A computer-implemented method provides a job performance plan for a plurality of jobs to be performed at geographical locations. A first silicon nitride thin film and a second silicon nitride thin film are formed on opposite sides of the silicon substrate. The packing material is punched with a plurality of pinholes and has a water permeable rate of 13 to 81 millilitermin1 cm2 measured when head of water is 27 cm. Thus, it is possible to prevent generation of voltage fluctuation in the drive signal due to an electromotive force caused by a self-induction phenomenon of the inductor. The retrieval frame rate is then adjusted in accordance with the determined error.