• 조명전기설비학회논문지
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• 제24권8호
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• pp.1-7
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• 2010

전력계통의 신뢰도와 배전계통의 유지보수는 매우 밀접한 관계가 있다. 본 논문에서는 정전비용의 최소화를 목적함수로 배전계통의 유지보수 계획을 수립하는 방안을 제시한다. 시변고장률을 이용하여 배전계통 내 특정설비의 고장으로 인한 정전비용을 수식화하고 공급구역의 정전비용을 목적함수로 최적화를 수행하며 경제성 분석을 통하여 투자비용 제약을 적용하여 유지보수를 위한 투자설비 우선순위를 결정한다. 제안한 방안을 검증할 모델계통은 국내의 도심지역 변전소를 통해 만들었으며, 제안된 방안의 신뢰도의 이득을 평가함으로서 그 타당성을 검증하였다.

• 항공우주기술
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• 제1권2호
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• pp.45-50
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• 2002

본 논문에서는 지상 관제국과 2005SAT 위성 사이에서 RF 신호로써 명령 및 원격측정 데이터를 전달하는 기능을 수행하는 원격측정명령계 RF 서브시스템의 개념설계 단계의 링크버짓 해석을 수행하였다. 링크버짓 성능분석을 위해 업링크 및 다운링크 과정으로 나누고 업링크에 대해서는 위성체에서 전력흐름밀도 및 명령수신기에서 여유를 계산하고 다운링크에 대해서는 다운링크 EIRP 및 지상국에서 C/ $N_o$ 및 $E_b$/ $N_o$ 여유를 계산하여 전체적인 통신성능 여유를 만족하는지 조사를 하였다. 업링크 링크버짓 분석결과 명령수신기에서 충분한 전력 수신 여유가 있었으며 다운링크 링크버짓 분석결과 지상국에서 C/ No 및 $E_b$/ $N_o$의 여유가 적정함을 확인하였다.

• Journal of Communications and Networks
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• 제18권4호
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• pp.567-579
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• 2016

Several energy saving techniques in cellular wireless networks such as active base station (BS) selection, transmit power budget adaptation and user association have been studied independently or only part of these aspects have been considered together in literature. In this paper, we jointly tackle these three problems and propose an integrated framework, called dynamic cell reconfiguration (DCR). It manages three techniques operating on different time scales for ultimate energy conservation while guaranteeing the quality of service (QoS) level of users. Extensive simulations under various configurations, including the real dataset of BS topology and utilization, demonstrate that the proposed DCR can achieve the performance close to an optimal exhaustive search. Compared to the conventional static scheme where all BSs are always turned on with their maximum transmit powers, DCR can significantly reduce energy consumption, e.g., more than 30% and 50% savings in uniform and non-uniform traffic distribution, respectively.

• Journal of Korean Academy of Oral Health
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• 제42권4호
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• pp.145-151
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• 2018

Objectives: The purpose of this study was to interpret regional disparities in the number of teeth sealed with pit and fissure sealants, identify the factors that affect these disparities and find solutions for the same. Methods: Data were collected from the National Health Insurance Service and Korean statistical information service using metropolis-city-rural area dental health infrastructure variables, regional health behavior variables, and local finance-related variables. Results: In 2015, the number of teeth sealed with pit and fissure sealants per 100 people was higher in the metropolis or city than in the rural area. There was a positive correlation between the number of teeth sealed with pit and fissure sealants and the number of dentists, dental hygienists, dental institutions, standardization rate of subjective awareness of well-being, standardization rate of brushing after lunch, and the proportion of welfare budget in the general budget. There was a negative correlation with the annual standardization rate of health institution use, the standardization rate of unused medical services, and the local government's financial independence. According to the final model of the multiple regression analysis, while the impact of infrastructure on dentistry was not statistically significant, the statistical significance of standardization rate of brushing after lunch, the local government's financial independence, and the proportion of welfare budget in the general budget were maintained. Conclusions: To reduce regional disparities in the volume of use of pit and fissure sealants, it was concluded that it may be effective to select regions with a consideration of the level of regional economic power, implement separate and appropriate policies and projects, and improve the awareness in residents.

