• Honam Mathematical Journal
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• v.30 no.1
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• pp.147-164
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• 2008

In the setting of the half-plane of the complex plane, we show that for r > $-{\frac{1}{2}}$, the dual space of the weighted Bergman spaces $B^{1,r}$ is the Bloch space and we introduce some operators. We also study Toeplitz and Hankel operators and we find some characterization of Hankel operators.

• Journal of the Chungcheong Mathematical Society
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• v.23 no.3
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• pp.453-461
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• 2010

We first introduce a space of homogeneous type X, and develop the theory of the tent spaces on the generalized upper half-space $X{\times}(0,{\infty})$. The goal of this paper is to study that every element of the tent spaces $T_{\Omega}^{p}$($X{\times}(0,{\infty})$, $0, can be decomposed into elementary particles which are called "atoms."

• Journal of Positioning, Navigation, and Timing
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• v.6 no.2
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• pp.71-78
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• 2017

The sidereal day of a Global Positioning System (GPS) satellite was intended to equal one half of a sidereal day of the Earth. However, the sidereal day of GPS satellites has become unequal to one half of a sidereal day of the Earth. This is fundamentally caused by the non-sphericity of the Earth and the gravity of the Moon. The difference between sidereal days of GPS satellites and the Earth is known as a sidereal shift. The details surrounding sidereal shifts and their origins have yet to be fully understood. We calculated the periodicity of sidereal shifts for GPS satellites using broadcast ephemeris data. To conduct a periodic analysis of the sidereal shift, we employ the Lomb-Scargle periodogram method. It shows that the orbit periods of GPS satellites have small-amplitude perturbations with a 13.6-day period. In addition, we compare the GPS satellite orbit periods with the periodicity of geomagnetic indices and the solar wind parameters to identify the cause of the perturbations. Our results suggest that the solar wind stream might also affect the 13.6-day period of the sidereal shifts.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.245-248
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• 2005

In this paper, small sized half-wavelength circular loop antenna which attached beneath a visor of helmet is designed and fabricated at the resonant frequency of 449MHz. To reduce the size of the antenna, double series-shorted stubs are inserted inside the loop for practical use of a vacant space of loop inside. Also, It is designed for the printed type to install the helmet easily. The size of antenna on helmet is reduced to 87.75%(diameter : 70mm, height :.36mm) compare with general type antenna(diameter : 200mm height 101mm). The return loss, -10dB bandwidth and gain are -13.2dB, 17.6MHz(3.9%), and -1.78dBd. And, radiation pattern is omni-directional pattern at H-plane. Therefore, it can be seen that the half-wavelength circular loop antenna using double series-shorted stubs is proper structure for the miniaturization and the installed antenna of the helmet.

• Structural Engineering and Mechanics
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• v.58 no.4
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• pp.613-625
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• 2016

Contact interaction of a beam (flexible element) with an elastic half-plane is considered, when a soft inhomogeneous (functionally graded) interlayer is present between them. The beam is bent under the action of a distributed load applied to the surface and a reaction of the elastic interlayer and the half-space. Solution of the contact problem is obtained for different values of thickness and parameters of inhomogeneity of the layer. The interlayer is assumed to be significantly softer than the underlying half-plane; case of 100 times difference in Young's moduli is considered as an example. The influence of the interlayer thickness and gradient of elastic properties on the distribution of the contact stresses under the beam is studied.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.162-169
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• 2014

The analysis and comparation of the half-coiled short-pitch windings with different phase belt are presented in the paper. The half-coiled short-pitch windings can supply the odd and even harmonics simultaneously, which can be applied in multiphase bearingless motor (MBLM). The space harmonic distribution of the half-coiled short-pitch windings with two kinds of phase belt is studied wi th respect to different coil pitch, and the suitable coil pitch can be selected from the analysis results to reduce the additional radial force and torque pulse. The two kinds of half-coiled short-pitch windings are applied to the five- and six-phase bearingless motor, and the comparation from the Finite Element Method (FEM) results shows that the winding with $2{\pi}/m$ phase belt is fit for the five phase bearingless motor and the winding with ${\pi}/m$ phase belt is suitable for the six phase bearingless motor. Finally, a five phase surface-mounted permanent magnet (PM) bearingless motor is built and the experimental results are presented to verify the validity and feasibility of the analysis. The results presented in this paper will give useful guidelines for design optimization of the MBLM.

