Quick release bolt assembly included shank and head of larger cross-section than that of shank. The screw thread of shank is adapted to rotatably engage with a complementary screw thread in a nut. Disengagement means are adapted in use to disengage the head or the nut without rotation of the nut or shank. The disengagement means includes a material such as shape memory alloy or epoxy resin, adapted to change form to facilitate engagement when activated. Activation may take place by a direct power supply or remotely by a radio frequency, magnetic, ultrasonic or infra red signal. Bolt can be used for anchoring seat belts. Computer systems and methods for the identification of a target, including enquiring as to the status of the target and having means to command the target to change the status are also disclosed and claimed.