• 대한산업공학회지
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• 제26권2호
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• pp.88-94
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• 2000

For efficient operation, vital hand controls must be easily controlled by the operator from his or her normal working position. The primary working area based on the operator-perceived working comfort was developed to serve as a design guideline to the control panel layout. Six male and four female subjects voluntarily participated in the experiment in which working comfort was measured for two types of controls - knob and lever. The operator-perceived working comfort was examined for the frontal and sagittal distances from the body center and the slope of a work surface. The response surface methodology using a central composite design was employed to develop a prediction model for operator's working comfort on each type of controls. The proposed working areas based on the actual working comfort of an operator avoided the dichotomy that considers only the reachability of control devices, and showed a distinct shape, when compared to the existing normal working areas following the Farley's concept. It was shown that the distance from the body to control devices and the slope of a work surface have a quadratic relationship to the working comfort, and that the most comfortable area for seated tasks is located at the distance of about 2∼4 cm in the sagittal direction and about 42∼43 cm in the frontal direction from the shoulder, respectively. It was also found that the working comfort varies within the working area even at the positions with an equal distance from the body. It is expected that the isocomfort working area generated in the study will be used as a useful guideline for control panel layout.

• 한국항만경제학회지
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• 제27권4호
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• pp.145-164
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• 2011

최근 동북아시아지역의 교역규모가 급성장함에 따라 동북아시아 경제권이 세계경제에서 점유하는 비중이 점차 늘어나고 있다. 이러한 대륙 국가들과의 주요 연결로서 가장 큰 구심점 역할을 하고 있는 것이 Trans Siberian Railway(TSR) 등이라고 할 수 있다. TSR 이용의 경우 국내 도로운송과 부산항과 극동 러시아 항만간 해상운송, 대륙횡단철도, 최종목적지 도착이후의 도로운송을 포함하고 있어 항공운송을 제외한 복합운송의 전 영역에 걸쳐 있으며 최근 들어 국내 철도 화물운송을 활성화시켜 대륙횡단철도와 연계하여 운영하는 것에 대한 방안도 활발하게 논의되고 있다. 따라서 본 연구는 첫째, 러시아 및 중앙아시아향(向) 화물 운송의 선봉장 역할을 하고 있는 우리나라 TSR Service Operator들의 특징 및 역할을 파악하고 둘째, TSR Service Operator의 SWOT 분석으로 대변되는 대내 외적인 환경 분석과 우리나라 TSR Service Operator의 현황을 분석하고 셋째, 이를 바탕으로 우리나라 TSR Service Operator가 지속적인 경쟁우위를 확보하고 유지할 수 있는 발전 방향을 제시하는데 그 목적이 있다.

• Korean Journal of Mathematics
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• 제27권4호
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• pp.1005-1025
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• 2019

The paper is devoted to study local convergence of a continuation method under the assumption of majorant conditions. The method is used to approximate a zero of an operator in Banach space and is of third order. It is seen that the famous Kantorovich-type and Smale-type conditions are special cases of our majorant conditions. This infers that our result is a generalized one in comparison to results based on Kantorovich-type and Smale-type conditions. Finally a number of numerical examples have been computed to show applicability of the convergence analysis.

• 대한수학회논문집
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• 제23권1호
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• pp.133-140
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• 2008

Let {${\xi}_k,\;k\;{\in}\;{\mathbb{Z}}$} be a strictly stationary associated sequence of H-valued random variables with $E{\xi}_k\;=\;0$ and $E{\parallel}{\xi}_k{\parallel}^2\;<\;{\infty}$ and {$a_k,\;k\;{\in}\;{\mathbb{Z}}$} a sequence of linear operators such that ${\sum}_{j=-{\infty}}^{\infty}\;{\parallel}a_j{\parallel}_{L(H)}\;<\;{\infty}$. For a linear process $X_k\;=\;{\sum}_{j=-{\infty}}^{\infty}\;a_j{\xi}_{k-j}$ we derive that {$X_k} fulfills the functional central limit theorem.

• 한국화재소방학회논문지
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• 제30권3호
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• pp.79-85
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• 2016

원자력발전소의 방화지역에서 전기적인 단락, 지락, 전기회로 개방 등의 전기 문제로 화재가 발생할 수 있다. 전기 화재가 발생할 경우 안전계통 및 관련기기의 안전정지 기능이 상실된다. 이러한 사고를 예방하기 위하여 안전계통은 다중성, 독립성으로 설계되어 있다. 그러나 케이블 화재시 운전원은 오동작, 잘못된 지시 및 계측으로 발전소 상황을 잘 못 판단하여 적절한 조치를 하지 못할 수 있다. 따라서 주제어실 화재시 케이블 기능상실온도에서 최소 운전원 조치 요구시간인 5분은 매우 중요하다. 본 논문에서 주제어실 화재시 케이블의 기능상실온도 시간을 분석하여 운전원 조치시간이 충분한지 평가하여 주제어실 화재에 대한 안전성을 확인하였다.

• 대한수학회지
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• 제44권3호
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• pp.627-645
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• 2007

We investigate the eigenvalues of the semi-circulant preconditioned matrix for the finite difference scheme corresponding to the second-order elliptic operator with the variable coefficients given by $L_vu\;:=-{\Delta}u+a(x,\;y)u_x+b(x,\;y)u_y+d(x,\;y)u$, where a and b are continuously differentiable functions and d is a positive bounded function. The semi-circulant preconditioning operator $L_cu$ is constructed by using the leading term of $L_vu$ plus the constant reaction term such that $L_cu\;:=-{\Delta}u+d_cu$. Using the field of values arguments, we show that the eigenvalues of the preconditioned matrix are clustered at some number. Some numerical evidences are also provided.

• Kyungpook Mathematical Journal
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• 제59권4호
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• pp.679-688
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• 2019

In the present note, we study some approximation properties of the Szász type operators based on Charlier polynomials introduced by S. Varma and F. Taşdelen (Math. Comput. Modelling, 56 (5-6) (2012) 108-112). We establish the rates of A-statistical convergence of these operators. Finally, we prove a Voronovskaja type approximation theorem and local approximation theorem via the concept of A-statistical convergence.

• Korean Journal of Mathematics
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• 제25권4호
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• pp.513-535
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• 2017

As a continuation to the study in [8, 12, 15, 17], we construct bi-conservative central normal (BCN) and bi-conservative asymptomatic normal (BAN) ruled surfaces in Euclidean 3-space ${\mathbb{E}}^3$. For such surfaces, local study is given and some examples are constructed using computer aided geometric design (CAGD).

• 대한수학회보
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• 제39권4호
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• pp.527-534
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• 2002

The weighted shifts have been made a central role in the study of κ-hyponormality for hyponormal and subnormal operators in discrete notion. In this note we discuss the κ-hyponormality of weighted translation semigroups with a symbol function in continuous notion.

• Kyungpook Mathematical Journal
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• 제57권2호
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• pp.233-244
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• 2017

Differential subordination and superordination results associated with a generalized Hurwitz-Lerch Zeta function in the open unit disk are obtained by investigating appropriate classes of admissible functions. In particular some inequalities for generalized Hurwitz-Lerch Zeta function are obtained.