• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.297-302
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• 2015

Replacing a manual switch installed in a feeder for a distribution system with an automatic one increases the reliability of the electric power system. This is because the automatic switch can shorten the duration of a fault the customer experiences by splitting the faulty section faster than the manual one does. However, improving the reliability of the distribution system may increase investment costs. Here, the investment costs include automatic switch cost, replacement work cost and labor cost. For this reason, importance should be attached to the proper balance between the increase of the investment costs and the improvement of the reliability of the distribution system. This article analyzed reliability index and economics when manual switches installed in a feeder (RBTS Bus2 model) was replaced by automatic ones. In addition, it attempted to draw the optimum rate of automation of manual switches by automatic ones using the GRG optimization method, considering the current economic requirements.

• Korean Journal of Agricultural Science
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• v.39 no.2
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• pp.227-242
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• 2012

Accurate estimation of milk production cost is very important for dairy farmers in establishing strategies for business management (e.g. planning a program for milk production, deciding the size of business and investment, determining the milk price for sale). Since the estimated cost of milk production is used as an important index to determine the basal price of milk in Korea, there has been much interest and debate on the method used to estimate milk production cost among the stakeholder. This study was thus carried out to identify problems in the current methodology for estimating cost of milk production, and to find a better way to improve it. We propose several alternatives and better ways to improve the current method for estimating cost of milk production. Estimation of the income and cost per head should be based on the number of cattle converted to grown cows. Cost estimation per liter of milk should be made for both whole milk and 3.4% milk fat corrected milk. The value of purchased cows and raised replacement heifers should be the same as their market value. The productive life span of cows should be less 4 years, and the terminal or salvage value of cows needs to be 30 to 40% less than her initial value. When calculating depreciation of cows over the productive life span, however, the salvage value should be 0 or 1 Korean won. On calculating labor costs, the farm labor wage corresponding to the average wage of nonfarm industrial workers should be assumed. Beside of these, better estimation procedures for other items are also given. The proposed methods from this study should improve the accuracy of estimation of milk production cost and help to achieve consensus among the stakeholder.

• Korean Journal of Computational Design and Engineering
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• v.9 no.2
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• pp.148-157
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• 2004

Interactive simulators that simulate mechanical systems are being developed for the purpose of performance evaluation of product design, replacement of physical training, and entertainment game. Use of flight simulator is increasing to reduce risk and cost of physical training, and we need virtual environment which covers large area terrain. We need a method that can reduce development cost and construction time of virtual environment that simulate the real environment. There have been attempts to link GIS or remote sensing field with virtual reality. This paper examines a method that helps to construct virtual environment, and attempts to link geographic information with virtual reality. A construction method of virtual environment based on digital map and satellite image has been studied.

• The Journal of Fisheries Business Administration
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• v.54 no.2
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• pp.1-14
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• 2023

The sustainability of fishing villages is threatened by manpower shortages due to population aging and poor settlement conditions. In the reality of poor fishing villages, the importance of women's labor is more emphasized than that of the past because female workers are key workers in fishing labor, processing and sales of marine products. However, policy support for female fishermen is not sufficient. The reason for this is that policy makers did not properly recognize the labor value of female fishermen. In fact, fishing villages have emphasized the importance of female workforce as a slogan, but there has been no attempt to estimate the labor value. There was not even a review of the methodology for estimating the value of labor that was attempted in similar fields. As a result, the policy importance of female fishermen was underestimated for there was no attempt to evaluate their value even though women had been continuously participating in the fishery from the past. Female fishermen's labor is under the dual labor structure of housework and fishing labor. Therefore, in this study, housework and fishing labor were estimated separately and the total labor value was calculated. The basic data necessary for estimating the labor value of female fishermen were obtained through a survey. The method of estimating the labor value of female fishermen was used in combination with the present income method and the total replacement cost method. As a result of the study, the total labor value of female fishermen was about 4.4 trillion won, which is about half of the total fishery production of 9 trillion won in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.6
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• pp.361-371
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• 2002

Multifunctionality of agriculture has been an important international issue in terms of environmental benefits and public concerns. We calculated soil loss mass in national basis using the USLE, and attempted to evaluate its economical benefits by replacement cost method. Soil loss mass ranged from 1.4 to $18MT\;ha^{-1}\;yr^{-1}$ was fairly fitted to measured values for 13 cropping systems. In national basis, the factors in USLE were evaluated as: 429.4 for rainfall and runoff factor. R, 0.15 for soil erodibility factor, K, 1.72 for topographic factor, LS, 0.275 for cover and management factor, C, and 0.856 for support practice factor, P. The soil loss estimated from upland farming using the USLE was $26.1MT\;ha^{-1}\;yr^{-1}$, but soil loss from the bare soil was $110.8MT\;ha^{-1}\;yr^{-1}$, the ratio of soil loss from upland farming to bare soil was 23 percents. Function of reducing soil loss in comparison with the bare soil was $84.7MT\;ha^{-1}\;yr^{-1}$, of which national soil loss mass was 62.6 million MT per annum in south Korea. Agriculture economic replacement cost of soil loss reduction was 497 billion Wons(398 million dollars) for the cost of upland soil dressing. For conservational purposes to increase the environmental benefits of upland farming, the agricultural practice including contour, strip cropping, terracing and division ditches should be implemented.

