A method is provided, in which a base station allocates pilot signals to mobile terminals in a cell, obtains CSI from uplink pilot signals transmitted by mobile terminals, uses the CSI to precode messages, and transmits the messages in conformance with a TDD protocol. A first wavelength tuning element is associated with each laser source and is adjusted over time so that each laser source maintains its targeted emission wavelength. The mat has a rigid fixing base, a flexible core and an outer skin. Several embodiments are disclosed for a laser system with single or multiple output beams both with similar or dissimilar characteristics. A novelty object is disposed around a section of the straw tube. A method for performing an operation for image information includes: displaying a plurality of sets of image information so as to allow a user to select predetermined image information; determining a display item to be displayed, based on attribute information that corresponds to the selected image information; and changing the displayed item to be displayed, based on a determination result.