Introduction to Automata Languages and Computation

1. AUTOMATA
LANGUAGES &
COMPUTATION
Prof. Amey D.S.Kerkar,
Department of Computer Engineering,
Don Bosco College of Engineering, Fatorda-Goa
Third Year Computer Engineering,
Semester V, RC 2016-17.
Lecture 01 –Introduction

2. WHAT IS AUTOMATA THEORY?
Automata –
Self operating machine that
automatically follow/responds to a
predetermined sequence of operations

3. WHAT IS AUTOMATA THEORY?
Abstract Machine/Abstract computer –
Theoretical model of computer hardware
or software system used in automata
theory

4. WHAT IS AUTOMATA THEORY?
Formal Language Theory –
In linguistics, a formal language
consists of words whose letters are
taken from an alphabet and are well-
formed according to a specific set of
rules.

5. •The alphabet of a formal language
consist of symbols, letters, or tokens
that concatenate into strings of the
language.

6. • Each string concatenated from
symbols of this alphabet is called a
word
•The words that belong to a particular
formal language are sometimes
called well-formed words or well-
formed formulas.

7. • A formal language is defined by means
of a formal grammar such as a regular
grammar or context-free grammar,
which consists of its formation rules.

8. WHAT IS AUTOMATA THEORY?
• Study of –
1.Abstract Machines and
2.automata
3.computational problems that can be
solved using automata and abstract
machines.

9. WHAT IS AUTOMATA THEORY?
• Closely related to formal language
theory.

10. WHAT IS AUTOMATA THEORY?
• An automaton is a finite
representation of Formal Language
that may be an infinite set.

11. Automata are classified by class of
formal language they can recognize -
illustrated by Chomsky hierarchy.

12. Formal Language (L) Automata (M)
recognizing (L)
Regular Language (RL) Finite Automata (FA)
Context free Language
(CFL)
Push Down Automata
(PDA)
Context Sensitive
Language (CSL)
Linear Bounded
Automata (LBA)
Recursively
Enumerable
(REL)/Recursive
Languages (RL)
Turing Machine (TM)

13. ROLE OF AUTOMATA THEORY IN
COMPUTER ENGINEERING
1. Theory of Computation (TOC)

14. ROLE OF AUTOMATA THEORY IN
COMPUTER ENGINEERING
•In order to perform rigorous study of
Computation, mathematicians work
with mathematical abstraction of
computers called Model of Computation.

15. 2. Compiler Construction (CC)-
•Compiler transforms high level source
program to a low level target program
that is understood by the machine.
•Compiler design extensively involves
automata’s such as NFA, DFA

16. 3. Artificial Intelligence (AI) –
•It is an Intelligence demonstrated by
machines.
•Automata Theory finds its extensive
use in NLP, ML, Logic, ANN, Robotics
and so on.

17. •The ace Computer Physicist Alan
Turing is credited to have made a
very significant contribution to the
field of AI by coining a term Artificial
Intelligence using his “Imitation
Game” theory.

18. 5. Computer Networks (CN)-
•Internet protocol designing uses the
variant of finite automata called
Mealy and Moore Machines.

19. 6. Formal Verification –
•Act of proving or disproving the
correctness of an algorithm
underlying a system w.r.t. a certain
formal specification using formal
methods of mathematics.

20. 6.Formal Verification -
• Helps in proving correctness of
systems such as :
a.Cryptographic Protocols
b.Combinational Circuits
c.Digital circuits with internal
memory

21. 6.Formal Verification –
• Regular expressions (REs) are used
in many systems.

22. WHAT IS IN STORES FOR US?
Automata, Languages and
computation (ALC)
Includes study of :
1.Automata Theory
2.Formal Language Theory
3.Computation of computer problems
using the above tools.

