Abstract: Upon receiving a request for distribution of content data, determination is made whether or not the transmission can be performed, based upon a transmission reservation table. If a user has specified the transmission point in time, a transmission device refers to the reservation state corresponding to the specified point in time, and if available, the transmission device makes a reservation for the specified transmission point in time. Otherwise, the transmission device makes a reservation for an available transmission point in time near the specified point in time, as appropriate. If the user has not specified the transmission point in time, the transmission device transmits the content data at an available point in time, as appropriate. If the transmission device cannot acquire predetermined information, and accordingly cannot determine the transmission point in time, the transmission device generates a schedule indicating that the transmission point in time has not been fixed.

Abstract: The compensation amount of the pressure for keeping the index of refraction of the gas constant is calculated on the basis of the pressures and the temperatures that have been measured at different time. Only the pressure of the gas will be varied in accordance with the calculated compensation value of the pressure, whereby the index of the gas can be maintained constant and the oscillation frequency can be kept constant as the consequence. The pressure corresponding to a desired sweeping oscillation frequency is also calculated using the measured pressures and temperatures. The pressure of the gas is varied on the basis of the result of calculation. Synchronously with the variation of the pressure of the gas, the cavity length and the angle of the frequency selecting element are compensated.

Abstract: In method and apparatus for measuring a refractive index and a thickness of a thin film formed on a substrate, the thin film has m (m.gtoreq.1) layers and a transparent uppermost layer is set as a first layer. A total of (3m+1) parameters include a refractive index n(0) of an incident medium, a refractive index n(j) (j=1 to m) of a j-th layer, absorption coefficients k(j) (j=2 to m) of second to m-th layers, a refractive index n(m+1) and an absorption coefficient k(m+1) of the substrate, and thicknesses d(j) (j=2 to m) of the second to m-th layers. Arbitrary one of the (3m+1) parameters is unknown and the other 3m parameters are known. This method and apparatus measure the unknown parameter. Monochromatic light having a wavelength is incident to the film having the m-layers at a predetermined incident angle from a first layer side in the incident medium to measure reflectances about S and P polarized light.