• Structural Engineering and Mechanics
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• 제67권4호
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• pp.327-336
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• 2018

In this study, an efficient damage index is proposed to identify multiple damage cases in structural systems using the concepts of frequency response function (FRF) matrix and strain energy of a structure. The index is defined based on the change of strain energy of an element due to damage. For obtaining the strain energy stored in elements, the columnar coefficients of the FRF matrix is used. The new indicator is named here as frequency response function strain energy based index (FRFSEBI). In order to assess the performance of the proposed index for structural damage detection, some benchmark structures having a number of damage scenarios are considered. Numerical results demonstrate that the proposed index even with considering noise can accurately identify the actual location and approximate severity of the damage. In order to demonstrate the high efficiency of the proposed damage index, its performance is also compared with that of the flexibility strain energy based index (FSEBI) provided in the literature.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.112-119
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• 2008

In order to ensure building energy management at an appropriate level continuously, it is necessary to define clearly service work of energy management and to suggest evaluation index whether energy management in buildings is fit and improvement is needed or not. But, evaluation index of energy management level in buildings is not suggested yet in Korea. So, the purpose of this paper is to suggest evaluation index of energy management level in buildings, investigate the present state of Korean buildings and evaluate energy management levels. As a result of surveys of evaluation index of energy management, it is found that portion of level 1, which is the best level, is higher than any other level, level 2, level 3. And, throughout analysis, it is found that as total floor area is larger, evaluation index of energy management level is better, and, in order to increase energy management level, first of all, there is necessary for building's users to change understanding about energy saving and make a reform of national policy of energy management in buildings. Because there is rich relationship between items among evaluation index of this stuff and result value of evaluation index, evaluation index of energy management suggested in this study is available to evaluate energy management level in buildings.

• Journal of Biosystems Engineering
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• 제38권4호
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• pp.264-269
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• 2013

Purpose: This study was carried out to develop a classification index and grade levels to rate agricultural heaters for energy efficiency classification. Methods: The classification index was developed mainly by taking simplicity of calculation and easy access to relevant data into consideration. The grade levels were developed on the basis of a 5-grade classification system in which graded heaters are to be normally distributed over the grades. The value of each grade level were determined in terms of the classification index values calculated using the published performance data of agricultural heaters tested at the FACT in Korea over the past 12 years. Results: The thermal efficiency of agricultural heaters based on the enthalpy method was proposed as a reasonable classification index. The grade levels were proposed in equation form for three types of agricultural heaters: fossil fuel heaters, wood pellet heaters and wood pellet boilers. A reasonable energy efficiency classification of agricultural heaters could be performed using the proposed classification index and grade levels. Conclusions: It is expected that energy saving programs will be extended to agricultural machines in the near future. The classification index and grade levels to rate agricultural heaters for energy efficiency classification were developed and proposed for such near future to come.

• 한국태양에너지학회 논문집
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• 제39권3호
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• pp.47-57
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• 2019

Clear sky indices were estimated by various ways based on in-situ observation and satellite-derived solar irradiance. In principle, clear sky index defined by clear sky solar irradiance indicates the impacts of cloud on the incoming solar irradiance. However, clear sky index widely used in energy sciences is formulated by extraterrestrial irradiance, which implies the extinction of solar irradiance due to mainly aerosol, water vapor and clouds drops. This study examined the relative difference of clear sky indices and then major characteristics of clear sky irradiance when sky is clear are investigated. Clear sky is defined when clear sky index based on clear sky irradiance is higher than 0.9. In contrast, clear sky index defined by extraterrestrial irradiance is distributed between 0.4 and 0.8. When aerosol optical depth and air mass coefficient are relative larger, solar irradiance is lower due to enhanced extinction, which leads to the lower value of clear sky index defined by extraterrestrial irradiance.

• 신재생에너지
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• 제17권2호
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• pp.9-23
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• 2021

In Korea, various community investment renewable project models are being implemented to increase community acceptance of renewable energy. An important factor for enhancing local acceptance is that renewable energy projects have a positive effect on revitalizing the local economy such as income increase or job creation for residents and local companies. To maximize the local economic effect of large-scale community investment renewable energy projects, this study developed an evaluation index for local economy activation, whose indicators are the local return on investment, local companies' participation, local job creation, regional cooperation, transparency, and governance. Analysis of existing evaluation indicators and current renewable projects, financial analysis, and expert interviews were used in this research. The pilot evaluation determined that, the local economic effect was high in the following order: a fund investment wind project (Gangwon), benefit-sharing wind project (Jeju), and general wind project. In particular, residents' investment amount, the number of participating residents, and the amount and transparency of the regional cooperation fund were key factors to expand the effect of local economy activation. This evaluation index could be used in public bidding for renewable energy projects such as offshore wind zoning areas of local government.

