Methods and apparatuses for operating a portable device based on an accelerometer are described. The zero-power, energy-harvesting computational modules are powered by radio signals received from an interrogator, and requests from the interrogator are authenticated using an encrypted challenge-response mechanism. The computer implemented method also includes assigning the digital image to a first face cluster of a plurality of face clusters when a difference between data descriptive of the first identification region and data descriptive of a face cluster identification region of the first face cluster satisfies a threshold. To prevent spilling, the vented drinking vessel may include one or more valves, such as a one-way valve removable located within the vent tube andor a check valve removable located within the curved straw, typically at the end of the straw.