Lecture02

Knowledge Representation
in
Digital Humanities
Antonio Jiménez Mavillard
Department of Modern Languages and Literatures
Western University

Lecture 2
Knowledge Representation in Digital Humanities
* Contents:
1. Why this lecture?
2. Discussion
3. Chapter 2
4. Assignment
5. Bibliography
2

Why this lecture?
* This lecture...
· outlines programming languages as the
highest type of formal languages, which
makes them ideal for KR
· describes how computers, the essential
tool for DHers, work at programming
level
3

Last assignment discussion
* Time to...
· consolidate ideas and
concepts dealt in the readings
· discuss issues arised in the specific
solutions to the projects
4

Chapter 2
Principles of Computing
1. Overview on computers
2. Programming languages
Antonio Jiménez Mavillard5

Chapter 2
1 Overview on computers
1.1 What is a computer?
1.2 Computer components
1.3 How does a computer work?

Chapter 2
2 Programming languages
2.1 User vs programmer
2.2 What is a programming language?
2.3 Classification
2.4 History of programming languages

Overview on computers

What is a computer?
* Definition
· A computer is a programable machine
that processes input data and produce
output information

What is a computer?
* Computers in History
· Abacus
+ Calculating device
+ Three arithmetic
functions: + - x
+ Dated from 2700
to 2300 BC

What is a computer?
· Antikythera mechanism
+ Analog computer
+ Calculates
astronomical
positions
+ Dated to the
early 1st cent. BC

What is a computer?
· Pascaline
+ Adder machine
+ Invented by
Blaise Pascal
in 1640s

What is a computer?
· The Stepped Reckoner
+ Mechanical calculator
+ Four arithmetic
functions:
+ - x %
+ Invented by
Leibniz in 1673

What is a computer?
· Difference Engine &
Analytical Engine &
Difference Engine
No. 2

What is a computer?
· Difference Engine & Analytical Engine &
Difference Engine No. 2
+ First programable computer
+ Memory & Processing Units &
Punched-card Input
+ Invented by Charles Babbage
from 1821 to 1848

What is a computer?
· ENIAC
+ Electronic
calculator
+ Vacuum tubes
+ Invented by
John Mauchly
in 1942

What is a computer?
· Turing Machine
+ Theoretical
+ Equivalent to
any computer
+ Invented by
Alan Turing
in 1937

What is a computer?
· Modern computers
+ Turing-complete
+ Von Neumann
architecture
+ Integrated
circuits

References
“Computer History Museum.” N. p., n.d. Web. 30 Nov. 2013.
De la Rosa, Javier. “Computer Tools for Linguists.” Yutzu. N. p., n.d. Web. 16 Sept. 2013.
Georges Ifrah. “Chapter 5: From Clockwork to Computer: The History of Automatic Calculation.” The Universal History of
Computing: From the Abacus to the Quantum Computer. Wiley, 2001. Print.
Georges Ifrah. “Chapter 6: What is a Computer?” The Universal History of Computing: From the Abacus to the Quantum
Computer. Wiley, 2001. Print.

Computer components
* The architecture describes a computer in
terms of its componentes and their
relationships
* It also defines the instruction set
* Most of modern computers follow Von
Neumann's architecture

Computer components
* Von Neumann's architecture:

Computer components
* Hardware:
· CPU
· Memory
· Input/Output
* Operating System
* Software
· Applications
· Programming software

Computer components
* CPU (Central Processing Unit) or Processor
1. Read an instruction from memory
2. Read data from memory if needed
3. Execute the instruction
4. Write the result into memory if needed
5. Get ready for next instruction

Computer components
* RAM (Random Access Memory)
· Area where the system holds data (values
and program code) waiting to be
processed by the CPU
· This area can be seen as a huge “table”
where the rows are memory positions and
the columns are offsets with respect to
each memory position

Computer components
* RAM (Random Access Memory)

Computer components
* HD (Hard Disk/Drive)
· Area where the system stores information
· The way in which the Operating System
controls how information is stored and
retrieved is called file system
· The file format specifies how information
is encoded in a digital storage medium

Computer components
* RAM vs HD
· RAM: small, fast and temporal
· HD: big, slow and permanent
· The OS moves from the HD to the RAM
only the data (vales and program code)
it needs to run a program

Computer components
* Input
· Keyboard
· Mouse
· Microphone
* Output
· Screen
· Printer
· Speakers

Computer components
* Operating System
· Examples:
+ OS X
+ Ubuntu
+ Android
+ Windows 8

Computer components
* Operating System
· Connects software with hardware and
handles everything between both:
+ Memory
+ File system
+ I/O
+ ...
· Examples: Ubuntu, Android, OS X,
Windows 8...Knowledge Representation in Digital Humanities

Computer components
* Operating System
· The file system is the way in which the
OS controls how information is stored
and retrieved
· The file format specifies how information
is encoded information in a digital
storage medium

Computer components
* Operating System
· Two types of files:
+ Text file
- Contains human readable plain text
- Encoded in a encoding scheme
(UTF-8, Latin 1...)
- Examples: txt, HTML, CSV

Computer components
* Operating System
· Two types of files:
+ Binary file
- Contains any type of data
- Encoded in binary
- Examples: zip, JPEG, AVI

Computer components
* Operating System
· Size units:
1 B 8b
1 KB 1024 B
1 MB 1024 KB
1 GB 1024 MB
1 TB 1024 GB
b bit
B byte
KB kilobyte
MB megabyte
GB gigabyte
TB terabyte

Computer components
* Applications
· An application is a computer software
designed to help people to perform a
task
· Examples: word processor, spreadsheet,
image editor, videogame, web browser...

