definition data compression computer science

... single color. Our second way of classifying data compression methods is shown in Table 27- 1b. Most data compression programs operate by taking a group of data from the original file, compressing ... represent the information. Data compression is the general term for the various algorithms and programs developed to address this problem. A compression program is used to convert data from an easy-to-use ... established themselves as industry standards: LZW and JPEG. Data Compression Strategies Table 27-1 shows two different ways that data compression algorithms can be categorized. In (a), the methods...

Ngày tải lên: 13/09/2012, 09:50

Ngày tải lên: 13/09/2012, 10:21

... 3.5 In this problem, we will be reading in formatted data and generating a report. One of the common formats for interchange of formatted data is ’tab delimited’ where each line corresponds to ... characters. 4 Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science 6.087: Practical Programming in C IAP 2010 Problem Set 3 Control flow. Functions. ... First, the program reads a file containing words and their definitions into an easily searchable data structure. Then, the user can type a word, and the program will search the dictionary, and...

Ngày tải lên: 25/04/2013, 08:07

... Engineering and Computer Science 6.087: Practical Programming in C IAP 2010 Lab 2: Data compression In-Lab: Wednesday, January 20, 2010 Due: Monday, January 25, 2010 Overview Assume that the data ... symbols from a finite alphabet. Compression algorithms encode this data such that it can be transmitted/stored with minimum size. Huffman coding is a lossless data compression algorithm developed...

Ngày tải lên: 25/04/2013, 08:07

... using a database of 32 images with about 40,000 keypoints. Figure 10 shows how the matching reliability varies as a func- tion of database size. This figure was generated using a larger database ... matching descriptors in the database. The reason this line is flat is that the test was run over the full database for each value, while only varying the portion of the database used for distractors. ... keypoints in database (log scale) Matching location, scale, and orientation Nearest descriptor in database Figure 10: The dashed line shows the percent of keypoints correctly matched to a database...

Ngày tải lên: 13/12/2013, 16:15

... zeros. Dictionary-based compression methods exploit the fact that a typical data file is not random; it features patterns and repetitions. At any point during compression, the input file is divided into two parts, data ... knowledge of computer science; who know something about programming and data structures; who feel comfortable with terms such as bit, mega, ASCII, file, I/O,andbinary search;andwhowanttoknowhow data is ... involved. Variable-length codes are a natural choice for simple, effective compression of various types of data. Most types of data (such as text characters, pixels, and audio samples) are encoded...

Ngày tải lên: 14/12/2013, 15:15

... both compression and de- compression and has the added advantage that the code tables don’t have to be written on the compressed file. The compression performance, however, may suffer if the data being ... indicating mode 1, followed by the length LEN of the data, followed by LEN bytes of literal data. Notice that the maximum value of LEN is 65,535. 2. Compression with fixed code tables. Two code tables ... uncompressed data) . The Deflate decoder must be able to decode blocks of any size. Deflate offers three modes of compression, and each block can be in any mode. The modes are as follows: 1. No compression. ...

Ngày tải lên: 14/12/2013, 15:15

... which makes it so useful in data compression, is that it takes correlated input data and concentrates its energy in just the first few transform coefficients. If the input data consists of correlated ... most data compression methods that employ the DCT use this value of n. The following experiment illustrates the power of the DCT in one dimension. We start with the set of eight correlated data ... precisely reconstruct the original data (except for small errors caused by limited machine precision). Our goal, however, is to compress (with lossy compression) the data by quantizing the coefficients....

Ngày tải lên: 14/12/2013, 15:15

... user to adjust the amount of the data lost (and thus also the compression ratio) over a very wide range. Often, the eye cannot see any image degradation even at compression factors of 10 or 20. ... bitmap rows. JPEG has been designed as a compression method for continuous-tone images. The main goals of JPEG compression are the following: 1. High compression ratios, especially in cases where ... this corresponds to a compression factor of 64 ì 24/(46 ì 3) 11.13; very impressive! (Notice that the DC coefficient of 1118 has contributed 23 of the 46 bits. Subsequent data units encode the...

