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SIMS-201
What is the Information in the Information Revolution
Information Age, Information Technology
2
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..)