• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.93-108
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• 2016

Electric vehicle car sharing (EV-sharing) system is noted as an eco-friendly system of transportation in global warming crisis and has been practically implemented in some cities around the world. However, methodologies to find the efficient operation conditions of EV-sharing systems reflecting a typical characteristic 'charging' have not been fully investigated yet. In the paper a generalized model has been developed to identify optimal level of infrastructure for EV-sharing system which provides the optimum operation efficiency under service level constraints. From the simulation analysis based on the developed model the relationships between the operational variables to describe EV-sharing system have been identified and optimal capacity to maximize the operational efficiency have been found. From the analysis of simulation results it has been found that increases in the number of vehicles and chargers improve the service level until certain value beyond which increasing rate and the efficiency have been reduced. From the cost-revenue analysis the optimal numbers of vehicles and chargers have been identified which maximizes the annual operational profit.

• Nuclear Engineering and Technology
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• v.40 no.1
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• pp.49-68
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• 2008

The purpose of this paper is to extensively review the condition monitoring (CM) techniques using empirical models in an effort to reduce or eliminate unexpected downtimes in general industry, and to illustrate the feasibility of applying them to the nuclear industry. CM provides on-time warnings of system states to enable the optimal scheduling of maintenance and, ultimately, plant uptime is maximized. Currently, most maintenance processes tend to be either reactive, or part of scheduled, or preventive maintenance. Such maintenance is being increasingly reported as a poor practice for two reasons: first, the component does not necessarily require maintenance, thus the maintenance cost is wasted, and secondly, failure catalysts are introduced into properly working components, which is worse. This paper first summarizes the technical aspects of CM including state estimation and state monitoring. The mathematical background of CM is mature enough even for commercial use in the nuclear industry. Considering the current computational capabilities of CM, its application is not limited by technical difficulties, but by a lack of desire on the part of industry to implement it. For practical applications in the nuclear industry, it may be more important to clarify and quantify the negative impact of unexpected outcomes or failures in CM than it is to investigate its advantages. In other words, while issues regarding accuracy have been targeted to date, the concerns regarding robustness should now be concentrated on. Standardizing the anticipated failures and the possibly harsh operating conditions, and then evaluating the impact of the proposed CM under those conditions may be necessary. In order to make the CM techniques practical for the nuclear industry in the future, it is recommended that a prototype CM system be applied to a secondary system in which most of the components are non-safety grade. Recently, many activities to enhance the safety and efficiency of the secondary system have been encouraged. With the application of CM to nuclear power plants, it is expected to increase profit while addressing safety and economic issues.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.4
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• pp.333-342
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• 2018

In order to manage and rebuild fishery resources, the fishing effort should be controlled effectively. Especially in the setting up of the proper level of fishing efforts, economic standards as well as biological standards must be carefully considered to promote the sustainable and economically viable development of fisheries. This study is aimed to estimate optimal fishing effort of giant octopus by combo fishing which uses longline in Gangwon with statistical data. The result showed that current fishing effort is 28% higher than $E_{MEY}$. Unit fishing cost for each voyage will be 27% lower and unit fishing profit will be 17% higher than the current situation when the fishing effort meets $E_{MEY}$. Although current fishing effort is similar to the $E_{MSY}$, current catching is 16% higher than MSY and 22% higher than MEY.

• Journal of Cadastre & Land InformatiX
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• v.49 no.1
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• pp.29-43
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• 2019

In this study, to solve the problem of the Association-led Housing Reconstruction Business (AHRB), as an alternative to the AHRB, the reliability of the Trust company-led Housing Reconstruction Business (THRB) is verified. To this end, the AHRB and the THRB comparison analyses were performed for the project period, income and expenditure, and the calculation of the Reconstruction Charges (RC). The results of the study are as follows: First, the THRB's business period is shorter than the AHRB's. Second, the THRB's business value is likely to be superior to the AHRB's. Third, due to differences in the calculation period of excess profit for housing reconstruction and the cost items related to implementer, the THRB's RC will be less than the AHRB's RC. Thus, the stability of the THRB has been partially verified as an alternative to the AHRB. The THRB is expected to expand further in the future.

• Journal of Ginseng Culture
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• v.1
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• pp.67-77
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• 2019

This study tried to evaluate the official Korea Red Ginseng(Hongsam) trade in 19th century. The Hongsam trade activities of the 19th century also show that the collected amount of Posam taxes (Hongsam taxes) alone outweigh the amount of cost spent during the same time period to launch tributary actions. It is quite obvious that the Chosun dynasty, supported by the developed techniques of ginseng cultivation and preservation methods, managed to stop the silver leaks while also stimulating the domestic commerce, handicraft business and mining operations, by exporting Hongsam to China and importing raw material and other finished products in return. The Chosun government also managed to secure considerable amount of marginal profit which at times mounted to almost 2 hundred thousand Nyangs of silver during the latter half of the 19th century thanks to this Hongsam trade activities, and accumulated the hoof-shaped pieces of silver ingot at the office of Ministry of Taxation. Even under the mostly undesirable political environment featuring unjustified deeds of the powerful houses, the commercial activities were being strongly maintained, and the transactions conducted by merchants of the Gaeseong, Euiju areas and the capital city were prospering.

