• 제목/요약/키워드: omitted variables

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연령, 시간, 코호트효과를 고려한 소득 불평등: 수도권과 비수도권 간 비교 (Income Inequality Decomposed by Age, Period and Cohort Effects: A Comparison of the Capital and Non-Capital Regions)

  • 정준호
    • 한국경제지리학회지
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    • 제23권2호
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    • pp.166-181
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    • 2020
  • 본 논문은 수도권과 비수도권 거주자를 대상으로 1998~2018년 한국노동패널(KLIPS) 조사자료의 APC(Age-Period-Cohort) 모형 분석을 통해 지역별 소득 불평등의 강도와 추세 및 소득 불평등의 지역 간 격차 추세를 비교·분석한다. 주요 분석 결과는 다음과 같다. 첫째, 코호트와 연령효과 양자의 경우 수도권에 거주하는 소위 베이비붐 및 '386세대'를 포함하는 50~60대는 비수도권의 다른 연령대 및 코호트와 비교해 상대적인 소득 불평등 완화 효과가 있다. 둘째, 소득 불평등의 지역 간 격차를 설명하는 데에 미시적인 개인 특성도 무시할 수 없지만, 그보다는 누락변수의 구조적·제도적 요인과 특성변수의 사회적인 차별 효과가 더 의미가 있다. 전반적으로 코호트 내 및 코호트 간 소득 불평등이 중첩되어 나타나고 있다.

마이크로컴퓨터에 의한 시설재배의 자동화에 관한 기초연구(II) -자동화 시스템의 종합제어기 개발- (Fundamental Studies for the Automatic Control System in the Greenhouse Using Microcomputer(II) -A Development of a Controller for an Automatic Control System-)

  • 김진현;김철수
    • Journal of Biosystems Engineering
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    • 제20권1호
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    • pp.73-86
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    • 1995
  • The automatic control system in the greenhouse have to be developed to the direction of considering various factors the variables such as condition of the cultivation and greenhouse, the properties and types of products. Therefore, it is more important to set up variables appropriately than the problems of automatic control system itself, and the automatic control system which satisfy these problems should be simplified in the aspect of operation. In addition, even the individual automations are not perfect yet, so more studies are required for the development of comprehensive automatic system in korea. This study was carried out to automatize environment control systems for greenhouse, especially from most intensive labor requiring parts such as watering, irrigating liquefied fertilizer, spraying chemicals, mixing and ventilation system, etc. The results are summarized as follows. 1. Control type tensiometer was expected to be desirable in the automation of watering system, therefore, a new tensiometer was designed and developed through this study. 2. The chemical spraying system developed through this study was found to be excellent in the aspect of operation. 3. When pulse type water discharge meter was used in the mixing of liquefied fertilizer and chemical solution, the error of mixing were range $\pm$0.1~0.15%. 4. The water level switch of electrod type used for controlling water level was found to be affective in both control performance and operation cost. 5. The water and level control system can be omitted if each tank size are standardized in accordance with greenhouse size, therefore, the installation cost might be significantly reduced. 6. The developed general controller was excellent in hardware parts, but still remained to be improved in software parts.

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의류 제품의 통신 판매와 소비자 구매 의도 -쇼핑 비용 지각과 쾌락적 쇼핑 성향을 중심으로- (Effects of Consumers' Perception of Shopping Cost and Recreational Shopping Orientation on Catalog Shopping of Apparel)

  • 이은주;이은영
    • 한국의류학회지
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    • 제20권5호
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    • pp.826-840
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    • 1996
  • With rapid changes in social and marketing environments, catalog retailing emerges as a new method of selling clothes in Korea. In catalog shopping, in-store and multi·store search behavior are omitted saving consumers time and effort. On the other hand, consumers may lose recreational enjoyment of shopping when they purchase clothes through catalog. In this study, consumers perception of shopping cost and recreational shopping orientation were tested as consumer characteristic intervening catalog shopping behavior. The concept of shopping cost was derived from Darian(1987)'s analysis of cost and benefit of store shopping and in-home shopping. A national sample of 700 adult women was surveyed and 477 questionnaires were returned and used for statistical analysis. Nine shopping cost perception variables were found to have significant positive relationships with the purchase intention of apparel through catalog. As a result of confirmatory factor analysis, two factors of shopping cost were found; perception of lack of shopping time and perception of store search effort. Causal modeling of LISREL analysis showed that percetion of lack of shopping time was strongly related with patronizing intention of catalog shopping. Since catalog shopping exclude enjoyment of store shopping activity, it can be logically inferred that recreational store shoppers have less chance of being catalog shoppers. However, the result of LISREL analysis showed that there were no negative relationship between recreational shopping orientation and catalog shopping intention. This suggests that consumers might experience enjoyment of shopping through catalog when properly presented.