• 한국엔터테인먼트산업학회논문지
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• 제13권5호
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• pp.1-13
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• 2019

이 연구는 미국시장에서 개봉 첫 주 흥행 1위를 기록한 할리우드 영화의 흥행성과 결정요인을 분석하였다. 분석대상은 2014년부터 2018년까지 5년 동안의 주별 흥행 1위를 기록한 총 149편 영화이다. 흥행 성과의 경우 미국 내 흥행성과와 해외 매출을 포함한 전체 흥행성과 두 가지로 설정하였다. 흥행성과 결정요인은 제작비, 개봉스크린 규모, 전문가/네티즌 평점 및 참여빈도, 배급사, 리메이크 여부, 성수기 여부, 등급, 장르 등의 11개이다. 분석은 두 가지 흥행 성과에 대한 각각의 결정요인 검증을 중심으로 하였고, 장르별 제작비 규모 차이 또한 고려하는 방법을 적용해 진행하였다. 분석결과 미국 내 흥행성과와 해외를 포함한 전체 흥행성과의 경우 각각 서로 다른 결정요인이 확인되었으며, 제작비 1억불을 기준으로 장르를 구분해 분석할 경우 다수의 선행연구에서 흥행성과의 주요 결정요인으로 확인되었던 개봉스크린 규모의 영향력이 검증되지 않는 모델이 나타났다. 이는 새롭고 좀 더 세밀한 모델을 바탕으로 향후 흥행성과 연구가 진행될 필요가 있음을 보여준다.

• Ocean Systems Engineering
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• 제8권1호
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• pp.33-39
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• 2018

The paper presents a numerical underwater channel model developed in MATLAB for estimating the optical link budget between a light emitting diode (LED) based optical transmitter and a photo diode (PD) receiver when operated in the harbor, coastal and deep waters locations in the Bay of Bengal. The water samples are collected at different locations in the Bay of Bengal using a water sampler during an offshore research cruise. The optical attenuation, the main inherent parameter determining the range of the optical communication link is identified for the different waters using an underwater irradiance measurement system in the laboratory. The identified parameters are applied to the numerical model and found that a 10 W LED and a photo diode based system can provide the optical budget required for a horizontal underwater communication range of about 0.5, 14 and 35 m in the harbor, coastal and deep waters locations respectively. By increasing the transmitter power to 50 W, the operating range of the communication link could be increased up to 53 m in deep water locations in the Bay of Bengal.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
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• pp.561-564
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• 2004

The motion estimation which requires huge computation consumes large power in a video encoder. Although a number of fast-search algorithms are proposed to reduce the power consumption, the smaller the computation, the worse the performance they have. In this paper, we propose an architecture that a low energy management scheme can be applied with several fast-search algorithm. In addition. we show that ECVH, a software scheduling scheme which dynamically changes the search algorithm, the operating frequency, and the supply voltage using the remaining slack time within given power-budget, can be applied to the architecture, and show that the power consumption can be reduced.

• 한국시스템다이내믹스연구
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• 제7권1호
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• pp.67-90
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• 2006

A series of system dynamics model was developed for forecasting demand and supply of human resource in the electricity industry. To forecast demand of human resource in the electric power industry, BLS (Bureau of Labor Statistics) methodology was used. To forecast supply of human resource in the electric power industry, forecasting on the population of our country and the number of students in the department of electrical engineering were performed. After performing computer simulation with developed system dynamics model, it is discovered that the shortage of human resource in the electric power industry will be 3,000 persons per year from 2006 to 2015, and more than a double of current budget is required to overcome this shortage of human resource.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.79-80
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• 2015

With the government's support for new and renewable energy, photovoltaic equipment has rapidly been supplied. However, compared to supply rate, maintenance has not supported enough and relevant research has not much conducted. Therefore, the purpose of this study is to analyze maintenance effectiveness of photovoltaic equipment. What is the most important in maintenance effectiveness is a rise in power generation. It was estimated that if photovoltaic equipment for detached houses is maintained well, power generation increases by 4.0% at least, and by 6.5% on average. As a result, it was analyzed that it is necessary to maximize the effectiveness of the government's budget investment through well maintenance of photovoltaic equipment for detached houses.

• 한국연소학회지
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• 제17권3호
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• pp.30-45
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• 2012

An existing unit of power plant is considered to refurbish it for possible application of carbon capture and storage(CCS). Conceptual design of the plant includes basic considerations on the national and international situation of energy use, environmental concerns, required budget, and time schedule as well as the engineering concept of the plant. While major equipment of the recently upgraded power plant is going to be reused, a new boiler for air-oxy fired dual mode operation is to be designed. Cryogenic air separation unit is considered for optimized capacity, and combustion system accommodates flue gas recirculation with multiple cleaning and humidity removal units. The flue gas is purified for carbon dioxide separation and treatment. This paper presents the background of the project, participants, and industrial background. Proposed concept of the plant operation is discussed for the possible considerations on the engineering designs.