• 대한전기학회논문지:전력기술부문A
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• 제55권12호
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• pp.536-543
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• 2006

This paper uses Monte Carlo technique, which is one of probabilistic methods of estimating the economical quantity of electric power generation in consideration of voltage stability in the aspect of power generation companies. In the power exchange system in Korea, when power generation companies participate in tenders for power generation capacity at the power exchange, they need to determine their power supply capacity considering the stability of electric power system. Thus, we purposed to propose an algorithm for estimating economical power generation capacity in theaspect of power generation companies, through which we can estimate the margin for voltage stability through P-V curve analysis by capacity according to the change of power generation capacity in a simulated system and to conduct Monte Carlo simulation in consideration of the margin

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.447-450
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• 2004

This paper presents the basic application idea of superconductor cable for voltage stability limited power system. In bulk power system, the transfer capability of transmission line is often limited by the voltage stability, and superconductor cable could be on of the countermeasure to enhance heat transfer limit as well as voltage stability limit. Steady state voltage stability approach by P-V curve is used to calculate the maximum transfer capability of initial system and superconductor applied system IEEE-14 bus system is used to demonstrate its applicability.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.7-9
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• 2001

Many developing countries has been voltage unstable and the inter- change capability in Korea is limited by voltage instability. In analyzing voltage stability, load model has been considered as constant power, but actual loads vary as voltage changes. In order to incorporating voltage-dependent load model. we need the low-side of P-V curve that can not be obtained by general load flow algorithm. This paper proposes a modified GCF algorithm to obtain a full low-side of P-V curve and a accurate voltage assessment index considering load model. 5-bus sample system and 19-bus real power system are applied to simulate the proposed GCF. Also. the effect of reactive power compensation is illustrated in same systems.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1080-1084
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• 2011

Urban maglev should have such characteristics as not only environmentally friendliness and excellent driving capability but also curve negotiation performance because its routes have many sharp curves. Due to normal mechanism of urban maglev its relative displacements of secondary spring are bigger than conventional railway vehicle and the centering force of levitation magnet is smaller than wheel-on-rail system. These features of maglev affect the curving negotiation and so the additional steering device is to be required on Urban maglev to improve the running performance at sharp curve of less than about R50m. Some developed urban maglev had the passive steering device which consists of mechanical linkage or hydraulic cylinder and closed-route piping. But it has drawback as complexity of layout of understructure of vehicle and functional limitation of passive mechanism regarding transient curve. These demerits could be solved by using active steering system. But it has a weak point that an active device should have actuators and additional inverter or hydraulic power source. In this paper, the semi-active steering system for urban maglev is to be introduced.

• 한국구조물진단유지관리공학회 논문집
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• 제10권4호
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• pp.135-144
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• 2006

지진에 대한 구조물의 특성, 지반과의 상호작용, 현장 조건 등의 예측에 다수의 불확실성이 존재하는 경우 그 취약성 또는 손상도를 평가하는 방법이 필요하다. 본 연구에서는 범용구조해석 프로그램과 일반적인 확률밀도함수를 사용하여 면진 콘크리트 교량의 손상도 곡선을 구하는 방법을 제시하였으며, 제시된 방법을 교량에 적용하여 교량의 손상도를 평가하였다. 손상도 곡선을 작성하는 데에는 2변수를 갖는 대수정규분포를 사용하였으며, 지진의 여러 특성인 최대지반가속도(PGA), 최대지반속도(PGV), 스펙트럼가속도(SA), 스펙트럼속도(SV), 스펙트럼강도(SI) 등에 대해 납 면진받침(LRB)이 설치된 면진교량의 손상도 곡선을 구하였다. 또한 손상도 곡선의 합성 방법을 사용하여 합성된 면진교량의 손상도 곡선을 유도하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.24-30
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• 2008

One of the characteristics of the Maglev Train is the prominent capability of upgoing. Maglev train with the aim of longitudinal slope 7/100 is under development by the Center for Urban Maglev Program in Korea. To realize these slope, vertical curves must be inserted before and after the slope. The inserted curve has the radius of 3,000m generally. The insertion of these vertical curve results in the additional differences between the girder upper face and the guide rail, and the alignments are controlled by cast in place concrete at present. In this study, for longitudinal curved route with longitudinal slope 6/100, the applicability of PSC-U type girder and precast deck was evaluated for the span length 25m, 30m and vertical curve radii with 3,000m and 1,500m with respect to longitudinal slope 6/100.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.400-401
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• 2019

