On an optical disk, video object sets to be reproduced and video title set information serving as management information on the video object sets have been stored. A system maintains a vacuum in the chamber and another system provides sputtering and reactive gases. In this method, uranium leaching efficiency can be maximized by adding sulfuric acid to the uranium ore while applying ultrasound thereto. The communicating section control groove is configured such that pressures of the respective compression rooms in starting to communicate and finishing communicating the both compression rooms on the external line side and on the internal line side and the back pressure become the same. The constant values are determined using the pixel data of the second number of sample points.