A digital video signal processing device. The system includes an expansion device that embeds at least one internal peripheral without a controller andor at least one port for connecting an external peripheral. A spring member and a damper are each connected between the lower control arm and the side plate. The method comprises the following: indicate identification information on a tag regarding the piping structure; and attach the tag to the piping structure. A method for producing an ester compound, the method comprising the step of reacting an organic compound having at least one unsaturated carbon bond in the molecule, and a formic acid ester in the presence of a catalyst system containing: a ruthenium compound; a cobalt compound; and a halide salt. A speed switching device changes a rotational speed of the rotating body from the deployed position to the intermediate position different from that from the intermediate position to the standard position in a return rotational movement of the rotating body.