• The Korean Journal of Financial Management
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• v.12 no.2
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• pp.95-120
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• 1995

자본시장에서 자산가격결정이론의 대부분은 투자자산의 기대수익률과 변동성이 시간의 흐름에 따라 일정한 것으로 가정하여 왔다. 그러나 최근의 연구 성과에 의하면 주식수익률의 변동성이 동분산이라기 보다는 이분산일 가능성이 높다는 것이다. 1982년 Engle에 의하여 개발된 자기회귀 조건부 이분산모형(ARCH)이 제시된 이래 ARCH형태의 모형개발이 계속 이루어져 왔다. 본 논문은 ARCH형태의 이분산모형 가운데서 EGARCH모형을 이용하여 위험프레미엄과 조건부 이분산과의 관계와 더불어 기대하지 않은 수익률변화와 변동성과의 관계를 규명하고자 노력하였다. 1980년에서 1994년까지의 주가자료를 전체기간과 세부기간(4기간)으로 분류하여 기술 통계량 분석을 행하고, 종합주가지수초과수익률, 동일 가치 가중지수초과수익률, 대형주 주가지수초과수익률, 소형주 주가지수초과수익률에 대하여 EGARCH모형 을 적용하여 실증분석 하였다. 그 결과 위험프레미엄과 조건부 이분산은 시간이 지남에 따라 일정한 관계를 보여주지 못하고 있어 투자자의 위험회피도(危險回避度)가 변화함을 보여주었다. 기대하지 않은 수익률변화와 변동성 관계에서는 기대하지 않은 음(陰)(-)의 주식수익률이 기대하지 않은 양(陽)(+)의 주식수익률보다 상대적으로 더 큰 변동성을 가져오는 것으로 보여 우리나라 주식시장에서 주식수익률의 변동성 정보의 비대칭 반응효과가 존재하는 것으로 나타났다.

• Korea journal of population studies
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• v.23 no.1
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• pp.119-145
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• 2000

본 연구에서는 동아시아의 세 나라, 대만, 한국, 일본의 성별 직업분리의 추세를 비교하였다. 동아시아 사회의 성별 직업분리의 정도가 상식적으로 예상되는 것보다 지수상으로 낮게 나타나는 것에 대해 단일지수를 사용한 측정방법의 문제점이 지적되고 있다. 본 연구에서는 대수선형모형에 입각한 연관지수를 이용하여 직업분리에 단일 지수적 접근과 아울러 분리의 작업별 양상을 함께 비교하였다. 1960년과 1990년 사이에 동아시아 세 나라의 성별 분리지수는 전반적으로 감소하는 경향을 보인다. 세나라들 중에서 가장분리의 정도가 낮은 대만에서 감소의 폭 역시 크게 나타난다. 일본의 경우 1960년대 큰 폭의 감소가 있은 후 전반적으로 정체하는 경향을 보이며, 한국은 1960년대와 1980년대에 성별 직업분리의 감소경향이 두드러진다. 직업별 양샹을 보면 대만은 한국과 일본에 비해 행정관리직에서 여성의 비주이 계속 증대하고 있다. 이러한 현상에 대한 설명 요인으로서 여성 인력 공급의 측면에서 여성의 직업경력의 연속성 보장과 함께 수요의 측면에서 기업조직 내의 인력 관리상의 유연성과 차별적 관행의 개선을 들 수 있다.

• Journal of Korea Port Economic Association
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• v.36 no.4
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• pp.93-106
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• 2020

Trade is an important economic activity. In particular, since the establishment of the World Trade Organization (WTO), the scope of trade has been expanding due to events such as the entry of China into the WTO in 2001, the establishment of a multilateral trading system, mitigation and integration of trade barriers, and the establishment of the free trade agreement (FTA). Despite the expansion of the trade market, however, extreme events such as the 2008 global financial crisis, the 2016 Brexit, and the 2018 US-China trade war have had a direct negative impact on the trade market. Therefore, the present this study analyzed the dependence structure between the international shipping freight rate index, a variable representing trade activities, and the trade uncertainty between the US and China. The following is a summary of the analysis results. First, the US-Chinese trade policy uncertainty and international shipping freight rate index presented a Frank copula and rotated Clayton copula 270° distribution, respectively, showing the same distribution structure for each country. Second, the Kendall's tau correlation revealed a negative dependence between the international shipping freight rate index and US-Chinese trade policy uncertainty. The degree of dependence was greater in the combination of uncertainty in China's trade policy and international shipping freight rates. In other words, the dependence of global demand and trade policy uncertainty confirmed that China was stronger than the US. Finally, the tail dependence results revealed that the US-Chinese trade policy uncertainty and international shipping freight rates were independent of each other. This means that extreme events related to the trade policy uncertainty or international shipping rate index were not affected by each other.

• Journal of the Korean Society for information Management
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• v.32 no.2
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• pp.7-23
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• 2015

While there are several measures for node centralities, such as betweenness and degree, few centrality measures for local centralities in weighted networks have been suggested. This study developed a generalized centrality measure for calculating local centralities in weighted networks. Neighbor centrality, which was suggested in this study, is the generalization of the degree centrality for binary networks and the nearest neighbor centrality for weighted networks with the parameter ${\alpha}$. The characteristics of suggested measure and the proper value of parameter ${\alpha}$ are investigated with 6 real network datasets and the results are reported.

