Setup Dynamic DNS

Will likely sign-up with http://freedns.afraid.org/signup/.

Configure symhost to scan for wireless networks upon restart

Edit /etc/rc.local and add the following lines:

iwlist wlan0 scan

Using scp

The slow way

# -- Execute on local computer
# Copy hello.txt from local computer to remote home directory
$ scp -i skey.pem hello.txt ubuntu@ec2-54-218-73-84.us-west-2.compute.amazonaws.com:~/
# Copy hello.txt from local to remote home directory, renaming it foo.txt
$ scp -i skey.pem hello.txt ubuntu@ec2-54-218-73-84.us-west-2.compute.amazonaws.com:~/foo.txt
# Copying ~/foo.txt from remote to current local directory
$ scp -i skey.pem ubuntu@ec2-54-218-73-84.us-west-2.compute.amazonaws.com:~/foo.txt .
# Copying ~/foo.txt from remote to local directory cc, renaming it a.b
$ scp -i skey.pem ubuntu@ec2-54-218-73-84.us-west-2.compute.amazonaws.com:~/foo.txt cc/a.b

The fast way

First, setup the ~/.ssh/config file.

# -- Execute on local computer
# Copy hello.txt from local computer to remote home directory
$ scp hello.txt awshost1:~/

# Copy hello.txt from local to remote home directory, renaming it foo.txt
$ scp hello.txt awshost1:~/foo.txt

Setting up ssh config

Unwieldy SSH Execution

# -- Executed on local machine
# Login to AWS as the ubuntu user using your private key pair
$ cd downloads # or wherever your pem file is
$ ssh -i skey.pem ubuntu@ec2-54-218-73-84.us-west-2.compute.amazonaws.com

# Login to AWS as ubuntu using your private key pair and run uptime command
$ ssh -i skey.pem ubuntu@ec2-54-218-73-84.us-west-2.compute.amazonaws.com uptime

Setting up ~/.ssh/config

# -- Execute on local machine
$ mkdir -p ~/.ssh
$ cp ~/downloads/skey.pem ~/.ssh/
$ chmod 400 ~/.ssh/skey.pem
$ chmod 700 ~/.ssh
$ nano ~/.ssh/config # edit the file as shown below
$ cat ~/.ssh/config
Host awshost1
    HostName ec2-54-218-35-71.us-west-2.compute.amazonaws.com
    User ubuntu
    IdentityFile "~/.ssh/skey.pem"

Rapid SSH Execution

# -- Execute on local machine
# SSH using the ’awshost1’ alias defined in ~/.ssh/config
$ ssh awshost1
# SSH using an alias, run a command, and then exit
$ ssh awshost1 uptime

Install node and npm

# Update list of available packages
$ sudo apt-get update

# Install a special package
$ sudo apt-get install -y python-software-properties python g++ make

# Add a new repository for apt-get to search
$ sudo add-apt-repository ppa:chris-lea/node.js

# Update apt-get’s knowledge of which packages are where
$ sudo apt-get update

# Now install nodejs and npm
$ sudo apt-get install -y nodejs


# Check node and npm are installed
$ npm --version
1.2.32
$ node --version
v0.10.12

Setup git and heroku

# Execute these commands on your EC2 instance.
# Note that -qO- is not -q0-. O is the English letter, 0 is the number zero.

# 1) Install heroku and git
$ sudo apt-get install -y git-core
$ wget -qO- https://toolbelt.heroku.com/install-ubuntu.sh | sh
$ which git
$ which heroku
# 2) Login and set up your SSH keys
$ heroku login
$ ssh-keygen -t rsa
$ heroku keys:add

# 3) Clone a sample repo and push to heroku
$ git clone https://github.com/heroku/node-js-sample.git
$ cd node-js-sample
$ heroku create
$ git push heroku master

Simple ssh server and client setup on Ubuntu

See: http://www.cyberciti.biz/faq/ubuntu-linux-openssh-server-installation-and-configuration/

SSH Server and Client Installation

Type the following two command to install both ssh client and server:
# sudo apt-get install openssh-server openssh-client

SSHD Configuration & Commands
To be frank your server is ready by default. Just test it from your home computer or from same system with the command:
# ssh localhost
OR
# ssh user@your-server-ip-address

To stop ssh server, enter:
# sudo /etc/init.d/ssh stop

To start sshs server, enter:
# sudo /etc/init.d/ssh start

To restart ssh server, enter:
# sudo /etc/init.d/ssh restart

How do I use ssh client?

