Abstract: Bids on a power trading market can be performed to improve an economic balance of power generation plants and power companies. In order to solve the above problems, in the present invention, a plant operation assistance system 10 that assists the operation of a thermal power plant 1101 and a pumped storage power plant 1102, which supply power to a power transmission network A, specifies a power amount that can be bid on a power trading market based on net reserve power of the power plants including another company's power generation plant 3001 when power sales on the power transmission network A drop, transmits bid data including the power amount to a power exchange system 20, and can transmit power from the power generation plant to a power transmission network B if contracted by the power exchange system 20.

Abstract: A diaphragm is provided with a plurality of thick portions radially from an inner circumferential side to an outer circumferential side. The thick portions are composed of at least two kinds having different lengths in a radiation direction and formed to be gradually thinner in the radiation direction from the inner circumferential side to the outer circumferential side. With this configuration, separate vibrations in the diaphragm can be suppressed. Further, a speaker device provided with the diaphragm having the above-described configuration can reproduce sounds faithfully in accordance with input signals.

Abstract: A speaker device includes a speaker unit configured to reproduce a bass sound and arranged so as to face down; a bottom plate formed in a rectangular shape as viewed in plane and arranged apart from the speaker unit such that an upper surface of the bottom plate opposes the speaker unit; and four legs attached to a lower surface of the bottom plate. The four legs are provided respectively on lines each connecting between an intersection point of diagonal lines of the lower surface of the bottom plate and a corner of the lower surface of the bottom plate in a region where a ratio of a distance between the intersection point and an attachment position of the leg to a distance between the intersection point and the corner is 0.5-0.7.

Abstract: A diaphragm is provided with a plurality of thick portions radially from an inner circumferential side to an outer circumferential side. The thick portions are composed of at least two kinds having different lengths in a radiation direction and formed to be gradually thinner in the radiation direction from the inner circumferential side to the outer circumferential side. With this configuration, separate vibrations in the diaphragm can be suppressed. Further, a speaker device provided with the diaphragm having the above-described configuration can reproduce sounds faithfully in accordance with input signals.