• Environmental and Resource Economics Review
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• v.31 no.2
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• pp.233-260
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• 2022

In this paper, we analyzed how oil price fluctuations affect stock price by industry using the non-parametric quantile causality test method. We used weekly data of WTI spot price, KOSPI index, and 22 industrial stock indices from January 1998 to April 2021. The empirical results show that the effect of changes in oil prices on the KOSPI index was not significant, which can be attributed to mixed responses of diverse stock prices in several industries included in the KOSPI index. Looking at the stock price response to oil price by industry, the 9 of 18 industries, including Cloth, Paper, and Medicine show a causality with oil prices, while 9 industries, including Food, Chemical, and Non-metal do not show a causal relationship. Four industries including Medicine and Communication (0.45~0.85), Cloth (0.15~0.45), and Construction (0.5~0.6) show causality with oil prices more than three quantiles consecutively. However, the quantiles in which causality appeared were different for each industry. From the result, we find that the effects of oil price on the stock prices differ significantly by industry, and even in one industry, and the response to oil price changes is different depending on the market situation. This suggests that the government's macroeconomic policies, such as industrial and employment policies, should be performed in consideration of the differences in the effects of oil price fluctuations by industry and market conditions. It also shows that investors have to rebalance their portfolio by industry when oil prices fluctuate.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.6
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• pp.737-745
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• 2008

Recent developments of process and measurement technology bring much interest to the online monitoring of process operations such as milling, grinding, broaching, etc. The objective of online monitoring systems is to detect process changes as early as possible. This is helpful in protecting facilities against unexpected failures and then preventing unnecessary loss. This paper investigates, when the process monitoring data are obtained as a profile, the monitoring performances of a statistical $T^2$-statistic and a feedforward neural network by using a wavelet transform. Numerical experiments using cutting force data presented by Axinte show that the proposed wavelet based $T^2$-test has an acceptable power in detecting profile changes. However, its operating characteristic is very sensitive to autocorrelation. On the contrary, compared with $T^2$-test, the neural network has more stable performance in the presence of autocorrelation. This indicates that an adaptive feature to analyze noises should be incorporated into the wavelet based $T^2$-test.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.3
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• pp.257-264
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• 2018

The recent global climate change induced the drought, flooding, and insect pest outbreaks. These caused the severe damage to crop yield in the domesticated field and occurrence change of insect pest species. The sap-sucking insect pest, aphids are common in soybean [Glycine max (L.) Merr.] and cause serious yield losses. Thus, developing resistance cultivars is promising and efficient strategy to prevent the significant yield losses by aphid and screening germplasm is the essential procedure to achieve this goal. We tried to establish a resistance test indicator for foxglove aphid, Aulacorthum solani (Kaltenbach), in soybean and found that plant damage degree or infested plant damage is most suitable one. Also we screened around 1,200 of soybean germplasm including wild and cultivated species for its resistance to foxglove aphid from the various origins, and 67 soybeans, including PI 366121, showed antixenosis resistance, 31 germplasms among 67 antixenosis germplasms were showed antibiosis to foxglove aphid with non-choice test. The identified foxglove aphid resistant soybean resources showed significantly low rate in survival test. Furthermore, resistance type, (i.e., antibiosis or antixenosis) of each candidate were varied. In this research, we established the screening index for foxglove aphid resistance in soybean, and identified the resistance varieties. This result could be useful resources in breeding for new foxglove aphid resistance soybean cultivars, and provide fundamental information to investigate the resistance mechanism in soybean.

• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.170-182
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• 2013

The purpose of this study is to examine the influence of the leadership style of a CEO of a public performing arts theater to the quality management and business performance, with a focus on the differences by the leadership styles. For this purpose, a survey was conducted with the CEO of 165 public performing arts theaters in country, from whom 98 valid replies were collected for analysis and further validation of hypothesis of this study. The validation revealed that, first, the task oriented and change oriented leadership provided positive influences to the quality management activities, while relations oriented leadership failed to do so. Secondly, the quality management activities by the CEOs of the public performing arts theaters had positive correlations with the financial performance and market performance, which are part of the business performance indices of a performance art center. Thirdly, while the task oriented and change oriented leadership styles did have influences over the business performance; it was revealed that the quality management activities wielded only indirect influence toward such elements. The relations oriented leadership style appeared to fail to influence with significance. Such results as above show that only the task oriented and change oriented leadership style of a CEO in a public performing arts theater had positive influences over the business performance, with an implication that the CEOs of such facilities shall keep this in mind and exercise such leadership styles. In addition, another implication of this study was that it is also important to give efforts to the quality management activities, which turned out to influence the business performance significantly. The implication of this study is that the study was conducted with direct participation by the CEOs themselves of public performing arts theaters in country and an examination was made to see the differences by leadership styles.

