• Journal of Radiation Protection and Research
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• v.19 no.2
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• pp.121-132
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• 1994

This study concerns about the measurement and the investigation of environmental radiation characteristics which the components and the distribution of exposure rates by terrestrial y-rays in Taegu area. $4^{'}{\phi}{\times}4^{'}$ NaI(T1) scintillation detector with a multichannel analyzer was used in the measurement of y-rays as a part of in-situ spectrometry at twenty eight different locations in this area. The conversion into the exposure rate from the measured ${\gamma}-ray$ spectrum has been carried out leading to a net exposure rate and component ones by $^{40}K,\;^{238}U$ series and $^{232}Th$ series products which are known by the major parts in the terrestrial ${\gamma}-rays$ generally. As a result, the average exposure rate by the terrestrial ${\gamma}-rays$ in Taegu area is $9.4{\mu}R/h$ and the distribution of individual exposure rates shows more or less differences between these locations even after the consideration of diurnal and yearly variations which are always involved in these measurements. The component parts of exposure rates are distributed $^{40}K\;2.9{\sim}4.6{\mu}R/h,\;^{238}U$ series $1.2{\sim}3,\;1{\mu}R/h,\;^{232}Th$ series $2.5{\sim}5.0{\mu}R/h$ over the measured locations.

• Journal of the Korean Home Economics Association
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• v.27 no.4
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• pp.85-103
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• 1989

The purpose of this study is to figure out the urban low-income consumers' present possesion condition of electric appliances, the way of purchasing, shopping scope of groceries and electric appliances, and the shopping scope and information seeking behavior of groceries and electric appliances according to the socioeconomic variables, and the shopping scope of electric appliances according to the way of paying price. For this purpose 129 low-income consumers living in Inchon were interviewed through questionnares. Finally 100 questionnares were analyzed. The first major of this study is that the possesion rates of color television set and refrigerator are comparativelyl high, while those of washing machine, record player and camera are low. In case of electric appliances, consumers usually purchase things on credit and as a shopping place, they usually go to a commercial agent. In case of groceries, they usually buy things for cash, and in case of one price labeled groceries they usually buy things at a supermarket. Second, according to the way of paying price, the shopping scope of some electric appliances is broader in case of purchase for cach than in case of purchase on credit. Third, the shopping scope and information seeking behavior classified by the socioeconomic variables according to the income, age and education. That is as the income and education become higher and the age becomes lower, the shopping scope becomes broader, mass media information source is much more uaed and the frequency of seeking becomes higher. Through this study, I would like to suggest the followings. (1) The problem of low-income consumers is closely connected with the low education level, so it can be solved a bit through consumer education. (2) Especially the consumers' problem is more serious in case of those who are aged and get very low income and education. Therefore special attention is needed to those consumers.

• Transactions on Electrical and Electronic Materials
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• v.13 no.4
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• pp.181-184
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• 2012

$BaTiO_3$ based multilayer ceramic capacitors with Ni electrodes can be explained as 2-2 composites with different thermal expansion coefficient and sintering behaviors. To achieve the high capacitance and reliability of MLCCs, a homogenous Ni electrode configuration with high connectivity is required. We controlled the heating rates during sintering to achieve densification by suppressing grain growth. Experimental results revealed that a large heating rate gave high connectivity of Ni electrode, high capacitance, small dissipation factor, high breakdown voltage, and high reliability of MLCC chips.

