User talk:Ksaareme

Decimal <--> Hexadecimal

Hexadecimal	Decimal
    0	          0
    1	          1
    2	          2
    3	          3
    4	          4
    5	          5
    6	          6
    7	          7
    8	          8
    9	          9
    A	          10
    B	          11
    C	          12
    D	          13
    E	          14
    F	          15

Radio station is streaming MP3 audio at 192kbps. How many 500GB harddisks are required in order to archive 8 years of shows?

192 kbps = 192 000 bps 1 536 000 Bps

1500 Kb/s 1.46484375 MB/s

8 years = 2920 days = 70080 hours = 4204800 minutes = 252288000 seconds

172 228608 MB 16 8192 GB 336.384 500GB harddrives

Audio and Images

Audio
In digital audio, 44,100 Hz (alternately represented as 44.1 kHz) is a common sampling frequency. 
Analog audio is recorded by sampling it 44,100 times per second, and then these samples are used 
to reconstruct the audio signal when playing it back.

Images
PNG supports palette-based images (with palettes of 24-bit RGB or 32-bit RGBA colors), grayscale images (with or without alpha channel),
and full-color non-palette-based RGB[A] images (with or without alpha channel). PNG was designed for transferring images on the Internet,
not for professional-quality print graphics, and therefore does not support non-RGB color spaces such as CMYK.

JPEG/JFIF supports a maximum image size of 65,535×65,535 pixels, hence up to 4 gigapixels (for an aspect ratio of 1:1).
JPEG is a commonly used method of lossy compression for digital images, particularly for those images 
produced by digital photography. The degree of  compression can be adjusted, allowing a selectable tradeoff between storage size 
and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality.

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Compact Disc
Capacity 	Typically up to 700 MiB (up to 80 minutes audio)
Read mechanism 	780 nm wavelength (infrared and red edge) semiconductor laser, 1200 Kibit/s (1×)
Write mechanism 	1200 Kibit/s (1×)

Sampling 4 bit audio (2^4) gives us only 16 values, a far cry from 16-bit audio's 65,536! sample rate. 
Sample rate refers to the number of samples or measurements taken each  second from a recording. 
The typical CD sample rate is 44.1kHz, or 44,100 samples per second.

The bit rate is quantified using the bits per second unit bit/s, often in conjunction with an SI prefix such as "kilo" 
(1 kbit/s = 1000 bit/s), "mega" (1 Mbit/s = 1000 kbit/s), "giga" (1 Gbit/s = 1000 Mbit/s) or "tera" (1 Tbit/s = 1000 Gbit/s).
The non-standard abbreviation "bps" is often used to replace the standard symbol "bit/s", so that, for example, "1 Mbps" is
used to mean one million bits per second.
One byte per second (1 B/s) corresponds to 8 bit/s.

The RGB565 color format is the same as the RGB555 color format, except that 6 bits are used for 
the green value instead of 5. Therefore, all 16 bits are in use. The  organization of the pixels 
in the image buffer is from left to right and bottom up.
RGB888 --> 24-bit RGB (888)

Statistics Lecture One, 02.01.16

Primary Material:
Course Homepage: http://www.cs.ioc.ee/ITKStat
e-Book:           http://onlinestatbook.com/Online_Statistics_Education.pdf

Primary Software
R: https://www.r-project.org/

Introduction to Statistics
Descriptive statistics are used for presenting, organizing and summarizing data. 
Inferential statistics are about drawing conclusions about a population based on data observed in a sample.

Data Analysis Process
Data collection and preparation: Collect Data, prepare codebook, set up structure of data, enter data, screen data for errors
Exploration of data: Descriptive statistics, graphs
Analysis: Explore relationship between variables, compare groups

Python Lecture and Practicum Notes

Lecture 1

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Get an idea what to do by next week. Ideas:

// 1. Pyglet,pygame or kivy for a game or simulation:
    1.1. MP beat em' up
    1.2. Survival space sim, use webcam for dynamic view
    1.3. Planet rotation simulation
    Check out 
    http://nehe.gamedev.net/
    http://learnpythonthehardway.org/

// 2. WebApp
    2.1. Budget Management with a GUI

// Notes: 
   * Set up RPi web-server
   * Use XMind to map the idea first
   * Run basic website and deploy webapp to it. 
   * Check out RPi components and sensors. 
   * Buy a breadboard.
   * Check out Notepad++

Web App Programming Lecture and Practicum Notes

database: MySQL -- hosts data, indexed
php: Generates html, server side language
Apache: reads php files and over excecution to PHP interpreter
html: Structure and contents of the web page, (dom-tree)
css: styling information
javascript: client side programming, interacts with html
ubuntu: hosts the programs ( packetization, tcp segmentation )

HTTP requests
node.js -- php
ngix -- apache
nchan

http sockets, streaming push module
WAMP for Windows

http://enos.itcollege.ee/phpmyadmin/
PHP and APACHE is there

http://enos.itcollege.ee/~ksaareme to see changes

W3C validation https://validator.w3.org/

Node.js

Stuff about node.js.