Transcript M105 Units 1 & 2 Handouts

Welcome to…
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T. Jumana Abu Shmais – AOU - Riyadh
Agenda
□ Essentials
□ Getting Help
□ Course Tour
□ Unit 1: Data and Information
□ Unit 2: Representation
□ What’s Next
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Essentials
• Know your course!
Read the Course Guide, skim the units…etc.
This will help you to:
• Make sure that this is the right course for you (if it’s not a
mandatory for your major);
• Know what you’re stepping into and plan and manage resources
(time) accordingly;
• Keep your expectations real.
• Don’t rely merely on tutorial sessions and
summaries.
• Avoid: late submissions and plagiarism
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Getting Help
• Learning Management System (LMS)
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TMA submission & Quizzes (MEs)
E-Conferences (forums)
Private massages
Chatting
Supporting materials (Files, SAQs …etc.)
TMA feedback
E-Library
• Face-to-face meetings (tutorial sessions)
• Your Tutor
• Student study groups
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Agenda
Essentials
Getting Help
□ Course Tour
□ Unit 1: Data and Information
□ Unit 2: Representation
□ What’s Next
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DATA COMPUTING AND
INFORMATION … What’s in a title?
• DATA
(such as a person’s name, or the number of a bus route)
• COMPUTING
computers and how they can be made to work with data
(e.g. storing it, changing it, and displaying it)
• INFORMATION
(which is generated by linking items of data to answer
questions of interest).
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Course Aims Summary
To help you attain and improve:
• Knowledge of facts and concepts relating to the course themes.
• Computing skills: The course aims at making you a better
computer user. You will learn how to write simple computer programs to
solve problems.
• Study Skills: Because this is a level 1 course there is a lot of
emphasis on developing and improving study skills. With good study skills
you can make a success of any course. Some of the skills that you’ll learn:
Time Management
Critical Reading
Note Taking
Effective Writing
Communicating Online
Finding Information on the Web
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The Course Blocks
Block 1: DATA
– Capturing data
– Representing it
– Storing and Sending it
Block 2: COMPUTING
– Hardware and software
– Software and Programming Concepts
– Programming in JavaScript
Block 1 Unit 1
Unit 2
Unit 3
Unit 4
Unit 5
Part I
Block 2 Unit 6
Unit 7
Unit 8
Unit 9*
Unit 10*
Block 3: INFORMATION
– Human Computer Interaction
– Multimedia
– Security and Cryptography
Block 3 Unit 11
Unit 12
Unit 13
Unit 14
Unit 15
Unit 16
Part II
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Assessment
4 TMAs,
2 Quizzes
(Midterm Exams)
TMA01
8%
TMA02
10%
Quiz 1
7%
Final Exam 1 25%
and
2 Final Exams.
TMA03
10%
TMA04
7%
Quiz 2
8%
Final Exam 2 25%
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Agenda
Essentials
Getting Help
Course Tour
□ Unit 1: Data and Information
□ Unit 2: Representation
□ What’s Next
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Data, Information and Computers
• Data: A discrete (separate or distinct) item such as a number,
character, symbol…etc.
Must be interpreted, by
a human or machine,
to derive meaning
The word ‘data’ is the plural of the Latin word
‘datum’ but it is generally used as a singular
word in English.
• Information: The item of knowledge created by linking
together two or more items of data. Information is interpreted data.
• Computers: Used to manipulate, analyse and store data and turn
it into information.
A computer system is the combination of:
– the computer (with its processor and storage);
– other equipment (peripherals – input/output devices);
– the software programs that make it all work.
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Sensing data and turning it into
something usable (Making sensation make sense)
• Perceptual Data: What we perceive with our
senses (the most primitive form of data).
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human beings don’t just react instinctively; they respond reflectively,
using thought. In other words, we seek to name, to classify and finally to
understand and communicate what we perceive.
• A sign or symbol is a way of representing data. For
example, the word ‘blue’ is a sign of a particular color
sensation.
• A sign (or symbol) can be defined as something that
conveys some information by means other than direct
representation.
• Types of signs:
• visual
• Audible
• Tactile (e.g. The Braille System – Louis Braille)
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One person’s data could be another’s
information
The distinction between data and information isn’t always very clear.
Whether something is data or information depends partly
on the perspective of the user. Data becomes information
in users’ minds when it informs them e.g. answers a
question.
Human beings turn data into information through a process
of:
– creating signs to represent the data;
– agreeing on what the signs symbolize;
– linking these signs in a variety of ways to create information;
– communicating that information to other people.
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Computers as tools for finding
1. Geographical Locations
2. Information
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1. Geographical Locations
• Maps can be made up of separate layers of
geographical data, such as:
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the underlying grid of latitude and longitude;
contour lines showing altitude;
features such as rivers, roads, buildings and boundaries;
the names of towns, roads, hills, rivers and other notable
features of the landscape.
Such geographical data will usually be stored in databases (to eliminate
duplication by reuse) in a form that computers understand.
Applications: constructing maps – route-planning services
Fitness-for-Purpose: adding or removing layers makes a map fit for a
specific purpose. Computers facilitate that.
