• 한국수학교육학회지시리즈A:수학교육
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• 제21권3호
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• pp.7-11
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• 1983

A measurable function f defined on a measurable subset A of the real line R is called pth power summable on A if │f│$^{p}$ is integrable on A and the set of all pth power summable functions on A is denoted by L$^{p}$ (A). For each member f in L$^{p}$ (A), we define ∥f∥$_{p}$ =(equation omitted) For real numbers p and q where (equation omitted) and (equation omitted), we discuss the Holder's inequality ∥fg∥$_1$<∥f∥$_{p}$ ∥g∥$_{q}$ , f$\in$L$^{p}$ (A), g$\in$L$^{q}$ (A) and the Minkowski inequality ∥＋g∥$_{p}$ <∥f∥$_{p}$ ＋∥g∥$_{p}$ , f,g$\in$L$^{p}$ (A). In this paper also discuss that L$_{p}$ (A) becomes a metric space with the metric $\rho$ : L$^{p}$ (A) $\times$L$^{p}$ (A) longrightarrow R where $\rho$(f,g)=∥f-g∥$_{p}$ , f,g$\in$L$^{p}$ (A). Then, in this paper prove the Riesz-Fischer theorem, i.e., the space L$^{p}$ (A) is complete and that the space L$^{p}$ (A) is separable.

• 건축역사연구
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• 제8권4호
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• pp.9-24
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• 1999

This study is on architectural characteristics of the existing ㅁ-shaped Yo-Sa with two stories in Buddhist temple. The Yo-Sa has had the function of space for not only monasticism but also living of buddhist priests and been one of the important spaces in Buddhist temple from the beginning of it. The Yo-Sa with two stories appeared mostly in the later Chosun Dynasty, so the origin of the Yo-Sa with two stories is thought that it might relate to the circumstances of temples in the later Chosun Dynasty. Having got in the period of Chosun Dynasty, Buddhism lost the power that he has enjoyed since Korea Dynasty was established and the economic power of temples as well. Because of a change for the worse, the Buddhist priests should manage with reduced income and combine many buildings with various functions into a singular to overcome their circumstances. Therefore a waekened economic power might be a primary factor which urged to change form of Yo-Sa from one-storied to two-storied. The ㅁ-shaped Yo-Sa with two stories have the Dae-Bang-Chae for worship, Seung-Bang for Buddhist's living room in the bottom floor and garnering spaces to store up the agricultural produce, miscellaneous article, etc in the top floor. The composition methods depend on the condition of the lay of land, intentional design, and so on. Therefore, the ㅁ-shped Yo-Sa with two stories shows the diversity of space composition and architectural characteristics.

• 한국항공우주학회지
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• 제31권8호
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• pp.91-98
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• 2003

발사체의 구조해석적인 측면에서 외부하중에 따른 발사체의 반응을 파악하는 것은 중요한 일이다. 기본적으로 발사체는 응력집중이나 내부 모듈간의 변위 간섭 등이 일어나지 않게 설계되어야한다. 이를 위해서는 외부하중에 관한 연구가 선행되어야 한다. 발사체에 작용하는 외부하중 중 연소 및 배기에 의해 발생하는 음향하중은 통계적 방법으로 다루어야 하는 랜덤 하중이다. 본 연구에서는 발사시 작용하는 음향하중에 대하여 하중 함수를 구성하고, 이를 이용하여 발사체의 하중해석을 수행하였다. 음원 할당 방법으로 음향하중을 추정하여 하중함수를 구성하였고, 이를 발사체의 유한요소 모델에 적용하였다. 응력해석을 이용하여 발사체의 구조 강성을 확인할 수 있었으며, 발사체 각 섹션의 경계면에서의 가속도 파워 스펙트럴 밀도함수를 구할 수 있었다. 이러한 결과를 이용하여 각 섹션의 진동 시험에 필요한 스펙을 도출할 수 있다.

• Journal of Applied and Pure Mathematics
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• 제5권3_4호
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• pp.129-164
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• 2023

The aim of this work is to present some interesting results on weighted ergodic functions and prove the existence and uniqueness of Stepanov-like pseudo almost automorphic solutions using the spectral decomposition of the phase space developed by Adimy and co-authors. We also give the next challenge of this work.

• 한국항공우주학회지
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• 제46권4호
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• pp.315-323
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• 2018

캔 위성은 음료수 캔 크기로 위성의 전반적인 시스템을 모사할 수 있어 교육프로그램 일환으로서 큰 각광을 받고 있으며, 국내에서는 2012년도부터 매년 캔 위성 경연대회가 개최되고 있다. 본 논문에서 제안된 캔 위성은 2015년도 국내 캔 위성 경연대회에 출전한 P.P.T CanSat으로 태양에너지 무선전송시스템 및 피에조, 풍력 에너지 하베스팅 시스템을 통해 생성된 전력으로 LED 점멸 및 MEMS기반의 센서 모듈을 자가 구동하는 것을 임무목표로 한다. 본 논문에서는 상기 캔 위성의 시스템 설계 및 주요 임무 탑재체 기능검증 시험, 비행시험, 실패원인 분석 및 재시험에 대해 기술하였다.

