4.Data.Representation - Data Representation With thanks to...

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1 Data Representation With thanks to Dr. Haipeng Guo Lecture 4
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2 Introductory Stuff r Have Fun! r Please turn off your phones! r r DO DO interact with me!
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3 Outline r Distinguish between analogue and digital information r Explain data compression and compression ratios r Examine the binary formats for negative values r Describe the characteristics of the ASCII and Unicode character sets r Explain the nature of sound and its representation r Explain how RGB values define a colour r Look at representing Audio Information r r Look at representing Video Information
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4 Data Representation r Data comes in many forms s Numbers: 235, 11.01, -24, … s Text: “hello, world!” “ 你好! s Audio: .mp3 s Images and graphics: .bmp, gif, JPEG s Video: .avi r All of the data is stored in computers as binary digits r Data must be represented in a way that s Captures the essence of the information s And in a form that is convenient for computer processing
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5 Data Compression r Data compression s Reduction in the amount of space needed to store a piece of data r Compression ratio s The size of the compressed data divided by the size of the original data r Data compression techniques can be s lossless , which means the data can be retrieved without any loss of the original information, s lossy , which means some information may be lost in the process of compaction
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6 WinRAR r Currently the best archiver r WinRAR Tutorial http://users.pandora.be/soulmaniacs/winrar.html
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7 Analogue and Digital Information r Computers are finite r Computer memory and other hardware devices have only so much room to store and manipulate a certain amount of data r The goal is to represent enough of the world to satisfy our computational needs and our senses of sight and sound
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8 Analogue and Digital Information r Information can be represented in one of two ways: analogue or digital Analogue data : A continuous representation, analogous to the actual information it represents Digital data : A discrete representation, breaking the information up into separate elements r A mercury thermometer is an analogue device r The mercury rises in a continuous flow in the tube in direct proportion to the temperature
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9 Analogue Data r A mercury thermometer is an analogue device. The mercury rises in a continuous flow in the tube in direct proportion to the temperature.
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10 Analogue and Digital Information r Computers, cannot work well with analogue information r So we digitize information by breaking it into pieces and representing those pieces separately r Why do we use binary? s
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This note was uploaded on 03/28/2010 for the course COMPUTER H 2012 taught by Professor Dave during the Spring '10 term at Quebec Abitibi-Temiscamingue.

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4.Data.Representation - Data Representation With thanks to...

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