Ngày tải lên: 14/12/2013, 15:15

... in data compression. It discusses sources of data redundancies, correlation of data items, variable-length codes, the use of dictionaries, and the power of transforms. About a dozen specific compression ... kinds of data, not just numbers. Previous chapters dis- cussed digital images and methods for their compression, and this chapter concentrates on audio data. An important fact about audio compression ... watermark. 6 Audio Compression In the Introduction, it is mentioned that the electronic digital computer was originally conceived as a fast, reliable calculating machine. It did not take computer users...

Ngày tải lên: 14/12/2013, 15:15

... grayscale compression) , color space, 184 companding, 14 companding (audio compression) , 229–231 compression factor, 17, 273 compression gain, 17, 273 compression performance measures, 16–17 compression ... between pixels, 8, 22, 65 da Vinci, Leonardo (1452–1519), 178 data compression (approaches to), 21–58 data hiding (steganography), viii data structures, ix, 81, 273 Daubechies, Ingrid (1954–), 199 decoder, ... Department of Computer Science, University of Auckland, December. This is also available online. Fenwick, P. (1996b) Symbol Ranking Text Compression, Tech. Rep. 132, Dept. of Com- puter Science, University...

Ngày tải lên: 14/12/2013, 15:15

... (See also Zip.) Dictionary-Based Compression. Compression methods (Chapter 3) that save pieces of the data in a “dictionary” data structure. If a string of new data is identical to a piece that ... Joan L. Mitchell (1992) JPEG Still Image Data Compres- sion Standard, New York, Van Nostrand Reinhold. Phillips, Dwayne (1992) “LZW Data Compression, ” The Computer Application Journal Circuit Cellar ... nine bits. Since the uncoded data requires just two bits (01 or 10), the compression ratio is 9/2=4.5 (the compressed data is 4.5 times bigger than the original data; a significant expansion). ...

Ngày tải lên: 14/12/2013, 15:15

Ngày tải lên: 18/12/2013, 15:37

... marking your answers on the answer sheet. 7 COMPUTER SCIENCE TEST PRACTICE BOOK Range of Raw Scores* Needed to Earn Selected Scaled Scores on Three Computer Science Test Editions That Differ in Difficulty Raw ... Both the worksheet on page 48 and the table on page 49 use performance data from GRE Computer Science Test examinees. The data in the worksheet on page 48 are based on the performance of a sample ... other GRE Computer Science Test examinees, however, you will be able to determine your strengths and weaknesses and can then plan a program of study to prepare yourself for taking the GRE Computer Science...

Ngày tải lên: 17/01/2014, 05:20

... COMPUTING FUNDAMENTALS 2 This book is an introduction to computer science. Computer science is the study of computer hardware, algorithms, and data structures and how they fit together to provide information ... Cataloging-in-Publication Data Hughes, David (David John Frederick), 1952- Fundamentals of computer science using Java / David Hughes. p. cm. ISBN 0-7637-1761-4 1. Computer science. 2. Java (Computer program ... program applies the computer to a particular task. Instead of working on physical materials, computers work on data facts, figures, and ideas. Computers synthesize these data into information—reports,...

Ngày tải lên: 17/01/2014, 06:20

... subroot-> ;data = DataIn 3. return success 2. else if (DataIn.key < subroot-> ;data. key) 1. return recursive_Insert(subroot->left, DataIn) 3. else if (DataIn.key > subroot-> ;data. key) ... recursive_Insert(subroot->right, DataIn) 4. else 1. return duplicate_error 5. End recursive_Insert Faculty of Computer Science and Engineering Department of Computer Science 2/4 Return element ... (compute(a,n)>compute(a,n-1))?compute(a,n):compute(a,n-1) 3233 6,5,4 4,5,6 Faculty of Computer Science and Engineering Department of Computer Science 1/4 DATA STRUCTURES & ALGORITHMS Tutorial 3 Questions Recursion...

Ngày tải lên: 13/02/2014, 13:20

... Faculty of Computer Science and Engineering Department of Computer Science 2/3 Question 6. Suggest a data structure that supports the following operation ... { E data; Node left, right; } Node root; } Faculty of Computer Science and Engineering Department of Computer Science 3/3 Write a recursive method called isCompleteBinaryTree() ... 9. The following class definition will be used for the problem that follow: public class BinaryTree <E extends Comparable<E>> { private class Node { E data; Node left, right;...

Ngày tải lên: 13/02/2014, 13:20

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Ngày tải lên: 21/02/2014, 09:20