• Korean Journal of Remote Sensing
• /
• v.34 no.6_2
• /
• pp.1261-1272
• /
• 2018

It is important to measure the Arctic surface air temperature because it plays a key-role in the exchange of energy between the ocean, sea ice, and the atmosphere. Although in-situ observations provide accurate measurements of air temperature, they are spatially limited to show the distribution of Arctic surface air temperature. In this study, we proposed machine learning-based models to estimate the Arctic surface air temperature in summer based on buoy data and Advanced Microwave Scanning Radiometer 2 (AMSR2)satellite data. Two machine learning approaches-random forest (RF) and support vector machine (SVM)-were used to estimate the air temperature twice a day according to AMSR2 observation time. Both RF and SVM showed $R^2$ of 0.84-0.88 and RMSE of $1.31-1.53^{\circ}C$. The results were compared to the surface air temperature and spatial distribution of the ERA-Interim reanalysis data from the European Center for Medium-Range Weather Forecasts (ECMWF). They tended to underestimate the Barents Sea, the Kara Sea, and the Baffin Bay region where no IABP buoy observations exist. This study showed both possibility and limitations of the empirical estimation of Arctic surface temperature using AMSR2 data.

• Journal of Technology Innovation
• /
• v.27 no.1
• /
• pp.45-77
• /
• 2019

The balance between exploration for new possibility and exploitation for existing certainty is an important issue in strategy, innovation, R&D as well as organization learning. Among the convergence trends of technologies, many firms seek to have the wider technological knowledge assets and the deeper technology capabilities for the sustainable competitive advantage at the same time. While firms plan technology portfolio strategies, they should consider the attribute of the technology. Nanotechnology, a cutting-edge technology, is a general purpose technology, unlike conventional product-oriented technologies. This empirical study was focused on how multi-national firms' exploration and exploitation strategies for nanotechnology affect their innovative and financial performance. It uses multiple regression analysis on panel data. This result shows that the more diversified and specialized nanotechnology as platform technology is positively related to their innovative and financial performance, unlike the research results for product-oriented technologies. In addition, exploratory innovation is more effective to firm performance than exploitation. This implies how global firms can manage effectively platform technology strategies under the constraints of resources.

• Journal of Technology Innovation
• /
• v.26 no.4
• /
• pp.57-97
• /
• 2018

Big Data has spread rapidly in various industries since 2010. We analyzed the general characteristics of big data through time series analysis on the initial process of spreading big data and investigated the difference of diffusion characteristics in each industry. By analyzing papers, patents, news data, and Google Trend using Big Data as a keyword, we searched for data corresponding to the leading indicator, and confirmed that trends in news and Google Trend preceded the papers and patents by two years. We used Google Trend to compare the introduction period of domestic, US, Japan, and China and quantify the process of spreading the eight main industries in Korea through news data. Through this study, we present an empirical research method on how the general technology spreads in several industry sectors and we have figured out where the spreading speed difference of big data originated in each industry in Korea. The method presented here can be used to analyze the technology introduced from foreign countries in developing countries because it can be analyzed in diffusion process of other technologies besides big data and corresponds to the diffusion of technology keywords in a specific country. And, on the corporate side, this approach shows what path is effective when it comes to launching and spreading new technologies.

• Environmental and Resource Economics Review
• /
• v.28 no.3
• /
• pp.355-383
• /
• 2019

This study is to investigate whether averting costs for wearing $anti-PM_{10}$ masks and using air purifiers at home to reduce exposure from $PM_{10}$ are influenced by subjective risk perceptions and/or objective $PM_{10}$ concentration levels, whose estimates will be used to measure the willingness to pay for $PM_{10}$ risk reduction. An empirical analysis was conducted on a sample of 1,224 respondents who participated in the web-based survey in the late October of 2017. As we reflect the potential endogeniety bias in the estimation of averting cost functions of using air purifiers, the coefficients of risk perception were differed by 6~7 times. Respondents. subjective risk perceptions were influenced by individuals' knowledge, attitudes and demographic variables, as well as the levels of $PM_{10}$ concentrations in their residential region. The marginal willingness to pay for risk reductions at the mean levels of their risk perceptions were measured at 1,000 won per month from wearing $anti-PM_{10}$ masks and 6,000 won for using air purifiers respectively.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.21 no.2
• /
• pp.75-84
• /
• 2019

In this study, the random forest approach was used to predict the national mean rice yield of South Korea by using mean climatic factors at a national scale. A random forest model that used monthly climate variable and year as an important predictor in predicting crop yield. Annual yield change would be affected by technical improvement for crop management as well as climate. Year as prediction factor represent technical improvement. Thus, it is likely that the variables of importance identified for the random forest model could result in a large error in prediction of rice yield in practice. It was also found that elimination of the trend of yield data resulted in reasonable accuracy in prediction of yield using the random forest model. For example, yield prediction using the training set (data obtained from 1991 to 2005) had a relatively high degree of agreement statistics. Although the degree of agreement statistics for yield prediction for the test set (2006-2015) was not as good as those for the training set, the value of relative root mean square error (RRMSE) was less than 5%. In the variable importance plot, significant difference was noted in the importance of climate factors between the training and test sets. This difference could be attributed to the shifting of the transplanting date, which might have affected the growing season. This suggested that acceptable yield prediction could be achieved using random forest, when the data set included consistent planting or transplanting dates in the predicted area.

