• Title/Summary/Keyword: Panel Data Regression Model

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Sea-Level Trend at the Korean Coast

  • Cho, Kwangwoo
    • Journal of Environmental Science International
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    • v.11 no.11
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    • pp.1141-1147
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    • 2002
  • Based on the tide gauge data from the Permanent Service for Meau Sea Level (PSMSL) collected at 23 locations in the Korean coast, the long-term sea-level trend was computed using a simple linear regression fit over the recorded length of the monthly mean sea-level data. The computed sea-level trend was also corrected for the vertical land movement due to post glacial rebound(PGR) using the ICE-4G(VM2) model output. It was found that the PGR-corrected sea-level trend near Korea was 2.310 $\pm$ 2.220 mm/yr, which is higher than the global average at 1.0∼2.0mm/yr, as assessed by the Intergovernmental Panel on Climate Change(IPCC). The regional distribution of the long-term sea-level trend near Korea revealed that the South Sea had the largest sea-level rise followed by the West Sea and East Sea, respectively, supporting the results of the previous study by Seo et al. However, due to the relatively short record period and large spatial variability, the sea-level trend from the tide gauge data for the Korean coast could be biased with a steric sea-level rise by the global warming during the 20th century.

The Role of Overconfident CEO to Dividend Policy in Industrial Enterprises

  • HOANG, Lam Xuan;DANG, Duong Quy;TRAN, Thuan Duc
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.7
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    • pp.361-367
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    • 2020
  • Researching the influence and role of CEO overconfidence to dividend policy is important for stock market investors. Therefore, this study was conducted to find out the relationship between CEO overconfidence and dividend policy in industrial enterprises in Vietnam. Data collected from 222 industry enterprises listed on the Vietnam Stock Exchange from 2012 to 2018. Data is collected on financial statements of listed companies. GLS model with panel data is used to analyze regression results. The results show that CEO overconfidence has dividend yield higher than CEO non-overconfidence. At the same time, the dividend payout ratio of enterprises has no difference between CEO overconfidence and CEO non-overconfidence. The results also showed that revenue growth has a positive impact on dividend yield in small enterprises, but negative impact on dividend payout in large enterprises. Research results by firm size have similar results with the general analysis for all enterprises. At the same time, the analysis of ownership type shows that CEO overconfidence has a positive impact on dividend yield of non-state enterprises without affecting other types of enterprises. From these results, the authors also made a number of recommendations to help investors choose businesses to invest in accordance with their strategies.

The health status, aging anxiety, social networking, generativity, and happiness of late middle-aged adults (중년후기 성인의 건강상태, 노화불안, 사회관계망, 생성감 및 행복)

  • Chang, Hae Kyung
    • The Journal of Korean Academic Society of Nursing Education
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    • v.27 no.4
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    • pp.392-401
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    • 2021
  • Purpose: This study was conducted to identify the relationship of health status, aging anxiety, social networking, generativity, and happiness and to investigate the main factors influencing happiness of late middle-aged adults. Methods: The study collected data from a total of 153 middle-aged men and women aged 50 to 64 years old from a consumer panel of Macromill-Embrain, the biggest online survey provider in Korea. The data were analyzed using descriptive statistics, Pearson's correlation coefficient and a stepwise multiple regression using the SPSS 22.0 program. Results: The subjects' happiness mean score was 16.17±9.29. Statistically significant differences in happiness were found according to education (F=4.38, p=.014), economic status (t=5.13, p<.001), and religion (t=2.18, p=.031). Happiness was correlated significantly with health status (r=.41, p<.001), aging anxiety (r=-.62, p<.001), family support (r=.43, p<.001), friend support (r=.36, p<.001) and generativity (r=.63, p<.001). The factors influencing happiness of late middle-aged adults were generativity (𝛽=.37, p<.001), aging anxiety (𝛽=-.35, p<.001), family support (𝛽=.20, p<.001), and economic status (𝛽=.13, p=.033). The explanatory power of the model was 58.0%. Conclusion: This study will be used as basic data when developing a nursing intervention program for successful aging by identifying factors that affect the happiness of late middle-aged adults.

