• Title/Summary/Keyword: 인과효과 추정

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Study on the Expected Effects of KS Certification on Companies (KS표시인증이 기업에 기대되는 효과에 관한 연구)

  • Kim, Kwang-Soo;NamGung, Jak;Chung, Soon-Suk
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.7 no.1
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    • pp.19-26
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    • 2012
  • This study is aimed to measure the cause and effect relationship on observation on KS evaluation by surveys related to KS certification, opinions and satisfaction on KS certification, expected effect through KS certification, profitability performance, financial performance, and productivity performance based on department heads and acting chiefs working on KS certification, to SMEs which have acquired KS certification mark in Korea. This study also aims to examine how KS certification is impacting on companies' expected effects, management performance and development by examining the realistic effects of KS certification in various aspects and expected effects on companies.

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The Effect of Environmental Regulation Considering the Endogeneity on the Productivity of Korean Manufacturing Sectors (내생성을 고려한 환경규제 강화가 우리나라 제조업 부문 생산성에 미친 영향 분석)

  • Kim, Taeyoung;Kim, Hongkyun
    • 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.

An Empirical Analysis on the Service Quality of the National Library of Korea and Its Effect (국립중앙도서관의 서비스품질과 그 효과에 대한 실증적 분석)

  • Han, Sang-Il;Kim, Young-Jea;Yu, Pyeong-Jun;Bae, Deuk-Jong
    • Journal of the Korean Society for Library and Information Science
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    • v.42 no.1
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    • pp.295-311
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    • 2008
  • The authors examine the service quality of the National Library of Korea and its effects on the customer satisfaction and the annual number of visit. In particular this article tests the actual effects of the extension of opening hour that has been famous for increasing ratio of library operation and employing more librarians. A survey of 332 customers was conducted to measure individual perceptions on the customer service and satisfactions and estimate structural equation models across two time slots: the daytime, and night hour. The major findings of this study are that the service quality tends to increase customer satisfaction.

Factor Analysis of Seaborne Trade Volume Affecting on The World Economy (품목별 해상 물동량이 세계 경제에 미치는 영향 요인분석)

  • Ahn, Young-Gyun;Lee, Min-Kyu;Park, Ju-Dong
    • Korea Trade Review
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    • v.42 no.2
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    • pp.277-296
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    • 2017
  • More than 95% of imports and exports in the World are being transported by vessels. In other words, marine transportation accounts for a large portion of share in the world trade. The purpose of this study is to analyze factors of seaborne trade volume according to items affecting on the world economy. This study conducted a linear regression analysis between seaborne trade volume and the world economy (world GDP) to estimate the correlation between them. Panel data analysis and random effects model analysis have been applied to examine the effect of seaborne trade volume. For this study, the seaborne trade volume is categorized into 10 items, and estimated how much global GDP will be affected when the trade volume changes. In addition, the granger causality test was conducted to verify the relationship between seaborne trade volume and the world GDP. As a result, seaborne trade volume and the world GDP were mutually influenced each other. However, seaborne trade volume affects the world economy more significantly. The items affecting world economic growth include petroleum products, crude oil, chemical products, and so on. The estimated value of the coefficients of petroleum products, crude oil and chemical products were 1.014, 1.013 and 1.010, respectively. The estimated value 1.014 of petroleum products means that the growth rate is 1.014 times higher than the current world GDP growth rate when the seaborne trade volume of petroleum products increased by one unit Lastly, this study examines the seaborne trade volume of 10 categories and then verifies whether the growth rate of world GDP will increase when the volume of seaborne trade increased. This study is expected to provide policy-makers with useful information about formulating policies related to international trade.

