Build a Real Universal Turing Machine

Document Sample
Build a Real Universal Turing Machine Powered By Docstoc
					  Build a Real Universal Turing Machine
 By now had all necessary ideas… 1946 Turing’s plans got approval
       Automatic Computing Engine (ACE)
       Progress was slow – lack of cooperation
       Turing without influence, disillusioned
       (…full ACE was not actually complete until 1957 (obsolete))
 1947 Turing back to Cambridge
     Interest in Neurology
     Wrote early paper on Neural Nets
     Believed complex mechanical system could exhibit learning ability
 1948 Turing and Champernowne wrote a chess program
     (for a computer that did not yet exist.)
 1948 Manchester Computer completed
       Turing accepted post as deputy director
       Worked on software for Manchester Mark I
       1950 “Computing Machinery and Intelligence” published
       … but became more interested in biology - morphogenesis
        “The 'skin of an onion' analogy is also helpful.
  In considering the functions of the mind or the brain we
   find certain operations which we can explain in purely
  mechanical terms. This we say does not correspond to the
 real mind: it is a sort of skin which we must strip off if we
are to find the real mind. But then in what remains we find
          a further skin to be stripped off, and so on.
Proceeding in this way do we ever come to the 'real' mind, or
 do we eventually come to the skin which has nothing in it?
       In the latter case the whole mind is mechanical.”



                                   Alan Turing
                         Turing’s End
 March 1952 Arrested for “Gross Indecency”
     No denial - Saw no wrong with his actions
 Convicted – given choice
     Prison
     Oestrogen injections
 Lost security clearance for GCHQ
 June 1954
     Why apple?




 Conspiracy theories…
     Security risk


 Recognition: Turing Award established (ACM, 1966)
                1956 Dartmouth Conference:
                 The Founding Fathers of AI




John McCarthy    Marvin Minsky    Claude Shannon      Ray Solomonoff

Alan Newell     Herbert Simon    Arthur Samuel

                                                 And three others…
                                                 Oliver Selfridge
                                                   (Pandemonium theory)
                                                 Nathaniel Rochester
                                                  (IBM, designed 701)
                                                 Trenchard More
                                                  (Natural Deduction)
  Dartmouth Conference: The Founding Fathers of AI


                 First degree in mathematics
                 Graduate work on finite automata
                 Got interested in digital computers after
                  Summer working at IBM
                 Was teaching at Dartmouth
John McCarthy        Brought together the researchers
                 Labelled the field “Artificial Intelligence”

                Later…
                 Worked on Formal Logic side of AI
                 Invented LISP programming language
                 Won Turing Award in 1971
  Dartmouth Conference: The Founding Fathers of AI

                              1951 built a neural net out of
                               vacuum tubes,
                               to train a simulated rat to get
                               out of a maze
                              Combined learning with
                               planning ahead in his Ph.D.
                               thesis
Later…           Marvin Minsky

 Society of Mind idea
 Work on artificial neural networks:
   proved perceptrons can’t solve some problems
 Work in theoretical Computer Science:
   2-pushdown-stack automaton = Turing Machine
 Won Turing Award in 1969
 Recent book: The Emotion Machine
  Dartmouth Conference: The Founding Fathers of AI

Most famous of all participants,
but not for AI….
Worked on analogue computer
  with cogs and wheels
Showed that electromechanical
  relay switches could solve
  boolean algebra problems       Claude Shannon
     digital instead of analogue
     Lead to digital calculators
1948 “A Mathematical Theory of Communication”
1950 created mechanical mouse
     Could find its way out of a maze
     Learnt from experience
1950 wrote about chess playing computer program
Made a fortune in Las Vegas applying his maths to roulette etc.
  Dartmouth Conference: The Founding Fathers of AI

Algorithmic Probability
     probability of some string having been generated
      by an algorithm
Applied to Induction
     Optimal Machine Learner
Theoretical idea…
     Not computable
                                                         Ray Solomonoff
     But can be approximated
  Dartmouth Conference: The Founding Fathers of AI

 Originally a political scientist – how bureaucracies function
 Became interested in organisational decision making
 Around 1954 he decided…
  best way to study problem-solving is to simulate on computer
 Developed experimental technique of verbal protocol analysis
 Interested in role of knowledge in expertise
 1978 won Nobel Prize in Economics
               Herbert Simon

                                      “Over Christmas,
                                 Allen Newell and I created
                                   a thinking machine.”

