• Journal of Magnetics
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• v.20 no.4
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• pp.394-399
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• 2015

Electromagnetic Induction Launchers (EIL) have been receiving great attention due to their advantages of non-contact between the coils and a projectile. This paper describes the modeling and design of 3-stage EIL to accelerate a copper projectile of 50 kg with 290 mm diameter. Our EIL consists of three independent driving coils and pulsed power modules to generate separate driving currents. To find efficient acceleration conditions, the appropriate shape of the driving coils and the position of the projectile have been calculated by using a finite element analysis (FEA) method. The results showed that the projectile can be accelerated more effectively as the gap between the coils is smaller; a final velocity of 45 m/s was obtained. The acceleration efficiency was estimated to be 23.4% when a total electrical energy of 216 kJ was discharged.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.11
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• pp.1457-1462
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• 2020

There are dozens of applications on the smartphone. The service application that manages the loading, deletion, and deployment of these applications is called a smartphone launcher, and various launchers are used. Some of the existing launchers provide a function to automatically place icons by analyzing user application usage patterns. In this paper, we present a method of automatically arranging icons so that the icons are balanced on the smartphone screen. The usefulness of our method is illustrated by some exaples. In this case, it is proved that in an m × n screen layout with a height of m and a width of n, if n is an odd number, the entire screen can always be arranged in a balanced manner regardless of the n value by mathematical induction method.