Download General Game Playing

8/13/12
General Game Playing!
Yngvi Björnsson
Reykjavik University / CADIA"
"
GAI Summer School 2012
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Artificial Intelligence (AI) and Games"
•  Games have played a central role
in the development of AI"
–  1950 Alan Turing"
–  1952 Arthur Samuel"
–  …"
–  1997 Deep Blue!
–  2007 Checkers solved"
•  Lab for AI Research"
–  Simple rules (Minutes to learn)"
–  Complex strategy (Lifetime to master)"
GAI Summer School 2012
Stefan Gustafsson ©, from
Stanford News Service
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In 1958: 10 more years …"
•  Deep Blue (1997)"
–  Hardware"
•  Special purpose for
chess playing"
•  +200 million pos./sec."
–  Software"
•  Adversary search
algorithm"
•  Hand-crafted and
(mostly) hand-tuned
evaluation function"
•  +2000 features"
•  Engineering and/or AI?"
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Criticisms"
•  Computer chess has developed much as genetics
might have if geneticists had concentrated their
efforts … on breeding racing Drosophila [fruit fly]. We would have some science, but mainly … very
fast fruit flies. " - John McCarthy
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Intelligent Systems"
•  Want to build intelligent
systems capable of:"
–  Learning, thus become better
at solving tasks over time."
–  Handling unknown
scenarios, e.g., by adapting
existing knowledge from
different but related tasks."
–  Acting autonomously, i.e.
with minimal human
supervision."
Chess brain (from http://missboll.over-blog.com)
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General Game Playing (GGP)"
•  Intelligent Game Playing Systems"
–  … capable of playing many different games!
–  … even games they have never seen before!
GGP
Agent
GGP
Server
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General Game-Playing (GGP)"
•  Play a wide variety of games!
–  n-player games ( n ≥ 1)"
–  Adversary, co-operative"
–  Some limitations:"
•  Deterministic and perfect-information
games"
•  Game rules described using"
–  GDL (Game Description Lang.)"
–  Logic based (Prolog-like)"
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General Game Playing Research"
•  Initiated (2005) by AI research group at Stanford
University"
•  Well-established research community"
–  Stanford University, University of California Los Angeles,
University of Texas Austin, Technical University Dresden,
University of New South Wales, University of Paris,
Maastricht University, India Institute of Tech., Reykjavik
University, and more …"
•  International GGP Competition (AAAI/IJCAI)"
–  Motivation and Community Building"
–  Measure progress"
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GGP Research Challenges"
•  Knowledge Representation and Reasoning"
–  More efficient reasoning …"
•  Heuristic Search"
–  Search space reductions"
–  Game Tree Search"
–  Simulation-based Search (MCTS)"
•  Machine Learning"
–  Evaluation functions"
–  Search-control knowledge"
–  Transfer learning"
•  Extensions"
–  Imperfect Information and Non-Deterministic Games"
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GGP Research Challenges (cont.)"
•  No a priori knowledge about domain"
–  Different games may require a different game-playing
strategies"
–  Search:"
•  Which algorithms and enhancements to use?"
–  Knowledge:"
•  How to evaluate game states?"
•  Learning must take place online!"
–  How do we know how good the learned knowledge is?"
–  State-space properties"
•  Detect symmetries / structures (for efficiency)"
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CadiaPlayer"
•  CadiaPlayer"
–  CADIA/Reykjavik University’s GGP Agent"
•  Team"
– 
– 
– 
– 
– 
Yngvi Björnsson (PI)"
Hilmar Finnsson (PhD student graduated)"
Stefán Freyr Guðmundsson (PhD student)"
Stephan Schiffel (Post-doc)"
Alumni:"
•  Gylfi Þór Guðmundsson (MSc student graduated)"
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CADIA-Player Architecture
•  Has many different
components
–  C++
–  Prolog
•  “Thinking-ahead”
–  Simulations
–  MCTS
–  “Smartness”
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Techniques"
•  “Thinking”"
–  Monte-Carlo Tree Search!
•  Simulations"
–  Playing many games in the
“background” (WarGames!)!
•  Build up a game-tree as we go"
–  Learning Search Control !
•  MAST!
•  PAST!
•  FAST !
–  Reinforcement Learning"
•  “Evaluation”"
–  Board/Piece/Cell features"
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CADIA Player"
•  CADIA Player has participated in the
International GGP Competitions
since 2007:
"
– 
– 
– 
– 
– 
– 
1st place in 2007"
1st place in 2008"
6th place in 2009"
3rd place in 2010"
2nd place in 2011"
1st place in 2012
!
•  The most victorious GGP player ever "
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SUMMARY"
•  General Game Playing "
–  Important research direction for AI"
–  GGP systems move us one step towards general
intelligence based systems"
•  Reykjavik University / CADIA "
–  In the forefront of research into such systems"
–  Many interesting unanswered research questions"
•  Knowledge transfer?"
•  How to evaluate in real-time the quality of the knowledge
learned?"
•  ..."
•  Resources: http://www.general-game-playing.de/"
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QUESTIONS?"
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