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Analysis of Causality of the Increase in the Port Congestion due to the COVID-19 Pandemic and BDI(Baltic Dry Index) (COVID-19 팬데믹으로 인한 체선율 증가와 부정기선 운임지수의 인과성 분석)

  • Lee, Choong-Ho;Park, Keun-Sik
    • Journal of Korea Port Economic Association
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    • v.37 no.4
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    • pp.161-173
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    • 2021
  • The shipping industry plummeted and was depressed due to the global economic crisis caused by the bankruptcy of Lehman Brothers in the US in 2008. In 2020, the shipping market also suffered from a collapse in the unstable global economic situation due to the COVID-19 pandemic, but unexpectedly, it changed to an upward trend from the end of 2020, and in 2021, it exceeded the market of the boom period of 2008. According to the Clarksons report published in May 2021, the decrease in cargo volume due to the COVID-19 pandemic in 2020 has returned to the pre-corona level by the end of 2020, and the tramper bulk carrier capacity of 103~104% of the Panamax has been in the ports due to congestion. Earnings across the bulker segments have risen to ten-year highs in recent months. In this study, as factors affecting BDI, the capacity and congestion ratio of Cape and Panamax ships on the supply side, iron ore and coal seaborne tonnge on the demand side and Granger causality test, IRF(Impulse Response Function) and FEVD(Forecast Error Variance Decomposition) were performed using VAR model to analyze the impact on BDI by congestion caused by strengthen quarantine at the port due to the COVID-19 pandemic and the loading and discharging operation delay due to the infection of the stevedore, etc and to predict the shipping market after the pandemic. As a result of the Granger causality test of variables and BDI using time series data from January 2016 to July 2021, causality was found in the Fleet and Congestion variables, and as a result of the Impulse Response Function, Congestion variable was found to have significant at both upper and lower limit of the confidence interval. As a result of the Forecast Error Variance Decomposition, Congestion variable showed an explanatory power upto 25% for the change in BDI. If the congestion in ports decreases after With Corona, it is expected that there is down-risk in the shipping market. The COVID-19 pandemic occurred not from economic factors but from an ecological factor by the pandemic is different from the past economic crisis. It is necessary to analyze from a different point of view than the past economic crisis. This study has meaningful to analyze the causality and explanatory power of Congestion factor by pandemic.

A Study on the Linear Causality between KOSPI200 Intraday Futures Returns and Cash Returns (KOSPI 200 하루중 선물수익률과 현물수익률간의 선형인과성에 관한 연구)

  • Kim, Tae-Hyuk;Kang, Seok-Kyu
    • The Korean Journal of Financial Management
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    • v.17 no.1
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    • pp.203-226
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    • 2000
  • 본 연구는 주가지수 선물시장이 도입된 1996년 5월 3일부터 1998년 12월 5일까지 1분 간격 KOSPI 200 선물가격과 현물가격의 거래자료를 이용하여 각 선물가격과 기초자산가격간의 관계와 상호작용을 검토하는데 있다. 특히 본 연구는 차익거래자나 초단기 투기자(scalper)들이 거래체결을 위해 촌각을 다투는 선물시장의 거래행태에서 볼 때, 경제적 의미를 부여할 수 있는 1분 간격 수익률 자료를 이용함으로써 시장참여자의 실제 거래에서 표출되는 정형화된 현상을 정확히 파악한다는 점에서 중요하다. 본 연구의 주요 결과를 제시하면 다음과 같다. 첫째, 주가지수 선물시장과 현물시장간에 체계적이고 긴 선도-지연 관계가 발견되었다. 주가지수 선물가격의 변화가 현물가격의 변화를 대략 26분 정도 선도하고 있으며, 대략 5분 정도 현물시장의 선도효과도 발견된다. 따라서 KOSPI 200 선물수익률과 현물수익률간의 선도-지연 관계는 한 시장에서 다른 시장으로의 일방적인 것이 아니라 시장간의 피드백(feedback)효과가 존재하며, 선물의 선도효과가 지배적인 것으로 보인다. 이러한 선도-지연 현상은 노이즈에 의한 비동시거래보다는 거래비용과 공매제약 차이 등 각 시장의 제도적 차이에 의해 발생하는 것으로 보여진다. 둘째, 약세시장 하에서 선물의 선도효과가 더욱 크게 나타났다. 이러한 현상은 약세시장 하에서 현물시장의 공매제약이 선물가격과 현물가격간의 괴리를 더욱 크게 하여 선물가격이 현물지수를 더욱 선도하게 하는 요인이 될 수도 있음을 나타내는 것이다. 셋째, 만기별 하위기간 중 97년 6월과 97년 12월을 제외한 기간은 선물과 현물가격간에 장기 안정적인 균형관계가 성립함을 발견하였다. 넷째, ARMA(p, q) 여과를 거친 선물과 현물수익률을 이용하여 97년 6월과 12월은 백터자기회귀(VAR)모형, 그 외의 기간은 오차수정(EC)모형으로 추정하였다. 표본전체기간동안 장기균형오차에 대한 조정은 선물과 현물시장에서 동시에 이루어지고 있으며, 시장간에 발생하는 불균형 상황은 아비트라지 거래로 조정되고 있음이 발견되었다. 각 만기별 모든 하위기간에 있어서는 시장간의 장기 불균형 상황이 현물시장을 통해서 조정되고 있으며, 시장이 성숙된 최근의 만기 98년 12월 하위기간에서는 선물의 15분 선도효과와 현물의 1분 선도효과가 발견되어 선물의 선도효과가 지배적임을 발견하였다.