A Study for Building Credit Scoring Model using Enterprise Human Resource Factors (기업 인적자원 관련 변수를 이용한 기업 신용점수 모형 구축에 관한 연구)

  • Lee, Yung-Seop;Park, Joo-Wan
    • The Korean Journal of Applied Statistics
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    • v.20 no.3
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    • pp.423-440
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    • 2007
  • Although various models have been developed to establish the enterprise credit scoring, no model has utilized the enterprise human resource so far. The purpose of this study was to build an enterprise credit scoring model using enterprise human resource factors. The data to measure the enterprise credit score were made by the first-year research material of HCCP was used to investigate the enterprise human resource and 2004 Credit Rating Score generated from KIS-Credit Scoring Model. The independent variables were chosen among questionnaires of HCCP based on Mclagan(1989)'s HR wheel model, and the credit score of Korean Information Service was used for the dependent variables. The statistical method used for data analysis was logistic regression. As a result of constructing a model, 22 variables were selected. To see these specifically by each large area, 6 variables in human resource development(HRD) area, 15 in human resource management(HRM) area, and 1 in the other area were chosen. As a consequence of 10 fold cross validation, misclassification rate and G-mean were 30.81 and 68.27 respectively. Decile having the highest response rate was bigger than the one having the lowest response rate by 6.08 times, and had a tendency to decrease. Therefore, the result of study showed that the proposed model was appropriate to measure enterprise credit score using enterprise human resource variables.

Development and application of prediction model of hyperlipidemia using SVM and meta-learning algorithm (SVM과 meta-learning algorithm을 이용한 고지혈증 유병 예측모형 개발과 활용)

  • Lee, Seulki;Shin, Taeksoo
    • Journal of Intelligence and Information Systems
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    • v.24 no.2
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    • pp.111-124
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    • 2018
  • This study aims to develop a classification model for predicting the occurrence of hyperlipidemia, one of the chronic diseases. Prior studies applying data mining techniques for predicting disease can be classified into a model design study for predicting cardiovascular disease and a study comparing disease prediction research results. In the case of foreign literatures, studies predicting cardiovascular disease were predominant in predicting disease using data mining techniques. Although domestic studies were not much different from those of foreign countries, studies focusing on hypertension and diabetes were mainly conducted. Since hypertension and diabetes as well as chronic diseases, hyperlipidemia, are also of high importance, this study selected hyperlipidemia as the disease to be analyzed. We also developed a model for predicting hyperlipidemia using SVM and meta learning algorithms, which are already known to have excellent predictive power. In order to achieve the purpose of this study, we used data set from Korea Health Panel 2012. The Korean Health Panel produces basic data on the level of health expenditure, health level and health behavior, and has conducted an annual survey since 2008. In this study, 1,088 patients with hyperlipidemia were randomly selected from the hospitalized, outpatient, emergency, and chronic disease data of the Korean Health Panel in 2012, and 1,088 nonpatients were also randomly extracted. A total of 2,176 people were selected for the study. Three methods were used to select input variables for predicting hyperlipidemia. First, stepwise method was performed using logistic regression. Among the 17 variables, the categorical variables(except for length of smoking) are expressed as dummy variables, which are assumed to be separate variables on the basis of the reference group, and these variables were analyzed. Six variables (age, BMI, education level, marital status, smoking status, gender) excluding income level and smoking period were selected based on significance level 0.1. Second, C4.5 as a decision tree algorithm is used. The significant input variables were age, smoking status, and education level. Finally, C4.5 as a decision tree algorithm is used. In SVM, the input variables selected by genetic algorithms consisted of 6 variables such as age, marital status, education level, economic activity, smoking period, and physical activity status, and the input variables selected by genetic algorithms in artificial neural network consist of 3 variables such as age, marital status, and education level. Based on the selected parameters, we compared SVM, meta learning algorithm and other prediction models for hyperlipidemia patients, and compared the classification performances using TP rate and precision. The main results of the analysis are as follows. First, the accuracy of the SVM was 88.4% and the accuracy of the artificial neural network was 86.7%. Second, the accuracy of classification models using the selected input variables through stepwise method was slightly higher than that of classification models using the whole variables. Third, the precision of artificial neural network was higher than that of SVM when only three variables as input variables were selected by decision trees. As a result of classification models based on the input variables selected through the genetic algorithm, classification accuracy of SVM was 88.5% and that of artificial neural network was 87.9%. Finally, this study indicated that stacking as the meta learning algorithm proposed in this study, has the best performance when it uses the predicted outputs of SVM and MLP as input variables of SVM, which is a meta classifier. The purpose of this study was to predict hyperlipidemia, one of the representative chronic diseases. To do this, we used SVM and meta-learning algorithms, which is known to have high accuracy. As a result, the accuracy of classification of hyperlipidemia in the stacking as a meta learner was higher than other meta-learning algorithms. However, the predictive performance of the meta-learning algorithm proposed in this study is the same as that of SVM with the best performance (88.6%) among the single models. The limitations of this study are as follows. First, various variable selection methods were tried, but most variables used in the study were categorical dummy variables. In the case with a large number of categorical variables, the results may be different if continuous variables are used because the model can be better suited to categorical variables such as decision trees than general models such as neural networks. Despite these limitations, this study has significance in predicting hyperlipidemia with hybrid models such as met learning algorithms which have not been studied previously. It can be said that the result of improving the model accuracy by applying various variable selection techniques is meaningful. In addition, it is expected that our proposed model will be effective for the prevention and management of hyperlipidemia.