• Journal of the Korean Home Economics Association
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• v.25 no.4
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• pp.99-111
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• 1987

The purpose of this study is to survey alternative methods of valuation of housework, and then to estimate the economic value of housework done by fulltime housewives in Korea. Four different methods-Self Estimation by Housewives, Opportunity Cost, Individual Function Cost and Housekeeper Replacement cost-are tried for the estimation of economic value of housework. The results of this study can be summarized as follows: (1) The economic value of housework varies substantially by the methods of estimation. The average are: *Estimates of Economic values of Housework by Each Method of Estimation (2) The economic value of housework varies with the level of education, ages, household income, the size of family, the number of children, the number of preschool children.

• Journal of Family Resource Management and Policy Review
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• v.17 no.2
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• pp.55-74
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• 2013

This research developed standardized satellite accounts for household production to measure the entire production in Korea using representative Korean data. This study utilized standardized methods for measuring the expenditure and consumption of expendable supplies as an element of intermediate goods in household production. The results of this research can be summarized as follows. First, the total value of household production in Korea in 2009 turned was 268 trillion won, which would be 10.16% of the GDP, based on using the method of replacement by specialty for estimating the value of housework, while it was 356 trillion won, which would be 13.5% of the GDP (2,636 trillion won), based on the method of opportunity cost. Second, the economic value of labor invested in household production was 220 trillion won when using the data from 12 main corresponding wages in the market, while it was 203 trillion won when using the method of total replacement, which used the wages of housekeepers, and 290 trillion won when using the method of opportunity cost in measuring the value of housework labor. Third, in estimating the proportion by section in terms of the total value of household production, the portion of labor in household production was measured from 76% to 82%, depending on the methods used, which is the most significant section. These results indicate that housework has the characteristics of labor-centered work. On the other hand, the value of expenditure on and consumption of expendable supplies, as one element of intermediate goods, is 63 trillion won, which is 17.7% (using the method of opportunity cost in measuring the labor of housework) of household production. Also, the value of capital goods, as the other element of intermediate goods is 2.3 trillion won, which is 0.9% (using the method of opportunity cost) of household production. In conclusion, as an element of household production, housework labor was higher in household production than expenditures on expendables, especially for cooking, cleaning, and caring for children. In the future, people should be cautious about estimating that the amount of household work could be reduced, as women's labor in the market and the household work produced by the market will increase.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.4
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• pp.705-713
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• 2016

For the soft ground construction, the factors not considered in the design stage occurs in the construction stage so that they cause the increase of the construction cost due to the structural stability and the design change. The subject of the study is the construction section of the industrial complex access road made in the Ochang region of Chungcheongbuk-do. The study is concerned with selecting the soft ground handling method such as the replacement method using rock debris and the surcharge reflecting the service load as the soft ground handling measure and analyzing the effect of reducing the construction cost with the stability of structures and the reduction of the construction period. The soft ground in the study section consists of sandy and cohesive soil and is 2.4m to 5.5m deep. It is distributed unevenly between the 1.5m to 5.9m stratums under the ground surface. Settlement is not serious, but the future uneven settlement and difference are expected so that the future settlement behavior is estimated by analyzing the site measurement results after the soft ground treatment. Moreover, in consideration of the regional characteristics and economic efficiency, soil with good quality is replaced with rock debris as the replacement material so that 29% of the construction cost is reduced due to the increase of stability and the reduction of duration. If the estimation of the dispersion of the pore water pressure within the dam body and the change of the underground water level and the relation of the actually measured soft ground with consolidation is studied further on the basis of the study, it is expected that the behavior of the soft ground will be correctly estimated in various site conditions.

• Industrial Engineering and Management Systems
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• v.2 no.1
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• pp.63-70
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• 2003

In this study, we employed an arithmetic process (AP) approach to resolve gearbox maintenance problems. The approach is realistic and direct in modelling the characteristics of a deteriorating system such as a gearbox since a decreasing AP can model a gearbox's successive operating times and an increasing AP can model the corresponding consecutive repair times. First of all, two test statistics were used to check whether the process is arithmetic or not. Next, model parameters of the AP were estimated using the simple linear regression method. Finally, the optimal replacement policy based on minimising the long-run average cost per day was determined for each type of gearbox.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.1-9
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• 2015

Due to the increasing number of deteriorated bridges worldwide, the importance of maintenance and replacement of existing bridges are being emphasized. Cast-in-place concrete deck which is mainly applied to deck replacement of existing bridges have problems such as deterioration concerns by initial crack, labor cost increase, difficulties of maintenance and replacement, construction time increase, and indirect cost increase by traffic congestion. On the contrary, a precast concrete deck is considered as an effective alternative because of its quality assurance and accelerated construction. The connection method ensuring the required strength and durability is especially important, because the connection part of the precast concrete deck is vulnerable to cracks and leakage. Therefore, this study proposes precast bridge decks with ribbed connection which are more improved than existing bridge deck joints, and flexural performance is verified through various parameter tests.