SIMS-201 What is the Information in the Information Revolution Information Age, Information Technology.

SIMS-201

What is the Information in the Information Revolution

Information Age, Information Technology

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Overview:

Introduction to information systems

Definition of information, messages and signals Examples and components of information systems Representing and Quantifying Information Analog and digital representation of signals Examples of analog and digital systems

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Information and Technology:

Information (Latin: idea, conception) Knowledge communicated or received concerning a

particular fact or circumstance Quantity needed by a system to complete a task

Technology (Greek: systematic treatment) The practical application of knowledge in a particular

area (ex: Engineering, science, etc..)

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Information Technology:According to WhatIs.com

IT (information technology) is a term that encompasses all forms of technology used to create, store, exchange, and use information in its various forms (business data, voice conversations, still images, motion pictures, multimedia presentations, and other forms, including those not yet conceived). It is a convenient term for including both telephony and computer technology in the same word. It is the technology that is driving what has often been called “The Information Revolution."

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Can you give some applications of IT in your everyday life?

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Historical Perspective

Information and its uses have always been an integral part of mankind

The very first indication of information communication/storage/retrieval is considered to be through cave drawings

Mankind later developed pictures, words and subsequently languages to more efficiently communicate with each other

Information sharing was made possible by the invention of the printing press in the early 1450’s by Johannes Gutenberg through the process of printing and distributing manuscripts

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The printing press is widely thought of as the origin of mass communication. It marked Western culture's first viable method of disseminating ideas and information from a single source to a large and far-ranging audience (Jones telecom & multimedia encyclopedia)

Significant developments in IT include: The telegraph by Samuel Morse in 1837 The Atlantic cable in 1858 The telephone by Alexander Graham Bell in 1876 Black and white TV in the 1940’s The ENIAC during WW-II The transistor by Bell lab scientists, replacing the vacuum tube in 1947 The integrated circuit by Jack Kilby in the late 1950’s The digital computer in the 1970’s The world wide web in 1993

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Information Technology Timeline

Egyptian Book of the Dead

Johannes Gutenberg

Telegraph KeyCirca 1840

Bell’s Telephone

1876

Flat Disk Gramophone

1887

75,000 B.C.Rock

Carvings

<4000 B.C.Hieroglyphi

cs2200 B.C.Papyrus

1500 B.C.Alphabetic

Writing

1450 A.D.Printing Press

1876 Telephon

e

1835Photograph

y

1895Silent Movies

1894 Wireless Telegraph

1840Telegraph

1876 Phonograph

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Information Technology Timeline (cont.)

Sputnik 1957

Fiber Optics 1977

Apple Mac1984

IBM PC1981

AOL has 200K Subscribers1992

1922 Radio

Broadcasts

1993 World Wide

Web

1965 Local

Cable TV

1973 Fax Machines

1980s Cell

Phones

1970s

VCR

1954 Transistor

Radio1983 CDs1977 Apple II

Home Computers

1990 Digital

Photography

1998 MP-3 (Compressed Sound

Files)

1940 Black and White TV

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The Information Age Information technology impacts every

aspect of our lives Work: IT industry-has become a major economic

sector Home: Information appliances, information utilities Leisure: audio/video, gaming Social: Web communities Financial: on-line trading and banking And so on…

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Benefits of Information Technology

Increased productivity Information flow Access to information (ex: the Internet) Access to personnel Data entry

Personal flexibility Virtual workplaces

Recreation Gaming

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Costs of Information Technology Equipment expense

Equipment obsolescence. Example: personal computers and CPU’s

Social costs Increased unemployment Job elimination Reduction in middle management

Personal costs Relearn new techniques and technologies Career obsolescence (ex: typing pools)

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Impact of Information Technology in the last 30 years

1970 1999

Cost of 1 MHz processing power

$7,601 $0.17

Cost of 1 Mbit memory $5,257 $0.17

Cost of sending a trillion bits of information

$150,000 $0.12

Source: The Economist, Sept. 23, 2000

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Information, Messages and Signals Some definitions Information: Knowledge communicated or received concerning

a particular fact or circumstance It is important to distinguish between information, message

and signal Signal: The actual entity (electrical, mechanical, etc) that is

transmitted from sender to receiver (ex: electrical signals, sound waves, optical pulses)

Message: The content of the signal (ex: binary representations, alphanumeric characters, speech etc.)

Information: The content of the message, i.e. the knowledge that is communicated/received by the message.

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As an example, consider the following scenario:

Yes, Mr. Faraday would like to meet you

at 4:00 p.m. today Sure, I’ll be there!

