• 한국정보통신학회논문지
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• 제19권6호
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• pp.1455-1461
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• 2015

마이크로 그리드는 기존의 대규모 전력망이 가진 여러 문제점을 해결할 수 있는 새로운 전력망 개념으로 세계적으로 국가차원에서 연구 및 개발 중이다. 이러한 배경에서 마이크로 그리드 내 장치 및 시스템 간 상호운영기술 및 신규시장 Enabler 확보를 위해 마이크로 그리드용 공통 플랫폼이 개발 중으로 이는 Third-Party 사업자에게 개방형 API 기능을 통해 전력정보를 제공하여 비즈니스 모델을 지원하도록 한다. 마이크로 그리드용 공용 플랫폼에 접속하여 전력 어플리케이션을 개발하고자하는 사업자는 서비스 개발 및 배포를 지원하는 통합 개발 환경이 필요하다. 이에 본 논문은 마이크로그리드용 공통플랫폼의 어플리케이션 개발 및 배포를 위한 PaaS(Platform as a Service) 형태의 서비스 개발도구를 제안한다.

• 조명전기설비학회논문지
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• 제19권7호
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• pp.60-66
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• 2005

본 연구에서는 단일전력단 Two-Switch Forward 컨버터에 관하여 논하였다. 최근 국제적으로 제정된 ICE 61000-3-2와 IEEE 519같은 규정에서 입력 전류에 대한 고조파 규제가 강화되면서 전원 공급 장치의 역률개선 회로가 필수적으로 되었다. 따라서 본 연구에서는 저전압 대전류 출력에 적합한 방안으로 단일전력단 Two-Switch Forward 컨버터 회로를 제안하고, 모드별 동작, 특성 및 설계에 관하여 논하였으며, MOSFET를 사용하여 200[W](5[V], 40[A])급 시작품을 제작, 100[kHz]에서 실험하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.112-115
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• 2001

This paper illustrates a new nodal effective load model for nodal probabilistic production cost simulation of the load point in a composite power system. The new effective load model includes capacities and uncertainties of generators as well as transmission lines. The CMELDC based on the new effective load model at HLII has been developed also. The CMELDC can be obtain from convolution integral processing of the outage capacity probabilistic distribution function of the fictitious generator and the original load duration curve given at the load point. It is expected that the new model for the CMELDC proposed. In this study will provide some solutions to many problems based on nodal and decentralized operation and control of an electric power systems under competition environment in future. The CMELDC based on the new model at HLII will extend the application areas of nodal probabilistic production cost simulation, outage cost assessment and reliability evaluation etc. at load points. The characteristics and effectiveness of this new model are illustrated by a case study of a test system.

• Smart Structures and Systems
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• 제18권4호
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• pp.755-786
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• 2016

The hygro-thermo-mechanical bending behavior of sigmoid functionally graded material (S-FGM) plate resting on variable two-parameter elastic foundations is discussed using a four-variable refined plate theory. The material characteristics are distributed within the thickness direction according to the two power law variation in terms of volume fractions of the constituents of the material. By employing a four variable refined plate model, both a trigonometric distribution of the transverse shear strains within the thickness and the zero traction boundary conditions on the top and bottom surfaces of the plate are respected without utilizing shear correction factors. The number of independent variables of the current formulation is four, as against five in other shear deformation models. The governing equations are deduced based on the four-variable refined plate theory incorporating the external load and hygro-thermal influences. The results of this work are compared with those of other shear deformation models. Various numerical examples introducing the influence of power-law index, plate aspect ratio, temperature difference, elastic foundation parameters, and side-to-thickness ratio on the static behavior of S-FGM plates are investigated.

• 대한임베디드공학회논문지
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• 제15권5호
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• pp.205-214
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• 2020

With the recent development of hardware and software technology, interest in the development of wearable devices is increasing. In particular, wearable devices require algorithms suitable for low-power and low-capacity embedded devices. Among them, there is an increasing demand for a signal compression algorithm that reduces communication overhead, in order to increase the efficiency of storage and transmission of electrocardiogram (ECG) signals requiring long-time measurement. Because normal beats occupy most of the signal with similar shapes, a high rate of signal compression is possible if normal beats are represented by a template. In this paper, we propose an algorithm for determining the normal beat template using the template cluster and Pearson similarity. Also, the template is expressed effectively as a few vertices through linear approximation algorithm. In experiment of Datum 234 of MIT-BIH arrhythmia database (MIT-BIH ADB) provided by Physionet, a compression ratio was 33.44:1, and an average distribution of root mean square error (RMSE) was 1.55%.

