Embodiments of the invention provide methods and apparatus for recommending items from a catalog of items to a user by parsing the catalog of items into a plurality of catalog clusters of related items and recommending catalog items to the user from catalog clusters to which items previously preferred by the user belong. A semiconductor substrate is provided, in which two deep trenches having deep trench capacitors respectively are formed, and the deep trench capacitors are lower than a top surface of the semiconductor substrate. The alignment forming layer is obtained by polymerizing two or more reactive mesogens having light absorption peaks in different wavelengths from each other. A verification whether the portable electronic device is authorized to communicate with the wide area network at the enhanced data rate is then performed. Finally, the introduced first and second impurities are diffused by a heat treatment so as to form a sourcedrain region and a well region. The present resin composition comprises a novel fluorine-containing polymer containing repeating units represented by the general formulae and and having Mw of 1,000-50,000, a resin having an acid-unstable group, a radiation-sensitive acid generator, a nitrogen-containing compound and a solvent.