• Smart Media Journal
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• v.10 no.3
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• pp.39-47
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• 2021

Enhanced index tracking is a problem of optimizing the objective function to generate returns above the index based on the index tracking that follows the market return. In order to avoid problems such as large transaction costs and illiquidity, we used a method of constructing a portfolio by selecting only some of the stocks included in the index. Commonly used enhanced index tracking methods tried to find the optimal portfolio with only one objective function in all tested periods, but it is almost impossible to find the ultimate strategy that always works well in the volatile financial market. In addition, it is important to improve generalization performance beyond optimizing the objective function for training data due to the nature of the financial market, where statistical characteristics change significantly over time, but existing methods have a limitation in that there is no direct discussion for this. In order to solve these problems, this paper proposes ensemble learning that composes a portfolio by combining several objective functions and a 3-stage portfolio selection algorithm that can select a portfolio by applying criteria other than the objective function to the training data. The proposed method in an experiment using the S&P500 index shows Sharpe ratio that is 27% higher than the index and the existing methods, showing that the 3-stage portfolio selection algorithm and ensemble learning are effective in selecting an enhanced index portfolio.

• Korean Journal of Comparative Education
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• v.19 no.1
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• pp.25-58
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• 2009

This study aimed to establish a conceptual scheme of the quality of university and to develop a set of structured indicators for assessing the quality of university based on the result of comparative analysis of major approaches in foreign countries. Reviewing extensive literatures regarding the quality of higher education, a conceptual scheme of the quality of university, in which three representative approaches such as a goal-accomplishment approach, a customer-satisfaction approach, and a value-added approach were emphasized, was proposed and the quality of university was defined as a function of harmonization of input-process-output elements of universities. To develop indicators for assessing the quality of university, four types of approaches including university accreditation system, commercially-producted university ranking system, college student survey, and direct assessment of students' learning outcomes were reviewed. Finally thirteen sets of evaluation indicators out of six countries were comparatively analyzed. The analyses focused on the format, the content, and the primary concept of the quality in each instrument and a draft of the assessment indicators were structured. The draft of the assessment indicators were verified through a panel of professionals. The final indicators assessing the quality of university consist of three dimensions and seven areas. The input dimension comprised institutional goals, human resources, and physical resources. In the process dimension, curriculum and learning process areas were included. And, finally, the output dimension consists of educational outputs and research outputs. Based on the outcomes of the study, the recommendations were suggested for improving and utilizing the assessment indicators of the quality of university.

• Journal of The Korean Association For Science Education
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• v.29 no.4
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• pp.463-476
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• 2009

The purpose of this research was to find out if the analogical role-playing class activity had an effect on the students' academic achievements on cellular respirations as well as their science learning motivation for those who took part in the cellular respiration. To examine the effects of applying the activity, the research was conducted targeting a high school with humanities and social sciences courses, located in Busan. The target was specified as two classes that had selected a Biology II class, with one class (27 students) set as the test group and the other class (28 students) set as the control group. The conclusion drawn from this research was as follows: First, it seemed that the analogical role-playing activity helped the students to take their own parts in cellular respiration and gave them an opportunity to explain the concepts through direct physical activities, enhancing their academic achievements. Second, it was concluded that as the students found confidence and relevance in scientific knowledge as well as obtained a sense of accomplishment, the analogical role-playing class activity increased their level of satisfaction and their science learning motives. Third, as a result of the interviews on the change of the concept, students expressed some dissatisfaction over the new concept, and thought of the analogical role-playing activity as an intelligible alternative. It appeared that the alternative was plausible and fruitful.

• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.933-948
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• 2023

Atmospheric aerosols not only have adverse effects on human health but also exert direct and indirect impacts on the climate system. Consequently, it is imperative to comprehend the characteristics and spatiotemporal distribution of aerosols. Numerous research endeavors have been undertaken to monitor aerosols, predominantly through the retrieval of aerosol optical depth (AOD) via satellite-based observations. Nonetheless, this approach primarily relies on a look-up table-based inversion algorithm, characterized by computationally intensive operations and associated uncertainties. In this study, a novel high-resolution AOD direct retrieval algorithm, leveraging machine learning, was developed using top-of-atmosphere reflectance data derived from the Geostationary Ocean Color Imager-II (GOCI-II), in conjunction with their differences from the past 30-day minimum reflectance, and meteorological variables from numerical models. The Light Gradient Boosting Machine (LGBM) technique was harnessed, and the resultant estimates underwent rigorous validation encompassing random, temporal, and spatial N-fold cross-validation (CV) using ground-based observation data from Aerosol Robotic Network (AERONET) AOD. The three CV results consistently demonstrated robust performance, yielding R²=0.70-0.80, RMSE=0.08-0.09, and within the expected error (EE) of 75.2-85.1%. The Shapley Additive exPlanations(SHAP) analysis confirmed the substantial influence of reflectance-related variables on AOD estimation. A comprehensive examination of the spatiotemporal distribution of AOD in Seoul and Ulsan revealed that the developed LGBM model yielded results that are in close concordance with AERONET AOD over time, thereby confirming its suitability for AOD retrieval at high spatiotemporal resolution (i.e., hourly, 250 m). Furthermore, upon comparing data coverage, it was ascertained that the LGBM model enhanced data retrieval frequency by approximately 8.8% in comparison to the GOCI-II L2 AOD products, ameliorating issues associated with excessive masking over very illuminated surfaces that are often encountered in physics-based AOD retrieval processes.

