• Journal of Climate Change Research
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• v.1 no.3
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• pp.205-210
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• 2010

LED light has various advantages such as an energy saving effect of over 80% compared to existing lighting and environmentally friendly characteristics; however, there has been no affordable market for LED lighting because of its expensive price. This study discussed the validity of the expansion of distribution of LED lighting through an assessment of economic efficiency concerning LED lightening in order to analyze its efficiency in terms of energy savings and maintenance and repair, which will be generated as a result of the change from existing incandescent bulbs to LED lighting in the public sector. As to the target of analysis, the paper reviewed the validity of change to LED lighting as a result of the elimination of existing incandescent bulbs, by referring to 'the current incandescent bulb use and elimination performance' published by the Ministry of Knowledge Economy based on the "Elimination management system" executed by Korea Energy Management Corporation. The paper considered expenses for change, annual power savings amount and electric charges savings amount, repair and maintenance cost, $CO_2$ reduction volume, and the profit from the sale of CER (certified emission reduction). As a result of analyzing economic efficiency, when the discount rate during the change of existing incandescent bulb lighting to LED lighting is 3.26%, the profit was 8,648,400,000 won. Accordingly, NPV was analyzed to have a 'positive (+)' value, which means that this change is profitable.

• Journal of agriculture & life science
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• v.52 no.6
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• pp.155-162
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• 2018

This study attempts to analyze the consumers' preference on Korean Red Ginseng Tonic, which is an essential product to revitalize Korean ginseng industry, using choice experiment method. The attributes used in the choice experiment were the ginseng age, good agricultural products(GAP), sugar, and price. A total of 1,796 experiments were collected and the value of each preferred attributes was estimated using a multinomial logistic model. The result shows that the products made from six-year-old and GAP(Good Agriculture Practice) approved Korean ginseng with less sugar were preferred. These estimated monetary values of marginal willingness to pay were about 94,000 KRW, 89,000 KRW, 5,000 KRW, respectively. Thus, the efforts to introduce and advertize GAP approved ginseng while developing new products with preferred attributes by general publics are necessary in the short run. In addition, we may need to consider developing the way to promote products using 4- and 5-year-old ginsengs, which are relatively underestimated in their health effectiveness but highly productive for farmers in the long run.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.10
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• pp.25-32
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• 2018

The ending of the warranty under the current Multi-Housing Management Act has a lot of problem as it is very disadvantageous to the business entity and it makes hard for the contractor to finish the repair work. It is almost none for the business entity to get the written confirmation of the expiration of warranty liability from the client even though it sincerely completed their warranty obligation. It is because the client asks for the works other than fair repair arising from the defect in the work, such as the upgrade work for the enhancement of the value of their assets and the repair work which the client should take care before it issues the written confirmation of the expiration of warranty liability to the contractor. "So, though there is the law specifying this matter, the parties are relying on the unnecessary civil agreement. This leads to the big social and economic losses. If there is no agreement made between the client and the contractor, that leads to the legal dispute. This research on cases of 10 apartments shows that the types of works which the apartment residents ask for depend on the characteristics and conditions of the apartments and that they ask for various kinds of compensational works. In addition, it was found that there were many cases in which even the civil agreement is not recognized as the ending of the warranty obligation even if the proper procedure is taken for the ending of warranty by the contractor or business entity. If the collateral is to be offered to the client, the contractor would get more hard because there is the additional cost other than the warranty obligation, thus damaging the legal objective of the laws trying to minimize the damage made to the resident of the apartments. It means that the increase in the unnecessary warranty cost would lead to the increase in the selling price of apartment and the ending of the dispute through the civil procedure would make the Multi-Housing Act ineffective.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.303-309
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• 2021