본 논문에서는 전동기 제정수와 전압 및 전류제한 값에 따른 단상 영구자석 동기전동기의 능력곡선을 분석하였다. 역기전력 상수와 고정자 인덕턴스 및 전압 전류 제한값에 따라 영구자석 동기전동기의 능력곡선이 변하게 되며, 최대토크를 얻을 수 있는 인가전압의 크기 및 위상이 결정된다. 제안한 능력곡선의 분석방법을 통하여 얻은 최대토크에서의 인가전압을 컴퓨터 모의실험으로 검증하였다.

• Smart Structures and Systems
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• 제13권6호
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• pp.975-991
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• 2014

The objective of this study is to develop a reliable method for locating cracks in a beam using data fusion of fractal dimension features of operating deflection shapes. The Katz's fractal dimension curve of an operating deflection shape is used as a basic feature of damage. Like most available damage features, the Katz's fractal dimension curve has a notable limitation in characterizing damage: it is unresponsive to damage near the nodes of structural deformation responses, e.g., operating deflection shapes. To address this limitation, data fusion of Katz's fractal dimension curves of various operating deflection shapes is used to create a sophisticated fractal damage feature, the 'overall Katz's fractal dimension curve'. This overall Katz's fractal dimension curve has the distinctive capability of overcoming the nodal effect of operating deflection shapes so that it maximizes responsiveness to damage and reliability of damage localization. The method is applied to the detection of damage in numerical and experimental cases of cantilever beams with single/multiple cracks, with high-resolution operating deflection shapes acquired by a scanning laser vibrometer. Results show that the overall Katz's fractal dimension curve can locate single/multiple cracks in beams with significantly improved accuracy and reliability in comparison to the existing method. Data fusion of fractal dimension features of operating deflection shapes provides a viable strategy for identifying damage in beam-type structures, with robustness against node effects.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권6호
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• pp.484-488
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• 2006

Alteration of illumination with optimum carbon dioxide fixation-based curve in this research successfully enhanced the $CO_{2}-fixation\;(q_CO_{2}$ capability of Chlorella vulgaris Buitenzorg cultivated in a bubble column photo bioreactor. The level of $CO_{2}$ fixation was up to 1.91 times that observed from cultivation with intensification of illumination on an optimum growth-based curve. During 144 h of cultivation, alteration of light intensity on an optimum $CO_{2}-fixation-based$ curve produced a $q_CO_{2}$ of $12.8\;h^{-1}$. Meanwhile, alteration of light intensity with a growth-based curve only produced a $q_CO_{2}$ of $6.68\;h^{-1}$. Increases in light intensity based on a curve of optimum $CO_{2}-fixation$ produced a final cell concentration of about 5.78 g/L. Both cultivation methods were carried out under ambient pressure at a temperature of $29^{\circ}C$ with a superficial gas velocity of $2.4\;m/h(U_{G}$. Cells were grown on Beneck medium in a 1.0 L Bubble Column Photo bioreactor illuminated by a Phillips Halogen Lamp (20 W/12 V/50 Hz). The inlet gas had a carbon dioxide content of 10%.

• 한국정보통신학회논문지
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• 제12권1호
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• pp.1-9
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• 2008

소프트웨어의 테스트노력 곡선으로서 현재까지는 로지스틱 곡선이 가장 이상적인 것으로 연구되고 있다. 테스트 단계중에 소요되는 테스트노력의 양에 대한 결함 검출비를 현재의 결함 내용에 비례하는 것으로 가정하여 소프트웨어 신뢰도 성장 모델을 비동차 포아송 프로세스(NHPP)로 공식화하되, 이 모델을 이용하여 소프트웨어 신뢰도 척도에 대한 데이터 분석기법을 개발한다. 모든 소프트웨어 개발 환경에서 지금까지 제시된 여러 곡선 중 하나에 의해서 테스트노력 소요 곡선을 표현하는 것은 적절하지 못하다는 것이 밝혀지고 있다. 그러므로, 본 논문에서는 로지스틱 테스트노력 곡선이 소프트웨어의 개발/테스트 노력곡선으로 적절하게 표현될 수 있다는 것과 실제 데이터를 근거로 하여 적용하여서 예측성이 매우 좋은 능력을 가지고 있다는 것을 보이고자 한다.