• Management & Information Systems Review
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• v.31 no.4
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• pp.469-490
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• 2012

This study reviews the issue of endogeneity which has gained in importance in the empirical accounting researches in recent years. In so doing, I aim to call attention to the extent to which the presence of endogeneity limits the validity of empirical testing of models. More specifically, this paper explains what endogeneity is, its causes and consequences, and potential ways of managing the problem. The issues that concern endogeneity include, in the main, omitted variables, simultaneity, equilibrium conditions, choice variables. In this paper, I also discuss the implications derived from several selected empirical accounting research topics, that explicitly dealt with the problem of endogeneity. These include, among others, Oswald and Zarowin's (2007) study on the informativeness of capitalization of R&D, Hazarika et al. (2012) focusing on the relationship among internal corporate governance, CEO turnover, and earnings management, and a series of literature devoted to the associations between corporate governance structure and firm values. Finally, possible approaches for dealing with endogeneity are discussed.

• Environmental and Resource Economics Review
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• v.26 no.4
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• pp.473-498
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• 2017

This study examines the effect of environmental regulation considering the endogeneity on the productivity of Korean manufacturing industry based on the Porter hypothesis using data from the Mining and Manufacturing Survey, Survey of Research and Development in Korea, and Environmental Statistics Portal from 2003 to 2013 with fixed effect model. In order to eliminate the bias of the missing variables that may occur in the existing studies, we analyze factors affecting productivity such as market competition, R&D investment as explanatory variables. And, in order to eliminate measurement error and inverse causality, we use instrumental variable approach. The main results are as follows. First, our findings that the environmental regulation improve the productivity of Korean manufacturing in the long-run support the Porter hypothesis. Second, our findings suggest that measurement error and reverse causality are main sources of the endogeneity, while omitted variable is not. Finally, environmental technology R&D has reduced productivity in the short-run.

• Journal of Labour Economics
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• v.40 no.3
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• pp.105-131
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• 2017

This study analyses the effect of a minimum wage on employment by using the government's progressiveness as an instrumental variable. The Ordinary Least Squares regression (OLS) can result in upward biased employment effect due to the endogeneity among variables. Therefore, it is necessary to analyse the casuality that removed endogeneity between variables by using proper instrumental variables. The analysis using instrumental variable shows that the growth of the increasing rate of the minimum wage reduces employment. The negative effect of employment depending on the increase of minimum wage corresponds with the predictions of Neoclassical Economics.

• Journal of Labour Economics
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• v.43 no.2
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• pp.109-133
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• 2020

This paper estimates a matching function in Korea by using the method of Borowczyk-Martins et al. (2013) in order to mitigate endogeneity problems. The endogeneity was controlled through the GMM estimation by approximating the unobserved matching efficiency with the ARMA(p,q) process. The monthly data from the Economically Active Population Survey and Labor Force Survey at Establishments from June 2009 to December 2019 were used for the estimation. The matching elasticity that indicates the elasticity of new hires with respect to vacancies was estimated to be 0.859. When excluding 2019 samples, which had a large number of direct jobs provided by the government, the matching elasticity was lowered to 0.755, but still higher than that of other countries.

• The Journal of the Korea Contents Association
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• v.18 no.1
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• pp.268-276
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• 2018

This study examined the effects of indemnity private health insurance on the medical utilization among the Korean adults. The used data were the 2014 survey data of Korea Health Panel, and the number of subjects was 11,436. Authors employed instrumental variable regression model where the instrument variables for controlling for endogeneity of indemnity were the purchasing of private pension and number of family members. The results showed that the number of outpatient visits and the number of hospitalizations for indemnity private health insurance subscribers were higher than non-subscribers. The number of household members and the private pension variables were proved to be appropriate as instrumental variables. This paper recommends the Korean government to monitor and evaluate the effects of indemnity private health insurance on the medical utilization in order to improve the efficiency of health care finance.