                                         January 1956
   Dartmouth Conference: The Founding Fathers of AI




Alan Newell

               1955 designed a chess playing program

              Later…
               1983 Developed SOAR architecture
                   Attempting a unified theory of cognition
   Dartmouth Conference: The Founding Fathers of AI

 1956 Logic Theory Machine
     Saw that theorem proving can be reduced to search
     Search tree to find a proof for a theorem
     Considered to be first AI program
 1957 General Problem Solver
     Heuristics
     Means-ends analysis
 1975 won Turing Award
Alan Newell      Herbert Simon
Dartmouth Conference: The Founding Fathers of AI



        Developed a checkers playing program
        Developed alpha-beta tree idea
        Made his program learn to improve itself
        1962 his program beat a state champion


                            Arthur Samuel
  “We propose that a 2 month, 10 man study of artificial
 intelligence be carried out during the summer of 1956 at
      Dartmouth College in Hanover, New Hampshire.
  The study is to proceed on the basis of the conjecture that
every aspect of learning or any other feature of intelligence
can in principle be so precisely described that a machine can
                    be made to simulate it.
An attempt will be made to find how to make machines use
 language, form abstractions and concepts, solve kinds of
problems now reserved for humans, and improve themselves.
We think that a significant advance can be made in one or
   more of these problems if a carefully selected group of
        scientists work on it together for a summer.”

                                      McCarthy et al 1955
   1956 Dartmouth Conference: What was achieved?


 Not much
 People didn’t agree on the format and weren’t all there together
 Newell and Simon didn’t spend much time…
     Too busy working on their logic theorist
 McCarthy was disappointed
 But got people to know each other…
         AI Developments from 1956 - 1963


     Main Thrusts of Work in Early Days…
1.   Reduce the search tree for search programs
         For example, search programs for:
         Logic Theorems
         Geometry theorems
         Algebra
2.   Make computers learn for themselves
         For example:
         Chess playing machines
         Checkers playing machines
         Pattern recognition
        “It is not my aim to surprise or shock you –
 but the simplest way I can summarize is to say that there
  are now in the world machines that can think, that can
                   learn and that can create.
Moreover, their ability to do these things is going to increase
 rapidly until – in a visible future – the range of problems
they can handle will be coextensive with the range to which
              the human mind has been applied.”




                                 Herbert Simon, 1957
        Newell and Simon’s progress…
   Discovered that humans don’t really act like Logic Theorist
   Psychologists Moore and Anderson had pioneered “think aloud”
    experiments
   Other AI researchers were merely concerned with programs that
    performed well
   Newell and Simon wanted programs that solved problems in the
    same ways as humans
       They branched off…
       More Cognitive Science than core AI
   Developed the general problem solver (GPS)
       Using heuristics
       Using means-end analysis
       Solved monkey-chair-banana type problems
                      Work at IBM…
   Minsky hired Herbert Gelernter to work on new IBM 704
   Geometry Theorem Prover
   Gave visual input of geometry problem by coding it in (not camera)
   This input reduced branching factor from 1000 to 5
   Took Gelernter 3 yrs to program it (much longer than expected)

   Also at IBM
       Samuel working on his checkers program
       Alex Bernstein working on chess program
                     Trouble at IBM…
   AI work noticed by popular press
   Publicity attracted attention of IBM shareholders
   Asked T. J. Watson (president of IBM)
       explain why research dollars were being used for "frivolous matters"
   IBM noticed that customers were frightened of idea of
    "electronic brains" and "thinking machines“
   1960 Internal report prepared recommended IBM stop AI
   IBM told customers
       computers will only do what they were told


   Bernstein became psychiatrist
   Gelernter became physicist
   Samuel went to Europe
              McCarthy’s progress…
   Developed LISP programming language
   List Processing
   Makes it easy to program AI ideas
   Makes it easy for a program to alter its own instructions
   McCarthy wanted programs to add to their own
    commonsense
       To deduce consequences
   Started looking at IF-THEN rules (like later expert systems)
   LISP was heavy on computer power – more useful in 1970s

   McCarthy also pioneered idea of time-sharing computers
            Minsky’s progress at MIT…
   Sputnik left US behind technologically
   US created DARPA
   1963 MIT got over $2M for Machine Aided Cognition
   MAC project brought MIT about $3M a year in grants thereafter

 Minsky’s student James Slagle worked on SAINT program
          Solved symbolic integration problems
          Later evolved into MACSYMA