• 제목/요약/키워드: Omitted Variables

검색결과 57건 처리시간 0.024초

실증적 회계학연구에 있어서의 내생성 문제 (Endogeneity Issues in Empirical Accounting Research)

  • 최종서
    • 경영과정보연구
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    • 제31권4호
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    • pp.469-490
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    • 2012
  • 본 연구에서는 최근 실증적 회계학연구에서 그 중요성이 점증하고 있는 내생성 문제에 대하여 개관한다. 이를 통하여 내생성의 존재가 실증모형 검증의 타당성을 제약할 수 있는 정도에 대해 주의를 환기시키고자 한다. 보다 구체적으로 본고에서는 내생성이란 무엇이며, 내생성의 원인과 그에 따른 영향, 내생성을 해결할 수 있는 방안에 대해 살펴본다. 내생성을 초래하게 되는 맥락은 주로 생략변수, 연립성, 균형조건, 선택변수의 존재 등과 관련된다. 본고에서는 이와 더불어 최근의 실증적 회계연구 가운데 내생성의 문제를 명시적으로 다루고 있는 몇 가지 사례에 대해서도 검토하였다. 예를 들면 연구개발 지출의 자본화에 따른 정보효과를 분석한 Oswald and Zarowin(2007), 경영자 교체와 이익조정의 관련성을 조사한 Hazarika et al.(2012), 기업의 지배구조와 기업가치의 관련성을 연구한 일련의 연구를 들 수 있다. 아울러 향후의 회계연구에서 잠재적 내생성의 문제에 대처해 나갈 방안에 대해서도 논의하였다.

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A Model Study of Hypoxia in the Rappahannock Estuary, Verginia

  • Park, Kyeong
    • 한국해안해양공학회:학술대회논문집
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    • 한국해안해양공학회 1995년도 정기학술강연회 발표논문 초록집
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    • pp.108-109
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    • 1995
  • Hypoxia has persisted during summer in the bottom water of the lower portion of the Rappahannock Estuary, a western shore tributary of Chesapeake Bay. A laterally integrated two-dimensional, real-time model, consisting of linked hydrodynamic and water quality models, was developed to study the contributing processes for hypoxia. The hydrodynamic model gives the information of physical transport processes, both advective and diffusive, to the water quality model, which simulates the spatial and temporal distributions of eight water quality state variables. (omitted)

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EXTREMAL DISTANCE AND GREEN'S FUNCTION

  • Chung, Bo Hyun
    • 한국수학교육학회지시리즈B:순수및응용수학
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    • 제1권1호
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    • pp.29-33
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    • 1994
  • There are various aspects of the solution of boundary-value problems for second-order linear elliptic equations in two independent variables. One useful method of solving such boundary-value problems for Laplace's equation is by means of suitable integral representations of solutions and these representations are obtained most directly in terms of particular singular solutions, termed Green's functions.(omitted)

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시스템 다이나믹스 기법을 활용한 국가 연구시설의 기여도 분석 (Assessment of National Contribution of Research Facilities via the System Dynamics Method)

  • 김지용;곽상만;최기련
    • 한국시스템다이내믹스학회:학술대회논문집
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    • 한국시스템다이내믹스학회 2004년도 춘계 학술대회 발표논문집
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    • pp.109-128
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    • 2004
  • A system dynamics model is developed in order to evaluate the contribution level of the activities regarding HANARO, which is the research reactor in Korea. The system dynamics model has room to be improved, but it is logically sound enough to evaluate the general level of contributions and to develop strategies for the HANARO to be more contributable. Considering the uncertainty involved with the input variables, the contribution level is ranged from 3 times to about 30 times of the investment made on it. The evaluation results can be summarized as follows : (Table Omitted).

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Algorithm for finding the best regression models using NIR spectra

  • Cho, Jung-Hwan;Huh, Yun-Jung;Park, Young-Joo
    • 대한약학회:학술대회논문집
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    • 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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    • pp.402.2-402.2
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    • 2002
  • An algorithm for finding the best regression models has been developed using NIR spectral data. In cases of regression analysis for quantitation with NIR spectral data, it is very critical to find essential features from the spectral data. This task was accessed in two ways. The first one was to use all-possible combinations of varibles (wavelengths). Correlation coefficients at each spectral points were calculated to get initial set of variables and all of the possible combinations of variable sets were tested with SEC. SEP and/or $R^2$. (omitted)

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Thermo-sensitive lipid nanoparticles as a novel topical delivery system of retinol