• 대한수학회지
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• 제55권1호
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• pp.101-129
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• 2018

From an analytical perspective, we introduce a sequence of Cartier operators that act on the field of formal Laurent series in one variable with coefficients in a field of positive characteristic p. In this work, we discover the binomial inversion formula between Hasse derivatives and Cartier operators, implying that Cartier operators can play a prominent role in various objects of study in function field arithmetic, as a suitable substitute for higher derivatives. For an applicable object, the Wronskian criteria associated with Cartier operators are introduced. These results stem from a careful study of two types of Cartier operators on the power series ring ${\mathbf{F}}_q$[[T]] in one variable T over a finite field ${\mathbf{F}}_q$ of q elements. Accordingly, we show that two sequences of Cartier operators are an orthonormal basis of the space of continuous ${\mathbf{F}}_q$-linear functions on ${\mathbf{F}}_q$[[T]]. According to the digit principle, every continuous function on ${\mathbf{F}}_q$[[T]] is uniquely written in terms of a q-adic extension of Cartier operators, with a closed-form of expansion coefficients for each of the two cases. Moreover, the p-adic analogues of Cartier operators are discussed as orthonormal bases for the space of continuous functions on ${\mathbf{Z}}_p$.

• 조명전기설비학회논문지
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• 제24권12호
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• pp.17-24
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• 2010

Recently, BIPV system which is good enough for maintenance and functions with the shading system is being used. However BIPV system with the shading system is different from existing PV module because of using flexible PV module. Prior to the application of the BIPV system, the clearness index was calculated by Erbs et al.(1982) and analyzed for the amount of electric power generation of sky irradiance with measured data. To predict electric lighting energy savings in daylit space, electric lighting power savings with amount of PV module electric power generation was compared by using Relux 2010 software in this study.

• 전기학회논문지P
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• 제63권4호
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• pp.333-338
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• 2014

This paper concerns the development of the transformer that can reduce harmonics supplied to the system if the output of photovoltaic inverter in the photovoltaic system is grid-connected, and suggests that problems of harmonics and power factor degradation in the grid-connected photovoltaic system can be improved. In this study, the burden of increasing the investment in new facilities and securing their installation space due to harmonics has been substantially eased through the development of a hybrid transformer possessing unbalanced function and harmonics reduction function using zig-zag coils, and most of all, it is expected that the development of such high efficiency hybrid transformer possessing functions of transformation and reducing harmonics can improve the power quality as well as prevent damages caused by harmonics, leading to suppress unnecessary loss of electric power and thereby contribute to energy savings.

• Journal of Astronomy and Space Sciences
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• 제35권4호
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• pp.253-261
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• 2018

Korea Astronomy and Space Science Institute (KASI) has been developing the space optical and laser tracking (SOLT) system for space geodesy, space situational awareness, and Korean space missions. The SOLT system comprises satellite laser ranging (SLR), adaptive optics (AO), and debris laser tracking (DLT) systems, which share numerous subsystems, such as an optical telescope and tracking mount. It is designed to be capable of laser ranging up to geosynchronous Earth orbit satellites with a laser retro-reflector array, space objects imaging brighter than magnitude 10, and laser tracking low Earth orbit space debris of uncooperative targets. For the realization of multiple functions in a novel configuration, the SOLT system employs a switching mirror that is installed inside the telescope pedestal and feeds the beam path to each system. The SLR and AO systems have already been established at the Geochang station, whereas the DLT system is currently under development and the AO system is being prepared for testing. In this study, the design and development of the SOLT system are addressed and the SLR data quality is evaluated compared to the International Laser Ranging Service (ILRS) tracking stations in terms of single-shot ranging precision. The analysis results indicate that the SLR system has a good ranging performance, to a few millimeters precision. Therefore, it is expected that the SLR system will not only play an important role as a member of the ILRS tracking network, but also contribute to future Korean space missions.

• Journal of Power Electronics
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• 제11권5호
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• pp.621-631
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• 2011

In space qualified DC-DC converters, optimization of the following electrical characteristics is of greater interest in comparison with other specifications; power loss/efficiency, output voltage ripple and volume/weight. The main goal of this paper is to present an appropriate solution for optimizing the above mentioned characteristics. For this purpose, a comprehensive power loss model of a DC-DC converter is fully developed. Proper models are also demonstrated for assessment of the output voltage ripple and the utilized transformer volume as the bulkiest component in a DC-DC converter. In order to provide a test bed for evaluation of the proposed models, a 50W push-pull DC-DC converter is designed and implemented. Finally, a novel cost function with three assigned weight functions is proposed in order to have a trade-off among the power loss, the output voltage ripple and the utilized transformer volume of the converter. The cost function is optimized for applications in which volume has the highest priority in comparison with power loss and ripple. The optimization results show that the transformer volume can be decreased by up to 51% and this result is verified by experimental results. The developed models and algorithms in this paper can be used for other DC-DC converter topologies with some minor modifications.