This study examined how consumers in their 20s and 30s perceive luxury goods, masstige brands, and counterfeits, which have high social value, and whether the propensity for conspicuous consumption and conformity can explain them. Consumers were classified based on the similarity of attitudes toward these brands and purchase intentions. The groups were compared on the sub-dimensions of conspicuous consumption and conformity. Clustering analysis identified four groups, and the MANOVA result confirmed the differences among the groups. Personality (F=4.282, p=.006) and brand orientation (F=23.178, p=.000) were positively related to luxury and masstige brands. Fashion orientation (F=8.376, p=.000) was high for both groups, which likes luxury and masstige brands very much, and which likes counterfeits. High-price orientation did not make any significant difference among the groups. Conformity (F=3.537, p=.015) was high for all the groups, except for the group that liked luxury and masstige brands and did not like counterfeits. This study comprehensively examined the attitudes and purchase intentions of luxury and masstige brands and their counterfeits and can be the groundwork for further research on brand categorization.

• Journal of the Korean GEO-environmental Society
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• v.12 no.12
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• pp.37-46
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• 2011

An application frequency of vertical drainage method is increasing as an effective consolidation acceleration method. PBD method is most frequently used as a consolidation acceleration method in vertical drainage methods. PBD is economical and easy to operate but has some problems those are an environmental pollution and a decrease of a discharge capacity caused by bending of drainage materials when it is used in great depth. SCP method was frequently used because it's discharge capacity was good but now it is rarely used because of an increase of the material price because of an order imbalance. As the way to solve these problems, GCP method has been to the fore. For analyzing the effect of GCP method on the discharge capacity, three types of composite discharge capacity tests are done by using GCP, SCP and PBD respectively with the circle case, ${\phi}38{\times}h70cm$. On the contrary to this, GCP shows the worst discharge capacity for a decrease of the void ratio and the clogging phenomenon caused by increasing load. Also to figure out the clogging range of GCP, the clogging of GCP is checked in each load stage with a large case($1.0m{\times}0.5m{\times}1.1m$) which has clear acrylic front face. The diameter of GCP was 35cm and a clogging phenomenon occurred in 10% approximately. The result shows that the discharge capacity of GCP was given the lowest value for a decrease of the void ratio and the clogging phenomenon causing by increasing load. And the clogging phenomenon mostly occurred within 10% of GCP's diameter range.

• Animal Bioscience
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• v.34 no.4
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• pp.567-574
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• 2021

Objective: In this study we investigated the effect of seasonal thermal stress on milk production and milk compositions between Holstein and Jersey dairy cows under the temperate-climate in Korea. Methods: A total of 9 Holstein lactating dairy cows (2.0±0.11 parity) which had a daily milk yield of 29.77±0.45 kg, and days in milk of 111.2±10.29 were selected similarly at the beginning of the experiments in each season. Also, a total of 9 Jersey lactating dairy cows (1.7±0.12 parity) which had a daily milk yield of 20.01±0.43 kg, and days in milk of 114.0±9.74 were selected similarly at the beginning of the experiments. Results: Results showed that the average ambient temperature (℃) and temperature-humidity index (THI) were higher in summer, and were lower in winter (p<0.05). The average relative humidity (RH, %) was higher in autumn than that of other seasons (p<0.05). Milk production was significantly decreased (Holstein 29.02 kg/d and Jersey 19.75 kg/d) in autumn than in other seasons (Holstein 30.14 kg/d and Jersey 20.96 kg/d). However, the milk production was negatively correlated in Holstein cows, and positively correlated in Jersey cows with THI values increased from 16 to 80. In addition, milk yield was increased by 15% in Holstein cows and decreased by 11% in Jersey cows with the THI values increased from 16 to 20. The fat and protein content percentage was significantly higher in Jersey milk than in Holstein milk, furthermore the fat and protein content yield was higher in Jersey cow milk than that of Holstein cow's milk with all THIs. Conclusion: From the study results, we concluded that Jersey cows might be less adaptable to low temperature of the winter, and this would have a negative impact on dairy farmer income since Korea's milk price estimation system places a higher value on milk yield than on milk compositions or sanitary grades.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.34-46
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• 2020

