Representing characters from some
input alphabet using another
Example: input characters from the Latin
alphabet, output strings of binary digits.
Fixed-length binary character code: for
an input alphabet of size n, re
DSS generally provide support for unstructured, or semi-structured decisions (decisions that
cannot be described in detail).
DSS problems are often characterized by incomplete or uncertain knowledge, or the use of
Dhaval S Chokshi
Krishna U Patel
Prof. Rajan Datt
This Seminar Includes
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V I RT U A L
1 5 M C A 0 1 1 D H AVA L C H O K S H I
O P E R AT I N G S Y S T E M
WHAT IS FILE SYSTEM?
Afilesystemis the methods and data
structures that an operatingsystemuses
to keep track offileson a disk or partition.
15MCA011 Dhaval Chokshi
15MCA021 Krishna Patel
Simple Mail Transfer Protocol
The actual mail transfer requires message transfer agents (MTAs). The protocol that
defines the MTA client and server in the Internet is called Simple Mail Transfer
Lempel-Ziv-Welch (LZW) Compression Algorithm
Introduction to the LZW Algorithm
Example 1: Encoding using LZW
Example 2: Decoding using LZW
LZW: Concluding Notes
Introduction to LZW
As mentioned earlier, static coding schemes require some
The next symbol can be statistically predicted
from the past.
Code with context
Code the difference
Move to front, then code
Goal of prediction
Does not use statistical knowledge of data.
Encoder: As the input is processed develop a
dictionary and transmit the index of strings
found in the dictionary.
Nevill-Manning and Witten, 1996.
Uses a context-free grammar (without
recursion) to represent a string.
The grammar is inferred from the string.
If there is structure and repetition in the string
Reals in Binary
Any real number x in the interval [0,1) can be
represented in binary as .b1b2. where bi is a
CSEP 590 - Lecture 3 - Autumn 2007
Adaptive Huffman Coding
Adaptive Huffman Coding
During the pass calculate the frequencies
Update the Huffman tree accordingly
Coder new Huffman tree computed after transmitting the
Decoder new Huf
Wavelet Transform Coding
A family of transformations that filters the data into
low resolution data plus detail data.
low pass filter