Clustering complexity

Here is a paper, which says "Clustering is difficult, only where it does not matter".

Speech Recognition and Hidden Markov Models

Putting up this link/thesis as a note.

Some Basic PHP Internals

http://stackoverflow.com/questions/971279/how-the-sausage-is-made-tour-of-apache-php-mysql-interaction

The above link led me to this, and from there info about the Zend Engine and PHP request life cycle.