<code:diesel /> /* PHP & MySQL Journal */

Most people are familiar with recommendation systems on websites, wherein after you select an item you are presented with a list of similar items other people purchased . Amazon being the popular one and also one of the first to use it. Below is shown a snapshot from Amazon.

Collaborative filtering algorithms work by searching a large group of users or items and finding a smaller llist from it with tastes similar to yours.

PHP is a wonderful dynamic language, and the addition of Unicode support, namespaces in the upcoming version 6 will make it even better.
If you are new to PHP or are thinking of moving to PHP form other language then the following list of books will provide you with the required knowledge to become a seasoned PHP programmer. Of course, the list is subjective and you may have a different list of books in mind.

Mark Woodman has created a nifty class which lets you query Google pagerank info in PHP 5 and above. The complete classes are available here.

The minimum classes required are ‘cacher.class.php‘ and ‘google_pagerank.class.php‘.

Sample code is shown below.

Using lines, points and other geometrical objects to visualize data has always fascinated me; specially time series. Time series charts let you visualize data points separated by time intervals.

The following image shows an example of a time series data representing the salary of software engineers for a particular duration.

MIT’s Simile project has a new addition to their open source tools, ‘Seek‘. Seek adds a faceted browsing feature for Thunderbird, which lets you search through email or RSS feeds easily.

A faceted classification scheme allows one to assign multiple classes to an object rather then a single predefined taxonomic class. Facets are more commonly used by web pages in navigation. Take an example of computer monitors. When you visit a website that sell monitors, you will usually see them classified by ‘Company’, ‘Screen size’, ‘Color’, Price’ etc. rather then a long list of monitors. All these are facets or dimensions of the product. One person may search by ‘Company’, another by ‘Price’.