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Forecasting Modeling of Heavy Tail Typed Demand using Student's t-Copula Fitting in Supply Chain Management (Student's t-Copula 적합을 통한 Heavy Tail형 SCM 수요 데이터의 모델링 및 분석)

  • Kim, Taesung;Lee, Hyunsoo
    • Journal of Digital Convergence
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    • v.11 no.9
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    • pp.103-111
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    • 2013
  • As the demand-oriented management has been getting important in Supply Chain Management (SCM), various forecasting methods have been suggested including regression analyses. However, dependency structures among variables have been captured by a correlation coefficient, only. It results in inaccurate demand predictions. This paper suggests a new and effective forecasting modeling framework using student's t-copula function. In order to show overall modeling procedures framework, heavy tail typed numerical data and its copula estimations are provided. The suggested methodology can contribute to decrease the bullwhip effect and to stabilize volatile environment in a supply chain network.

Discriminatory Attitudes towards IV/AIDS (PWHAs) Patents by Middle and High School Students (HIV/AIDS 감염인에 대한 차별의식에 미치는 영향의 중고등학생 간 비교: 에이즈 낙인의 매개효과)

  • Chun, Sung-Soo;Kim, Ju-Ri;Shin, Seung-Bae;Sohn, Ae-Ree
    • The Journal of Korean Society for School & Community Health Education
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    • v.9 no.1
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    • pp.63-83
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    • 2008
  • Objectives: This study was to examine HIV/AIDS knowledge of transmission, attitudes toward homosexuals on stigma of HIV/AIDS and discriminatory attitudes towards person with HIV/AIDS (PWHAs) by middle and high school students in Seoul, Korea. Methods: The population of this study is middle and high school students in Seoul, Korea. Eight junior high schools and eight senior high schools were selected randomly. Three thousand and one hundred thirty-one students (1704 males and 1397 males) from 16 schools participated in the survey, and 2.977 cases were analyzed. A self-administered questionnaire measuring socio-demographic variables, HIV/AIDS knowledge of transmission, sigma of HIV/AIDS (3 items, 5-point Likert-type scale) and discriminatory attitudes PWHAs (5 items, 5-point Likert-type scale) was utilized. The Structural Equation Modeling was employed to investigate the research Model. Results: The empirical study shows that a number of statistical hypotheses are significant. The stigma and discriminatory attitudes PWHAs were significantly different by middle and high school students. The attitudes toward homosexuals and HIV/AIDS knowledge of transmission were important factors on stigma and discriminatory attitudes PWHAs. Socio-demographical variables such as sex was related to the stigma and discriminatory attitudes PWHAs. Conclusion: Therefore, it is important to design HIV prevention strategies that increase in positive attitudes towards PWHAs.