• Korean Journal of Culture and Social Issue
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• v.10 no.3
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• pp.37-59
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• 2004

This study examines longitudinally influences that parents have on their children's academic achievement and the mediating role of various psychological factors. In terms of parents-child relationship, the following variables are examined: Social support from parents, achievement pressure, parental expectation, sense of indebtedness to parents, and respect for parents. For adolescents functioning, the following variables are examined: Efficacy for self-regulated learning, achievement motivation, studying time, and academic achievement. In the first phase of the longitudinal study, a total of 961 Grade 6 students completed a questionnaire. In the second phrase, a total of 856 students completed a questionnaire when they were Grade 7. In the third phrase, a total of 830 students completed a questionnaire when they were Grade 9. In the third phase, a matched sample of 722 fathers and 767 mothers of the adolescents completed a questionnaire. From the sample, 694 matched sample of adolescents, mothers, and fathers have been selected for the following analysis. The results of the path analysis indicate that adolescents' past academic grade was the most powerful predictor of adolescents' current academic achievement. Second, a sense of indebtedness felt towards the parents increased adolescents' achievement motivation, which increased their studying time and which in turn positively affected their academic achievement. Third, adolescents' respect for their parents increased their efficacy for self-regulated learning, which had a positive effect on their academic achievement. Fourth, parental social support increased adolescents' efficacy for self-regulated learning and parental achievement pressure increased adolescents' achievement motivation. Fifth, parental expectation had positive influence on adolescents' academic achievement. Sixth, efficacy for self-regulated learning had direct positive influence on academic achievement. These results indicate that the past achievement is the most important predictor of adolescents' current academic achievement and parent-child relationship and efficacy for self-regulated learning are also important variables that influence adolescents' achievement.

• Korean small business review
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• v.31 no.2
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• pp.19-37
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• 2009

