Some older work:

Joomla! 2.0 Architecture on "J and Beyond" 2011:

• Slides: www.slideshare.net/HermanPeeren/joomla20-architecture
• Video: http://vimeo.com/23724600

Some slides:

• Design Patterns Illustrated - May/June 2010. There also is a video (unfortunately without any slides in it) of my presentation at J and Beyond.
• Webservices: connecting Joomla! with other programs - May/June 2010. And the video of the presentation at J and Beyond (with slides on the video too...)
• Flash templates for joomla - June 2009

Articles (for Blaise Pascal Magazine):

• Design Patterns Illustrated (with some explanation) - May 2010
• Practical Database Normalisation - February 2008