• Journal of the Korean Institute of Rural Architecture
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• v.14 no.2
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• pp.1-10
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• 2012

The purpose of this study is to provide the method of saving the construction cost per unit area of the New Hanok using the inner space of a roof as a floor space with a structural modification of it's roof. The proportion of a roof of the Traditional Hanok accounts for about a half of it's elevation, so it is an essential element of it. But, compare to the whole construction cost of the Traditional Hanok, it costs over a half of expenses to build it. Recently, at the traditional building type, it is found that the inner space of a roof of it is used as a floor space with a structural modification of it's roof. It can be divided into two types, the storage type and the living type. The New Hanok at downtown can accommodate various new lifestyle, so the length of it's Yangtong is longer than that of the Traditional Hanok. When we adjust the proportion of the traditional Hanok to the New Hanok, the height of the column and the roof of the New Hanok becomes also higher than those of the traditional Hanok. So, using the upper part of the column and the roof of the New Hanok, we can make the inner space of a roof of the New Hanok as a floor space -like a bed room, tea room, personal work space and a storage- vertically connect with the 1st floor as the main living area. As a result, it is expected to save the unit construction cost of the New Hanok and has an extensity of space when we build the New Hanok at downtown.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.46.3-47
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• 2020

Variations in the brightness of asteroids are caused by their spins, irregular shapes and companions. Thus, in principle, the spin state and shape model of a single object or, a combined model of spins, shapes and mutual orbit of a multiple components can be constructed from the analysis of light curves obtained from the time-series photometry. Using ground- and space-based facilities, a number of time-series photometric observations of asteroids have been conducted to find the possible causes of their light variations. Nonetheless, only about 2% of the known asteroids have been confirmed for their rotation periods. Therefore, a follow-on systematic photometric survey of asteroids is essential. We started an asteroid light curve survey for this purpose using Korea Microlensing Telescope Network (KMTNet) during 199 nights between the second half of 2019 and the first half of 2020. We monitored within a 2° × 14° region of the sky per each night with 25 min cadences. In order to observe as many asteroids as possible with a single exposure, we mostly focus on the ecliptic plane. In our survey, 25,925 asteroids were observed and about 8,000 of them were confirmed for their rotation periods. In addition, using KMTNet's 24-hour continuous monitoring, we collected many composite light curves of slow rotating asteroids that were rarely obtained with previous observations. In this presentation, we will introduce the typical light curves of asteroids obtained from our survey and present a statistical analysis of spin states and shapes of the asteroids from this study.

• Journal of Applied and Pure Mathematics
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• v.5 no.3_4
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• pp.187-196
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• 2023

This study is about spin half add operations in 𝓑₂ and 𝓑₃. The burden of technological structures has increased due to the increase in the use of today's technological applications or the processes in the digital systems used. This has increased the importance of fast transactions and storage areas. For this, less transactions, more gain and storage space are foreseen. We have handle tit (triple digit) system instead of bit (binary digit). 729 is reached in 3⁶ in 𝓑₃ while 256 is reached with 2⁸ in 𝓑₂. The volume and number of transactions are shortened in 𝓑₃. The limited storage space at the maximum level is storaged. The logic connectors and the complement of an element in 𝓑₂ and the course of the connectors and the complements of the elements in 𝓑₃ are examined. "Carry" calculations in calculating addition and "borrow" in calculating difference are given in 𝓑₃. The logic structure 𝓑₂ is seen to embedded in the logic structure 𝓑₃. This situation enriches the logic structure. Some theorems and lemmas and properties in logic structure 𝓑₂ are extended to logic structure 𝓑₃.

• Bulletin of the Korean Mathematical Society
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• v.36 no.4
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• pp.701-706
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• 1999

A characterization of geodesic spheres in the simply connected space forms in terms of the ratio of the Gauss-Kronecker curvature and the (usual) mean curvature is given: An immersion of n dimensional compact oriented manifold without boundary into the n + 1 dimensional Euclidean space, hyperbolic space or open half sphere is a totally umbilicimmersion if the mean curvature $H_1$ does not vanish and the ratio $H_n$/$H_1$ of the Gauss-Kronecker curvature $H_n$ and $H_1$ is constant.