JLoader::register('HelperClassName', dirname(__FILE__) . DS . 'helpers' . DS . 'helper.php');
JLoader is a class that handles loading libraries or other files (like helpers)
register is a method in JLoader that register a class to autoload list. It accepts two parameters. The first one is the name of the class where in our example is HelperClassName. The second one is the location of the file.