• Journal of Practical Agriculture & Fisheries Research
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• v.11 no.1
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• pp.159-171
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• 2009

Required total substrates amounts for mushroom production are 212,186M/T in Korea. 80% of these total substrates amounts, 169,748 M/T is used for main substrates. Also 20%of these total substrates amounts, 42,438 M/T is used for additives. Main substrates 169,748 M/T is composed of sawdust, waste cotton, cotton seed hull, straw and com cob etc.. Additives 42,438 M/T is composed of rice bran, wheat bran and beet pulp etc. In the mushroom management, the cost of substrates purchase is composed for the most of management. Substrates amount is limited to supply, and the demand of mushroom substrates is on the increase continuously. So there is nothing but the cost of substrates are raising. Therefore the most important thing must develop the cheap substrates for the mushroom production.

• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.48-53
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• 2012

Due to the customer needs of reducing cost and delivery date shorting, prompt change in the production plan became more important. In the multi period system (For instance, production line.) where target processing time exists, production, idle and delay risks occur repeatedly for multiple periods. In such situations, delay of one process may influence the delivery date of an entire process. In this paper, we discuss the minimum expected cost of the case mentioned above, where the risk depends on the previous situation and occurs repeatedly for multiple periods. This paper considers the optimal switching frequency to minimize the total expected cost of the production process. In this paper, first, the optimal switching frequency model is proposed. Next, the mathematic formulation of the total expectation is presented. Finally, the policy of optimal switching frequency is investigated by numerical experiments.

• Journal of Forest and Environmental Science
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• v.34 no.4
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• pp.304-312
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• 2018

This study investigates to identify the impact factors of timber production cost on the relationship between production cost components and revenues generated by evaluating the entire timber supply chain. In this research, selected 13 logging zones as target areas and classified 14 forest production cost factors, six groups. Additionally, established 13 externalenvironmental factors with related stakeholders and forestry experts. And the BCR (Benefit Cost Ratio) method was then used to analyze the economics of each zone. Filled up a checklist and rated using 5 point scale for each target region, and extracted major cost factors for the production economy of the item. The analysis of major cost factors in the timber production revealed that wood grab equipment usage fee was the first ranked and forest trees purchase cost was ranked in the $2^{nd}$Also, the $3^{rd}$ranking was logging expenses, and transport cost, which accounted for 84% of the total cost, was ranked in the $4^{th}$. In addition, the rock land ratio, slope, timber payment (forest trees purchase cost), special timber, ratio of timber, DBH (Diameter at Breast Height), and mixed forest ratio were the factors that most affected the timber supply chain cost.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.35
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• pp.131-138
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• 1995

For the purpose of the reduction of tile cost, a production/inventory model including the interference phenomenon was developed. By investigating the cause and the characteristics of the direct/indirect cost due to the interference phenomenon, a strategy for suitable production was developed. The developed model was quantitatively validated using an existing-EPQ model and the SIMAN package was used to simulate and animate the model. Consequently, it was presented that the total operating cost of the system could be decreased with tile proposed model.

• Journal of Animal Science and Technology
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• v.48 no.1
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• pp.115-122
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• 2006

This experiment was conducted to evaluate the effect of tillage system and fertilizer type on the forage yield, quality, and production cost of winter rye. This experiment was a 2×2 factorial arrangement for two tillage system (Tillage and No-tillage) and two fertilizer type (Chemical and Manure compost). There was no difference in dry matter (DM) content, TDN (total digestible nutrients) yield, and CP (crude protein) yield of rye, but the DM yield was significantly higher for rye in tillage compared to the no-tillage system. The use of chemical fertilizer type also showed significant increase in DM, TDN and CP yields compared to the use of manure compost as fertilizer. The CP content for rye was significantly higher in no-tillage compared to tillage system, but the type of fertilizer used has no significant effect. No significant effects were observed for NDF (neutral detergent fiber), ADF (acid detergent fiber), and TDN in tillage system and fertilizer type of rye. The total cost to prepare 1 ha is lower in no-tillage compared to tillage, but production cost in rye per kg of fresh, DM and TDN were almost the same as tillage system because of lower forage production. The total cost to prepare 1 ha with the use of chemical fertilizer was higher than using manure compost as fertilizer, however, the cost to produce 1 kg of fresh, DM and TDN were lower when using chemical as fertilizer because of higher yield. Based on the results of this study, tillage system and fertilizer type affected forage yield more than forage quality. Production cost per 1 kg of tillage was lower compared to no-tillage, and that of chemical was lower than manure because of higher forage yield.

