great!)
Jos Uiterwijk
30/36
And many other games ...
• Much progress on:
–
–
–
–
Games with chance (Poker, Backgammon)
Multi-player games (Chinese checkers)
Imperfect-information games (Bridge)
Real-time strategy (RTS) games
Jos Uiterwijk
31/36
Applications in Physics
• Just mentioning some physics domain:
–
–
–
–
–
–
Nuclear physics (safety!)
Medical physics (data analysis; data mining)
Robotics (large progress)
Vision (still difficult)
Intelligent design
Many kinds of simulations, from microscopic
small to astronomic large
Jos Uiterwijk
32/36
• They all benefit from computer science and
AI in particular, such as:
– Fast calculations
– Machine learning
– Pattern recognition / data mining
Jos Uiterwijk
33/36
Conclusions
• Chess (and other games)
– Drosophila melanogaster of AI
– Tool for development of new techniques
– Insight into human intelligence
• Computers can play many (board) games at
(supra) expert level
• Other games are still a challenge (Go).
Jos Uiterwijk
34/36
• Can and will computers beat the human
brain?
– Yes, in many complex (but otherwise dumb)
domains
– No, in several not so complex, but intelligent,
domains, for a long time to go!
– Much game research has to be done!
Jos Uiterwijk
35/36
The End!
Jos Uiterwijk
36/36