• 한국해양학회지
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• 제19권1호
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• pp.18-23
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• 1984

타원형 섬에 의한 조석파의 산란 이론에 근거하여, 제주도 주변의 M$_{2}$ 반일주조 조석을 구명하였다. 제주도를 수심이 일정한 해양 가운데 놓여있는 타원형의 섬으로 근사화한 후, 입사파와 산란파의 진폭을 연안 경계조건와 7개 검조소의 조화상수에 대한 최소자승법을 통하여 결정하였다. 이와 같은 이론식에 근거하여 제주도 주변M$_{2}$조에 대한 조석도를 해석적으로 작성하였다.

• 한국안전학회지
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• 제21권2호
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• pp.1-6
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• 2006

It is well known that pipelines have the highest capacity and are the safest and least environmentally disruptive form of transporting oil and gas. However, pipeline damage caused by both internal and external corrosion is a major concern threatening the reliability of oil and gas transportation and the soundness of the pipeline structure. In this study, we estimate the allowable damage by comparing the ASTM B31G code to a modified theory considering diverse detailed corrosive forms. The ASTM B31 G code has been developed as the evaluation method for reliability and incident prevention of damaged pipelines based on the amount of loss due to corrosion and the yield strength of materials. Furthermore, we suggest a method for estimating the expected life span of used pipelines by utilizing the reliability method based on major variables such as the depth and length of damage and the corrosion rate affecting the life expectancy of the pipelines.

• 한국철도학회논문집
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• 제8권1호
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• pp.93-100
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• 2005

The turnout system is typical railway facility to be in the way of conventional railway line's speed-up. The KNR(Korean National Railroad) has a speed limit regulation (130km/h) for the passing the turnout to guarantee a safety. This research had been performed to confirm the propriety of this regulation by using experimental and analytical way before it was carried out. The reasonableness of the speed-limit regulation was judged base on the several experiments. It was proved that the regulation was not useless as it had been regarded and very important guide at least up to now.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.246-247
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• 2013

This paper investigates control algorithms for a doubly fed induction generator with a back-to-back three-level neutral-point clamped voltage source converter in medium voltage wind power system under unbalanced grid conditions. Control algorithms to compensate for unbalanced conditions have been investigated with respect to four performance factors; fault ride-through capability, instantaneous active power pulsation, harmonic distortions, and torque pulsation. The control algorithm having zero amplitude of torque ripple shows the most cost-effective performance concerning torque pulsation. The least active power pulsation is produced by control algorithm that nullifies the oscillating component of the instantaneous stator active and reactive power. Combination of these two control algorithms depending on the operating requirements and depth of grid unbalance presents most optimized performance factors under the generalized unbalanced operating conditions leading to high performance DFIG wind turbine system. The proposed control algorithms are verified through transient response in the simulation.

• 가정과삶의질연구
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• 제22권1호
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• pp.181-191
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• 2004

The purpose of this study was to examine the social support network for divorced single mother families. The data were gathered through in-depth interviews with seven divorced single mothers who had at least one school-age child. Qualitative analysis of data showed that divorced single mothers evaluated themselves based on other people's perception. There were mainly three different kinds of self-images, which were “a competent divorced woman,” “a bad child to my parents,” and “a socially weak person.” We also found that there were two factors that influenced the everyday lives of single mothers: all of them .;offered hardships in living as a divorced woman with children, and they also had to deal with the weakened solidarity with family of origin, relatives, and neighbors. Single mothers shared common problems yet their lifestyles and adjustment strategies were diverse. Therefore, diverse social welfare policies for education and counseling for single mothers are urgently needed to support and empower divorced single mothers.

• 한국산학기술학회논문지
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• 제17권1호
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• pp.304-314
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• 2016

본 연구는 암 병동에 근무하는 간호사의 공감피로 경험의 의미와 본질을 이해하기 위해 수행되었다. 연구 참여자는 암 병동 근무기간이 최소 6개월 이상인 11명을 대상으로 하였다. 심층면담을 실시하여 자료를 수집하였으며, Giorgi의 현상학적 방법으로 분석하였다. 연구결과 신체적으로 힘듦, 환자의 상황에 갇힌 마음, 암이라는 병 앞에서 무너짐, 되새겨지는 환자관련 기억, 변화된 자신의 모습을 발견함, 회복의 길을 찾아감의 6개의 범주로 도출되었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.273-274
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• 2012

This paper investigates control algorithms for a doubly fed induction generator(DFIG) with a back-to-back three-level neutral-point clamped voltage source converter in medium voltage wind power system under unbalanced grid conditions. Two different control algorithms to compensate for unbalanced conditions are proposed. Evaluation factors of control algorithm are fault ride-through(FRT) capability, efficiency, harmonic distortions and torque pulsation. Zero regulated negative sequence stator current control algorithm has the most effective performance concerning FRT capability and efficiency. Ripple-free control algorithm nullifies oscillation component of active power and reactive power. Ripple-free control algorithm shows the least harmonic distortions and torque pulsation. Combination of zero regulated negative sequence stator current and ripple-free control algorithm control algorithm depending on the operating requirements and depth of grid unbalance presents the most optimized performance factors under the generalized unbalanced operating conditions leading to high performance DFIG wind turbine system.

• 한국표면공학회지
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• 제31권5호
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• pp.245-250
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• 1998

There is clear pressing need to reduce bias field(Ha,) used on linear magenetomechanical resonator tag by at least a factor of two to allow low-bias operation near the frequency minimum since reducing Ha causes a dramatic increase in well depth, which implies increased stability. However, this makes it more difficult to maintain tight frequncy specs. It can be solved by a reduction of magnetomechanical coupling(k). We determined from an equivalent circuit model that optimal reduced, k, is near 0.3 Also, We determiend the material properties($lambda_s$, :saturated magenetostriction, $M_s$, and,$H_a$) that give k=0.3. From these evaluations, we suggested that on optimal comosition with adequate mathrial properties is $Fe_{55}Co_{15}Cr_6Nb_2B_{18}Si_4$.

• 지구물리와물리탐사
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• 제6권4호
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• pp.180-186
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• 2003

수평(HCP)및 수직동일면(VCP)배열을 사용하는 다중 주파수 소형루프 전자탐사 자료의 1차원 역산 프로그램을 개발하였다. 역산방법은 ACB 최소자승법을 사용하였으며, Jacobian 행렬을 해석적으로 계산하였다. 간단한 1차원 모델에 대한 이론자료를 계산하고, 동상 및 이상성분 자료를 사용하여 역산을 수행하였다. 역산 결과 동상 및 이상성분을 모두 사용할 경우 가장 정확하게 각 층의 전기전도도 및 심도를 추정하는 것으로 나타났다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2022년도 하계학술대회
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• pp.154-155
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• 2022

본 논문에서는 RGB-D 카메라 캘리브레이션의 결과를 개선하는 새로운 기법을 제안한다. 멀티 뷰 카메라 캘리브레이션은 카메라를 통해 획득한 이미지에서 특징점을 찾아 다른 카메라에서 촬영된 동일한 특징점을 기준으로 캘리브레이션을 진행하는 것이 일반적이다. 그러나 카메라를 통해 획득된 RGB-D 영상은 필연적으로 렌즈와 Depth senor에 의한 오차가 포함되기 때문에 정확한 캘리브레이션 결과를 획득하는 것은 어려운 과정이다. 본 논문에서는 이를 개선하기 위해 획득한 특징점을 기반으로 캘리브레이션을 진행한 후, 최소제곱법을 통해 각 특징점간의 거리가 최소가 되는 카메라 파라미터를 획득하여 결과를 개선하는 기법을 제안한다.