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48 Cards in this Set
- Front
- Back
Data
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Basic values or facts
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Information
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Data that has been organized and/or processed in a way that is useful in solving some kind of problem.
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Types of Information
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* Numbers
* Text * Audio * Images and graphics * Video |
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Data Compression
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Process of reducing the amount of space needed to store a piece of data.
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Bandwidth
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Restrictions that define the maximum number of bits or bytes that can be transmitted from one place to another in a fixed amount of time.
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Compression Ratio
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Gives an indication of how much compression occurs. It is the size of the compressed data divided by the size of the original data.
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Lossless Compression
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A data compression technique in which here is no loss of information.
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Lossy Compression
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A data compression technique in which there is a loss of information.
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Analog Data
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A continuous representation of data.
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Digital Data
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A discrete representation of data. That is, not continuous. This is the data represented in the computer.
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Digitize
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The act of break information down into discrete pieces
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Digital Signals
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Electronic signals used in the computer that have either a high or a low state, hence binary representation.
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Pulse-Code Modulations
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Variation in a signal that jumps sharply between two extremes.
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Reclock
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The act of reasserting an original digital signal before too much degradation occurs.
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Signed-Magnitude Representation
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Number representation in which the sign representes the ordering of the number (negative or positive) and the value represents the magnitude.
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Fixed-Sized Numbers
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A way to represent negative numbers as just integer values, where half of them represent negative numbers
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Two's Complement
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A representation of negative numbers such that the negative of 'I' is 2 raised to k minus I.
negative(I) = 2^k - I |
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Overflow
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A situation where a calculated value cannot fit into the number of digits reserved for it. Example of a problem with trying to map a infinite world on a finite machine.
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Radix Point
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The dot that separates the whole part from the fractional part in a real number in any base. Basically the decimal point.
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Decimal Places in Binary
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The positions to the right of the radix point in binary are the halves position (2^-1) or the quarters position (2^-2)
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Floating Point
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A way to represent real numbers in the computer. This is the formula:
sign * mantissa * 2^exp. Called floating point because the number of digits is fixed by the radix point floats. |
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Scientific Notation
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An alternative floating point representation.
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What is the continuous, analog, entity when representing text?
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The document a user is working on
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What are the discrete, or digital, elements when representing text?
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The separate characters that need to be represented and stored in the computer's memory.
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Word Processing
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Different than representing text, word procressing is what Word does--formatting and adding images and stuff.
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Character Set
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A list of the characters and the codes used to respresent each one.
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ASCII Character Set
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American Standard Code for Imformation Interchange. Originally used seven bits to represent each character, allowing for 128 unique characters.
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Check Bit
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Used in the original ASCII character set to help ensure proper data transmission.
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Latin-1 Extended ASCII Character Set
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Updated eight-bit version of the ASCII character set that represented 256 characters, accented letters, and special symbols.
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Unicode Character Set
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Another character set for international use. Represents characters from all languages using 16 bits per character. It is also flexible so that it can use more space per character if needed to represent additional characters. Unicode is a superset of ASCII - first 256 characters are the same so they can fit together.
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What are the three types of text compression?
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1. Keyword Encoding
2. Run-Length Encoding 3. Huffman Encoding |
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Keyword Encoding
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Replacing a frequently used word with a single character. To decompress the document, reverse the process.
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Limitations to Keyword Encoding
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1. The characters we use to encode the keywords cannot be part of the original text.
2. Uppercase and lowercase are represented differently so you'd need a different symbol 3. No gain from encoding one letter words. |
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Run-Length Encoding
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Replacing a long series of a repeated character with a count of the repetition.
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Flag Character
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Used in run-length encoding where a sequence of repeated characters is replaced with this flag character and followed by a digit indicating the number of times it's repeated.
Example: *A7 (* = flag character) |
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Huffman Encoding
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Uses a variable-length binary string to represent a character so that frequently used characters have short codes.
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Sampling
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Digitizing a sound signal by periodically measuring the voltage of the signal and recording the appropriate numeric value.
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RGB Color Representation in the Computer
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Red, green, blue values, which are actually three numbers that indicate the relative contribution of each of these three primary colors.
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Color Depth
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The amount of data that is used to represent a color.
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HiColor
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16-bit color depth.
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TrueColor
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24-bit color depth.
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Pixels
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Individual dots used to represent a picture; stands for picture elements.
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Resolution
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The number of pixels used to represent a picture
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Raster-Graphics format
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Storing image information pixel by pixel. Raster-graphics file formats include bitmap, GIF, and JPEG.
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Vector Graphics
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Representation of an image in terms of lines and shapes.
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Video Codec
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Methods used to shrink the size of a movie. Stands for Compressor/Decompressor.
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Temporal Compression
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Movie compression technique based on differences between consecutive frames.
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Spatial Compression
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Movie compression technique based on the same compression techniques used for still images.
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