The purpose of this research is to explore differences between small and medium-sized companies and large-sized companies in the impact of human resource innovativeness(HRI), learning orientation(LO), and HRI-LO interaction on innovation effect and business performance. Although learning orientation has long been considered as a key factor influencing good performance of a business, little research was devoted to exploring the effect of HRI-LO interaction on innovation effect and business performance. In this study, it is investigated whether there is a synergy effect between innovative human workforce and learning orientation corporate culture, in addition to each by itself, to generate good business performance as well as a success of new innovations in the market. Research hypotheses were as follows, including H1) human resource innovativeness(HRI), learning orientation(LO), and interactions of HRI and LO(HRI-LO interaction) positively affect innovation effect, H2) there is a difference of the effect of HRI, LO, and HRI-LO interaction on innovation effect between large-sized and small-sized companies, H3) HRI, LO, HRI-LO interaction, innovation effect positively affect business performance, and H4) there is a difference of the effect of HRI, LO, HRI-LO interaction, and innovation effect on business performance between large-sized and small-sized companies. Data were obtained from 479 practitioners through a web survey since the web survey is an efficient method to collect a national data at a variety of fields. A single respondent from a company was allowed to participate in the study after checking whether they have more than 5-year work experiences in the company. To check whether a common source bias is existed in the sample, additional data from a convenient sample of 97 companies were gathered through the traditional survey method, and were used to confirm correlations between research variables of the original sample and the additional sample. Data were divided into two groups according to company size, such as 352 small and medium-sized companies with less than 300 employees and 127 large-sized companies with 300 or more employees. Data were analyzed through t-test and regression analyses. HRI which is the innovativeness of human resources in the company was measured with 9 items assessing the innovativenss of practitioners in staff, manager, and executive-level positions. LO is the company's effort to encourage employees' development, sharing, and utilizing of knowledge through consistent learning. LO was measured by 18 items assessing commitment to learning, vision sharing, and open-mindedness. Innovation effect which assesses a success of new products/services in the market, was measured with 3 items. Business performance was measured by respondents' evaluations on profitability, sales increase, market share, and general business performance, compared to other companies in the same field. All items were measured by using 6-point Likert scales. Means of multiple items measuring a construct were used as variables based on acceptable reliability and validity. To reduce multi-collinearity problems generated on the regression analysis of interaction terms, centered data were used for HRI, LO, and Innovation effect on regression analyses. In group comparison, large-sized companies were superior on annual sales, annual net profit, the number of new products/services in the last 3 years, the number of new processes advanced in the last 3 years, and the number of R&D personnel, compared to small and medium-sized companies. Also, large-sized companies indicated a higher level of HRI, LO, HRI-LO interaction, innovation effect and business performance than did small and medium-sized companies. The results indicate that large-sized companies tend to have more innovative human resources and invest more on learning orientation than did small-sized companies, therefore, large-sized companies tend to have more success of a new product/service in the market, generating better business performance. In order to test research hypotheses, a series of multiple-regression analysis was conducted. In the regression analysis examining the impact on innovation effect, important results were generated as : 1) HRI, LO, and HRI-LO affected innovation effect, and 2) company size indicated a moderating effect. Based on the result, the impact of HRI on innovation effect would be greater in small and medium-sized companies than in large-sized companies whereas the impact of LO on innovation effect would be greater in large-sized companies than in small and medium-sized companies. In other words, innovative workforce would be more important in making new products/services that would be successful in the market for small and medium-sized companies than for large-sized companies. Otherwise, learning orientation culture would be more effective in making successful products/services for large-sized companies than for small and medium-sized companies. Based on these results, research hypotheses 1 and 2 were supported. In the analysis of a regression examining the impact on business performance, important results were generated as : 1) innovation effect, LO, and HRI-LO affected business performance, 2) HRI by itself did not have a direct effect on business performance regardless of company size, and 3) company size indicated a moderating effect. Specifically, an effect of the HRI-LO interaction on business performance was stronger in large-sized companies than in small and medium-sized companies. It means that the synergy effect of innovative human resources and learning orientation culture tends to be stronger as company is larger. Referring to these result, research hypothesis 3 was partially supported whereas hypothesis 4 was supported. Based on research results, implications for companies were generated. Regardless of company size, companies need to develop the learning orientation corporate culture as well as human resources' innovativeness together in order to achieve successful development of innovative products and services as well as to improve sales and profits. However, the effectiveness of the HRI-LO interaction would be varied by company size. Specifically, the synergy effect of HRI-LO was stronger to make a success of new products/services in small and medium-sized companies than in large-sized companies. However, the synergy effect of HRI-LO was more effective to increase business performance of large-sized companies than that of small and medium-sized companies. In the case of small and medium-sized companies, business performance was achieved more through the success of new products/services than much directly affected by HRI-LO. The most meaningful result of this study is that the effect of HRI-LO interaction on innovation effect and business performance was confirmed. It was often ignored in the previous research. Also, it was found that the innovativeness of human workforce would not directly influence in generating good business performance, however, innovative human resources would indirectly affect making good business performance by contributing to achieving the development of new products/services that would be successful in the market. These findings would provide valuable managerial implications specifically in regard to the development of corporate culture and education program of small and medium-sized as well as large-sized companies in a variety of fields.

• Journal of Korean Public Health Nursing
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• v.13 no.2
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• pp.26-44
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• 1999

The study was done to improve the job training course for Community Health Practioners (CHPs) by evaluating the level of help that the training provided to the CHPs in carrying out their work and to analyze the management activities of the CHPs in order to develop a more effective CHP training program. The methodologies used in the study were a questionnaire survey. The survey results were analyzed using SPSS Windows. The study results are as follows. 1. The total average level of help from the job training(Theory. Practice and Field Practice) for carrying out the CHP work was found to be $3.04\pm.53$ (of a possible 4), which indicates a high level of help. The average for clinical practices was $3.16\pm.60$. for theory. $3.11\pm.40$ and for field practice. $2.84\pm.60$. 2. For the theory content of the job training courses. the help level was low in the area of mother and child health management/family planning with an average of $2.65\pm.62$ and in the area of health information system development with an average of $2.62\pm.83$. The reason for these deficiencies were. in order of frequency. few opportunities to apply learning. training content that was inadequate. training methodologies which were incongruent with content. improper training items and insufficient class hours. For the practice. the clinical work in rehabilitation/orthopedics departments and in ENT/Opthalmology departments had averages of $2.96\pm.86$ and $2.97\pm.80$ respectively. This low level resulted from the lack of direct experience. lack of sincerity during the practice time. lack of practice guidance. insufficient time and lack of practice equipment. in that order. For the field practice. the delivery management averaged $2.06\pm.90$ as the lowest help level. In this case 68% of respondents replied that there were no relevant reasons for this deficiency. 21% responsed that there was a lack of direct experience, 7%, a lack of practice guidance and 4.8%, insufficient time. 3. There were significant differences for several demographic variables when comparing the help level of the clinical courses (practice and Field Practice). A higher help level was reported by older nurses as compared to younger ones, experienced nurses as compared to scholarship nurses, and married over single. Also for nurses who had finished more other programs and were qualified or licensed in several areas the level was high. Although it was not statistically significant the level was higher if the work area was in a rural county, not a city, and if one had more recently completed the job training(P<,05). 4. Of the respondents 58.6% replies stated the period of job training for the CHP was adequate, but 51.7% reported that the period for theory courses was too short while an other 48.3% responded that it was sufficient. For practice locations, 50% responsed that it was good to practice in medical institutions(primary, secondary and tertiary) at the same time. While 48.3% agreed that doing theory and practice simultaneously was good, and 56.9% agreed that field practice should be done after completing theory and practice training. Hence, the development of new field practice guidelines suitable for changing environments of health management are required in place of the existing ones which were considered low in help level to the practical work of the CHPs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.641-648
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• 2020