Computer components
* Programming software
· A programming tool or software
development tool is a program or
application that software developers use
to create, debug, maintain, or otherwise
support other programs and applications

Computer components
* Programming software
• An IDE (Integrated Development
Environments) combines the features of
many tools into one package
+ source code editor
+ build automation tools
+ debugger
· Examples: Eclipse, Jbuilder, Komodo

References
Andrew S. Tanenbaum. “Chapter 1: Introduction.” Modern Operating Systems. 2nd edition. Pearson, 2001. Print.
Barata, Kimberly. Understanding Computers: An Overview for Records and Archives Staff. International Records
Management Trust/International Council on Archives, 1999. Print.
John Hennessy, and David Patterson. “Chapter 1: Fundamentals of Quantitative Design and Analysis.” Computer
Architecture: A Quantitative Approach. 5th Edition. Morgan Kaufmann, 2011. Print.

How does a computer work?
* The computer...
1. accepts input data
2. performs pertinent operations with
input and stored data (processing)
3. stores data and keep processing while
needed
4. produces output information

* How does a modern computer work?
The concrete behaviour depends on the
particular application

Type of
program
Input What does the
program does
Output
Word processor Characters
typed from
the keyboard
Formats the
text, corrects
the spelling...
Displays and
prints neatly
organized text
Video game Keystrokes,
joystick
movements
Calculates how
fast and far
to move a
cartoon figure
on-screen
Moves a
cartoon figure
on-screen

Type of
program
Input What does the
program does
Output
Web browser HTML codes on
other
computers
Converts the
HTML codes
into text and
graphics
Displays web
pages
on-screen
OCR software Text from a
scanner
Recognizes
shapes of
characters
Converts
scanned
documents into
a text file

Programming languages

User vs programmer
* Tipically, to use a computer, someone can:
· Use an application previously developed
by a programmer (user rol)
· Develop their own application by using a
programming software (programmer rol)

What is a programming language?
* Definition
· A programming language is a formal
language designed to communicate
instructions to a computer
· Formal/Artificial vs Human/Natural

* Definition
· A formal language:
+ has a formalized morphology, syntax
and semantics
+ is computationally processable

* Definition
· morphology: keywords (vocabulary)
+ Example: var, defun, if
· syntax: grammar rules
+ Example: x = y + 1; (assignment)
· semantics: meaning
+ Example: x * 2 + 1 ≡ (x * 2) + 1
(operator precedence and associativity)

Classification
* Language levels
· Low-level languages
+ Close to machine
· High-level languages
+ Close to human

Classification
* Programming paradigms
· Imperative (how)
+ Procedural (statements)
+ Object-oriented (interacting objects)
· Declarative (what)
+ Logic (logical sentences)
+ Functional (mathematical functions)

Classification
* Compiled vs Interpreted
· Compiled language
+ Program translated (compiled) into
machine language instructions by a
compiler and executed by a hardware
· Interpreted language
+ Program executed (interpreted) by an
interpreter (run-time environment)

History of programming languages
* Prehistory of programming languages
· Programmers of Babylon (1790 BC)
+ Written language
to describe
computational
procedures

· Muhammad Al-Khwarizmi (762 AD)
+ Inventor of algorithms
+ Wrote
Kitâ al-jabr
wa'l-muqabâla
+ Translated into
Latin as Algoritmi de numero Indorum

· Augusta Ada,
Lady Lovelace
+ First programmer
in history (1842)
+ Wrote a program
for Babbage Engine

· Konrad Zuse
+ Designed Plankalkül (1945)
+ Never implemented as a real language
+ Many modern languages share
Plankalkül's features

· Konrad Zuse
+ Plankalkül's features
- expressions, assignments
- types: bit, integer, real, arrays
- conditionals, loops, subrutines

* Fortran (1957)
· Paradigm: imperative
· First high-level language
· Scientific-oriented computing

* Fortran (1957)
· Introduced
+ variables
+ loops
+ procedures
+ datatypes: boolean, integer, real...

