• 대한수학회보
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• 제47권5호
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• pp.907-913
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• 2010

Let D be an integrally closed domain with quotient field K, * be a star operation on D, X, Y be indeterminates over D, $N_*\;=\;\{f\;{\in}\;D[X]|\;(c_D(f))^*\;=\;D\}$ and $R\;=\;D[X]_{N_*}$. Let b be the b-operation on R, and let $*_c$ be the star operation on D defined by $I^{*_c}\;=\;(ID[X]_{N_*})^b\;{\cap}\;K$. Finally, let Kr(R, b) (resp., Kr(D, $*_c$)) be the Kronecker function ring of R (resp., D) with respect to Y (resp., X, Y). In this paper, we show that Kr(R, b) $\subseteq$ Kr(D, $*_c$) and Kr(R, b) is a kfr with respect to K(Y) and X in the notion of [2]. We also prove that Kr(R, b) = Kr(D, $*_c$) if and only if D is a $P{\ast}MD$. As a corollary, we have that if D is not a $P{\ast}MD$, then Kr(R, b) is an example of a kfr with respect to K(Y) and X but not a Kronecker function ring with respect to K(Y) and X.

• 한국항공운항학회지
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• 제30권4호
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• pp.132-144
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• 2022

In response to the recent surge in aviation demand, major airport and aviation authorities continue to make efforts to formulate arrival procedures that take into account efficient aircraft separation, noise and environmental issues related to carbon (CO₂) emissions. In order to ensure efficient traffic control and environmental issues, as a result, a new concept Trombone, Point Merge, etc. have been introduced and widely used. However, these new concept incisions are becoming a factor that hinders operational efficiency and stability due to the restricted domestic airspace such as military airspace and excessive constraints of altitude, speed, etc. which do not reflect the concept of continuous descent operation and eventually needs to be modified to make continuous descent operation as feasible as possible. We herewith analyze and propose the way of improving flight safety and efficiency in the arrival operation procedure by supplementary modification which consequently contribute to the aviation industry international competitiveness.

• Korean Journal of Mathematics
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• 제20권2호
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• pp.185-191
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• 2012

Let D be an integral domain and SF(D) be the set of star operations of finite type on D. We show that if ${\mid}SF(D){\mid}$ < ${\infty}$, then every maximal ideal of D is a $t$-ideal. We give an example of integrally closed quasi-local domains D in which the maximal ideal is divisorial (so a $t$-ideal) but ${\mid}SF(D){\mid}={\infty}$. We also study the integrally closed domains D with ${\mid}SF(D){\mid}{\leq}2$.

• 한국정보과학회논문지:시스템및이론
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• 제26권4호
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• pp.389-405
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• 1999

본 논문에서는 상호 연결망의 노드를 행렬로 표현하고 행렬연산을 이용하여 에지를 정의한 새로운 상호 연결망으로 행렬-스타 그래프를 제안한다. 행렬-스타 그래프는 널리 알려진 스타 그래프를 일반화한 그래프이다. 먼저, 행렬-스타 그래프의 노드를 2 $\times$ n 행렬로 표현한 행렬-스타 그래프 MS2,n 에 대하여 주요 망 척도인 분지수, 연결도, 확장성, 대칭성, 리우팅 ,지름 방송등을 분석한다. 다음으로, 행렬-스타 그래프 MS2,n의 노드를 2차원과 3차원으로 일반화한 행렬-스타 그래크 MSk,n과 MS k,n,p를 정의하고 행렬-스타그래프 MSk,n,p 의 라우팅 알고리즘과 지름을 분석한다. 상호연결망의 중요 망 척도중 하나는 망 비용이고 상호연결망의 망 비용은 그 연결망의 분지수와 지름의 곱으로 정의된다. star 그래프는 다른 상호 연결망보다 작은 망 비용을 갖는다. 최근에 제안된 Macro-Star 그래픈 star 그래프에 비해 상대적으로 망 비용이 작은 값을 갖는 연결망이다. (n2)!개의 노드를 갖는 행렬-스타 그래프 MSk,k,k(k={{{{ `^{ 3} SQRT { n$^2$} }}}} )와 ((n-1)2 + 1)!개의 노드를 갖는 Macro-Star 그래프 MS(n-1, n-1)의 망 비용은 행렬-스타그래프 MSk,k,k(k={{{{ `^{ 3} SQRT { n$^2$} }}}})는 O(n2,7)이고, Macro-Star 그래프 MS(n-1 , n-1)은 O(n3) 이다. 이는 행렬-스타 그래프가 스타 그래프와 Macro-Star 그래프보다 망비용이 우수함을 의미한다.