• Environmental and Resource Economics Review
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• v.14 no.1
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• pp.135-166
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• 2005

This paper measures integrated pollution intensities and changes in pollution intensity, and figure out environmental performance. We introduce a new definition of pollution intensity and its method measuring integrated pollution intensities. We distinguish 24 manufacturing industries into light industry and heavy industry, and divide heavy industry into pollution industry and the other residual heavy industry to measure the integrated pollution intensities and their changes. While the pollution industry within heavy industry, based on the integrated pollution intensity, was the most pollution-intensive, the other residual heavy industry within the heavy industry was the most successive in reducing pollutants. The annualized average index of the integrated pollution intensities grew as much as 9.1 percent, of which the annualized change in the index of pollution emission increased 13.3 percent, but the improvement of 3.9 percent in the change of output quantity offset the increase in the index of pollution emission. The changes in the integrated pollution intensity for the light and heavy industries were 1.125 and 1.042, respectively. The reason the heavy industry showed the lower change in the index of pollution intensity, while the change in the pollution industry was very high, was because the average change in the other heavy industry decreased around 9 percent.

• Communications for Statistical Applications and Methods
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• v.4 no.2
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• pp.557-563
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• 1997

Marshall-Olkin의 이변량 지수모형을 따르는 두개의 부품으로 이루어진 시스템에서, 두 부품의 수명들이 이변량 1종 중단된 자료로 관찰되는 경우, 모수에 대한 최우추정량을 구한다. 그리고 두 부품의 수명에 대한 근사적 독립성과 동일성 검정법을 제안하고 몬테칼로 모의실험을 통하여 검정력을 비교하였다.

• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.80-89
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• 2016

Recently, the paradigm shift of new construction into efficient operation and maintenance of infrastructure is seen. Also, concerns about infrastructure safety, especially the aged infrastructure, are on the increase. This study evaluates the current status of infrastructure safety and maintenance using data from 1994 to 2014 in Facility Management System operated by Korea Infrastructure Safety Corporation. Also, a quantitative analysis of safety performance of infrastructure is conducted to find out the enhancement of infrastructure safety in Korea. It was found that safety of facilities in Korea have been enhanced for the past decades. Improvement of safety performance of facilities is attributed to periodic safety inspection and repair and reinforcement. The result of the study can be used as a basic material for efficient and effective facility maintenance policies and strategies.

• Journal of the Korean Society for information Management
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• v.30 no.4
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• pp.7-29
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• 2013

As interdisciplinary research has been dominant in various fields, the purpose of this study is to analyze the relationship between interdisciplinarity and research impact in the field of Library and Information Science. For a data set, ten journals ranked as the top of 2011 JCR's in terms of JIF (Journal Impact Factor) were selected. The citation data of 1,873 articles from the ten journals were collected from the WoS during the period from 2006 to 2010. In order to achieve the purpose of this study, as network analysis was conducted to investigate the interdisciplinarity of LIS field, interdisciplinarity indicators, and research impact factors were statistically analyzed. The findings of this study confirmed the interdisciplinary knowledge structure of the LIS field as previous studies identified. More importantly, this study demonstrated that a positive correlation existed between interdisciplinarity represented as betweenness centrality and research impact.

• Journal of KIISE:Software and Applications
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• v.31 no.5
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• pp.658-666
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• 2004

Separable systems are defined in term rewriting systems, respecting the notion of separability in the λ-calculus. In this research, we generalize separable systems of term rewriting systems, which was studied in restrictive systems such as constructive systems. We also associate separability with index-transitivity and with forward branching Separability is identified with forward branching, and strong sequentiality with index-transitivity satisfies separability. These are such good properties that enable us to describe the procedure of pattern-matching as an index tree, which is a sort of automata, and to transform separable systems into a constructor system with a simple pattern. Separable systems, in particular, can be translated into the λ-calculus. This research can serve a theoretical basis which allows functional languages to be explained by the λ-calculus, since functional languages such as ML and Haskell belong to a subclass of separable systems.

• The Journal of the Korea Contents Association
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• v.22 no.8
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• pp.329-338
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• 2022

As the non-face-to-face economic situation developed due to the COVID-19 pandemic, untact stock groups appeared in the stock market. This study proposed the Korea COVID-19 fear index following the spread of infectious diseases in the COVID-19 pandemic situation and analyzed the influence on the untact stock and contact stock returns. The results of the empirical analysis are as follows. First, as a result of the Granger causality analysis using the Korea COVID-19 fear index, significant causality was found in the return of contact stocks such as Korean Air, Hana Tour, CJ CGV, and Paradise. Second, as a result of stock price prediction based on the LSTM model, Kakao, Korean Air, and Naver's prediction performance was high. Third, the investment performances of the Alexander filter entry rule using the predicted stock price were high in Naver futures and Kakao futures. This study can find a difference from previous studies in that it analyzed the influence of the spread of the COVID-19 pandemic on untact and contact stocks in the COVID-19 situation where the non-face-to-face economy is in full swing.