  • Jee, Jun-Pil;Lee, Mi-Kyung;Kim, Chong-Kook
    • 대한약학회:학술대회논문집
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    • 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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    • pp.425.2-425.2
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    • 2002
  • The purpose of this study was to prepare thermo-sensitive solid-lipid nanoparticles (SLNs) with a lipid melted at human body temperature and to evaluate physicochemical properties of SLNs containing retinol. anti-wrinkle agent. as a model drug. SLNs were prepared using a high pressure homogenizing method. The SLNs were composed of retinol as a model drug. thermo-sensitive lipid (DS-CBS) as a lipid core. and egg phosphatidylcholine and Tween 80 as surfactants. Manufacturing variables such as homogenization pressure. (omitted)

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BOES imaging performance variation using FWHM of ThAr reference spectra

  • Kang, A-Ram;Hyunjin Jeong;Lee, Jae-Woo;Kim, Sug-Whan
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
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    • 한국우주과학회 2004년도 한국우주과학회보 제13권1호
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    • pp.94-94
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    • 2004
  • We report an investigation of BOES imaging performance variation against observational variables. Average FWHM of the ThAr reference spectra recorded in 10 spectral image frames observed during the night of January 5th, 2004 was computed. The averaged FWHM data was then correlated with observational variables including telescope altitude, air mass, focus position, exposure time, detector temperature, gain settings and S/N ratio. (omitted)

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Numeric simulation of near-surface moisture migration and stress development in concrete exposed to fire

  • Consolazio, Gary R.;Chung, Jae H.
    • Computers and Concrete
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    • 제1권1호
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    • pp.31-46
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    • 2004
  • A methodology is presented for computing stresses in structural concrete members exposed to fire. Coupled heat and moisture migration simulations are used to establish temperature, pore pressure, and liquid-saturation state variables within near-surface zones of heated concrete members. Particular attention is placed on the use of coupled heat and multiphase fluid flow simulations to study phenomena such as moisture-clogging. Once the state variables are determined, a procedure for combining the effects of thermal dilation, mechanical loads, pore pressure, and boundary conditions is proposed and demonstrated. Combined stresses are computed for varying displacement boundary conditions using data obtained from coupled heat and moisture flow simulations. These stresses are then compared to stresses computed from thermal analyses in which moisture effects are omitted. The results demonstrate that moisture migration has a significant influence on the development of thermal stresses.

CHARACTERIZATIONS OF THE EXPONENTIAL DISTRIBUTION BY ORDER STATISTICS AND CONDITIONAL

  • Lee, Min-Young;Chang, Se-Kyung;Jung, Kap-Hun
    • 대한수학회논문집
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    • 제17권3호
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    • pp.535-540
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    • 2002
  • Let X$_1$, X$_2$‥‥,X$\_$n/ be n independent and identically distributed random variables with continuous cumulative distribution function F(x). Let us rearrange the X's in the increasing order X$\_$1:n/ $\leq$ X$\_$2:n/ $\leq$ ‥‥ $\leq$ X$\_$n:n/. We call X$\_$k:n/ the k-th order statistic. Then X$\_$n:n/ - X$\_$n-1:n/ and X$\_$n-1:n/ are independent if and only if f(x) = 1-e(equation omitted) with some c > 0. And X$\_$j/ is an upper record value of this sequence lf X$\_$j/ > max(X$_1$, X$_2$,¨¨ ,X$\_$j-1/). We define u(n) = min(j|j > u(n-1),X$\_$j/ > X$\_$u(n-1)/, n $\geq$ 2) with u(1) = 1. Then F(x) = 1 - e(equation omitted), x > 0 if and only if E[X$\_$u(n+3)/ - X$\_$u(n)/ | X$\_$u(m)/ = y] = 3c, or E[X$\_$u(n+4)/ - X$\_$u(n)/|X$\_$u(m)/ = y] = 4c, n m+1.

주가 변동성과 파생상품거래 (Stock Volatility and Derivative Trading)

  • 장대홍
    • 재무관리연구
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    • 제26권4호
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    • pp.63-81
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    • 2009
  • 논문은 주식가격의 변동성과 거시경제변수 및 파생상품거래와의 관계를 실증적으로 분석한다. 이전 연구들에서 밝혀진 바와 같이 주식수익률의 변동성은 거시 경제변수의 변동성에 비해 훨씬 크게 나타날 뿐 아니라, 변수의 설명력도 약해서 거시경제변수-주식가격 변동성의 이론적 관계를 확인하기에 충분하지 않다. 1980년 이후의 한국 데이터를 사용한 분석의 결과도 이런 결과를 확인해 준다. 그러나 이들 결과는 금융활동 변수들이 누락되었기 때문일 수 있다. 이 논문은 특히 파생상품 거래의 변동성이 주식수익률 변동성을 상당 부분 설명할 수 있을 뿐 아니라, 거시경제 변수의 설명력도 복원시킬 수 있음을 확인해준다.

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