• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.143-146
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• 2000

This paper presents a study on design for the k-junction of a feeder waveguide with an inductive wall using FDTD method. The feed structure consists of a single waveguide plated on the same layer as radiating waveguide and is characterized by the unit divider, railed a $\pi$-Junction. This $\pi$-Junction with an inductive wall splits part of the power into two branch waveguide through one coupling window, and can excite densely arrayed waveguide at equal phase and amplitude. The power dividing characteristics of a $\pi$ -Junction obtained by FDTD method are compared with one of Galerkin's method of moments. The scattering matrices a $\pi$ -junction calculated by FDTD method are realized.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1086-1089
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• 2003

We investigated the electro-optical (EO) performances of the super twisted nematic liquid crystal display (STN-LCD) on the polyimide (PI) surface using polymer film. Monodomain alignment of the plastic STN-LCD can be observed. A stable voltage-transmittance (V-T) curve of the plastic STN-LCD was observed on the polyimide (PI) surfaces using polymer film. Also, a faster response time for the plastic STN-LCD on the polyimide (PI) surfaces using polymer film can be achieved. Therefore, the EO performances of the plastic STN-LCD on the polyimide (PI) surfaces using polymer film is almost the same as that of the glass STN-LCD on a polyimide (PI) surface.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.326-328
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• 2009

we an autotuning algorithm for PI controller with unknown plant. The proposed algorithm uses a saturation function and time delay element as a test signal. Since the integral element of PI controller reduces a phase margin and amplitude margin in the closed loop system, the closed loop system could be resulted in unstable with PI controller, To avoid unstable in the closed loop system with PI controller, the proposed algorithm identifies one point information in the 3rd quadrant of Nyquist plot with a time delay element. The proposed method improves an accuracy of one point identified information with one saturation function.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.9
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• pp.1177-1183
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• 1995

This paper proposes a new modulation scheme of $\pi$/4-DQPSK with stepped phase for a frequency selective fading channel. In the proposed modulation scheme, the phase of transmitted signal is shifted in the mid of a symbol duration in order to reduce the effect of multipath delay spread. It reduces the irreducible error of $\pi$/4-DQPSK over a frequency selective fading channel. It is shown that $\pi$/4-DQPSK with stepped phase achieves smaller average bit error probability than regular $\pi$/4- DQPSK by simulation. The former achieves much smaller average bit error probability than the latter for small TEX>${\tau}/T_{s}$.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.4
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• pp.332-337
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• 1997

디스크립터(Descriptor) 표현은 상태공간 표현을 확장시킨 일반적인 시스템의 기술방법으로 파라미터의 물리적인 구조를 보존하고 있으며, 임펄스를 포함한 현상을 기술할 수 있다. 또한, 대규모 시스템의 모델화가 용이하며, 프로퍼(Proper)이지 않은 시스템을 기술할 수 있고 구속조건을 가진 동적시스템의 기술이 가능하는 등의 특징을 지니고 있다. 그러나, 디스크립터 시스템의 해는 미분항을 포함하고 있으므로 노이즈 및 파라미터 변동에 대해서 매우 민감하여, 관측기설계시 강인(Robust)한 관측기설계가 요구된다. 본 논문에서는 디스크립터 시스템에 대해 로바스트 관측기의 일종인 비례적분(PI) 관측기의 설계에 대해서 논한다. 먼저, 디스크립터 시스템에 대한 PI 관측기의 존재조건을 유도하였으며, 체계적인 설계법을 보였다. 또한, PI 관측기의 존재조건이 Rosenbrock의 가관측 조건하에서 간단히 보여지며, 이것은 시스템 행렬의 Rank 조건에 의해 쉽게 구해질 수 있다.

• Communications of the Korean Mathematical Society
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• v.22 no.4
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• pp.527-534
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• 2007

This paper deals with the BK-AK property of the integrated rate space ${\int}{\ell}_{\pi}$. Importance of ${\delta}^{(k)}$ in this content is pointed out. We investigate a determining set for the integrated rate space ${\int}{\ell}_{\pi}$. The set of all infinite matrices transforming ${\int}{\ell}_{\pi}$, into BK-AK space Y is denoted $({\int}{\ell}_{\pi}:\;Y)$. We characterize the classes $({\int}{\ell}_{\pi}:\;Y)$. When $Y={\ell}_{\infty},\;c_0,\;c,\;{\ell}^p,\;bv,\;bv_0,\;bs,\;cs,\;{\ell}_p,\;{\ell}_{\pi}$. In summary we have the following table:

• Kyungpook Mathematical Journal
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• v.47 no.3
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• pp.363-372
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• 2007

An element $a$ in a ring R is called left morphic if $$R/Ra{\simeq_-}1(a)$$. A ring is called left morphic if every element is left morphic. In this paper, an element $a$ in a ring R is called left ${\pi}$-morphic (resp. left G-morphic) if there exists a positive number $n$ such that $a^n$ (resp. $a^n{\neq}0$) is left morphic. A ring R is called left ${\pi}$-morphic (resp. left G-morphic) if every element is left ${\pi}$-morphic (resp. left G-morphic). The Morita invariance of left ${\pi}$-morphic (resp. left G-morphic) rings is discussed. Several relevant properties are proved. In particular, it is shown that a left Noetherian ring R with $M_4(R)$ left G-morphic or $M_2(R)$ left morphic is QF. Some known results of left morphic rings are extended to left G-morphic rings and left ${\pi}$-morphic rings.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.1948-1959
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• 1999

The error rate performance of the proposed $\pi$/4-differential quadructure phase shift keying( $\pi$/4-DQPSK) with nonredundant multiple error correction is analyzed for Nakagami fading channel. The scheme for differential detection of $\pi$/4-QPSK with nonredundant multiple error correction utilizes the output that employ the received signal delayed by more than two time slots. It was observed that the performance increased as the error correction capability increased.

• Molecules and Cells
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• v.42 no.12
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• pp.828-835
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• 2019

PIWI Argonaute proteins and Piwi-interacting RNAs (piRNAs) are expressed in all animal species and play a critical role in cellular defense by inhibiting the activation of transposable elements in the germline. Recently, new evidence suggests that PIWI proteins and piRNAs also play important roles in various somatic tissues, including neurons. This review summarizes the neuronal functions of the PIWI-piRNA pathway in multiple animal species, including their involvement in axon regeneration, behavior, memory formation, and transgenerational epigenetic inheritance of adaptive memory. This review also discusses the consequences of dysregulation of neuronal PIWI-piRNA pathways in certain neurological disorders, including neurodevelopmental and neurodegenerative diseases. A full understanding of neuronal PIWI-piRNA pathways will ultimately provide novel insights into small RNA biology and could potentially provide precise targets for therapeutic applications.

• Korean Journal of Pharmacognosy
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• v.39 no.1
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• pp.50-55
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• 2008

"Ga Si O Gal Pi" is one of the Korean crude drugs used mainly to cure arthritis, acute gastritis, and beriberi. With regard to the botanical origin of "Ga Si O Gal Pi", it has been considered to be Acanthopanax species of Araliaceae, but there was no pharmacognostical confirmation on it. To clarify the botanical origin of "Ga Si O Gal Pi", the anatomical characteristics of the branch of Acanthopanax species growing wild in Korea and Japan, A. chiisanensis, A. divaricatus, A. koreanum, A. rufinerve, A. senticosus, A. seoulense, A. sessiliflorus, A. sieboldiaum were studied. As a result, it was clarified that "Ga Si O Gal Pi" was the branch and rarely the bark of branch of Acanthopanax senticosus.