Quiz on Ch

[Pages:133]Quiz on Ch.2

Convert 201023 to decimal

Quiz on Ch.2

Convert the decimal number 51 to binary using repeated division.

Chapter 03 Data Representation

Data and Computers

Computers are multimedia devices, dealing with a vast array of information categories Computers store, present, and help us modify

? Numbers ? Text ? Audio ? Images and graphics ? Video ? Smell (machine olfaction!)

4

Data compression

Reduction in the amount of space (memory) needed to store the data Measured by the Compression ratio = The size of the compressed data divided by the size of the original data

Example: Two files are compressed with the ZIP utility: ? One is originally 200 MB, and becomes 150 MB after compression ? The other is originally 15 MB, and 11 MB after compression

Which file is better compressed?

5

Quiz

A video file is originally 3.5 GB long. We compress it to 490 MB. What is the compression ratio?

6

Data compression

The Compression ratio is always between 0 and 1 (between 0% and 100%)

Compression techniques can be Lossless the data can be retrieved without any loss of the original information Lossy some information may be lost in the process (but it doesn't matter for the purposes of the intended application)

7

Analog vs. Digital

Many quantities of interest in the real-world are infinite and continuous ? Zeno's paradox: "That which is in locomotion must arrive at the half-way stage before it arrives at the goal. " -- Aristotle, Physics VI:9

But computers are finite and discrete! How do we represent an infinite and continuous quantity in a computer?

Answer: We approximate represent only enough to satisfy our computational needs and our senses of sight and sound.

8

 ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download