A non-energy dissipating, curvature sensing device senses curvature variation of a sample and comprises an outer layer, an inner layer and at least one spacer. A system and method for purging the EGR system is provided. The polishing method includes performing a first polishing process of removing the metal film, after the first polishing process, performing a second polishing process of removing the barrier film, after the second polishing process, performing a third polishing process of polishing the insulating film. The method includes inserting first information of image processing parameters, which are used to print the document, into the document when printing the document, and optimizing second information of image processing parameters to be used for copying the document using the first information of image processing parameters inserted into the document when copying the document. The motor drives the first roller according to the first amount. In addition, by providing the connector terminal, it is possible to provide a socket that can similarly prevent conduction failure caused by foreign material.