A visual data transfer channel is established between a mobile device and a computing entity to facilitate a decoupled cryptographic scheme. Combined pressure and vertical particle velocity signals are generated by combining the recorded pressure and merged velocity signals. Because speakers use prosody to convey units of speech to listeners, the method and apparatus performs endpoint detection by extracting and interpreting the relevant prosodic properties of speech. The first tunneling barrier has a MR ratio that differs from a MR ratio of the second tunneling barrier. This invention achieves precise verification of radiation beam alignment with a radiation beam detection apparatus mounted on a gimbal assembly.