• Journal of the Korean Wood Science and Technology
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• v.24 no.4
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• pp.93-99
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• 1996

In order to investigate the extent of fixation of new water-borne preservatives in blocks of pinus densiflora sapwoods the streaming potential through the column with preservative treated wood was measured at various conditions. The rates of leachability of ingredients in the treated wood were estimated by the measurement of electric conductivity of the solution with the leached components. The solution was also analyzed by Atomic absorption spectrophotometer (AA). As a results, the experimental data indicated that the fixation of CCB, CCFZ and ACQ in wood were relatively unstable. The fixation rates of CCB, CCFZ were improved by increasing heat and drying time. The amounts of the leached ingredients were apparently higher in CCB and CCFZ than in CCA, while the rate of leaching of ACQ was not changed at various drying temperature.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.7
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• pp.889-895
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• 2014

Korea electric power industry had been under vertical monopoly but is typically getting restructured for free competition. An ideal pricing system under the competitive market system is 'unbundled pricing system' and 'marginal pricing system', but the current pricing system still adheres to the traditional bundled system and the average cost pricing system. Especially, progressive electricity rates for residential use reflect governmental policy-making which is focused on income redistribution & welfare, industrial supports and energy saving. This study proposes new and reasonable residential electricity pricing systems which are Time-Of-Use (TOU) and Real-Time Pricing (RTP) to reflect variations in the wholesale price of electricity. It also presents examples of various tariffs for residential electricity pricing systems.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.154-157
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• 2010

In this paper, the Time-varying Failure Rates(TFR) of power distribution system components are extracted from the recorded failure data of KEPCO(Korea Electric Power Corporation) and the reliability of power distribution system is evaluated using Mean Failure Rate(MFR) and TFR. The TFR is approximated to bathtub curve using the exponential and Weibull distribution function. In addition, Kaplan-Meier estimation is applied to TFR extraction because of incomplete failure data of KEPCO. Also the reliability of the real power distribution system of Korea is evaluated using the MFR and TFR extracted from real failure data, respectively and the results of each case are compared with each other. As a result, it is proved that the reliability evaluation using the TFR is more realistic than MFR. In addition, it is presented that the application method at power distribution system maintenance and repair using the result of TFR.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.5
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• pp.64-70
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• 1995

This paper presents a practical approach to evaluate the reliability indices of electric distribution systems. The use of reliability evaluation is placed with framework of distribution system planning and operation. In this paper, the reliability model is based on an analytical method, connecting component failure to load point outage in each section. Five cases are reported in the paper to study the effect of varying failure rates and repair times on real distribution systems. Simulations are preformed by the developed reliability evaluation program.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1703-1711
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• 2010

Electric power utilities are facing increasing uncertainties regarding the economic, political, societal, environmental constraints under they operate and plan their future systems. The utilities have to integrate consumers' interruption cost representing reliability worth of electricity into the process of determining the optimum investment level. In order to do so, the estimated outage cost must be included into quantitative index corresponding to system capital and operation investment cost to establish an optimal expansion plan. This paper is a study on the outage cost assessment by using macro approach for calculating IEAR(Interrupted Energy Assessment Rates) and the TRELSS(Transmission Reliability Evaluation for Large-Scale Systems) program was used to calculate EENS(Expected Energy Not Served).

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.1
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• pp.33-37
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• 2017

This paper describes the modeling of the failure rate estimation technique for applying the asset management technique to electric power facilities. There are many modeling techniques to estimate the failure rate. In this paper, the characteristics of the normal distribution, exponential distribution, weibull distribution, and piecewise linear functions are discussed. When evaluating reliability, the evaluation may be less meaningful if the sample data is insufficient. Therefore, Weibull distribution and piecewise linear function are adopted as the most suitable functions for estimating the failure rate of power facilities and the resulting failure rate function is derived.

• Journal of Institute of Convergence Technology
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• v.1 no.1
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• pp.5-8
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• 2011

Thermal analysis of a cooling module using Peltier elements are performed using a commercial software, CFD-ACE+. A standard k-e two-equation turbulent model is applied in order to represent the turbulent shear stress. Computed values are compared with the theoretical values for the validation. The effect of mass flow rates and transferred heat amounts on the temperature distributions inside the cooling system is analyzed. It was found that the increase in the mass flow rates causes the exit temperature rise. The increase in the absorbed heat amount diminished the overall temperature on the fin surfaces. In the present analysis, the material characteristics of the Peltier element itself are not considered. In the future, the effect of the turbulence models and material characteristics will be studied in detail.