• The Korean Journal of Mycology
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• v.47 no.1
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• pp.43-50
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• 2019

We investigated the biodiversity of endophytic fungi of Bolboschoenus planiculmis and Schoenoplectus triqueter in Korea. Twenty five of these host plants were collected from six sampling sites. Internal transcribed spacer analysis identified a total of eighty five isolates from the collected plants. The isolates comprised nineteen taxa; most of the isolates (92%) belonged to class Dothideomycetes, followed by Sordariomyetes (4.8%), Agaricomycetes (1.6%), and Eurotiomycetes (0.8%). The most prevalent fungus was Cladosporium perangustum in B. planiculmis and Macrospora scirpicola in S. triqueter. There are very few studies of endophytic fungi in halophytes and these have reported biodiversity patterns different from those of previous studies in Korea. Our results should provide useful information for future research in Korea.

• International Area Studies Review
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• v.20 no.1
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• pp.147-165
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• 2016

We empirically examine the validity of second generation endogenous growth theory suing 21 OECD countries' panel data(1981~2011). Due to non-stationarity in all variables, we test the cointegrated relationships strongly supporting the semi-endogenous growth model. In the estimation of total factor productivity growth function, the growth of domestic and foreign R&D investment levels statistically significantly affect total factor productivity growth. R&D intensity, however, has significant impacts on the total factor productivity growth only in a few models, and international technology gap also has positive impacts on GDP growth. Thus the semi-endogenous growth model is relatively supported while fully endogenous growth model is weakly and occasionally supported in OECD countries. The policy implication of supporting the semi-endogenous growth model is that the sustaining growth requires increasing R&D expenditures.

• Journal of Teachers' Pension
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• v.4
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• pp.57-90
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• 2019

본 연구는 사학연금의 장기적 재정건전성을 확보하기 위한 재정추계 및 정책평가 방법에 관하여 논의한다. 먼저 재정안정화 시나리오의 설정에 있어서 기간간 예산제약식을 이용하여 장기적으로 균제상태(steady state)를 달성할 수 있는 납부율 및 급여율의 선정이 어떻게 이루어질 수 있는지 살펴본다. 또한 재정추계에 있어서 정책 변화에 따라 개인들의 행동 패턴이 달라질 가능성이 있음을 강조하고, 조기퇴직 결정에 관한 캘리브레이션을 통해 재정추계에서 내생성에 대한 고려가 어떻게 이루어질 수 있는지 예시한다. 마지막으로 힉스 보상의 개념에 기초하여 안정화 정책에 대한 평가가 연금 재정지표에 미치는 효과만이 아니라 가입자 / 수급자의 후생에 미치는 영향까지 같이 고려하여 이루어질 필요가 있음을 설명한다.

• The Korean Journal of Mycology
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• v.49 no.4
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• pp.497-505
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• 2021

Endophytic fungal strains were isolated from leaves, stems, and roots of Angelica gigas. The fungal strains were identified based on their morphological characteristics and molecular analysis of the internal transcribed spacer (ITS). A total 35 species of endophytic fungi were identified. The diversity between the endophytic fungal communities differed depending on the tissues of A. gigas. The isolated endophytic fungi were screened for antifungal activity against a pathogenic fungus, Phoma sp. Y11, using a dual culture method. Fourteen species of endophytic fungi showed the standout inhibition effect against the Y11 strain. The results suggest that the endophytic fungi isolated from A. gigas could be used as a biological control agent against leaf spot disease of A. gigas.

• The Korean Journal of Mycology
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• v.42 no.4
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• pp.269-275
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• 2014

Halophytes of seven species, Carex scabrifolia Steud., Limonium tetragonum Bullock, Salicornia europaea L., Suaeda glauca Bunge, Suaeda japonica Makino, Suaeda maritima Dumort., and Triglochin maritimum L. were collected from the Taean Peninsula. Thirty-seven endophytic fungi were isolated from the root of halophytes, and analyzed using the DNA sequences of internal transcribed spacers (ITS). The diversity of all endophytic fungi was analyzed using diversity indices. The endophytic fungi associated with the halophytes belonged to seven orders; Eurotiales (78%), Capnodiales (5%), Hypocreales (5%), Agaricales (3%), Corticiales (3%), Glomerellales (3%), and Pleosporales (3%). At the phylum level, the endophytic fungi were composed of Ascomycota and Basidiomycota. At the genus level, Alternaria, Aspergillus, Cladosporium, Paecilomyces, Penicillium, Phanerochaete, Schizophyllum, Talaromyces, and Verticillium were confirmed. Among them, Penicillium was the most abundant in the roots of the halophytes. This study analyzed the distribution and diversity of endophytic fungi on halophytes in the Taean Peninsula.