• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.322-323
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• 2010

본 논문은 2MW급 풍력시스템의 이중여자유도형 발전기(DFIG)를 제어하기 위한 PCS의 전력변환장치와 주변장치 및 제어기술에 대해서 기술한다. 최근 국내 뿐만 아니라 해외 전력회사에서는 계통전원 사고 시 풍력시스템이 계통연계를 유지하면서 계통의 전력품질에 기여할 수 있는 기능(FRT)을 요구하고 있다. FRT기능 구현을 위한 H/W와 제어 시퀀스를 소개한다.

• Honam Mathematical Journal
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• v.8 no.1
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• pp.51-74
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• 1986

The thery of measure is significant in that we extend from it to the theory of integration. AS specific metric outer measures we can take Hausdorff outer measure and Lebesgue-Stieltjes outer measure connecting measure with monotone functions.([12]) The purpose of this paper is to find some properties of Lebesgue-Stieltjes measure by extending it from $R^1$ to $R^n(n{\geq}1)$ $({\S}3)$ and differentiation of the integral defined by Borel measure $({\S}4)$. If in detail, as follows. We proved that if $_n{\lambda}_{f}^{\ast}$ is Lebesgue-Stieltjes outer measure defined on a finite monotone increasing function $f:R{\rightarrow}R$ with the right continuity, then $$_n{\lambda}_{f}^{\ast}(I)=\prod_{j=1}^{n}(f(b_j)-f(a_j))$$, where $I={(x_1,...,x_n){\mid}a_j$<$x_j{\leq}b_j,\;j=1,...,n}$. (Theorem 3.6). We've reached the conclusion of an extension of Lebesgue Differentiation Theorem in the course of proving that the class of continuous function on $R^n$ with compact support is dense in $L^p(d{\mu})$ ($1{\leq$}p<$\infty$) (Proposition 2.4). That is, if f is locally $\mu$-integrable on $R^n$, then $\lim_{h\to\0}\left(\frac{1}{{\mu}(Q_x(h))}\right)\int_{Qx(h)}f\;d{\mu}=f(x)\;a.e.(\mu)$.

• Bulletin of the Korean Mathematical Society
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• v.33 no.1
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• pp.107-110
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• 1996

Usng the Pochhammer symbol $(\lambda)_n$ given by $$ (1.1) (\lambda)_n = {1, if n = 0 {\lambda(\lambda + 1) \cdots (\lambda + n - 1), if n \in N = {1, 2, 3, \ldots}, $$ we define a general double hypergeometric series by [3, pp.27] $$ (1.2) F_{q:s;\upsilon}^{p:r;u} [\alpha_1, \ldots, \alpha_p : \gamma_1, \ldots, \gamma_r; \lambda_1, \ldots, \lambda_u;_{x,y}][\beta_1, \ldots, \beta_q : \delta_1, \ldots, \delta_s; \mu_1, \ldots, \mu_v; ] = \sum_{l,m = 0}^{\infty} \frac {\prod_{j=1}^{q} (\beta_j)_{l+m} \prod_{j=1}^{s} (\delta_j)_l \prod_{j=1}^{v} (\mu_j)_m)}{\prod_{j=1}^{p} (\alpha_j)_{l+m} \prod_{j=1}^{r} (\gamma_j)_l \prod_{j=1}^{u} (\lambda_j)_m} \frac{l!}{x^l} \frac{m!}{y^m} $$ provided that the double series converges.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.29 no.1
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• pp.185-193
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• 2003

• Bulletin of the Korean Mathematical Society
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• v.61 no.1
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• pp.273-280
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• 2024

Let I be an ideal of a commutative Noetherian semi-local ring R and M be an R-module. It is shown that if dim M ≤ 2 and Supp_R M ⊆ V (I), then M is I-weakly cofinite if (and only if) the R-modules Hom_R(R/I, M) and Ext¹_R(R/I, M) are weakly Laskerian. As a consequence of this result, it is shown that the category of all I-weakly cofinite modules X with dim X ≤ 2, forms an Abelian subcategory of the category of all R-modules. Finally, it is shown that if dim R/I ≤ 2, then for each pair of finitely generated R-modules M and N and each pair of the integers i, j ≥ 0, the R-modules Tor^R_i(N, H^j_I(M)) and Extⁱ_R(N, H^j_I(M)) are I-weakly cofinite.

• Bulletin of the Korean Mathematical Society
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• v.56 no.1
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• pp.57-71
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• 2019

Let R be an associative ring with identity, M a t.u.p. monoid with only one unit and ${\omega}:M{\rightarrow}End(R)$ a monoid homomorphism. Let R be a reversible, M-compatible ring and ${\alpha}=a_1g_1+{\cdots}+a_ng_n$ a non-zero element in skew monoid ring $R{\ast}M$. It is proved that if there exists a non-zero element ${\beta}=b_1h_1+{\cdots}+b_mh_m$ in $R{\ast}M$ with ${\alpha}{\beta}=c$ is a constant, then there exist $1{\leq}i_0{\leq}n$, $1{\leq}j_0{\leq}m$ such that $g_{i_0}=e=h_{j_0}$ and $a_{i_0}b_{j_0}=c$ and there exist elements a, $0{\neq}r$ in R with ${\alpha}r=ca$. As a consequence, it is proved that ${\alpha}{\in}R*M$ is unit if and only if there exists $1{\leq}i_0{\leq}n$ such that $g_{i_0}=e$, $a_{i_0}$ is unit and aj is nilpotent for each $j{\neq}i_0$, where R is a reversible or right duo ring. Furthermore, we determine the relation between clean and nil clean elements of R and those elements in skew monoid ring $R{\ast}M$, where R is a reversible or right duo ring.

• The Korea Swine Journal
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• v.12 no.4 s.128
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• pp.94-97
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• 1990

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.6
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• pp.539-546
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• 2016

In this paper, the effect of J-R curve changes on the determination of parameters in a failure model owing to the presence or absence of a side groove in a C(T) specimen is investigated. A stress-modified fracture strain model is implemented for FE damage simulations. C(T) specimens were taken from SA508 grade 1a low-alloy steel piping material, and some of them were processed with a side groove. Fracture toughness tests were performed at room temperature and at $316^{\circ}C$. The parameters of the failure model were determined by damage simulations using the J-R curves obtained from the tests. Finally, the results show that the determination of failure model parameters is not affected by variations in J-R curves owing to the presence or absence of a side groove.

• Journal of the Korean Magnetics Society
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• v.11 no.5
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• pp.202-210
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• 2001

Spin dependent tunneling (SDT) junction devices of Ta/NiFe/Ta/NiFe/FeMn/NiFe/AlOx/CoFe/NiFe/Al with in-situ naturally oxidized Al barrier were fabricated using ion beam deposition and dc sputtering in UHV chamber of 10$^{-9}$ Torr. The maximum tunneling magnetoresistance (TMR) and the product resistance by junction (R$_{j}$ A) are 16-17% and 50-60 $\Omega$${\mu}{\textrm}{m}$$^2$, respectively. The values of TMR and (R$_{j}$ A) with field annealing were slightly increased. The TMR and (R$_{j}$ A) dependence versus the junction area size was observed. These results were explained by using sheet resistance effect of bottom electrode and spin channel effects.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2013-2015
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• 1997

Elevator stops emergently when power failures happen during operation. In that case, the passenger should wait with frightened in the car untill they are rescued by repair man or power resumes. This paper describes an automatic landing device for power-failure(ALP) that consists of UPS and battery charge control system. The excellence of the ALP operation is verified by experiments in elevator test tower.