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A continuous solution of the heat equation based on a fuzzy system

  • Moon, Byung-Soo;Hwang, In-Koo;Kwon, Kee-Choon
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제3권1호
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    • pp.13-17
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    • 2003
  • A continuous solution of the Dirichlet boundary value problem for the heat equation $u_t$$a2u_{xx}$ using a fuzzy system is described. We first apply the Crank-Nicolson method to obtain a discrete solution at the grid points for the heat equation. Then we find a continuous function to represent approximately the discrete values at the grid points in the form of a bicubic spline function (equation omitted) that can in turn be represented exactly by a fuzzy system. We show that the computed values at non-grid points using the bicubic spline function is much smaller than the ones obtained by linear interpolations of the values at the grid points. We also show that the fuzzy rule table in the fuzzy system representation of the bicubic spline function can be viewed as a gray scale image. Hence, the fuzzy rules provide a visual representation of the functions of two variables where the contours of different levels for the function are shown in different gray scale levels

Direct Shear Test of Retrofit Anchors Using Deformed Reinforcement and Adhesive

  • Choi, Dong-Uk;Kim, Yong-Gon
    • KCI Concrete Journal
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    • 제12권1호
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    • pp.91-99
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    • 2000
  • A new type of retrof=t anchor bolt that uses deformed reinforcing bars and a commercial adhesive was developed and then an experimental study was carried out to determine the behavior of the anchors in direct shear. The steel-to-concl몫ete interface was tested. Plain concrete slabs with about 20-MPa compressive strength were used for 23 direct shear tests performed Test variables were anchor diameters (D16, D22. and D29) and edge effect. Three different shear tests were completed: simple shear, edge shear where anchors were pulled against the concrete core, and edge shear where anchors were pushed against the concrete cover In the simple and the edge shear tests where the anchors were pulled against the core, the theoretical dowel strength determined by (equation omitted) was achieved but with relatively large displacements. The shear resistances increased with the increasing displacements. In the edge shear test where the anchors were pushrd against the cover, the peak shear strengths signif=cantly lower than the theoretical dowel strength were determined due to cracks developed in concrete when the edge distance was 80 mm. The peak strengths were about 50% of the dowel strength for Dl6 bar. and about 25% or less of the dowel strength for D22 and D29 bars. Test results revealed that the edge shear where the anchor was pushed against the cover controled.

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기업의 사회적 책임과 내부 경영 활동 관계에 관한 연구 (A Study on the Relationship of Corporate Social Responsibility and Internal Corporate Management)

  • 한만용;강수진;성중안;최재웅
    • 디지털산업정보학회논문지
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    • 제9권4호
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    • pp.267-279
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    • 2013
  • To many, recent allegations of earnings management at Enron, coupled with similar ones at many other corporations, are a strong indication of a serious decay in business ethics. Nevertheless, the field of Corporate Social Responsibility(CSR) has grown exponentially in the last decade. This study investigates the effects of CSR on earnings management. Different to precedent works which focus on Financial Performance, this study attempts to provide empirical evidence for relevance of CSR and Discretionary Accruals(DA). The study used variables in the sustainability report, and DA for its earning management too progress empirical analysis because it is believed that the measurement of accounting transparency is highly related to the CEO's opportunistic selection of the accounting. In terms of Sustainable management activities, Employee training time(ETT) is significantly and negatively associated with Discretionary accruals(DA). And also Industrial Accidents Ratio(IAR) is significantly and negatively associated with Discretionary accruals. Consequently, empirical results suggest that Discretionary accruals associated with the company's CSR activities, such as ETT, and IAR. In this study, there are limitation of generalizations and omitted variable problem.

The Impact of Auditor-Client Traffic Convenience on Earnings Management in China

  • YIN, Hong;DU, Yanbin
    • Asian Journal of Business Environment
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    • 제11권4호
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    • pp.5-16
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    • 2021
  • Purpose: This study aims to investigate the impact of auditor-client traffic convenience on accrual -based and real earnings management of the client firms. Research design, data and methodology: Using a sample of firms listed in Shanghai and Shenzhen Stock Exchanges over the period of 2007 to 2018, this paper empirically investigates the association between auditor-client traffic convenience and earnings management. We use three measures of auditor-client traffic convenience: railway traffic convenience, expressway traffic convenience, and air traffic convenience. The accrual-based earnings management is measured by abnormal accruals estimated by industry and year using the Modified Jones Model. Results: Findings indicate that traffic convenience is conducive to detecting and restraining positive accrual earnings management and real earnings management. After changing the measurement of independent variable and dependent variable, including potential omitted variables, the results are statistically unchanged. Further, the research shows that traffic convenience can not only improve audit quality, but also lead to higher fee premiums. Auditors didn't share with clients the cost reduction benefits caused by traffic convenience. Conclusions: Traffic convenience provides auditors with easy access to the client firms, alleviating the information asymmetry and improving corporate earnings quality. The findings have implications for regulators, audit practitioners and stakeholders.