An Analysis of Distributed Lag Effects of Expenditure by Type of R&D on Scientific Production: Focusing on the National Research Development Program (연구개발단계별 연구개발투자와 논문 성과 간의 시차효과 분석: 국가연구개발사업을 중심으로)

  • Pak, Cheol-Min;Ku, Bon-Chul
    • Journal of Korea Technology Innovation Society
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    • v.19 no.4
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    • pp.687-710
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    • 2016
  • This study aims to empirically estimate distributed lag effects of expenditure by type of R&D on scientific publication in the national R&D program. To analyze the lag structure between them, we used a dataset comprised of panel data from 104 technologies categorized by 6T (IT, BT, NT, ST, ET, CT) from 2007 to 2014, and employed multiple regression analysis based on the polynomial distributed lag model. This is because it is highly likely to emerge multicollinearity, if a distributed lag model without special restrictions is applied to multiple regression analysis. The main results are as follows. In the case of basic research, its lag effects are relatively evenly distributed during four years. On the other hand, the applied research and experimental development have distributed lag effects for three years and two years respectively. Therefore, when it comes to analyzing performance of scientific publication, it is necessary to be performed with characteristics of the time lag by type of R&D.

The Moderating Effect of Internal Control on Performance of Cross-Border M&A under the Uncertainty of Economic Policy: Evidence from China

  • Huang, Xiao-Lin;Chen, Guan-Ting;Lee, Eun-Hye
    • Journal of Korea Trade
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    • v.23 no.7
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    • pp.128-146
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    • 2019
  • Purpose - The purpose of this paper is to investigate the relationship between internal control, economic policy uncertainty, and performance of cross-border merger and acquisition (M&A) based on the panel data of Chinese listed firms. The authors expected that internal control has a positive moderating effect on the performance of cross-border M&A and that it mainly occurs during periods when economic policies are relatively stable. In addition, the authors tried to find out the mechanism of internal control affecting cross-border M&A and the corporate performance. Design/methodology - The authors tested the hypotheses by a multivariate regression model based on the panel data of Chinese listed firms from 2009 to 2017. The dependent variable is the change value of business performance (DROA_1,2,3) and the explanatory variables are cross-border M&A (MA), China's uncertainty of economic policy (EPU), and internal control level (IC) respectively. Findings - The authors find that internal control has a positive moderating effect on the relationship between cross-border M&A and corporate performance. Further, the authors find that the moderating effect is more significant in state-owned enterprises and that it mainly occurs during periods when economic policies are relatively stable. Originality/value - This paper is the leading study that tries to analyze empirically the relationship between internal control, economic policy uncertainty, and performance of cross-border M&A. It provides a new avenue through which internal control might reasonably mitigate the risks of cross-border M&A and correspondingly improve the performance of cross-border M&A. It also confirms the moderating effect of internal control on the performance of cross-border M&A under the uncertainty of economic policy.