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GPS: Global Positioning System
The system involves a network of satellites in orbit around the
earth, which provide specially coded signals that can be processed
in a GPS receiver. Signals from four GPS satellites enable the
computer in the receiver to compute the receiver’s position and
update the map accordingly (transforms data into information).
The worldwide GPS is funded and controlled by the US Department
of Defense (DOD)
Applications:
• Navigation (audible directions)
• Tracking
• Surveying
• Plate tectonic studies
GPS is an example of how a computer can transform data into
information in ways not previously thought possible.
Hand-held
GPS
receiver
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2. Information
Search Engines - Gateways
• The World Wide Web (Web) is the collection
of linked data stored on the Internet which is
accessed using a browser. It’s a vast storehouse
of ever changing, linked information.
• The Internet refers to the physical
interconnection of large numbers of smaller data
communications networks to form a huge,
publicly accessible ‘network of networks’.
• A browser is a computer application used to
access the Web. (e.g. Internet Explorer, Firefox …etc.)
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Search Engines
• Search Engine: The computer program that uses keywords
to facilitate finding things on the Web.
• A computer program is essentially a step-by-step set of
instructions that tell the computer what to do.
The process:
1. The keywords are transmitted over the Internet to a special computer
known as a web server. This web server contains an index to
websites. Each website is associated with a series of keywords which
can be found in the site’s title, address or contents. The index keywords
and the user’s requested keywords are compared by the server.
2. The web server then retrieves references to those websites that contain
the right keywords and sends details of each reference back to the
user’s browser.
3. The browser then displays the references for the user.
Here, data (the keywords) is used to assemble information (the
references to websites)
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Gateways
A gateway can also refer to a computer that acts
as a message router on the internet.
• A gateway on the web is a website
intended to direct users to other preselected websites containing information
on a particular topic.
• University librarians often set up gateways
for particular areas of study.
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Computers as tools for working with
data
• Combining simple elements of data can generate a huge amount of
complex information.
• Computers, using only two symbols (0/1) that can be combined
according to simple rules, can produce an infinite number of outputs.
• The flexibility of a computer system is key to being able
to use them creatively. It is the computer program
(software, in general) that makes such flexibility
possible.
• advantage of the computer as an artist’s tool is that it
can produce effects that would be difficult or impossible
using traditional media.
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Controlling Things using computers
• Virtually all electronic appliances sold in the last decade
or so are controlled using microcomputers
(microcontrollers) of some type. Before that, such control
was provided by mechanical systems (wear, break
down, replacement, limited complexity).
• To work, the microcomputer connects to
– actuators that cause mechanical parts of the system to work;
– sensors that sense the state of some aspect of the machine.
• The user controls the machine through a user interface. Generally,
a user interface is a display/control panel that enables the user to
control a machine or interact with a program.
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Selling Things using computers
• Web-based selling seems to be concentrated in
three main categories of company:
– existing catalogue sales companies which have put
their catalogues online to allow customers to buy
using the web;
– existing companies whose products are largely
information and which have used the web as a
means of providing a personalized service or one with
a very quick response; (the most financially
successful – e.g. publishers)
– companies which have started from scratch using the
Web as their only sales medium (e.g. Amazon).
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Using a Sales Website
A visitor to a sales website is usually able to:
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browse through the details of the goods for sale;
search for a particular product;
check on the availability of goods;
read reviews of the products by other purchasers;
register to receive newsletters which detail new items of
interest;
• buy products using credit or debit cards, and in some
cases, other payment methods such as cheques.
• see what items are most popular;
• check the status of their order.
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Security: are your credit card details
safe?
You can be reasonably confident of buying from a
Website if it displays one of two things:
Another safety precaution is to deal only with Web
sellers you know are reputable.
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Database Servers
• To be able to search a website requires not only
a web server but a database server. Like a
Web server, a database server is a computer
that responds to requests from other computers.
Its task is to find and extract data from a
database.
• The Web and database servers form part of a
distributed system. This means that separate
computers exchange data and information
across a network (e.g. Internet) to produce
results for a user.
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Agenda
Essentials
Getting Help
Course Tour
Unit 1: Data and Information
□ Unit 2: Representation
□ What’s Next
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Communication, convention
and representation
• Communication is the act of imparting
information.
• Communication relies on agreed
representations (conventions) which
associate a symbol with a meaning.
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We use computers to:
• communicate with each other.
(chat, e-mail…etc.)
• solve problems.
This implies that:
– we need to communicate with computers;
– computers need to communicate with us;
– computers need to communicate with each
other
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E-m
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• Netiquette
• Emotions
• Pros:
immediate . global . cheap . multimedia
• Cons:
– less time for reflection;
– the risk of sending mail to the wrong person(s) is high (BCC and
Reply);
– short informal communication (which is not always appropriate);
– easily misunderstood.
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Using computers to solve problems
To be able to delegate problems to computers, four-way
communication is needed.
1. Programmers need to instruct computers how to solve
the problem given a variety of inputs.
