• Smart Media Journal
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• v.7 no.4
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• pp.37-43
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• 2018

Most of fruit quality classification has been done by time consuming, inaccurate and intensive manual labor. This study proposed an automated fruit grading system based on appearances and internal flavors. In this study, image processing technique and a weight checker were used to measure the value of appearance features and the near infrared spectroscopy analysis method was used to estimate the value of internal flavors. Additionally, I suggested 8x8x5x5 ANN based fruit quality classifier model to grade fruits quality. The proposed automated fruit quality classification system is expected to be very beneficial for many farms where heavy manual labor is usually needed for fruit quality classification.

• Journal of Korea Multimedia Society
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• v.24 no.2
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• pp.245-254
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• 2021

We proposed the research on an analysis and prediction model that allows the identification of outliers or abnormality in the data followed by effective and rapid imputation of missing values was conducted. This model is expected to analyze efficiently the problems in the data based on the calibrated raw data. As a result, a system that can adequately utilize the data was constructed by using the introduced KNN + MLE algorithm. With this algorithm, the problems in some of the existing KNN-based missing data imputation algorithms such as ignoring the missing values in some data sections or discarding normal observations were effectively addressed. A comparative evaluation was performed between the existing imputation approaches such as K-means, KNN, MEI, and MI as well as the data missing mechanisms including MCAR, MAR, and NI to check the effectiveness/efficiency of the proposed algorithm, and its superiority in all aspects was confirmed.

• Bulletin of the Korean Mathematical Society
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• v.58 no.2
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• pp.349-364
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• 2021

This paper studies the optimal surrender policies for a variable annuity (VA) contract with a surrender option and a fixed insurance fee for guaranteed minimum maturity benefits (GMMB). In our proposed model, a policyholder pays the fixed insurance fee. Based on the integral transform techniques, we derive the analytic integral equations for the optimal surrender boundary and the value function of the VA contract that can be solved numerically by recursive integration method. We provide numerical values for the value function, the optimal surrender boundary, and the expected optimal surrender time.

• Journal of Hydrogen and New Energy
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• v.33 no.6
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• pp.838-844
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• 2022

In this paper, an experimental study was conducted on the energy efficiency ratio of performance for air source heat pump. The energy efficiency ratio presents the operating efficiency of heat pump performance. In order to improve reliability in the energy efficiency ratio test of air source heat pump, the measurement uncertainty of the instrument was estimated. Measurement uncertainty refers to the uncertainty of a measurement, estimates the range in which the expected value of the measurement can be within a certain confidence level, and suggests a range in which the measured representative value is incorrect. The measurement uncertainty for the energy efficiency ratio test of air source heat pump was calculated and the measured results were presented.

• International Journal of Advanced Culture Technology
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• v.11 no.1
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• pp.103-109
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• 2023

This study examines the association between ownership structure and labor investment efficiency. Specifically, this study investigates whether owner-manager firms, where managers own a large percentage of shares in the firm, involve in more efficient labor investment. Based on the management entrenchment hypothesis, managers are more likely to make labor investment decisions to maximize their private benefits rather than creating value for shareholders, resulting in lower efficiency in labor investment. On the other hand, according to the incentive alignment hypothesis, managers tend to make labor investment decisions that will improve future firm performance as their interests are aligned with those of shareholders. In this situation, owner-manager firms are expected to have higher efficiency in labor investment. Our empirical results show that owner-manager firms engage in more efficient labor investment, which contributes to long-term firm value. This study provides empirical evidence that firms' labor investment behavior can vary depending on the characteristics of the ownership structure.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.27-28
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• 2022

There is a limit to preventing various types of safety accidents in advance at construction sites. Even for buildings of the same total floor area, it is expected that the more complex the building shape or the higher the number of floors, the higher the probability of a safety accident. Therefore, it is necessary to analyze the effect of the shape of a building on safety accidents using safety accident data generated during actual construction. The purpose of this study is to analyze the impact of building shape on safety accidents. As a result, the R2 value of shape factor and safety accident was 0.901, and the R2 value of construction difficulty and safety accident was 0.944. In the future, the results of this study will be used as basic data for improving safety management related systems.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.48.1-48.1
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• 2020

The cosmological constant is accountable for the accelerated expansion of our Universe. Observational data have provided a tight constraint on the cosmic star formation history from z = 8 to the present. What happens to the star formation rate beyond z=0? I will discuss the star formation rates, along with the properties of the intergalactic mediumfrom our suite of simulations into the future. Since Lambda becomes dominant in the future of our universe, I further simulate counter-factual universes to assign anthropic weights to each universe within the multiverse setting. I will argue that using the asymptotic star formation efficiency as weights, we almost double previous estimates of observers living in universes similar to ours. The expected value of the energy density of Lambda is also closer to the observed value. I will also discuss potential future works to improve the applicability of the anthropic reasoning of the cosmological constant.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.746-747
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• 2015

Recently, Korea has achieved accumulated total value of orders of six hundred billion dollars in international construction market, and it is facing a new turning point by entering the overseas construction market. However, according to the statistics on the current internal construction market, the accumulated value of orders has been mainly obtained by plant projects in the Middle-East area. To improve international competitiveness of Korean construction industry, it is required to expand and diversify the target areas and construction business sectors. To expand markets, each construction firm should establish the expansion strategy and assess the capability which includes the strength and weakness of their firm. Therefore, this research aims to evaluate the capability of the Korean construction firms for overseas expansion. Through the research, Korean construction industry is expected to strengthen competitiveness toward the overseas markets. Furthermore, this research contributes to expanding and diversifying markets for domestic construction firms.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.280-285
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• 2011

This study aims to propose an assessment model on environmental economics which will provide useful information in making a decision for the implementation of pro-environmental and economical construction projects. To meet the objective, this study suggests a procedure to estimate environmental cost of construction projects. The model combines environmental load assessment and environmental value assessment. The environmental cost of pollutant generated from the construction project was estimated utilizing the Contingent Valuation Method (CVM) which is a value assessment method borrowed from economic science. The devised model is expected to provide a useful methodology that will scientifically support the planning and management of sustainable construction not only in the environmental aspect but also in the economical aspect.

• East Asian Economic Review
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• v.28 no.2
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• pp.143-174
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• 2024

This paper empirically examines the relationship between outward foreign direct investment (OFDI) of Korean manufacturing firms and the servicification of domestic employment using a firm-level panel data. In this study, considering the issue of low productivity in the Korean service sector, we categorize service employment into core and non-core services and investigate their relationship with OFDI using the firm-fixed effects model. The empirical results show that the share of core service employment exhibits a positive correlation with the extensive OFDI. On the other hand, the share of non-core service employment, which is expected to generate relatively low value-added, does not show a significant relationship with the extensive OFDI. When we divide the samples based on host countries and the type of subsidiaries, the impact on servicification varies depending on the technological capabilities of host countries and their participation in global value chains. Our study suggests that Korean manufacturing firm's internationalization strategies may facilitate a transition from labor-intensive employment, like the cases in advanced countries, to technology-intensive employment through OFDI and other means.