A floor latch assembly includes a mounting bracket secured to the seat cushion of an automotive seat. The rear-edge horizontal grooves are each a combination of a groove recessed portion provided with a predetermined depth in the blade outer-circumferential surface and a groove wrapping portion continuous with the groove recessed portion and provided at the terminal end of the blade rear-edge portion. The single optical element may have an integral sealing surface for sealable connection to the signal housing and no countersinking so that it is capable of manufacture by injection molding. The wavelet expansion coefficients are weighted based on at least the influence levels of the wavelet expansion coefficients to the spectrum. To make use of the content, the mobile station decrypts the content for use, and deletes the decrypted content once it has been used.