• 한국자동차공학회논문집
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• 제21권1호
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• pp.23-29
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• 2013

In recent years, development of energy conversion systems using hydrogen as an energy source has been accelerated globally. Even though hydrogen is an environment-friendly energy source, safety and effectiveness issues in storage, transportation, and usage of hydrogen should be clearly resolved in every application. Therefore, sensors for detecting hydrogen leakage, especially for fuel cell electric vehicles, should be designed to have much higher resolution and accuracy in comparison with conventional gas sensors. In this study, we conducted to determine the design parameters for the semiconductor hydrogen sensor with optimized sensing conditions under the thermal distribution characteristic and thermal transfer characteristic. The heat generation study on power supply voltage was studied for correlation analysis of thermal energy according to the power supply voltage variation from 1.0 voltage to 10.0 voltage every 0.5 voltage. And we studied for the temperature coefficient of resistance with hydrogen sensor.

• 한국전자통신학회논문지
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• 제9권6호
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• pp.641-647
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• 2014

독립형 태양광발전시스템은 배전선로와 계통 연계되지 않고 독립적으로 운영된다는 장점이 있어 시공설비가 간단하고 비용이 적게 드는 장점이 있지만 MPPT를 포함한 컨버터와 생산된 에너지를 배터리에 저장하기 위한 충전회로 및 배터리 매니징 회로가 요구된다. 기존의 대체에너지분야의 이용은 복합발전의 형태보다는 하나의 발전 형태를 주로 채택하고 있으나 태양광/풍력 복합발전시스템을 최적설계하고 배터리능력을 향상시켜 설치가격을 합리화 할 수 있는 통합형 제어시스템이 필요하다.

• International Journal of Fluid Machinery and Systems
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• 제4권1호
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• pp.150-160
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• 2011

This study focuses on the Achard turbine, a vertical axis, cross-flow, marine current turbine module. Similar modules can be superposed to form towers. A marine or river hydropower farm consists of a cluster of barges, each gathering several parallel rows of towers, running in stabilized current. Two-dimensional numerical modelling is performed in a horizontal cross-section of all towers, using FLUENT and COMSOL Multiphysics. Numerical models validation with experimental results is performed through the velocity distribution, depicted by Acoustic Doppler Velocimetry, in the wake of the middle turbine within a farm model. As long as the numerical flow in the wake fits the experiments, the numerical results for the power coefficient (turbine efficiency) are trustworthy. The overall farm efficiency, with respect to the spatial arrangement of the towers, was depicted by 2D modelling of the unsteady flow inside the farm, using COMSOL Multiphysics. Rows of overlapping parallel towers ensure the increase of global efficiency of the farm.

• 조명전기설비학회논문지
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• 제22권1호
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• pp.58-65
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• 2008

본 논문은 신뢰도 기반 유지보수(RCM : Reliability-Centered Maintenance) 계획에 의한 발전설비의 유지보수주기를 평가하고 있다. 유지보수주기는 발전설비의 안정성 및 비용을 결정하기 위한 기준으로 활용된다. 본 논문에서는 설비 수명평가를 통해 확률분포를 이용한 확률론적 FMECA(Failure Mode, Effects and Criticality Analysis)에 대해 논하고, 국내 발전 설비 중 비교적 평균수명이 짧은 복합화력 발전소를 선정하여 유지보수 주기를 평가하였다. 발전소 유지보수 평가는 향후 구조 개편된 전력시장에서 유지보수계획 수립 방법의 유용한 지표로 활용 가능할 것이다.

• 한국태양에너지학회 논문집
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• 제27권1호
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• pp.91-98
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• 2007

Perimeter zone is one of the weakest area in buildings and it makes an increase of heating and cooling loads, in addition to condensation or discomfort with cold-draft to residents in winter. Because of this, it needs to be reinforced by active systems. However, they use fossil fuel, and ultimately greenhouse effect is urged. Thus, we proposed BIPV system functioned as solar collector which can substitute active system. As an fundamental stage, heat balance equation in steady-state by Fortran was used not only, in winter for pre-heating effect and electric power capacity during the day, but also in summer, for the latter during the day and sky radiation effect during the night. Especially, we should have considered shading on PV by IES Suncast, since even a little bit of it makes the efficiency too low for the PV modules to work. As a result, in summer day, the PV panel should be tiled in 70 degrees to gain the most electric power. Moreover, we could verify that this model makes higher temperature and heat flux under 0.02 m/s. On the other hand, the PV had the high efficiency with high velocity because of cooling effect behind the PV. Therefore, we should regard the air current distribution later on.