• 통상정보연구
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• 제12권4호
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• pp.151-170
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• 2010

The present study made an empirical analysis for investigating the competitiveness of technology trades in Korea. In particular, the study deduced the correlation between technology export and technology import using the variables of Gross Domestic Expenditure on R&D and Per capita industry value added Productivity and employed fixed effect model in panel linear regression model. It is found that the R&D expenditure of OECD countries made a significant effect on the technology import and the value-added labor productivity made a significant result on both technology export and import. Therefore, it showed that the technology trade in Korea made a sensitive response to labor productivity in OECD countries. By panel analysis, machine, construction, ICT, and service industry affect most on technology export in Korea for recent 5 years. For technology import, electric-electron, chemical, service, and construction industry have significant effects. This study contributed to understanding of industrial characteristics affecting technology trades in Korea and empirical analysis to show correlation between the factors affecting technology trade.

• Journal of the Korean Statistical Society
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• 제30권3호
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• pp.511-527
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• 2001

This paper consider the testing problem of variance component for the unbalanced tow=-way error component model. We provide a conditional LM test statistic for testing zero individual(time) effects assuming that the other time-specific(individual)efefcts are present. This test is extension of Baltagi, Chang and Li(1998, 1992). Monte Carlo experiments are conducted to study the performance of this LM test.

• 응용통계연구
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• 제34권5호
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• pp.697-710
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• 2021

상대오차를 이용한 예측법은 상대오차(혹은 퍼센트오차)가 중요시되는 분야, 특히 계량경제학이나 소프트웨어 엔지니어링, 또는 정부기관 공식통계 부분에서 기존 예측방법 외에 선호되는 예측방법이다. 그 동안 상대오차를 이용한 예측법은 선형 혹은 비선형 회귀분석 뿐 아니라, 커널회귀를 이용한 비모수 회귀모형, 그리고 정상시계열분석에 이르기까지 그 범위가 확장되어 왔다. 그러나, 지금까지의 분석은 고정효과(fixed effect)만을 고려한 것이어서 임의효과(random effect)에 관한 상대오차 예측법에 대한 확장이 필요하였다. 본 논문의 목적은 상대오차예측법을 일반화선형혼합모형(GLMM)에 속한 감마회귀(gamma regression), 로그정규회귀(lognormal regression), 그리고 역가우스회귀(inverse gaussian regression)의 패널자료(panel data)에 적용시키는데 있다. 이를 위해 실제 자동차 보험회사의 손해액 자료를 사용하였고, 최량예측량과 최량상대오차예측량을 각각 적용-비교해 보았다.

• Journal of the Korean Statistical Society
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• 제29권1호
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• pp.63-80
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• 2000

We consider the panel data regression model with nested error componets. In this paper, the several Lagrange Multipler tests for the nested error component model are derived. These tests extend the earlier work of Honda(1985), Moulton and Randolph(1989), Baltagi, et al.(1992) and King and Wu(1997) to the nested error component case. Monte Carlo experiments are conducted to study the performance of these LM tests.

• 환경정책연구
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• 제3권2호
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• pp.89-112
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• 2004

This Study aims to demonstrate how much flood vulnerability in urban area changed for the past 32 years by using the panel model. At the same time, this study strives to determine the primary factors and to construct an effective counter-plan by means of empirical research. After selecting research hypotheses based on considerations of issues concerning causes for urban flooding, their relevance is put to the test by conducting empirical research in individual case locations. This research verifies the four research hypotheses by using one-way error component regression model. In conclusion, this research has shown that urban land use and local characteristics act as significant flood determinants, with forests acting to reduce flood dangers. Moreover, constructing embankments can no longer represent a reliable flood control policy. The changes in future flood control policies need to incorporate local characteristics and to minimize natural destruction, so that humans and nature can coexist through environmentally friendly flood management policies.

• 한국지리정보학회지
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• 제21권1호
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• pp.46-56
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• 2018

본 연구에서는 지표면 온도 변화에 미치는 주요 지역특성인자를 도출하고 각각의 인자가 미치는 확률적 영향계수를 추정하였다. 연구대상지역은 충청북도 전역이며 패널 분석을 위해 시 군 행정 단위로 분할하였다. 지표면온도 및 지역특성 시계열자료들은 MODIS 영상과 통계청자료를 사용하여 각각 구축하였다. 그리고 지표면온도와 횡단면자료인 지역특성인자들을 다중회귀관계로 설정하고 패널 모형 분석을 통하여 회귀계수 추정치를 산정하였다. 지표면온도와 지역특성인자는 패널 모형 분석에서 종속변수와 설명변수로 각각 사용하였다. 패널 자료 분석은 상용 통계프로그램 STATA14를 사용하였으며, 일원 개체 고정효과모형이 본 연구의 지표면온도 변화 해석에 가장 적절한 모형으로 선정되었다. 지표면온도 변화에 미치는 설명변수의 영향수준을 나타내는 기여율은 회귀방정식의 추정회귀계수로부터 구했다. 설명변수별 기여율은 도시 공업지역이 3.746로 가장 컸으며, 다음으로 평균고도${\times}$대지면적비율이 2.856, 전력사용량 2.742, 평균풍속 0.553, 비도시관리지역 0.102, 농림지역과 자연 환경보전지역은 0.085와 0.071 그리고 시 군의 평균강우량 한 단위 변화가 지표면온도 변화에 미치는 기여율은 0.003으로 추정되었다.