Future water quality analysis of the Anseongcheon River basin, Korea under climate change

  • Kim, Deokwhan;Kim, Jungwook;Joo, Hongjun;Han, Daegun;Kim, Hung Soo
    • Membrane and Water Treatment
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    • v.10 no.1
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    • pp.1-11
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    • 2019
  • The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) predicted that recent extreme hydrological events would affect water quality and aggravate various forms of water pollution. To analyze changes in water quality due to future climate change, input data (precipitation, average temperature, relative humidity, average wind speed and sunlight) were established using the Representative Concentration Pathways (RCP) 8.5 climate change scenario suggested by the AR5 and calculated the future runoff for each target period (Reference:1989-2015; I: 2016-2040; II: 2041-2070; and III: 2071-2099) using the semi-distributed land use-based runoff processes (SLURP) model. Meteorological factors that affect water quality (precipitation, temperature and runoff) were inputted into the multiple linear regression analysis (MLRA) and artificial neural network (ANN) models to analyze water quality data, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), total nitrogen (T-N) and total phosphorus (T-P). Future water quality prediction of the Anseongcheon River basin shows that DO at Gongdo station in the river will drop by 35% in autumn by the end of the $21^{st}$ century and that BOD, COD and SS will increase by 36%, 20% and 42%, respectively. Analysis revealed that the oxygen demand at Dongyeongyo station will decrease by 17% in summer and BOD, COD and SS will increase by 30%, 12% and 17%, respectively. This study suggests that there is a need to continuously monitor the water quality of the Anseongcheon River basin for long-term management. A more reliable prediction of future water quality will be achieved if various social scenarios and climate data are taken into consideration.

A Study on Development of the Concrete Pavement Condition Index (콘크리트 포장상태 평가지수의 개발에 관한 연구)

  • Kwon, Soo-Ahn;Kim, Nam-Ho;Seo, Young-Chan
    • International Journal of Highway Engineering
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    • v.2 no.3
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    • pp.145-153
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    • 2000
  • Pavement evaluation is a fundamental component for rational pavement management. Optimal rehabilitation method and the priority of rehabilitation should be based on the evaluation data. Some types of pavement condition index are needed for objective evaluation of Pavement condition and management of road network. In this study a expressway concrete pavement condition index model is developed through regression analysis that correlates panel rating with distress measurement from the test sections. The derived condition index can be used for network level PMS for the expressway concrete pavement. Correlation coefficient of the model was 0.68. The selected independent variables were International Roughness Index, crack and area of patching.

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Tax Avoidance and Corporate Risk: Evidence from a Market Facing Economic Sanction Country

  • SALEHI, Mahdi;KHAZAEI, Sharbanoo;TARIGHI, Hossein
    • The Journal of Asian Finance, Economics and Business
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    • v.6 no.4
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    • pp.45-52
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    • 2019
  • The current study aims to investigate the relationship between tax avoidance and firm risk in an emerging market called Iran. The study population consists of 400 observations and 80 companies listed on the Tehran Stock Exchange (TSE) over a five-year period during 2012 and 2016. The statistical model used in this study is a multivariate regression model; besides, the statistical technique used to test the hypotheses proposed in this research is panel data. The results showed that low effective tax rate (tax avoidance) is more consistent than the higher effective tax rate. Moreover, there is no significant relationship between tax avoidance and future tax rate volatility. The findings also proved that lower effective tax rates are positively associated with future stock price volatility. This implies that since Iranian firms have many financial problems because of economic sanctions, they have a tendency to delay the disclosure of bad news about their firms. Needless to say, when a huge number of negative news reaches its peak, they immediately will enter the market and lead to a remarkable fluctuation in stock prices.