The method measures the temperature, emissivity, and other properties of relatively smooth surfaces radiating thermal energy, and is especially adapted for monitoring semiconductor fabrication processes. In one implementation, a method includes forming a wireless link between a device and a first wireless receiver site, receiving a portion of a data set from the device, relinquishing the wireless link, and then transmitting the portion of the data set from the first wireless receiver site to a service provider. The sliding mode control computes a distance to a sliding surface, computes a reaching law gain, and processes the distance and reaching law gain to generate a sliding mode control action that is in absolute value less that a maximum desired feedback control action. The behaviometric server may be used to compare recorded behavior data and compare them to stored profiles of users in order to generate authentication information based on the comparison.