This study was undertaken to provide basic data for the development of a mental health promotion intervention program, by confirming the mediating effects of social support in relation to the effect on the life stress and meaning of life in middle-aged women. The subjects of this study were 201 middle-aged women from D and K cities. The data were analyzed with descriptive statistics and Pearson's correlations using a statistical program for structural equation modeling (SEM); fitness of the final model was RMSEA 0.03, CFI 0.98, and NFI 0.95. The major learning from this study was that life stress has a direct effect on meaning of life and social support. Life stress (β=0.05, p< 0.001), meaning of life (β=0.05, p< 0.001), and social support (β=0.05, p< 0.001) have a significant and direct effect on depression. The findings also suggest that life stress indirectly affects the mediating effect between meaning of life and social support, and also depression of middle-aged women. We believe that results of this study encompass basic data that will aid in developing a program to promote the mental health of middle-aged women.

• International Commerce and Information Review
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• v.7 no.4
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• pp.387-407
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• 2005

This paper is to study globalization motives and strategies of Japanese and Korean industries by analyzing the causes and patterns of foreign direct investment (FDI) of the firms of the two countries during the 1980s and 1990s. First we develop a FDI function from the profit maximizing model of firms. Then we use regression analysis to determine internally driving-out factors and externally-inducing factors. Japanese FDI strategy has gone through three different stages; from natural resource-seeking investment in the 1950s and 1960s to market-expansion investment in the 1970s and 1980s and to a combination of cost-reducing (low-cost labor-seeking) investment and market-penetrating investment in the 1990s. On the other hand, Korean FDI behavior has gone through four different stages; from the learning stage with small investments in the 1970s, to natural resource-seeking investment in the early and mid 1980s, to the growth stage in the late 1980s and the early 1990s, to the maturity stage of the mid and late 1990s. The last two stages were characterized by a combination of cost-reducing investment and market-seeking investment. As a late comer, Korea began its FDI two decades later than Japan, but caught up the patterns of Japanese FDI by the mid 1990s and is in a competing position with Japan. Our findings show that both Japanese FDI and Korean FDI in Asia and other developing countries tendto be in labor-intensive sectors where their firms are losing their comparative advantages at home. The main motive for FDI into these regions is low-cost resource seeking. On the other hand, both Japanese FDI and Korean FDI in the U.S. and Europe tend to be knowledge-intensive sectors where Japanese and Korean firms attempt to internalize transaction and information costs by globalizing its production. The main motive for FDI into these regions is market-seeking. Firms in both countries have increased their investments in Mexico and Western and Eastern Europe in order to penetrate large economic blocs such as the EU and NAFTA area. Korean firms are more aggressive in expanding into new and untested markets than are their counterpart in Japan. Evidence of this can be seen in the scarcity of Japanese FDI and abundance of Korean FDI in Eastern Europe and China.

• Journal of Elementary Mathematics Education in Korea
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• v.20 no.2
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• pp.215-238
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• 2016

The 2015 national revised curriculum was notified officially the last year. The intent and direction of the revision caused more or less change for mathematical contents to be taught and is expected to cause a considerable change in math class. In the level of elementary school mathematics, it turned that several contents were deleted or moved to the upper grades because the revision focused especially both on reducing students' burden of learning and on fostering the mathematical key competences. This study aims to examine the relevance of the change through investigation of the national curriculums for elementary school mathematics since 1946. The mathematical contents to be analyzed in this study were mixed calculation of natural numbers, mixed calculation of fractions and decimal fractions, position and direction of objects, are/hectare and ton, the range of numbers and estimating, surface and volume of cylinders, pattern and correspondence, and direct/inverse proportionality, which were changed in any aspect relative to 2009 national revised curriculum. Based on the results of these analyses, the discussion will provide some suggestions for setting the direction of elementary mathematics curriculum.