A semiconductor memory device includes a first ferromagnetic layer magnetically pinned and positioned within a first region of a substrate; a second ferromagnetic layer approximate the first ferromagnetic layer; and a barrier layer interposed between the first ferromagnetic layer and the first portion of the second ferromagnetic layer. The method includes receiving an input motion, determining an input motion model for the input motion sequence, and modifying an avatar motion model associated with the stored avatar to approximate the input motion model for the input motion sequence when the avatar motion model does not approximate the input motion model. The hinge coupling structures enables distance adjustment between the protective mask and the welder’s face in a state in which the head band is worn on the head, which provides more convenient wearing of the protective mask.