A method for providing presence notification for PTT chat group communications includes a server receiving, from a communication device of a member of a chat group, a session initiation message to start a session for the PTT chat group. The multilayered structure is formed by coating the substrate layer with a spacerpattern layer that defines the predetermined region and pressing a cover layer against the spacepattern layer. The first-conductivity-type semiconductor layer includes a first region and a second region having a smaller height than the first region, and the first region overlaps with the contact electrode. In one embodiment, a plurality of sloped pair splitters is located between two of the retainers and includes a sharp point for cutting through insulation material on a pair of bonded wires. The frame is constructed so as to be convertible between a first configuration in which children can enter and play in a fully enclosed play area and a second configuration in which the play area is shaded, but open to the outside. The controller updates the third coefficient set based on the first, second and third filter outputs.