definition data compression computer science
Data Compression
Ngày tải lên :
13/09/2012, 09:50
... 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...
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Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science
Ngày tải lên :
25/04/2013, 08:07
... 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...
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Lab 2: Data compression
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... 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...
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Tài liệu Distinctive Image Features from Scale-Invariant Keypoints David G. Lowe Computer Science Department ppt
Ngày tải lên :
13/12/2013, 16:15
... 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...
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Tài liệu A Concise Introduction to Data Compression- P1 pdf
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14/12/2013, 15:15
... 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...
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Tài liệu A Concise Introduction to Data Compression- P2 ppt
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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. ...
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Tài liệu A Concise Introduction to Data Compression- P3 pptx
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....
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Tài liệu A Concise Introduction to Data Compression- P4 pptx
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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...
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Tài liệu A Concise Introduction to Data Compression- P5 docx
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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...
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Tài liệu A Concise Introduction to Data Compression- P6 pptx
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...
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Tài liệu A Concise Introduction to Data Compression- P7 doc
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).
...
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Tài liệu GRE_ Computer Science Test docx
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17/01/2014, 05:20
... 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...
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Tài liệu Fundamentals of Computer Science using Java doc
Ngày tải lên :
17/01/2014, 06:20
... 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,...
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Tài liệu Feaculty of Computer Science and Engineering Department of Computer Scienc Tutorial 3 Questions pdf
Ngày tải lên :
13/02/2014, 13:20
... 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...
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Tài liệu Feaculty of Computer Science and Engineering Department of Computer Scienc Tutorial 4 Questions pptx
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;...
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