• 펄프종이기술
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• 제36권2호
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• pp.17-23
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• 2004

The effects of refining consistency and plate gap on the specific energy consumption and physical properties of liner were investigated. Higher refining consistency and narrower plate gap brought about the reduction of specific energy consumption to decrease the freeness. Refining consistency and plate gap did not affect the bulk, Taber stiffness and compression index. The reduction of freeness and/or the increase of specific energy consumption caused the decrease of bulk and Taber stiffness, but increased the compression index. The effect of grammage on bulk was not observed, but Taber stiffness and compression index were increased with grammage. The bulk was decreased with the reduction of freeness rapidly at the above 400 mL CSF, and then levelled off. It is expected that the reduction of energy consumption could be obtained from the application of higher refining consistency and narrower plate gap during refining.

• 한국태양에너지학회 논문집
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• 제31권1호
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• pp.87-92
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• 2011

Since the atmospheric clearness index is main factor for evaluating atmosphere environment, it is necessary to estimate its characteristics all over the major cities in Korea. We have begun collecting clearness index data since 1982 at 16 different cities and considerable effort has been made for constructing a standard value from measured data at each city. The new clearness data will be extensively used by evaluating atmospheric environment as well as by solar application system designer or users. Yearly mean 64% of the atmospheric clearness index was evaluated for clear day all over, and significant difference of horizontal global insolation is observed between 1982~1986 and 1987~1991, 1992~1996, 1997~2001, 2002~2009 through 16 different cities in Korea.

• 태양에너지
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• 제14권2호
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• pp.61-74
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• 1994

1982년부터 전국 주요 16개 도시에 측정장비를 설치하고, 대기청명도 자료를 수집하였다. 특정된 자료를 토대로 도시별 표준치를 설정하여, 이들 자료를 해당지역의 대기청명 상태의 평가자료로 이용될 수 있도록 하였다. 현지 측정사업의 내용을 중심으로 지금까지의 결과를 살펴보면, 1) 우리나라 주요 도시에서의 대기청명 조건은 연평균 청명한 날을 기준으로 대략 62% 정도이다. 2) 계절별 대기청명 조건은 연평균치에 비하여 봄과 여름철이 각각 63%, 64%로 다소 높았으며, 가을과 겨울철은 각각 61%, 59%로 낮게 나타났다. 3) $'82{\sim}'87$년과 $'88{\sim}'93$년 사이에 측정된 평균자료로 나누어 경년변화를 분석하여 보면, 매년 전 도시에서 공히 청명도가 감소하고 있음을 확인하였다.

• Journal of Biosystems Engineering
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• 제39권2호
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• pp.96-100
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• 2014

Purpose: The objective of this study was to develop a classification index and the grade levels for a five-grade energy efficiency classification of agricultural dryers in Korea. Methods: The classification index and the grade levels were determined by using the performance test data published by the FACT over the last eight years to reflect a state of the art technology for agricultural dryers in Korea. The five grades were designed to have the classified dryers distributed normally over the grades with 15% for the $1^{st}$ grade, 20% for the $2^{nd}$ grade, 30% for the $3^{rd}$ grade, 20% for the $4^{th}$ grade and 15% for the $5^{th}$ grade. Results: The classification index was defined as the total amount of fuel and electrical energy consumed per 1% of the wet basis moisture content evaporated from a unit mass of grain or agricultural crops during the drying process: 1 MT of paddy rice for grain dryers and 1 kg of red pepper for agricultural crop dryers as the standard mass. Conclusions: The grade levels for the five-grade energy efficiency classification of grain dryers, kerosene dryers, and electric dryers were proposed in terms of the classification index value.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.68-73
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• 2009

Since the atmospheric clearness index is main factor for evaluating atmosphere environment, it is necessary to estimate its characteristics all over the major cities in Korea Peninsula. We have begun collecting clearness index data since 1982 at 16 different cities in South Korea and estimated using empirical forecasting models at 21 different stations over the North Korea from 1982 to 2008. This considerable effort has been made for constructing a standard value from measured data at each city. The new clearness data for global-dimming analysis will be extensively used by evaluating atmospheric environment as well as by solar PV application system designer or users. From the results, we can conclude that. 1) Yearly mean 63.5 % of the atmospheric clearness index was evaluated for clear day all over the 37 cities in Korea Peninsula, 2) Clear day's atmospheric clearness index of spring and summer were 64.6% and 64.8%, and for fall and winter their values were 63.3% and 61.3% respectively in Korea Peninsula.