• 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.

• Journal of applied mathematics & informatics
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• v.12 no.1_2
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• pp.251-260
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• 2003

Generally, in deriving the solution of economic production quantity (EPQ) inventory model, we consider the demand rate and deterioration rate as constant quantity. But in case of real life problems, the demand rate and deterioration rate are not actually constant but slightly disturbed from their original crisp value. The motivation of this paper is to consider a more realistic EPQ inventory model with finite production rate, fuzzy demand rate and fuzzy deterioration rate. The effect of the loss in production quantity due to faulty/old machine have also been taken into consideration. The methodology to obtain the optimum value of the fuzzy total cost is derived and a numerical example is used to illustrate the computation procedure. A sensitivity analysis is also carried out to get the sensitiveness of the tolarance of different input parameters.

• Journal of Korea Society of Digital Industry and Information Management
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• v.17 no.2
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• pp.37-45
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• 2021

In this study, we want to analyze the difference in cost structure for the LAN audience system, which emerged as an alternative to the existing audience system due to the influence of Covid-19, and to analyze the utilization of the LAN audience system. To this end, the incremental cost difference between the existing audience system and the LAN audience system in the production of the broadcast program was compared and analyzed through the broadcasting production case by the actually performed LAN audience system. According to the research, the existing audience system has a linear cost structure that increases with the number of audience participants, while the LAN audience system has a calculated cost structure that gradually increases with the range of audience participants. These findings indicate that the LAN-line audience system costs more than the audience system, but the total cost is lower than the audience system for a certain number of people or more. This is a supplement to the existing audience system, which could not attract more audiences due to the lack of production costs, suggesting that the online audience system plays a role in supplementing the open broadcasting production system.

• Industrial Engineering and Management Systems
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• v.15 no.4
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• pp.403-431
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• 2016

The objective of this study is to integrate the business, maintenance and production processes of a manufacturing system by incorporating errors. First, the required functions are estimated according to the historical data. The system activities are simulated by Visual SLAM software and the required outputs are obtained. Several outputs including lead times in different dimensions, total cost and production rates are computed through simulation. Finally, data envelopment analysis (DEA) is utilized in order to select the best option between the defined scenarios due to the multi-criteria feature of the problem. This is the first study in which the lead times, cost and production rates are simultaneously considered in the integrated system imposed of business, maintenance and production processes by incorporating errors. In the current study, the major bottlenecks of the system being studied are identified and suggested different strategies to improve the system and make the best decision.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.151.1-151.1
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• 2010

Natural gas hydrates (NGH) provide 170 gas volumes per unit volume of the medium and are easier to make with moderate pressure and temperature (40 bar at 3 C). Once they form, their preservation temperature is 20 C at 1 bar, which is much milder than the LNG preservation. In case of using the NGH, The small and medium sized gas well has advantages for development because of NGH's these characteristics. According to the cost evaluation report of Gudmundsson in Norway and the research of MES in Japan, the gas well that uses the NGH has a cost saving effect about 10~20% compared LNG. The effect depends on distance and production. However, cost saving and efficiency of liquefaction process is increased by the development of LNG liquefaction technology. Therefore, these factors have to be reflected in economic analysis. The purpose of this research is to compare the cost of Gas Supply Chain according to the transport type, distance and gas reserves. Especially, we consider not only the cost of facility but also the total cost (production cost, transport cost, etc).