• Journal of Convergence for Information Technology
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• v.11 no.4
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• pp.203-210
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• 2021

This study analyzed the financing ratio by operation fund financing method and their impact on management performance according to the establishment operation management entity of the medical institution. For the analysis method, ANOVA, logistic regression, and regression analysis were conducted using financial information registered with HASPA.The results of the study, The ratio of gross revenue to operating funds differed significantly depending on the establishment operation management entity. In addition, it was found that the financing ratio of each operation fund financing method was significantly related to the management results(deficit, surplus), and the impact of the operation fund financing method on management performance differed according to the establishment operation management entity. As a result, the management of operating funds of medical institutions is deemed appropriate to apply cost management first considering the ratio of revenue to operating funds, and then to utilize internal operating funds.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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• pp.24-35
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• 2021

Due to increasing awareness on the treatment of end-of-use/life products, disassembly has been a fast-growing research area of interest for many researchers over recent decades. This paper introduces a novel lot-sizing problem that has not been studied in the literature, which is the service-parts lot-sizing with disassembly option. The disassembly option implies that the demands of service parts can be fulfilled by newly manufactured parts, but also by disassembled parts. The disassembled parts are the ones recovered after the disassembly of end-of-use/life products. The objective of the considered problem is to maximize the total profit, i.e., the revenue of selling the service parts minus the total cost of the fixed setup, production, disassembly, inventory holding, and disposal over a planning horizon. This paper proves that the single-period version of the considered problem is NP-hard and suggests a heuristic by combining a simulated annealing algorithm and a linear-programming relaxation. Computational experiment results show that the heuristic generates near-optimal solutions within reasonable computation time, which implies that the heuristic is a viable optimization tool for the service parts inventory management. In addition, sensitivity analyses indicate that deciding an appropriate price of disassembled parts and an appropriate collection amount of EOLs are very important for sustainable service parts systems.

• The Journal of Society for e-Business Studies
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• v.27 no.2
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• pp.21-36
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• 2022

Recently, as COVID-19 has made the e-commerce market expand widely, customers who have different consumption patterns appear in the market. Because companies can obtain opinions and information of customers from reviews, they increasingly face the requirements of managing customer reviews on online platform. In this study, we analyze customers and carry out market segmentation for classifying and defining type of customers in e-commerce. Specifically, K-means clustering was conducted on customer review data collected from Wemakeprice online shopping platform, which leads to the result that six clusters were derived. Finally, we define the characteristics of each cluster and propose a customer management plan. This paper is possible to be used as materials which identify types of customers and it can reduce the cost of customer management and make a profit for online platforms.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.285-294
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• 2023

The trade dispute between China and the U.S. began before Corona and is easing at this time by bringing new changes to the pendemic, and the development of the Chinese manufacturing industry has increased interdependence between the U.S. and China. However, the overall global trade should be less than before pendemic, and Korea's response strategy should be made serious at this time.However, new changes are taking place again these days. With the recent outbreak of COVID-19 in Shanghai, China, new changes are expected to occur in China's industrial chain. As the Chinese government strictly creates quarantine figures for COVID-19, many factories and companies among industries are forced to close for a while. As economic globalization and division of labor continue to deepen, multinationals choose suppliers and industrial chains within the world to form a global supply chain structure to pursue cost minimization and profit maximization. China is an indispensable part. Whether it is China, the U.S. or Korea, it can be a risk and an opportunity now.

• Journal of English Language & Literature
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• v.55 no.5
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• pp.767-792
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• 2009

The two fields, economics of art and literature, tend to be put together as part of cultural economic studies; yet the former has been widely popular as compared to the latter. Economics of art has been known as part of social science which studies art economically. Similarly, economics of literature is likely to be an interdisciplinary study of literature and economics. Literature is suggested usually to reflect the economic base of a society as a form of its superstructure in view of classical Marxism; so, it is interesting to see social, economic activities, such as individual values and social institutions, income, price and opportunity cost, in a particular way of analyzing economic ideas in literature. Capital seems to have an innate property of self-expansion in literature; this property thus features actual economic life since in capitalism money is the universal value between persons and literary works. Specifically, the field of economics of literature starts with such ideas: economics of literature is part of cultural economics; and economics of literature deals with the economic value of literature. Putting interdisciplinary fields of literature and economics together, this study is to examine the economic value of literature in which Karl Marx talked about commodities with exchange value, use value, and fetishism. The exchange value is commercial worth, the actual exchange value of a publication; yet, the use value is innate worth, the aesthetic use value of literature. With commodity fetishism, profit seems not as the outcome of a social relation, but of a work- "reification" as the would-be Marxists suggest. As a commodity, the literary work appears to be able to animate life and power in reality. As a result, this paper asserts that social, economical activities in literature as we may apply to the study of economics of literature increase its economic value, implying commercial and innate worth, as the capital in the marketplace.