2. Users need to give computers the inputs to a particular
problem.
3. Computers need to communicate the solution (or lack
of one) back to users.
4. For tasks or problems which require more than one
computer, the computers need to communicate with
each other to share the problem.
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Communication, conventions and
protocols
• A convention is an agreement between a
collection of participants about what a message
means.
– Public
– Local
– Private
• A human language is based on conventions
shared by its speakers.
• A protocol is one of the systems of
conventions designed to enable communication
with and between computers.
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Important Internet Protocols
• TCP/IP (Transmission Control Protocol/Internet Protocol)
– TCP takes data and bundles it up in appropriate parcels for
transmission.
– IP moves the parcels along networks and makes sure they are delivered
to the right address.
• FTP (File Transfer Protocol) lets authorized users download files
from (or send – upload - files to) any other computer connected to
the network.
• SMTP (Simple Mail Transfer Protocol) transfers e-mail across the
world via the network.
• HTTP (HyperText Transfer Protocol) is a Web protocol that
facilitates communication between Web servers and browsers.
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Representation
• A representation is an association between
a form (symbol) and a content (meaning)
which follows some convention.
The association between a particular
form and its content is not
predetermined. It’s up to people’s
choice.
Form
(symbol)
Why are representations central
to the ability to communicate?
Because they allow content (meaning)
to be given a symbol (form) that can be
Meaning/content:
EURO (currency)
perceived by others.
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Effective Representations
1. Must be perceivable in some way;
– Auditory – perceived as sound – spoken
language
– Visual – perceived as sight – traffic signs
– Tactile – perceived by touch – mouse,
keyboard, vibration
2. The relationship between form and
content is shared by all parties involved
in the communication process.
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Some useful properties of
representations
1. Context sensitivity
This is because the same form may be associated with different meanings,
depending on the context.
2. Ambiguity
An ambiguous representation is one which associates the same form with
more than one meaning in the same context. Uncommon in communication
with or between computers.
3. Precision
Replacing a more precise representation with a less precise one results in
information loss.
4. Redundancy
A representation contains redundancy if the meaning or content can
be recovered from only a part of its form.
Compression (detection and removal of redundancy) is important in
computing. [Lossy/Lossless]
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Picking Representations
• Choosing a representation that is fit-forpurpose can make a task easier to accomplish,
and vice versa.
• To be fit-for-purpose, a representation must
contain sufficient information for the purpose,
while stripping away irrelevant detail.
• This stripping away of irrelevant detail is an
example of a process called abstraction.
Abstraction is a process of fitting a problem to
the most effective representation.
Problem
Abstraction
Fit-for-purpose
Representation
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Complex Representation Systems
• Few representations are independent and most belong
to some complex representation system which is
assembled out of simpler representations according to
predetermined rules (which govern both form and
content).
• Complex representation systems have two
characteristics:
1. The form is made up of several more basic parts; and
2. The meaning is constructed from the meanings of the more
basic parts in some systematic way.
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Complex representations are central to computing.
All computer languages, including protocols, formats
and programming languages are instances of
complex representation systems.
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Examples of complex representation systems
symbol & color
number
shape & color
symbol or number
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Representation Systems and Languages
• Where there is a predictable relationship between form
and content, the representation system becomes a
language. (e.g. traffic signs)
• Computer languages are not so different in principle
from human languages but they are a lot simpler and
they are never ambiguous. They are formal languages:
artificial languages where, given the right context, each
expression has exactly one meaning.
Examples of computer languages:
Protocols, programming languages and file
Representations (formats)
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Sharing and Formats
• Formats are formal languages used to
represent the detail of the input and output
associated with particular applications.
• Document formats are necessary for two
reasons:
1. They ensure consistency. Applications need to be
able to display a document in the same way every
time it is opened.
2. They enable sharing. If a format is shared, or
‘understood’ by two applications, then they can
exchange inputs and outputs.
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The power of formats
• Formats not only enable sharing: they can also
prevent it.
• Types of formats:
– Proprietary: belong to a particular software vendor.
(Microsoft Word)
– Public: free to all (HTML)
• There are two ways of achieving compatibility
between formats:
– Standards: emerge from a wide group of users
agreeing to use a particular format (de facto) or from
deliberate standardization.
– Conversion: translating between the formats.
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Filenames and extensions
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Windows systems list filenames in two
parts separated by a dot:
1. the name you provide when saving the file;
2. the file extension.
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A file extension is a relatively short
sequence of letters that denotes the
format (representation) the file is held in.
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Agenda
Essentials
Getting Help
Course Tour
Unit 1: Data and Information
Unit 2: Representation
□ What’s Next
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Unit 3: Quick glance
• Analogue, discrete, digital.
• Number Systems:
– Decimal (base 10)
– Binary (base 2)
– Hexadecimal (base 16)
• Conversions between analogue and
digital.
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2Do
• Read Unit 3 and practice number system
conversions.
• Read TMA 01 and attempt the questions
you can answer at this point.
• LMS: ask your questions, initiate and
participate in course-related discussions.
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Any
Questions
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