A voice activity detection module analyzes a media file, such as an audio file or a video file, to determine whether one or more frames of the media file include speech. The scatterer irradiates near-field light to a recording medium, and the near-field light detection element detects an intensity change of the near-field light generated by a change of the dielectric constant of the recording medium based on an electrical conductivity change of the photoelectric conversion element. The mounting substrate includes a base body, first and second substrate electrodes. Additional image data associated with a surgical tool or a surgical plan may also be rendered on the device for planning andor training simulations. By curing the light-guide material, a light-guide board is formed, and the polarizer and the light-guide are integrated together. A building truss incorporating the double-hinged plate is provided which can be assembled and erected in a facilitated manner.