23. PIONEERS OF ALC
• In 1936, He studied the
abstract Machines even
before the Computers
existed!! Dr. Alan Turing (1912-1954)
An English Mathematician, computer
scientist, logician, cryptanalyst,
philosopher, and theoretical biologist and
“The Father of Modern Computer Science
and Artificial Intelligence”
A Pioneer of Automata Theory

24. PIONEERS OF ALC
• These machines were later
named as “Turing
Machines” .
Dr. Alan Turing (1912-1954)
An English Mathematician, computer
scientist, logician, cryptanalyst,
philosopher, and theoretical biologist and
“The Father of Modern Computer Science
and Artificial Intelligence”
A Pioneer of Automata Theory

25. PIONEERS OF ALC
• He is credited to have
designed the first
Hypothetical Computer
called Turing Machine. Dr. Alan Turing (1912-1954)
An English Mathematician, computer
scientist, logician, cryptanalyst,
philosopher, and theoretical biologist and
“The Father of Modern Computer Science
and Artificial Intelligence”
A Pioneer of Automata Theory

26. PIONEERS OF ALC
• During WW2 Turing played
a crucial role in cracking
Enigma Cipher Machine .
• Machine intercepted coded
messages that enabled the
Allies to defeat the Nazis in
many crucial engagements,
including the Battle of the
Atlantic, and helped win
the war.
Dr. Alan Turing (1912-1954)
An English Mathematician, computer
scientist, logician, cryptanalyst,
philosopher, and theoretical biologist and
“The Father of Modern Computer Science
and Artificial Intelligence”
A Pioneer of Automata Theory

27. PIONEERS OF ALC
• After the war Turing
worked at the National
Physical Laboratory, where
he designed the Automatic
Computing Engine- one of
the first designs for a
stored-program computer.
Dr. Alan Turing (1912-1954)
An English Mathematician, computer
scientist, logician, cryptanalyst,
philosopher, and theoretical biologist and
“The Father of Modern Computer Science
and Artificial Intelligence”
A Pioneer of Automata Theory

28. PIONEERS OF ALC
• The Turing test, developed
by Alan Turing in 1950, is a
test of a machine's ability
to exhibit intelligent
behavior equivalent to, or
indistinguishable from,
that of a human
Dr. Alan Turing (1912-1954)
An English Mathematician, computer
scientist, logician, cryptanalyst,
philosopher, and theoretical biologist and
“The Father of Modern Computer Science
and Artificial Intelligence”
A Pioneer of Automata Theory

29. PIONEERS OF ALC
• Finite State Machine
(FSM) diagrams were first
used by
neurophysiologists
(Warren McCulloch and
Walter Pitts), biologists,
mathematicians,
engineers and some of the
first computer scientists
Dr. Warren McCulloch
(November 16, 1898 – September 24, 1969)
An American neurophysiologist and
cybernetician ( Left photograph)
Walter Harry Pitts, Jr. ( 23 April 1923 – 14 May
1969)
Logician who worked in the field of
computational neuroscience. ( Right photograph)

30. PIONEERS OF ALC
• Mealy and Moore
machines were
extensions to the Finite
automata as these were
called as Finite automata
with outputs.
Dr.George H. Mealy (1927 –2010)
An American mathematician and computer scientist
Dr. Edward Forrest Moore (1925 -
2003 )
An American professor of mathematics and computer
science
.

31. PIONEERS OF ALC
• The machines were named
after their respective
inventors Dr.George H.
Mealy and Dr. Edward
Forrest Moore
Dr.George H. Mealy (1927 –2010)
An American mathematician and computer scientist
Dr. Edward Forrest Moore (1925 -
2003 )
An American professor of mathematics and computer
science
.

32. PIONEERS OF ALC
• In 1956
Noam Chomsky extended
the automata theory idea of
complexity hierarchy to a
formal language hierarchy.
• This led to the concept of
formal grammar –Chomsky
Hierarchy
Dr. Avram Noam Chomsky (born
December 7, 1928)
American linguist,
philosopher, cognitive scientist,
historian, social critic,
and political activist
“The Father of Modern Linguistics"

33. HISTORICAL PERSPECTIVE FOR
ALC
•1930s
Alan Turing studies Turing machines,
Decidability, Halting problem

34. HISTORICAL PERSPECTIVE FOR
ALC
• 1940-1950s
“Finite automata” machines studied
Noam Chomsky proposes the
“Chomsky Hierarchy” for formal
languages

35. HISTORICAL PERSPECTIVE FOR
ALC
• 1969
Cook introduces “intractable”
problems or “NP-Hard” problems

36. HISTORICAL PERSPECTIVE FOR
ALC
• 1970
 Modern computer science:
compilers, computational &
complexity theory evolve

37. PREREQUISITES
•Set Theory
•Discrete Mathematics
•Data Structures and Algorithms