In one embodiment, a method includes extracting, by a processor, components from an audio signal to generate a modulating signal. In one aspect, a digital image is received and brightness of the digital image is determined. WLAN access points may be classified based on their impact on a user’s position, speed of travel, and direction of travel estimation accuracy in a WLAN positioning system. This program includes a third list of a second set of application programs and a fourth list of application program windows corresponding to the second list of application programs. Additionally, at least one of the first and second receiving regions includes a channel capable of receiving at least a portion of at least a partially planar material therein. For each variable in a term, the stores are updated with a change in the term for each of the allowable changes of the value while maintaining other variables constant.