A Study on the Application of Analytic Nodal Method to a CANDU-600 Reactor Analysis

  • C.S. Yeom;Ryu, H.;Kim, H.J.;Kim, Y.H.;Kim, Y.B.
    • 한국에너지공학회:학술대회논문집
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    • 한국에너지공학회 2000년도 추계 학술발표회 논문집
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    • pp.115-120
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    • 2000
  • The analysis of flux distribution under stead-state in large power reactors with assymetry reactivity insertions requires the use of three-dimensional diffusion calculations. For the purpose, consistently formulated modern nodal methods based on higher order interface techniques have become popular tools for flux distributions in large commercial nuclear reactors. Among the earlier developments, the nodal Green's function method obtains its nodal interface equation from the transverse-integrated integral diffusion equation using a finite-medium Green's function. In this method, the outgoing current from a node surface is formulated as a response of the incoming currents and the spatially integrated neutron source within the same node. The well-known nodal expansion method is also based on an interface partial current formulation. Nodal methods high-level interface variables, i.e., interface net current and flux, may be more computationally efficient than the nodal Green's function method because they have one fewer unknown per interface. The Analytic Nodal Method(ANM), which can be classified as an interface net current technique and, was faster in solving some standard benchmark problems than the other two methods.(omitted)

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자기상관 오차항을 고려한 수정된 확산모형: CT-스캐너와 FPD TV에의 응용 (A Modified Diffusion Model Considering Autocorrelated Disturbances: Applications on CT Scanners and FPD TVs)

  • 차경천;김상훈
    • Asia Marketing Journal
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    • 제11권1호
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    • pp.29-38
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    • 2009
  • 시계열 확산 데이터를 활용하여 Bass 확산모형을 최소자승법(OLS)으로 추정하면, 초기에는 과다 추정하고 변곡점을 지나서는 수요를 낮게 추정하는 경향이 있다. 또한 확산모형에서 필요한 변수가 모형에서 빠짐으로 인해 발생하는 설정오류는 잔차의 자기상관을 발생시킬 수 있다. 자기상관이 오차항에 있을 경우, 추정된 모형의 모수들은 불편추정치이나 비효율적 추정치가 된다. 따라서 이러한 문제를 해결하는 확산모형의 개발이 요구된다. 본 연구에서는 자기상관 오차항을 고려한 수정된 확산모형을 제안하였다. 모형의 검증을 위해 미국의 CT-스캐너와 우리나라의 FPD TV 판매량를 제안된 모형에 응용하였다. 분석결과, 제안된 모형이 기존 모형에 비해 적합도와 모형의 주요 추정 통계량에서 우수함을 보였다.

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우리나라 상장기업의 소유구조 결정요인에 관한 실증적 연구 : 패널자료로부터의 근거 (An Empirical Study on the Determinants of Ownership Structure of Listed Companies in Korea : Evidence from Panel Data)

  • 이해영;이재춘
    • 재무관리연구
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    • 제20권2호
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    • pp.41-72
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    • 2003
  • 본 연구는 첫째, 우리나라 상장기업들의 소유구조결정요인을 식별하기 위하여 이론적 모형을 설정하고, 상장기업들의 횡단면 자료와 시계열 자료를 결합한 패널자료를 이용하여 이론적 모형을 실증적으로 분석하며, 둘째, 주식시장의 개방이라는 환경 요인이 우리나라에서 소유구조의 결정요인에 영향을 주는가를 확인하고, 주식시장의 개방 전후를 구분하여 기업의 소유구조를 결정하는 요인이 어떻게 변화하였는지를 분석하였다. 분석 결과, 본 연구에서 제시된 모형이 상당한 의미를 가지나, 모형의 설명력은 비교적 낮아 제시된 결정요인들이 대주주1인 지분율의 변동을 $9\sim11%$ 정도 설명하고 있으며, 본 연구에서 제시된 타인자본의존도, 배당, 자산특이성, 수익성, 성장성, 위험, 기관투자가 지분율, 재벌여부 가변수 등의 결정요인들이 통계적으로 의미있는 변수가 되고 있으나 다만 규모 변수만이 표본기간에 따라 통계적 유의성과 회귀계수 부호에 일관성을 보이고 있지 못하다. 또한 본 연구에서 제시된 주식시장의 개방이라는 환경적인 요인이 소유구조를 설명하는 의미 있는 변수가 되고 있으며, 주식시장의 개방을 전후 한 시점으로 나누어 소유구조결정요인의 변화를 분석한 결과 주식시장 개방이라는 환경변수는 소유구조결정요인에 긍정적인 영향을 미치고 있다.

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