A buoyancy-based lifting system can be dynamically controlled to lift, move, or hold a load an object of arbitrary size at a fixed depth. The aqueous dispersion primer based on a polymer for cement andor other subfloors is characterised in that it contains in an aqueous dispersion the following materials:a) \u226723% by weight of silanised styrene-acrylate copolymer andb) \u22677. The receiver is configured to receive a signal from radio frequency tag, and send the signal to the computing device. In another embodiment, the sounding packet is triggered by comparing measured correlations of channel characteristics against a programmable correlation threshold. At least one bearing for rotatably supporting the rotor is disposed radially inside the stator and between the permanent magnet for rotational driving and the member to be detected.