Assuming that your server hostname is userver.mydomain.com and username is vivek, you need to type the following command:
# ssh vivek@userver.mydomain.com

DJTube Design Concepts

Design Concepts

1. A series of images for animation
2. Animation playback speed
3. Synchronizing two audio loop - master loop determines loop of slave loop video and audio
4. graphics interaction - to determine if mouse hits a record

Implementation Techniques

1. Where to get images -- Internet Archive, access to huge array of copyright free video
2. Search for VJ Loops
3. Split video into individual frames using ImageSaver
4. .png files are transparent
5. current frame selects the frame

Synchronizing two audio loops - player 1 is master, player 2 is slave
player2.speed(player2.getLengthMs()/
              player1.getLengthMs());

Using speedAdjust variable to change speed of audio and video:
player1.speed(speedAdjust);
player2.speed(player2.getLengthMs()/
              player1.getLengthMs()*speedAdjust);
currentFrame = currentFrame + 1 * speedAdjust
// mouse interaction changes speedAdjust

Audio Concepts

Audio Concepts

Sample Rate - precision in time, horizontal
Bit Depth - precision in amplitude, vertical dimension

player.speed(1) // 1: normal speed, 2: double the speed
speed = map(mouseX, 0, width, 0, 2)

Audio Control

• speed
• stop/start

boolean buttonOn;
if (buttonOn) { fill(255,0,0) }
if (!buttonOn) { fill(,255,0) }

Image commands and concepts

Image commands

Pimage img = loadImage("file.png")
image(img, pos-x, pos-y, size-x, size-y)imageMode(CORNER);
    // CORNER -- Top left of image at pos-x, pos-y
    // CENTER -- Center of image at pos-x, pos-y

Layout Concepts

• margin
• layout in columns or rows
  

// Assuming imageMode(CENTER)
image(img, width/2, margin)
posX = width/2 - margin - img.width/2;   posY = height/2 + margin + img.height/2;
image(img, posX, posY)

Animation Concepts

• pausing -- use a boolean flag "playing"

boolean playing = false
playing = !playing;  // toggles playing state

Program Template

// Declarations
Pimage [] images; 
int currentPosition = 0;

// void setup()
images = loadImages("Animation_data/movie", ".jpg", 134);
size(images[0].width, images[0].height);

// void draw()
image(images[currentPosition], 0, 0);  // draw the current image
currentPosition += 1;                  // move to the next image
if(currentPosition >= images.length) 
   currentPosition = 0;                // when you get to the end, loop

Design of Sonic Painter

A few key design points that make Sonic Painter great:

• The key to making it look nice is about having really, really good sound and image integration, so that people really feel that it's interactive.
• And, also mapping information from one domain to another.
• What makes a really visual app is really, really good brushes
• Just because you've got only one input, doesn't mean you should only have those one inputs.
• You can use symmetry to create order out of something that doesn't look that ordered. The more layers of symmetry you add, the more people find it attractive

Basic idea of Sonic Painter:

• Draw shapes on the screen
• They slowly rub each other out
• There are different brushes
• As you make a gesture to draw a shape, it plays back and manipulates a sound.

The interactions in Sonic Painter (SP):
Between you and SP
Between objects in SP themselves

Color Design elements:

• mouse x-position => color red
• mouse y-position => color blue
• distance from some point e.g. center => green
• speed => alpha, lineWidth

Brush Design elements:

• size of circle changes with speed
• brush that generates more than one output 
• Symmetry - eight orders of symmetry!

Sound Design Elements

• contrasting sounds: ambient vs bells
• balance the sound volume player.volume(0.25)
• sound speed
• sound filter ... ambient sound "brighter" or "darker"

Other Design Techniques:

• mapping mouse position to color red 
• constraining variables e.g. lineWidth, constrain()

Where to get audio files?

1. Get them from freesound.org
2. Create them yourself using audacity

Enable Developer Mode on Android

On Android 2.2.1, go to
Settings > Applications > Development > USB debugging (Enabled)

Machine Learning Books

Machine Learning for Hackers
Machine Learning in Action
Programming Collective Intelligence

Machine Learning Skills

See http://www.quora.com/Machine-Learning/What-skills-are-needed-for-machine-learning-jobs

A decision tree to choose a Machine Learning algorithm

 

See the source.

Awesome course on Machine Learning

The Coursera course on Machine Learning by Andrew Ng is just awesome!