Artificial Intelligence in Computer Game

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Artificial Intelligence in Computer Game

• 1 What is Intelligence?
• 2 Current Frontier/Challenges/Examples
• 3 Which method do computer think?
• 4 General Problem in AI
• 5 Game AI
• 6 more Game AI Examples

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1 What is Intelligence ?

• Intelligence
• the capacity to learn and solve problems
• (Webster dictionary)
• the ability to think and act rationally
• Goal in Artificial Intelligence
• build and understand intelligent systems/agents
• synergy between
• philosophy, psychology, and cognitive science
• computer science and engineering
• mathematics and physics

source Thorsten Joachims tj_at_cs.cornell.edu,.
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Whats involved in Intelligence?

• A) Ability to interact with the real world
• to perceive, understand, and act
• speech recognition, understanding, and
  synthesis
• image understanding (computer vision)
• B) Reasoning and Planning
• modelling the external world
• problem solving, planning, and decision making
• ability to deal with unexpected problems,
  uncertainties
• C) Learning and Adaptation
• we are continuously learning and adapting
• Also we want systems that adapt to us!
• Major thrust of industry research.

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What is Artificial Intelligence ?

• Artificial Intelligence AI ?????????????
• Rich and Knight the study of how to make
  computers do
• things which, at the moment, people do better.
• Handbook of AI the part of computer science
  concerned
• with designing intelligent computer systems, that
  is,
• systems that exhibit the characteristics we
  associate with
• intelligence in human behavior understanding
• language, learning, reasoning, solving problems,
  etc.
• Dean, Allen and Aloimonos the design and study
  of the
• computer programs that behave intelligently.
• Russell and Norvig the study of rational
  agents that
• exist in an environment and perceive and act.

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Goals in AI

• engineering goal To solve real-world problems.
  Build systems that exhibit intelligent behavior.
• scientific goal To understand what kind of
  computational mechanisms are needed for modeling
  intelligent behavior.

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Classic AI Examples

• Chinese Room
• Turing Test
• Deep Blue
• Eliza

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Chinese Room
"Nobody just looking at my answers can tell that
I don't speak a word of Chinese," he writes.1

• The Chinese Room argument comprises a thought
  experiment and associated arguments by John
  Searle (Searle 1980), who attempts to show that a
  symbol-processing machine like a computer can
  never be properly described as having a "mind" or
  "understanding", regardless of how intelligently
  it may behave.

http//en.wikipedia.org/wiki/Chinese_room
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Turing Test

• Interrogator asks questions of two people
• who are out of sight and hearing.
• One is a person the other is a machine.
• 30 minutes to ask whatever he or she wants.
• Task to determine, only through the questions
  and answers
• typed into a computer terminal, which is which.
• If cant reliably distinguish the human from
  the computer,
• then the computer is deemed intelligent.
• Artificial intelligence is the enterprise of
  constructing an
• artifact that can pass the Turing test.

http//en.wikipedia.org/wiki/Turing_test
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Deep Blue

• Feng-hsiung Hsu, Thomas Anantharaman and Murray
  Campbell at Carnegie Mellon University - CMU
• Chiptest 50,000 moves per second
• Chiptest Bug 500,000 moves per second
• ChipTest-M won the North American Computer Chess
  Championship in 1987
• Deep Thought 0.01 was created in May 1988 720,000
  moves per second
• Deep Thought 0.02 won the World Computer Chess
  Championship with a perfect 5-0 score in 1989.

• Deep Blue 200 million positions per second
• Deep Fritz or Deep Junior ran on a personal
  computer containing two Intel Core 2 Duo CPUs,
  capable of evaluating only 8 million positions
  per second

http//en.wikipedia.org/wiki/ChipTest http//en.wi
kipedia.org/wiki/Deep_Blue_(chess_computer)
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2 The Current Frontier

• Deep Blue vs. Kasparov (May, 97)
• first match won against world-champion
• intelligent creative play
• 200 million board positions per second
• Kasparov I could feel I could smell a
• new kind of intelligence across the table.
• ... still understood 99.9 of Deep Blues moves.
• Intriguing issue How does human cognition deal
  with
• the combinatorics of chess?

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Eliza

• http//www-ai.ijs.si/eliza/eliza.html
• Chat Bot
• ELIZA is a computer program by Joseph Weizenbaum,
  designed in 1966, which parodied a Rogerian
  therapist, largely by rephrasing many of the
  patient's statements as questions and posing them
  to the patient. Thus, for example, the response
  to "My head hurts" might be "Why do you say your
  head hurts?" The response to "My mother hates me"
  might be "Who else in your family hates you?"
  ELIZA was named after Eliza Doolittle, a
  working-class character in George Bernard Shaw's
  play Pygmalion, who is taught to speak with an
  upper class accent.1

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Eliza

• http//en.wikipedia.org/wiki/ImageGNU_Emacs_ELIZA
  _example.png

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Rules and Learning

• Learning rules means adaption ..
• get reward/punishment
• (eg. In behavioral psychology give reward dog
  trainning experiment)

http//animals.howstuffworks.com/pets/dog-training
.htm
Ivan Palov
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3 Which method do computer think ? Structure

• The brain
• a neuron is the basic processing unit, gt100
  Billion neurons
• many more synapses connect the neurons
• cycle time EEG Theta 4-8 Hz Alpha 8-12Hz
  Gamma 26-70Hz

Computers 55Million or more transistors per
CPU supercomputer hundreds of CPUs cycle
times 3GHz
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Which method do computer think ? Algorithm
Experience

• The brain
• Experience ? Induction/ Inductive Reasoning
  (Learning from experience)

Computers Algorithm ? Fix method Algorithm ?
Induction (Learning from data)
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Game Play / Search Tree

• Example of Search Tree
• Possible Move

start
x
x
x
x
O
O
O
x
O
x
x
O
x
x
o
x
o
goal
o
x
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Heuristic Search

• Heuristic
• heuristic is a function h(x) defined on node of
  search tree
• Search will expand the lowest value for
  g(n)h(n)
• g(n) (exact) cost of the path from the initial
  state to the current node
• h(n) never over estimates the cost of reaching
  the goal
• Examples Solved n-Puzzle, Rubik

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4 Problem in AI

• Data Fitting / Data Prediction Problem
• future, who knows? eg. stock market

overfit
underfit
value
goodfit
time
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Problem in AI

• Classification Problem

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Problem in AI

• Optimization Problem
• Traveling Salesman Problem TSP
• Findout a new design to reduce cost, energy,
  efficiency ..

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5 Game AI

• Path Solver
• Expert System
• Finite Stage Machine FSM

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Path Finding

• Path Solver
• Automatic movement in map

http//theory.stanford.edu/amitp/GameProgramming/
AStarComparison.html
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Finite Stage Machine FSM

• Given Rules

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Drop Items..
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6 More Game AI examples

• RPGs
• Scripting (eg. Phython, Ruby )
• Rules based
• Agent, Bots

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Ethics in Game AI ?

• Should AI cheat ?
• Cheat Declaration
• Know opponent's data
• Know systems data
• no cheat hard code
• cheat easier code base on global data
• Game purpose is for fun. even AI cheating and
  people who play game still feel fun. do it.