• KEPCO Journal on Electric Power and Energy
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• v.3 no.1
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• pp.65-72
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• 2017

This study analyzed causal relationship between electricity consumption and economic output (GDP) for Korea from 2001 to 2014 employing the vector error-correction model estimation by manufacturing sector. The results of unit-roots tests show that all sectoral GDP and electricity consumptions were not stationary. And cointegration tests show that processed foods, Wood Pulp Paper, electricity apparatus, Precision Medical sectors had a linear combinations in the long run between electricity consumptions and economic growth. With respect to the direction of causality, manufacturing sector has a uni-directional running from economic output (GDP) to electricity consumption in short term. The results of study show that sectoral causal relation were different each other in short term and long term. These findings imply that electricity demand management policy focusing on efficiency improvement is necessary to minimize negative impacts on economic growth and to adopt suitable structural policies can induce energy conservation.

• Journal of Digital Convergence
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• v.17 no.9
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• pp.115-126
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• 2019

This study is a survey of people who are return to farming on the intention of accepting ICT convergence technology in agriculture. The research targets were 218 people based on convenience and judgment sampling methods, and the exploratory factor analysis and multiple return analysis were performed with SPSS 22.0. As a result, the independent variables such as performance expectation, effort expectation, and social influence had a positive effect on the acceptance intention of ICT convergence technology in agriculture. In addition, the moderating effects of innovation resistance on these influence relationships were also verified. The limitations of this study are the lack of verification of perception changes and the inability to control variables. As a result of this research, the results of the UTAUT in other fields were confirmed in this study. It is hoped that this study will further facilitate the research of agriculture in ICT convergence technology.

• Journal of Music and Human Behavior
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• v.6 no.1
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• pp.33-53
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• 2009

The purpose of this study is to examine the effects of a singing program on withdrawal behaviors of children in low-income families. To measure the effects of the singing program, the researcher compared the results of K-YSR and TRF withdrawal scales before and after the program. Finally, the researcher did research on the subjects' musical and non-musical behaviors related to withdrawal through a record of behavior observation. The results of this study were asfollows: First, after comparing the results of K-YSR and TRF withdrawal scales conducted before and after the singing program, the mean of the scores was decreased by 6.4 and 3.6 points respectively (p = .042). Second, an analysis of withdrawal-related behavioral changes in music activities after the program showed an increase in frequency of eye contact, as well as tone and volume of subjects' voices. The results of this study indicate that the singing program has positive effects on withdrawal behaviors of children in low-income familiesin addition, it is effective in alleviating withdrawal-related behaviors.

• Korean Journal of Poultry Science
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• v.39 no.3
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• pp.233-239
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• 2012

Public forecasts for broiler's prices such as Korea Rural Economic Institute (KREI) outlook information are important for producers and agribusiness decision makers in enhancing economic decision making. However, the KREI forecasts have not been fully evaluated so far. In this study agricultural outlook price forecasts for broiler are evaluated under accuracy-based measures and classification-based measures which test the ability to categorize price movements directionally or within a forecasted range. Agricultural outlook price forecasts for broiler are efficient but biased. In the aspect of the monthly direction of price change 59% of its forecasts over the sample period are correct, and actual prices fall within the forecasted range 32% of the time. Results suggest that it is necessary and meaningful for the agricultural outlook center to evaluate the current forecasting method and try to find an alternative method for improving the forecasting technique.

• Education of Primary School Mathematics
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• v.26 no.1
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• pp.1-13
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• 2023

One of major goals of mathematics education is to cultivate human resources which equip creative problem-solving ability. Thus, the enhancement of creative and converging ideas has been emphasized in the national curriculum since the 2009 revised curriculum. In the current study, we analyzed authorized textbook series to examine how each curriculum material addresses the creativity convergence competency. The foci of the analysis were creativity (originality, fluency, flexibility, elaboration) and convergence (intrinsic connection, extrinsic connection). In addition, we analyzed the national textbook which was based on the 2015 revised curriculum to investigate the transition between the national textbook and the authorized textbooks. We found the tasks that focused on fluency were the most frequent type regarding creativity and the tasks that connected with everyday life situations (extrinsic connection) were prevalent across the three textbook series. We provided suggestions about the development of mathematics textbooks and their implementation.

• Water for future
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• v.15 no.4
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• pp.39-44
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• 1982

A numerical computation of unsteady flow in the open channel was studied with the linearized four-point method of characteristics. A seiche test for this model was fulfilled and its result was very close to the exact solution. The effect of linearization to the accuracy of the result was small enough for the analysis of nearly horizontal flow, and this model would be applicable for the real unsteady flow problem because of its convenience.