• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2446-2448
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• 2001

In addition to the stabilization of electricity supply and the quality management of electricity, load balance has been an important strategy for achieving high quality load management. Among many techniques for load management, direct load management has been actively studied and applied for increasing the efficiency of power facility and suppressing peak load. In Korea, the highest peak load is demanded in summer rather than in winter, and almost 50% of the peak load comes from cooling load. Currently, applicable systems are limited to air conditioners that have the cooling capacity less than 2kW. This paper describes the development of remote controlled air conditioners and the result of the field test of the new type air conditioner. The technical specification based on the test will be applied to the new model of the remote controlled air conditioner. The wide distribution of the air conditioners to the public will be helpful to control peak demand due to cooling load in summer time. Financial investment to generating, transmission, distribution facilities will be decreased from flatting the seasonal power load.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.589-596
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• 2005

The public has negative understanding about dam construction nowadays although dam plays an important role in water supply to satisfy essential demand for living. Dam rehabilitation, in this actuality, has been recognized as an alternative to expedite continuous water policies related to irrigation and flood control. This study focused on dam rehabilitation and included its necessity and discussions on case histories associated with increasing reservoir capacity, spillway modification, overtopping protection, seepage control and improving stability of old dam. This paper, in geotechnical aspects, presents discussions of various rehabilitation methods and factors to be considered in designing dam rehabilitation.

• 한국정밀공학회지
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• 제25권6호
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• pp.71-79
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• 2008

In the manufacture of flat panel display devices, there is a strong demand for contactless glass panel handling devices that can manipulate a glass panel without contaminating or damaging it. To fulfill this requirement, an electrostatic suspension device far glass panels where the glass panel is supported by electrostatic forces without any mechanical contact is proposed. To implement the system with low cost and compactness, switched-voltage control scheme that is based on the relay feedback control is utilized. Relay feedback control method deploys only a single high-voltage power supply that can deliver a DC voltage of positive and/or negative polarity and thus high voltage amplifiers that are costly and bulky are not needed any more. It is shown that despite the inherent limit cycle property of the relay feedback based control, an excellent performance in vibration suppression is attained due to the presence of a relatively large squeeze film damping originating from the electrodes and levitated object. Using this scheme, a $100{\times}100mm^2$ glass panel was levitated stably with airgap variation decreasing down to $1\;{\mu}m$ at an airgap of $100\;{\mu}m$.

• 한국차세대컴퓨팅학회논문지
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• 제13권4호
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• pp.7-18
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• 2017

현대사회에서 가장 중요한 에너지원 중 하나인 전력 에너지는 적절한 수요 공급 조절이 매우 중요하다. 하지만 수요 예측을 위해 필요한 전력데이터는 전력 사용자의 행위에 대한 정보가 포함 될 수 있어, 이를 분석할 경우 프라이버시 침해 문제로 이어질 수 있다. 이에 본 논문에서는 사용자의 전력 사용 정보에 회귀 분석을 적용하여 사용자의 향후 전력 사용량을 예측하되, Intel SGX가 제공하는 안전한 실행 환경 상에서 이를 수행함으로써 사용자의 전력 사용 정보를 안전하게 보호하는 방법을 제안한다. 다양한 차수의 회귀 관계식에 대한 실험을 수행하여 오차를 최소로 하는 회귀 관계식을 선정하였으며, 제안하는 방법을 이용하면 프라이버시 보호 기능을 제공하는 기존의 전력 수요 예측 방법보다 낮은 평균오차율을 보임을 확인하였다.

• 전기학회논문지
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• 제62권4호
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• pp.566-572
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• 2013

A microgrid is a small scale power system. The microgrid is operated in two operation modes, the grid-connected mode and the islanded mode. In the islanded mode, the frequency of a microgrid should be maintained constantly. For this, the balance between power supply and power demand during islanded mode should be met. In general, energy storage systems (ESSs) are used to solve power imbalance. In this paper, the frequency control effect of a Lithium-ion battery energy storage system (Li-ion BESS) has been tested on the hardware-in-the loop simulation (HILS) system environment.

• 한국수자원학회논문집
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• 제33권6호
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• pp.733-744
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• 2000

불확실한 저수지 유입량과 수요량 때문에 최적의 저수지 조작기준은 정량화하기 쉽지 않다. 그렇지만 저수지 조작에 일정 수요를 충족시키면서 모의 발생시킨 유입량 시계열을 반영함으로써 음해 추계적 최적화 접근법을 이용하면 조작기준은 작성 가능하다. 이에 본 연구에서는 한강수계 7개 저수지 계통에 적절하도록 수력발전 최대화를 선형추적으로 모형화하고 최적제어를 이용하여 최적조작을 수행하였다. 이 때 2001년 수도권 용수수요를 만족시키도록 한 최적 조작 모형에는 다지점 마코브 모형에 의해 모의 발생된 유입량 자료가 입력된다. 그리고 최적 결과에 대하여 회구 분석과 통계 분석을 수행하여 월별 조작기준을 작성하고 계절별 저수위별 확률을 제시하였다. 이때 상대적으로 저수용량이 커서 조절능력이 좋은 화천댐, 소양강댐, 충주댐은 저류와 방류의 회귀 관계가 잘 형성되었다. 작성된 조작기준으로 실제 운영 기간동안에 대하여 모의조작을 수행하여 그 효율성을 검증하였다.

