SIMS-201 What is the Information in the Information Revolution Information Age, Information Technology
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
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..)
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."
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
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
Flat Disk Gramophone 1887 Telegraph Key Circa 1840 Johannes Gutenberg Bell’s Telephone 1876 Information Technology Timeline Egyptian Book of the Dead 1500 B.C. Alphabetic Writing <4000 B.C. Hieroglyphics 1835 Photography 1876 Telephone 1895 Silent Movies 75,000 B.C. Rock Carvings 2200 B.C. Papyrus 1450 A.D. Printing Press 1840 Telegraph 1876 Phonograph 1894 Wireless Telegraph
AOL has 200K Subscribers 1992 IBM PC 1981 Sputnik 1957 Fiber Optics 1977 Apple Mac 1984 Information Technology Timeline (cont.) 1993 World Wide Web 1954 Transistor Radio TODAY 1922 Radio Broadcasts 1970s VCR 1977 Apple II Home Computers 1983 CDs 1940 Black and White TV 1965 Local Cable TV 1973 Fax Machines 1980s Cell Phones 1990 Digital Photography 1998 MP-3 (Compressed Sound Files)
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…
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
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)
Impact of Information Technology in the last 30 years Source:The Economist, Sept. 23, 2000
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.
As an example, consider the following scenario: Information Message (speech) Information Yes, Mr. Faraday would like to meet you at 4:00 p.m. today Sure, I’ll be there! Electrical signal
Information Systems Definition: • 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)
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 The Phonograph
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
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 digitalis used to refer to information representations for which both time and the value being measured move in discretesteps i.e. when there are a finite number of possible values
Discrete and Continuous Representations of Temperature Please see Figure / Picture in the book
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 Examples of Analog and Digital Information
Analog Microphone Cassette player Radio Vinyl record player Photograph camera Digital: DVD Digital camera HDTV CD player New cell phones Fiber-optics Examples of Analog and Digital Devices:
The Natural World is Analog Human speech is an example of analog communication. Speech causes air to vibrate with varying amplitude (volume) and frequency (pitch). This continuous acoustical waveform can be detected by a microphone and converted into an analogous electrical waveform for transmission over a circuit.
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. Digital
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
Digital vs. Analog (cont..) If an analog signal provides such a close representation of information sources, why do we use digital? Noise • (unwanted electrical/ • electromagnetic energy) Analog signal Distorted Signal • 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.
Digital vs. Analog (cont..) Digital Signal Noise Distorted Signal Threshold Detector Regenerated Digital Signal Processor • 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.