The present invention discloses a workshop unit for use as a grinding center that includes a support frame having a drive motor and a multi-station tool mounted thereto. A compound aircraft has features of both a helicopter and a fixed wing aircraft and provides redundant control options. However, in order to perform the link allocation in due consideration of the link status, the present invention uses a link database including various status information, such as an equipment confirmation flag, a block flag, a current status, the total call user number, and the current call user number. In response to the operation, the controller application produces music piece information including the artist name and the like based the tag information of the AV file. Color data compression may also be achieved by eliminating at least one color from the set of chosen palette colors used to render an image color that fails to exceed a specified threshold value. A distance L1 from an inner surface of the container to an inner surface of the shield member at an end surface of the container is approximately N2 times the wavelength of the electromagnetic field in an area surrounded by the end surface of the container, the electromagnetic field supplying means and the shield member.