• 대한안전경영과학회지
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• 제15권3호
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• pp.151-161
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• 2013

This paper proposes a strategic model of linkage between productivity metrics and financial accounting metrics to properly evaluate the financial effect of TPM activities and the business performance. This linkage strategy provides a connection tool for clear communication between factory-level and headquarters that the metrics proposed by this paper ultimately improves a quality of support from the management by receiving the factors required for productivity activities in the practical field. This factor includes such as equipment, raw materials and labors. Here, we propose that chain reaction models using break down structure of productivity metrics and financial metrics enhance the knowledge sharing of KPI (Key Performance Indicator) which generally tend to create oversimplified communication between management in headquarters and employees in the practical fields. The productivity metrics include OEE(Overall Equipment Effectiveness) of TPM (Total Productive Maintenance), OLE (Overall Labor Effectiveness) of PAC(Performance and Analysis and Control) activities, and OYE (Overall Yield Effectiveness) of TMM(Total Material Management) activities. The financial accounting metrics include ROE(Return on Equity), ROA(Return on Asset), and AVR(Added-Value Rate). The suggested chain reaction model selects the financial metrics as initial stage and branch down until final stage of productivity metrics. When demand exceeds supply, an ideal speed rate, the lean OEE strategy can be initially applied to reduce the gap between the demand and supply, then apply variable costing to estimate correct amount of operating profit. In addition, the paper presents a new type of model for linkage between financial accounting metrics including CAPEX(Capital Expenditure), OPEX(Operating Expenditure), EVA(Economic Added Value), DCL(Degree of Combined Leverage), and TPM productivity activities including AM(Autonomous Maintenance), PM(Preventive Maintenance), MP(Maintenance Prevention) and QM(Quality Maintenance). In order to support the evidence of proposed linkage strategy, a case analysis on 52 projects from national TPM contest from 2011 to 2012 is analyzed. The case presents the classification of CAPEX and OPEX activities from TPM, and proposes the correct implementation of financial effect for TPM projects.

• 건축역사연구
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• 제27권3호
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• pp.15-26
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• 2018

As a result of reviewing various documents and existing researches, since the late Goryeo period, the most active period in the Ondol(溫突, Korean floor heating system) facilities is the 17th century. The phenomenological reason was recovering the buildings destroyed by the Japanese Invasion of Korea in 1592(壬辰倭亂) & the Manchu War of 1636(丙子胡亂), but the underlying cause was an abnormal climate in which a pair of summer and winter cold continued. In the 17th century, as the Ondol facilities grew rapidly without distinction between regions and classes, the supply and demand of fuel caused economic and natural environmental problems. And a negative and positive view on Ondol was suggested. Since the middle of the 18th century, when the demand and supply of Ondol reached its peak, which could no longer increase, a new awareness of Ondol began to grow. The room was called the Panbang(板房) and the Ondol, depending on the material that made up the floor. It was considered natural to have the Ondol from this time on. The Incan(因間) and Jo(竈) that were made to burn were started to be recorded as a kitchen, regardless of size and function. Changes in social awareness of Ondol have led to concerns about heating efficiency. A variety of architectural explorations were conducted. Such a search was later realized in concrete architectural form. There is a double Ondoll structure, and the column spacing is reduced compared to the previous one. The heat buffer space is formed around the Ondol room, and the double window can control the light and the air going in and out.

• 한국산학기술학회논문지
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• 제13권11호
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• pp.5163-5168
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• 2012

본 연구는 한라봉 수급 모형(동태 축차적 시뮬레이션 모형)을 개발하기 위해 수행되었다. 한라봉 수급부문에 대한 대안적인 정책 시나리오 도입의 파급효과를 분석하기 위해, 3가지 시나리오를 설정하여 각 시나리오별 시뮬레이션이 수행되었다(시뮬레이션 기간: 2011~2021년). 시뮬레이션 주요결과는 다음과 같다. 먼저 기준예측결과, 2021년 재배면적, 생산량, 농가수취가격은 각각 2,051ha, 62,049톤, 2,527.4원/kg으로 전망되었다. 시나리오 I에 의한 전망결과, 2021년 재배면적 2,079.4ha, 생산량 62,984톤, 농가수취가격 2,836.3원으로 나타났다. 시나리오 II에 의한 2021년 재배면적 2,039.5ha, 생산량 61,647.톤, 농가수취가격은 2,417원으로 각각 전망되었다. 끝으로, 시나리오 III에 의한 전망결과, 2021년 재배면적 2,053.7ha, 생산량 62,124.4톤, 농가수취가격은 2,574.8원으로 각각 나타났다. 이와 같은 분석결과, 경기침체에 따른 한라봉 수요 감소는 한라봉 가격 하락 및 산업 위축에 상당한 영향을 미칠 수 있는 것으로 나타난 반면, 한라봉 수출 및 가공 확대는 산업성장 및 소득증대에 매우 긍정적인 역할을 할 수 있는 것으로 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2650-2652
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• 1999

To satisfy the demand for small size, light weight. high density power supply, the switching frequency of DC/DC converters has been increased. The PWM control of the conventional SMPS have a switching frequency that a level of the conducted noise spectra contribute to switching frequency band. So the electronic equipment is not only affected from that but is restricted to internal regulation like CISPR, FCC, and VDE. In this paper, we analyzed Bi-FM. Bi-FM is two fixed switching frequency with a modulation frequency. So emission spectrum of Bi-FM control signal is spreaded and spectral power level is reduced. In this paper, we analyze the spectral analysis of Bi-FM control signal and the spectral comparison between the PWM control and Bi-FM control. And we confirm that reduced the spectrum power level through simulation using Pspice and experiment.