The present invention discloses processes for generating a hydrocarbon feedstock for biofuels synthesis from lignin via hydroprocessing. Consequently, the camera part follows the position of the user without using a large-scale follow-up mechanism, thereby making it possible to photograph the user at a good position. When an event occurs in the mobile terminal, the controller further processes the event and changes the display data of the screen image according to the event processing result, and displays the changed screen image during the specific state of the mobile terminal. The slave print device initiates updating the database of the master print device andor the server. The invention also features an operational system test method, comprising defining a fault model, inserting a test agent, identifying a memory area according to a test location, hooking the identified memory area, collecting test information, and removing the test agent.