In order to supply stable natural gas in the future, it is necessary to forecast the demand in advance and secure the quantity of supply. In this paper, we propose a method of estimating the demand function of industrial natural gas, which is the core of the increase of domestic natural gas demand in the future. The cross-sectional data of 304 domestic industries were used to estimate the demand function of the industrial natural gas, and the effect of industry specific characteristics such as capital investment, manufacturing cost. Finally, the least absolute deviation estimation method which is robust to outliers and does not assume the homogeneity of the error term and the normality, And the results were derived. In addition, the economic value of industrial city gas was estimated using the price elasticity of industrial city gas. Therefore, it can be seen that the continuous expansion and supply of city gas to the industrial sector is beneficial at the national level, and the government needs to promote expansion through the industrial city gas support policy.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.13-21
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• 2021

The purpose of this study is to develop the ship valuation model by utilizing the neural network model. The target of the valuation was secondhand VLCC. The variables were set as major factors inducing changes in the value of ship through prior research, and the corresponding data were collected on a monthly basis from January 2000 to August 2020. To determine the stability of subsequent variables, a multi-collinearity test was carried out and finally the research structure was designed by selecting six independent variables and one dependent variable. Based on this structure, a total of nine simulation models were designed using linear regression, neural network regression, and random forest algorithm. In addition, the accuracy of the evaluation results are improved through comparative verification between each model. As a result of the evaluation, it was found that the most accurate when the neural network regression model, which consist of a hidden layer composed of two layers, was simulated through comparison with actual VLCC values. The possible implications of this study first, creative research in terms of applying neural network model to ship valuation; this deviates from the existing formalized evaluation techniques. Second, the objectivity of research results was enhanced from a dynamic perspective by analyzing and predicting the factors of changes in the shipping. market.

• Journal of Cadastre & Land InformatiX
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• v.51 no.2
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• pp.125-139
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• 2021

Continuous subway line expansion over the years in Seoul metropolitan area has contributed to improved accessibility to public transport. Since public transport accessibility has a significant impact on housing decisions, quantitative analysis of correlation between housing prices and public transport accessibility is regarded as one of the most important factors for planning better housing policies. This study defines the reduction of traveling time resulted from the construction of new metro stations despite them not being the closest stations as 'Network Expansion Effect', and seeks to understand how the Network Expansion Effect impacts on housing prices. The study analyzes monthly rent data converted from upfront lump sum deposit, so called Jeonse in Korea, from 2012 to 2018, through 'A Modified Repeat Sales Model.' As a result, the effect of 'Network Expansion' on rental prices in Seoul has stronger during the period of 2017 to 2018 than the base period of 2012 to 2014, which suggests the 'Network Expansion' has a meaningful effect on rent. In addition, in comparison between the most and the least affected group of apartments by 'Network Expansion Effect', the most affected group has more price increase than the least affected group. These findings also indicate that different levels of 'Network Expansion Effect' have various influences on the value of residential real estate properties.

• The Journal of the Korea Contents Association
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• v.22 no.4
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• pp.118-129
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• 2022

The purpose of this report is to study a strategic model of promotion activities through various analysis and sales forecasting by selecting wearable products for domestic online companies and collecting sales data. For data analysis, various algorithms are used for analysis and the results are selected as the optimal model. The gradation boosting model, which is selected as the best result, will allow nine independent variables to be entered, including promotion type, price, amount, gender, model, company, grade, sales date, and region, when predicting dependent variables through supervised learning. In this study, the review values set as dependent variables for each type of sales promotion were studied in more detail through the ensemble analysis technique, and the main purpose is to analyze and predict them. The purpose of this study is to study the grades. As a result of the analysis, the evaluation result is 95% of AUC, and F1 is about 93%. In the end, it was confirmed that among the types of sales promotion activities, value-added benefits affected the number of reviews and review grades, and that major variables affected the review and review grades.