Abstract: A system and method are disclosed for generating a photoacoustic spectrum in an open or closed environment with reduced noise. A source may emit a beam to a target substance coated on a detector that measures acoustic waves generated as a result of a light beam being absorbed by the target substance. By emitting a chopped/pulsed light beam to the target substance on the detector, it may be possible to determine the target's optical absorbance as the wavelength of light is changed. Rejection may decrease the intensity of the acoustic waves on the detector while absorption may increase the intensity. Accordingly, an identifying spectrum of the target may be made with the intensity variation of the detector as a function of illuminating wavelength.

Abstract: A method for communication among mobile units and vehicular communication apparatus make it possible to automatically establish connection with a party who can provide required information on the basis of an environment or condition change of a driver or a vehicle or in response to a driver's request so as to permit communication with the party. An inter-vehicle communication apparatus of a vehicle acquires information from other mobile units through physical networks while it is moving or stopped, and registers, in a member table, mobile units satisfying predetermined conditions on the basis of the acquired information as the members of different virtual logic networks according to the conditions. In such a state, the inter-vehicle communication apparatus selects one virtual logic network from among a plurality of virtual logic networks on the basis of an environment or condition change of a driver or a vehicle or in response to a driver's request so as to permit communication with the party.