• Journal of Power Electronics
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• 제12권1호
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• pp.215-222
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• 2012

Lighting represents a significant component of commercial buildings, particularly office buildings. Fluorescent lighting is invariably used in all commercial, industrial and residential areas. A significant amount of lighting energy is wasted every day by leaving the lights on and not utilizing daylight energy. However, if daylight illuminance can be harnessed, this will reduce the electricity consumption of fluorescent lamps and save energy. This paper explains possible significant savings in lighting energy consumption and hence in costs, without reducing the performance and visual satisfaction in office or industrial buildings. It is proposed to obtain energy saving by reducing the supply voltage without degradation in lighting performance. Experimental results confirm that as much as 20% of electrical energy can be saved by reducing about 9% of the supply voltage, without noticeably affecting light output while complying with lighting standard limits.

• 응용통계연구
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• 제1권2호
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• pp.27-33
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• 1987

감마분포에 따르는 K($\geq$2)개의 처리들 중에서 최대 척도모수를 갖는 처리를 선택하는 제거형 이단 선택방법을 제안하고 주어진 $(\delta^*, p^*)$에 대하여 Kim(1985)이 제안한 선택확률의 하한을 만족할때 설계상수(nr, mr, c)와 총실험횟수의 평균을 Monte Carlo 방법으로 구하였다. 또한 총실험횟수를 작게한다는 점에서 일단 선택방법보다 유용함을 밝혔다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권4호
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• pp.626-648
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• 2011

Energy consumption of wireless access networks is in permanent increase, which necessitates development of more energy-efficient network management approaches. Such management schemes must result with adaptation of network energy consumption in accordance with daily variations in user activity. In this paper, we consider possible energy savings of wireless local area networks (WLANs) through development of a few integer linear programming (ILP) models. Effectiveness of ILP models providing energy-efficient management of network resources have been tested on several WLAN instances of different sizes. To cope with the problem of high computational time characteristic for some ILP models, we further develop several heuristic algorithms that are based on greedy methods and local search. Although heuristics obtains somewhat higher results of energy consumption in comparison with the ones of corresponding ILP models, heuristic algorithms ensures minimization of network energy consumption in an amount of time that is acceptable for practical implementations. This confirms that network management algorithms will play a significant role in practical realization of future energy-efficient network management systems.

• 상하수도학회지
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• 제19권1호
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• pp.8-15
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• 2005

Field measurement data on water leakage are not readily available and it causes inaccurate assessment of water demand and poor supply planning. In this study, the procedure for leakage detection and unaccounted water calculation is proposed and applied to a city. The city has suffered from the significant amount of leak water and the financial loss as a result. Measurements were made for pressure and flow at 18 locations before and after the repair. Repair of the leakage increased pressure up to $2.0kgf/cm^2$ and saved 17.1% of water supply from distribution reservoirs. Monetary value of annual water savings for the entire city amounts to 1 billion won. It is believed that leakage detection and data analysis conducted in this study will contribute to the change of current practice and to the establishment of better water supply management system.

• 조명전기설비학회논문지
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• 제28권9호
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• pp.20-27
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• 2014

The power consumption pattern of high-speed railway has rarely during night time. But, during service time, the power is consumed irregularly related to train operation. Especially certain unusual about 1-2 days of service time interval to indicate the power consumption is rapidly growing phenomenon, which causes the capacity of the power contract is the annual electricity bill to rise rapidly as the cause. Normally, amount of peak power consumption bill rate at railway substation is over 20% of total electrical bill. Therefore, high-speed railway substation is expected to be considerably larger savings by reducing the peak power of the default charge(demand power).

• 기술사
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• 제9권3호
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• pp.8-19
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• 1976

A set of study has been made on the table of vehicle running costs, officially used by Korean government, in view to clarifay the relative value of costs composition characteristic and reduction rate due to road surface improvement. The amount of vehicle running costs in Korea and of the components, has been compared, with the corresponding value of the USA, Japan, France, Great Britain and Italy. Findings are briefly summerized : vehicle running costs have been found to be generally much expensive in Korea than the four developed countries except Italy; and significant differences have been also found on the pattern of savings for components of vehicle running costs presumable by pavement construction on road surface, between two countries, Korea and the USA.

• Journal of the Korean Wood Science and Technology
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• 제20권1호
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• pp.5-14
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• 1992

Experimental external collector type solar lumber dryer of $1m^3$ of maximum capacity with $1.6m^3$ of collector area was designed and constructed. The seasonal performance of solar dryer, including air-conditions, energy efficiency, and drying characteristics of 3cm-thick red pine and douglas-fir lumber was investigated. Also, the economic analysis was carried out. Annual average solar drying rate was about 2 times faster than air-drying rate with no significant difference in the amount of drying defects. But in initial drying stage air-drying rate in winter was much faster and those in spring and autumn were slightly slower than solar drying rate in each season. Annual average energy efficiency of solar-dryer and-collector was 25% and 57%, respectively. Fuel savings were over 50% at 15% of energy inflation rate and the payback period was estimated as 6.10 years at 30% of energy inflation rate.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2009년 춘계학술발표대회 논문집
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• pp.187-192
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• 2009

Nowadays, global warming and high oil prices were a threat to the survival of the whole human race. One of a solution to respond to these problems is to reduce energy consumption of building. By adopting energy-saving design, the dissemination of low energy building is required. Therefore, to improve energy efficiency while reducing the usage of the design method is necessary to study actively. BIM-based systems applied to buildings, scheduled to be built by reducing the amount of energy reduction technologies can be analyzed. Depending on various design and equipment to set energy savings goals, you can select an alternative. If it is possible to predict the energy efficiency from the initial stage of design and support designing low energy building, we would be able to expect improvement in the economics of housing due to the reduction of energy consumption.

• 대한가정학회지
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• 제35권2호
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• pp.95-110
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• 1997

The purpose of this study were 1) to identity housing fund by the type of housing mobility and 2) to analyze the variable contributing to housing fund by the type of housing mobility. For these purposes, the 1993 KHPSD data was used and the sample in this study consisted of 2,796 couple households. Statistics employed for the analysis were frequencies, means, univariate analysis and multiple regression analysis. As the results, the composition and the amount of housing fund according to the type of housing mobility, were different respectively. Housing fund was consisted of previous housing sales price, savings deposits, loans, inheritance, subsidy, and personal debts. Households who already own houses used housing finance for their housing fund easily while renters were at a disadvantage to use housing finance. Moreover, among the contributing factors, home ownership, number of family member, residence, average monthly income, average monthly expenditure, husband's education attainment, satisfaction with housing, husband's job, and the type fo housing were positively associated with the amounts of housing funds. However, duration fo residence tended to negatively related to the amounts of housing funds.

• 가정과삶의질연구
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• 제22권3호
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• pp.11-21
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• 2004

This study examined factors associated with the ownership of stock investments and the amount of stock investments of households using the 2001 National Survey of Family Income and Expenditure by National Statistical Office. Households with large amounts of income, savings, and liabilities were more likely to invest in stocks and have large amounts of stock investments. Also, households with young and male householders, highly educated householders, a number of children in school, and housing ownership were more likely to invest in stocks and have large amounts of stock investments. On the other hand, self employed households and dual income households were less likely to invest in stocks and have small amounts of stock investments.