Electrical signal

Message (speech) Information Information

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Information SystemsDefinition: information system: 1. A system, whether automated or manual, that

comprises people, machines, and/or methods organized to collect, process, transmit, and disseminate data that represent user information. 2. Any communications and/or computer related equipment or interconnected system or subsystems of equipment that is used in the acquisition, storage, manipulation, management, movement, control, display, switching, interchange, transmission, or reception of voice and/or data, and includes software, firmware, and hardware. [NIS] 3. The entire infrastructure, organization, personnel, and components for the collection, processing, storage, transmission, display, dissemination, and disposition of information. [INFOSEC-99]

Source: telecom glossary (http://atis.org)

Examples of information systems include: The phonograph The telephone system (communication system)

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The Phonograph The phonograph, invented by

Thomas Edison in 1877 is a device that can record sounds and play them back

A diaphragm, which vibrates when sound waves are impinged on it, is connected to a stylus which can cut grooves in a solid material such as tin foil, wax, or vinyl. As the stylus is moved over the material, the vibration from the diaphragm produces a groove whose depth is proportional to the sound intensity

To play back, the stylus travels over the grooves of the recording, which vibrates the diaphragm and produces sound

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The Telephone System

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Components of Communication Systems

Input transducer: The device that converts a physical signal from the source to an electrical, mechanical or electromagnetic signal that is more suitable for communicating

Transmitter: The device that sends the transduced signal to the receiver

Transmission channel: The physical medium through which the signal is transmitted

Receiver: The device that recovers the transmitted signal from the channel

Output transducer: The device that converts the received signal back into a useful physical quantity

Exercise: Identify the above components for the phonograph and telephone system.

Please see Figure / Picture in the book

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Analog and Digital Information The term analog is used to refer to the natural world,

where time is continuous, and most parameters (like light, sound intensity, position, etc. ) can vary smoothly and continuously over some range, taking on an infinite number of possible values. Analog signals have properties of frequency, amplitude and phase

The term digital is used to refer to information representations for which both time and the value being measured move in discrete steps i.e. when there are a finite number of possible values

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Discrete and Continuous Representations of Temperature

Please see Figure / Picture in the book

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Examples of Analog and Digital Information

Analog: Sound waves Light intensity Temperature

Digital: The number of cars passing through a point on the freeway per

hour The flight time of a pilot per week

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Examples of Analog and Digital Devices:

Analog Microphone Cassette player Radio Vinyl record player Photograph camera

Digital: DVD Digital camera HDTV CD player New cell phones Fiber-optics

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The Natural World is Analog

This continuous acoustical waveform can be detected by a microphone and converted into an analogous electrical waveform for transmission over a circuit.

Human speech is an example of analog communication.Speech causes air to vibrate with varying amplitude (volume) and frequency (pitch).

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The Computer World is Digital Digital computers communicate using 2 discrete values. In other

words, they speak in binary (0 and 1). Of course, 0s and 1s are not literally transmitted

In an electrical network, variations in voltage represent one of the two discrete values.

In an optical network, pulses of light provide the discrete values. Recall that the 0s and 1s are the “message” and the pulses of light or

voltage variations are the “signal.” Two values in different combinations sufficiently encode text,

numbers, image, and video! Note that the telegraph was an early example of communications

using discrete, electrical pulse transmission.

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Digital vs. Analog

Analog signals are susceptible to distortion and inaccuracy due to other signals (interference)

Digital information can be compressed for efficient transmission and storage

Digital information can be encrypted for increased security and multiplexed for increased capacity

Digital technology is much cheaper Digital signals can be accurately reproduced Digital signals are easier to detect There is opportunity for error detection and correction in

digital technology

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Digital vs. Analog (cont..)

Analog signal

Noise

If an analog signal provides such a close representation of If an analog signal provides such a close representation of information sources, why do we use digital?information sources, why do we use digital?

Above is shown an analog signal on magnetic tape. Random fluctuations in the magnetic tape add “noise” to the signal. The tone-like noise components cannot be removed and become part of the subsequent versions of the analog signal.

Distorted Signal(unwanted electrical/electromagnetic energy)

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Restoration of digital signals stored on magnetic tape. Random fluctuations in the magnetic tape add noise to the digital signal. A processor, called a threshold detector, compares the signal to a threshold (dashed line) and decides that the data value is a 1 if the signal lies above the threshold, or a 0, otherwise.

Digital Signal Noise Distorted Signal

ThresholdDetector

Regenerated Digital SignalProcessor

Digital vs. Analog (cont..)