* Algol 58/60 (1958/1960)
· Ancestor of contemporary languages
· Introduced
+ block structure
+ recursion
+ formal definition

* Lisp (1958)
· Paradigm: functional
· Good for symbolic computing
· Language for Artificial Intelligence
· Syntax and computing based on lists

* Cobol (1959)
· Paradigm: object-oriented
· Business-oriented computations
· Non-academic language
· Elaborate data structures
· Introduced
+ Record type as data structure

* PL/I (1964)
· Combination of the best features of
Fortran, Algol 60 and Cobol
· First language for general applications
· Introduced
+ event handling

* Basic (1964)
· Paradigm: unstructured
· First language for personal computing
· Easy to learn
· Simple, limited, general-purpose

* Simula 67 (1967)
· Extension of Algol 60
· For concurrent processes
· Introduced
+ Object Orientation: classes and
encapsulation

* Algol 68 (1968)
· Extension of Algol 60
· General purpose language
· For academia

* Pascal (1970)
· Sucessor of Algol 60
· Academic language: excellent to teach
structured programming and good habits

* C (1972)
· For system programming (implementation
language of Unix) and personal
computing
· Very fast
· High-level and low-level language

* Prolog (1972)
· Paradigm: logic
· Very high-level language
· Based on logic with proofs
· Very powerful:
+ Backtracking
+ Pattern matching

* Smalltalk (1972)
· Sucessor of Simula 67
· The purest object-oriented language
· Very powerful

* Ada (1983)
· For general applications
· Completely standard
· Supports concurrency

* C++ (1983)
· Extension of C, based on Simula
· Introduced
+ Assignment operator overloading

* Haskell (1990)
· Paradigm: funcional
· Purely functional: no side effects
· Very high-level

* Java (1995)
· Based on C++
· Portable
· Full object-oriented language
· For internet programming but
general-purpose

* Perl (1987)
· For text processing

* Python (1991)
· For text processing

* Ruby (1995)
· Dinamically-typed

* Javascript (1995)
· For web programming

* PHP (1997)
· For web programming
· Dinamically-typed

References
Bergin,Jr., Thomas J., and Richard G. Gibson,Jr., eds. History of Programming Languages II. New York, NY, USA:
ACM, 1996. Print.
Fuegi, J., and J. Francis. “Lovelace & Babbage and the Creation of the 1843 ‘Notes.’” IEEE Annals of the History of
Computing 25.4 (2003): 16–26. IEEE Xplore. Web.
History of Programming Languages III. New York, NY, USA: ACM, 2007. Print.
Sammet, Jean E. “Programming Languages: History and Future.” Commun. ACM 15.7 (1972): 601–610. ACM Digital Library.
Print.
Wexelblat, Richard L., ed. History of Programming Languages I. New York, NY, USA: ACM, 1981. Print.

Assignment
* Assigment 2: Programming the Abacus
· Readings
+ Algorithm (Design And Analysis Of
Algorithms)
+ How to Program an Abacus
(http://baptiste.meles.free.fr/site/B.Meles-Abacus_presentation.pdf)

Assignment
* Assigment 2: Programming the Abacus
· Project
Let us have a 9-wired abacus with 9
beads on each wire:
+ Identify the CPU, memory and I/O
+ Define the instruction set
+ Write an algorithm that calculates the
sum of any two numbers

References
A.A.Puntambekar. “Algorithm.” Design And Analysis Of Algorithms. Technical Publications, 2010. Print.
Baptiste Mélès. “How to Program an Abacus.” N. p., n.d. Web. 5 Jan. 2014.

Bibliography
A.A.Puntambekar. “Algorithm.” Design And Analysis Of Algorithms. Technical Publications, 2010. Print.
Andrew S. Tanenbaum. Modern Operating Systems. 2nd edition. Pearson, 2001. Print.
Baptiste Mélès. “How to Program an Abacus.” N. p., n.d. Web. 5 Jan. 2014.
Barata, Kimberly. Understanding Computers: An Overview for Records and Archives Staff. International Records
Management Trust/International Council on Archives, 1999. Print.
Bergin,Jr., Thomas J., and Richard G. Gibson,Jr., eds. History of Programming Languages II. New York, NY, USA:
ACM, 1996. Print.
“Computer History Museum.” N. p., n.d. Web. 30 Nov. 2013.

Bibliography
Fuegi, J., and J. Francis. “Lovelace & Babbage and the Creation of the 1843 ‘Notes.’” IEEE Annals of the History of
Computing 25.4 (2003): 16–26. IEEE Xplore. Web.
Georges Ifrah. The Universal History of Computing: From the Abacus to the Quantum Computer. Wiley, 2001. Print.
History of Programming Languages III. New York, NY, USA: ACM, 2007. Print.
John Hennessy, and David Patterson. “Chapter 1: Fundamentals of Quantitative Design and Analysis.” Computer
Architecture: A Quantitative Approach. 5th Edition. Morgan Kaufmann, 2011. Print.
Sammet, Jean E. “Programming Languages: History and Future.” Commun. ACM 15.7 (1972): 601–610. ACM Digital Library.
Print.
Wexelblat, Richard L., ed. History of Programming Languages I. New York, NY, USA: ACM, 1981. Print.

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