• Journal of Cadastre & Land InformatiX
• /
• v.49 no.1
• /
• pp.45-63
• /
• 2019

Until recently, most people have invested in a traditional portfolio consisting of stocks, bonds and real estates based on the three-division method of properties in Korea. However, this study analyzed the impact of the composition of a portfolio combining representative real estate indirect investment products such as Reits and real estate funds on the investment performance. For this purpose, the empirical analysis using the mean variance model, which is the most appropriate method for the portfolio composition, was used. For variables used in this study, mixed asset portfolios were classified into Portfolio A through Portfolio G depending on the composition of assets, and the price indices selected as Kospi, Krx bond, Reits Trus Y7, Hanwha-Lasal fund, and Office (Seoul). The results are as follows; first Portfolio D, which combined bonds, stocks, Reits and Real Estate funds, and Portfolio G, which added the office, the actual real estate, were shown to have the lowest risk. second, Portfolio B composed of bonds, stocks and Reits and Portfolio D with added real estate funds had the lowest risk while Portfolio F composed of bonds, stocks, offices and real estate funds, and Portfolio G with added Reits were the most profitable. As a result, it has been analyzed that it was more effective to compose a portfolio including Reits and real estate funds, which were real estate indirect investment products that eliminated the illiquidity limitation of real estates than real estates, the traditional three-division method of properties. Therefore, it is possible to minimize the risk of investors and reduce the cost of ownership of the real estate by solving the illiquidity problem that is the biggest disadvantage of the direct investment, In addition, it is considered that it is more necessary to reinvigorate the real estate indirect investment market where small amounts can be invested.

• The Journal of Society for e-Business Studies
• /
• v.24 no.3
• /
• pp.35-51
• /
• 2019

The two main goals of this study are to derive independent factors affecting the success rate of crowdfunding and to empirically analyze the variation of independent factors' effects on the success of crowdfunding by industry (Internet, culture/art, manufacturing/distribution), and funding type (stock type, bond type). To identify the success factors of crowdfunding for invigoration and strategic utilization, first, several variables were refined after interviews with experts and platform operators with investment experiences in numerous crowdfunding projects. Then, independent factors affecting project involvement were categorized as follows: a characteristic of project, participant activity, and enterprise. Also, the results derived from the influence of independent variables on crowdfunding after moderating effects were driven. Selected independent factors in this study are as follows: crowdfunding period, target amount, visual contents, minimum account money, number of comments, number of SNS followers, level of interest, financial Statement disclosure, investment attraction, venture company, intellectual property rights disclosure, and business operation period. Selected moderating factors in this study are as follows: industry (Internet, culture/art, manufacturing/distribution), and funding type (stock type, bond type). In conclusion, a discussion of the academical and practical implications and a suggestion of directions for further research are explained.

• Korean Journal of Construction Engineering and Management
• /
• v.20 no.5
• /
• pp.104-114
• /
• 2019

This study explored to analyze the winning determinants of the lawsuit cases on the urban and housing redevelopment project based on jurimetric methods. Based on affirm-rate and staircase matrix tables, 441 lawsuit judgments are analyzed. Research findings in affirm-rate analysis indicate that past legal relation, no own defect of accreditation, no ownership or association member status, lapse of period of litigation, and no legal interest are identified as higher rate in order for the reason for plea on the merit. And so are defect on calculation of consent rate, defect in relation with written consent, approval before zoning designation, defect in relation with general meeting, and defect on zoning designation for the issue on the merit. It is noteworthy from the staircase matrix table analysis that the criteria for affecting the lawsuit outcome is determined based on key forecasting variables such as past legal relation and no ownership or association member status. This study intends to provide the implication that the unnecessary disputes can be reduced in the urban and housing redevelopment project by the implementation of jurimetric quantitative analysis methodology from the perspective of empirical law.

• The Journal of the Korea Contents Association
• /
• v.19 no.9
• /
• pp.152-161
• /
• 2019

The purpose of this study was to research the relationships among utilitarian perceptions, hedonic perceptions, perceived usefulness and behavioral intention. Recently, consumers rely heavily on user-generated contents of social media channels to support their purchase decisions, such as electronic word-of-mouth. Electronic word-of-mouth helps consumers to evaluate items before making purchase, to reduce purchase risks and to support their purchase decisions. This study was based on both the analysis derived from a hypothesis and literature reviews and data collected from 255 travelers who had used travel review website at least once. The results of empirical analysis showed as follows. First, Utilitarian perceptions(information quality) has a significant impact on the perceived usefulness of a travel review website. Second, Enjoyment has a significant impact on the perceived usefulness of a travel review website. Third, Curiosity fulfilment has a significant impact on the perceived usefulness of a travel review website. Finally, Perceived usefulness of a travel review website has a significant impact on behavioral intention. Based on these findings, the implications and limitations of the study were presented including some directions for future studies.

• Journal of the Korean Applied Science and Technology
• /
• v.36 no.1
• /
• pp.279-298
• /
• 2019

Many empirical studies are conducted in regards to protean career or boundaryless career. The concept and the notion of protean career and boundaryless career has extended so far. Yet, the gap in the literature exists. Previous literature focused on the relationship among protean career, boundaryless career, and subjective career success, but examined little about the influence of protean career and boundaryless career on positive career attitude or future learning readiness. Therefore, this study explores the moderating effect of supporting policy of career development among protean career orientation, boundaryless career, positive career attitude, and future learning readiness. There was moderating effect of supporting policy of career development among the relationships of protean career orientation and future learning readiness; the relationships of boundaryless career and future learning readiness. The moderating effect of supporting policy of career development implies that the intention of career development in self-directed way and learning are related. In addition, The role of HRD/HRM department which takes initiatives in career development can affect the learning readiness for future among workers.