• 수산경영론집
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• 제51권1호
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• pp.81-96
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• 2020

The purpose of this paper is to analyze factors affecting the net income of regional and industrial fisheries cooperatives in South Korea using panel data. This paper utilizes linear or GLS regression models such as pooled OLS model, fixed effects model, and random effects model to estimate affecting factors of the net income of regional and industrial fisheries cooperatives. After reviewing various tests, we eventually select random effects model. The results, based on panel data between 2013 and 2018 year and 64 fisheries cooperatives, indicate that capital and area dummy variables have positive effects and employment has negative effect on the net income of regional and industrial fisheries cooperatives as predicted. However, debt are opposite with our predictions. Specifically, it turns out that debt has positive effect on the net income of regional and industrial fisheries cooperatives although it has been increased. Additionally, this paper shows that the member of confreres does not show any significant effect on the net income of regional and industrial fisheries cooperatives in South Korea. This study is significant in that it analyzes the major factors influencing changes in the net income that have not been conducted recently for the fisheries cooperatives by region and industry.

• The Journal of Asian Finance, Economics and Business
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• 제7권7호
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• pp.139-147
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• 2020

This paper aims to explore the relationship between the quality of the audit and the level of stock return co-movement in the context of the Vietnamese emerging market. The empirical study is designed based on the quatitative method and deductive approach. The panel dataset includes 256 listed firms from different industries,with 1115 firm-year observations on Ho Chi Minh City Stock Exchange for the period from 2014 to 2018. In the research, we built the econometric regression model, using stock return synchronicity and audit quality as the dependent and independent variable, respectively. Some control variables are also added to the econometric regression models as they are well-documented in prior research to have an effect on stock price synchronicity. To improve the accuracy of the regression coefficients, beside the Ordinary Least Squares, we employ the Random Effects Model and the Fixed Effects Model for better statistical analysis of panel data set. The results show that the quality of the audit is positively correlated to stock price synchronicity. This finding suggests that stock returns of companies with higher quality of the audit are more synchronous with the market. Results for other control variables also support our reasoning for the main findings.

• The Journal of Asian Finance, Economics and Business
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• 제9권9호
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• pp.181-189
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• 2022

The current study examines the nexus between the capital structure (debt-equity) and firm value (Tobin's Q) by including profitability (alternatively Return on Assets (ROA) and Return on Equity (ROE)) as a moderator in the companies of Saudi Arabia. The study sample consists of 102 companies listed on Tadawul (the Saudi Arabian stock exchange) from different sectors of Saudi Arabia during the period 2013 to 2020. The study estimates pooled regression, panel regression with fixed and random effects, and dynamic panel regression models to report the results. The study results report that there is a negative and significant association between capital structure and firm value in model 1, while in models 2 and 3 there is a more negative and significant impact between the two study variables compared to model 1 after the inclusion of interaction variable, i.e. profitability in terms of ROA and ROE. The comparative result shows that the companies of Saudi Arabia hold more debt in their capital structure mix, hence evidencing a decrease in the firm value. The reported results also show that models 2 and 3 are better in explaining the impact of capital structure on firm value due to the interaction of profitability compared to model 1.

• Journal of the Korean Data and Information Science Society
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• 제28권3호
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• pp.547-557
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• 2017

건강 관련 삶의 질 자료는 정규분포를 따르지 않고 치우친 분포를 보이며, 등분산 가정을 만족하지 않는 경우가 대부분이다. 또한 건강 관련 삶의 질 자료는 범위가 정해져 있는 자료이며, 건강한 상태를 나타내는 경우 최대값을 가지는 천장효과가 있는 자료이다. 본 연구에서는 건강 관련 삶의 질 자료인 EQ-5D에 대해 선형회귀모형과 베타회귀모형, 그리고 평균과 정밀도에 대한 하위모형을 가지고 있는 확장된 베타회귀모형을 이용하여 예측모형을 개발하고 모형의 예측 정확도를 비교하였다. 선형회귀모형에 비해 확장된 베타회귀모형의 예측 정확도가 높기는 하지만 신뢰구간이 겹치고 있기 때문에 확장된 베타회귀모형의 정확도가 더 높다고 할 수는 없다. 하지만 확장된 베타회귀모형은 공변량에 따라 분산이 달라지는 부분을 설명할 수 있으며 선형회귀모형이 제한된 범위를 벗어난 값을 예측하는 부분을 개선할 수 있다. 따라서 범위가 제한되고 이분산이 있는 치우친 자료에 대해 공변량들이 평균 및 정밀도에 영향을 주는 정도를 동시에 고려하는 확장된 베타회귀모형은 건강 관련 삶의 질 자료인 EQ-5D를 분석하는 방법으로 적절하다고 할 수 있다.