• Korean Journal of Mathematics
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• 제20권4호
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• pp.371-379
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• 2012

Let D be an integral domain, $\bar{D}$ be the integral closure of D, * be a star operation of finite character on D, $*_w$ be the so-called $*_w$-operation on D induced by *, X be an indeterminate over D, $N_*=\{f{\in}D[X]{\mid}c(f)^*=D\}$, and $Kr(D,*)=\{0\}{\cup}\{\frac{f}{g}{\mid}0{\neq}f,\;g{\in}D[X]$ and there is an $0{\neq}h{\in}D[X]$ such that $(c(f)c(h))^*{\subseteq}(c(g)c(h))^*$}. In this paper, we show that D is a *-quasi-Pr$\ddot{u}$fer domain if and only if $\bar{D}[X]_{N_*}=Kr(D,*_w)$. As a corollary, we recover Fontana-Jara-Santos's result that D is a Pr$\ddot{u}$fer *-multiplication domain if and only if $D[X]_{N_*} = Kr(D,*_w)$.

• 한국항공운항학회지
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• 제31권1호
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• pp.79-91
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• 2023

In response to the recent surge in aviation demand, major airports and aviation authorities continue to make efforts to formulate arrival and approach procedures that take into account efficient aircraft separation, noise and environmental issues of carbon (CO2) emissions. In order to ensure efficient traffic control and environmental issues, as a result, a new concept Trombone, Point Merge, etc. have been introduced and widely used in the domestic airspace. However, these new concept procedures which do not properly reflect the characteristics of the aircraft operation performance and the FMS vertical descent guidance hinder flight efficiency as well as bring in turn negative factors such as level-off flight and the use of drag device at the busiest phase of the flight descent operation, like the Continuous Descent Operation (CDO). Accordingly, throughout modification the current Standard Terminal Arrival Route (STAR) and Instrument Approach Procedure(IAP) that reflect the aircraft descent performance and the FMS guidance, the flight operation safety and efficiency is expected to be improved eventually. We herewith analyze and propose the way of improving flight efficiency in the arrival operation procedure by supplementary modification which consequently contribute to the aviation industry international competitiveness.

• 한국광학회지
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• 제24권1호
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• pp.17-22
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• 2013

High performance plastic optical fiber (POF) $N{\times}N$ star couplers are implemented based on fusing and combining technology. A set of cladding-removed POFs are fused into a solid body by heating and pressing them together to form the transition region between the input and output sides. The operation principle of the proposed star coupler is explained based on ray optics. To demonstrate the performance of the device, $2{\times}2$, $4{\times}4$ and $6{\times}6$ type POF couplers were fabricated and characterized. Performances of the POF star couplers were evaluated in terms of the flatness of the coupling ratios and excess losses.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.775-778
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• 1992

In 1980, 154kV OF cable was installed at the Cheong-Pyeong pumped-storage power station. Effective head of this pumped-storage station is 250m between upper and lower re-servior and length of cable route is 750m. However, several failures have happened owing to steep slope during the operation. 154 kV XLPE cable was applied for this power station to eliminate a lack of stability on account of steep slope and successfully installed in 1991. Meanwhile, installation procedure brings about many problem to be solved. In this paper, we describe the counter measure of cable sliding phenomena caused by heat shrinkage as well as the method of installation of cable under the steep slope condition. And hereafter, we think this paper will be a good reference to design and installation of 154kV XLPE cables in steep slope turnnel at urban areas.

• 항공우주기술
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• 제11권2호
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• pp.87-95
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• 2012

본 기술논문에서는 고기동 고정밀 위성의 별 추적기 초기 점검 원격측정 데이터가 분석되었다. 최근에 발사된 위성은 고기동 고정밀 위성이므로 고도의 요구조건을 만족하기 위해 광학계, 전자부, 배플이 분리된 형태로 광학계 부분의 온도를 20 degC 근처로 유지하면서 저주파 오차 성능을 향상 시킨 프랑스 SODERN사의 SED36을 사용하였다. 본 논문에서는 위성으로부터 내려 받은 원격측정 데이터의 처리를 통해 초기 점검 상태, 요구 조건 만족 여부, 이상 현상 및 주요 임무 기동에서의 별 추적기 잡음각 성능 분석 결과를 제시하였다.

• Korean Journal of Mathematics
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• 제21권2호
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• pp.197-201
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• 2013

Let D be an integral domain with quotient field K, * a star-operation on D, $GV^*(D)$ the set of nonzero finitely generated ideals J of D such that $J_*=D$, and $*_{\omega}$ a star-operation on D defined by $I_{*_{\omega}}=\{x{\in}K{\mid}Jx{\subseteq}I\;for\;some\;J{\in}GV^*(D)\}$ for all nonzero fractional ideals I of D. In this article, we give a simple proof of Hilbert basis theorem for $*_{\omega}$-Noetherian domains.