Abstract: A continuous use authentication method includes: acquiring a normal state image and a current image for a user; determining an inferred classification state for the user from among a plurality of classification states by applying the normal state image and the current image to a low-depth inference model for the user; when the inferred classification state is included in an abnormality category, determining a high-depth inference model corresponding to the inferred classification state from among a plurality of high-depth inference models; and determining reliability of the inferred classification state by applying the current image to the high-depth inference model.

Abstract: A circuit board according to an embodiment includes an insulating layer including first to third regions; an outer circuit pattern disposed on upper surfaces of the first to third regions of the insulating layer, and a solder resist including a first part disposed on the first region of the insulating layer, a second part disposed on the second region, and a third part disposed on the third region, wherein the outer circuit pattern includes a first trace disposed on an upper surface of the first region of the insulating layer; a first pad disposed on an upper surface of the first region of the insulating layer; and a second trace disposed on an upper surface of the third region of the insulating layer; wherein an upper surface of the first part of the solder resist is positioned lower than an upper surface of the first trace; and a height of the first trace is different from a height of the first pad.