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Diffusion Patterns of Mobile Telecommunications Services in the European Countries (이동통신서비스 확산패턴 - 유럽국가 자료를 중심으로)

  • Kim, Jin Ki
    • Journal of Korea Technology Innovation Society
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    • v.20 no.4
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    • pp.1243-1261
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    • 2017
  • Mobile telecom markets have dramatically increased in the last decade due to a remarkable subscriber base growth. The diffusion patterns of the services are a major concern for mobile carriers preparing those new services. We assume that the diffusion patterns of those services will be similar to those of previous mobile services, and discovering the diffusion patterns of those services is an essential task of mobile carriers for preparing the next mobile services. This study attempts to classify some groups which show similar diffusion patterns of mobile services. Using a traditional diffusion model, this study estimates diffusion patterns of twenty five western European countries. The estimation is based on the monthly penetration ratio of those countries from 1993 to 2004. Based on the estimation, the cluster analysis discovers that there are two different countries groups in terms of mobile diffusion pattern: high imitation countries and low imitation countries. The critical point for classifying the two groups in terms of imitation effect was 0.90. The results provide the basis for developing a causal relationship model which explains the different diffusion pattern of mobile services and planning new networks for the advanced mobile services.

무역(貿易)과 산업조직(産業組織)의 연계성(連繫性)에 관한 고찰(考察)

  • Yu, Seung-Min
    • KDI Journal of Economic Policy
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    • v.10 no.3
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    • pp.65-94
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    • 1988
  • 한국경제(韓國經濟)의 대외의존도(對外依存度), 시장개방(市場開放)의 정도(程度)가 높아감에 따라 상품(商品), 자본(資本), 기술(技術)의 대외거래(對外去來)와 내수시장(內需市場)의 산업조직(産業組織)이 갖는 연계성(連繫性)은 한국(韓國)의 산업조직(産業組織)에 중요한 의미를 갖게 된다. 본고(本稿)에서는 수입(輸入) 등 해외(海外)로부터의 유입(流入)과 수출(輸出) 등 해외(海外)로의 유출(流出)이 산업조직(産業組織)의 주요변수(主要變數)들과 갖는 인과관계(因果關係)를 경험적(經驗的) 산업조직론(産業組織論)의 체계내(體系內)에서 이해하려는 시도로서, 이에 대한 제가설(諸假設)을 전개하며 실증분석(實證分析)을 시도하였다. 동시성(同時性)을 충분히 고려한 연립방정식체계(聯立方程式體系)의 추정결과(推定結果)는 동시성(同時性)을 무시한 경우보다 제가설(諸假設)의 주장에 더욱 근접한 것으로 나타났으며, 대부분의 경우 실증분석(實證分析) 결과(結果)는 가설(假說)을 지지하나 수출(輸出)의 경우에는 상반(相反)된 결과(結果)를 나타내고 있다. 본(本) 연구(硏究)의 분석결과(分析結果)에 의하면 그 동안 한국(韓國)의 수입정책(輸入政策)은 시장성과(市場成果)를 향상(向上)시키는 수단(手段)으로서의 기능보다는 단순히 수출증대(輸出增大)를 위한 수입확대(輸入擴大)의 기능을 해 온 것으로 나타났다. 또한 수입(輸入)에 대한 시장개방(市場開放)에 있어서 비관세장벽(非關稅障壁)의 제감(除減)은 시장성과(市場成果)에 대하여, 관세장벽(關稅障壁)의 인하(引下)는 수입(輸入)의 내수점유율(內需占有率)에 대하여 각각 상대적으로 높은 정(正)의 효과(效果)를 갖고 있는 것으로 나타났는데 이는 정책목표(政策目標)에 따른 정책수단(政策手段)의 선택(選擇)에 대하여 중요한 시사점(示唆點)을 갖는다.

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