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The purpose of this paper is to reduce eddy current loss in a wire that is affected by an alternating field passing through it. This allows the efficiency of transformers to be upgraded and the quality factor in coils to be increased.

The use of a magnetoplated wire (MPW) is proposed to reduce eddy current loss in a wire. An MPW is a copper wire (COW) whose circumference is plated with a magnetic thin film. In additional, the theoretical equation for eddy current loss in an MPW is derived for ease of analysis.

The eddy current loss in an MPW is calculated as a function of the relative permeability and resistivity of its magnetic thin film to reduce the resistance due to the proximity effect of a coil. The eddy current loss in an MPW whose magnetic thin film has a relative permeability of 500 and a resistivity of 0.12 μΩm can be reduced to 4 percent that of COW at a frequency of 1 MHz.

The use of MPW can be expected to upgrade the efficiency of transformers and to increase the quality factor in coils.

User authentication is generally used to protect personal information such as phone numbers, photos and account information stored in a mobile device by limiting the user to a specific person, e.g. the owner of the device. Authentication methods with password, PIN, face recognition and fingerprint identification have been widely used; however, these methods have problems of difficulty in one-handed operation, vulnerability to shoulder hacking and illegal access using fingerprint with either super glue or facial portrait. From viewpoints of usability and safety, strong and uncomplicated method is required.

In this paper, a user authentication method is proposed based on grip gestures using pressure sensors mounted on the lateral and back sides of a mobile phone. Grip gesture is an operation of grasping a mobile phone, which is assumed to be done instead of conventional unlock procedure. Grip gesture can be performed with one hand. Moreover, it is hard to imitate grip gestures, as finger movements and grip force during a grip gesture are hardly seen by the others.

The feature values of grip force are experimentally investigated and the proposed method from viewpoint of error rate is evaluated. From the result, this method achieved 0.02 of equal error rate, which is equivalent to face recognition.

Many researches using pressure sensors to recognize grip pattern have been proposed thus far; however, the conventional works just recognize grip patterns and do not identify users, or need long pressure data to finish confident authentication. This proposed method authenticates users with a short grip gesture.