Sensing and analysis of ambient contextual signals for discriminating between indoor and outdoor locations

A computer readable medium having computer-executable instructions for performing a method of determining context of a portable computing device, comprising:

• measuring a first parameter of a first context of the portable computing device;
• determining a second parameter of a second context of the portable computing device;
• and
• computing a probability inference based on the first and second parameters that the portable computing device moved from the first context to the second context and turning off a component of the device based on the inference;
• wherein location information is longitude/latitude data that is automatically accessed via a network and entered to facilitate determination of the device context.

A method of determining context of a portable computing device, comprising:

• determining a probability distribution of a first temperature of a first context of the portable computing device;
• measuring a second temperature of a second context of the portable computing device;
• and
• computing a probability inference based on the first and second temperatures that the portable computing device moved from the first context to the second context, wherein the probability inference is determined from at least one of a measured ambient temperature, and expected temperature inside a structure, and a temperature outside the structure derived from interpolation, and wherein the temperature outside the structure is derived by accessing longitude/latitude data.