• 경영과학
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• 제24권2호
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• pp.115-126
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• 2007

Weekly minima of daily log returns of Korean composite stock price index 200 and its five industry-based business divisions over the period from January 1990 to December 2005 are fitted using two block-based extreme distributions: Generalized Extreme Value(GEV) and Generalized Logistic(GLO). Parameters are estimated using the probability weighted moments. Applicability of two distributions is investigated using the Monte Carlo simulation based empirical p-values of Anderson Darling test. Our empirical results indicate that both the GLO and GEV models seem to be comparably applicable to the weekly minima. These findings are against the evidences in Gettinby et al.[7], who claimed that the GEV model was not valid in many cases, and supported the significant superiority of the GLO model.

• 수산해양교육연구
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• 제16권1호
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• pp.99-109
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• 2004

This study analyzed the multivariate impacts of subsidies on the sustainability of fish stock using a dynamic bioeconomic modeling and fisheries resources economic approaches for understanding impacts of a subsidy on the sustainability of a fish stock. According to the results of analysis, the conclusion of former studies is true only there are imperfect control of fishing effort and enforcement under management rerime and under open access. However, if there are perfect control of effort and enforcement, the subsidies do not give any negative impacts on the sustainability of fish stock. Further, if even so-called bad subsidy is also provided necessarily in response to the condition of fishing industry and the characteristic of fishermen, it can give positive impacts on fishing income by which fishermen can improve their fishing condition.

• Asia pacific journal of information systems
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• 제24권2호
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• pp.233-253
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• 2014

Can the stock market really be predicted? Stock market prediction has attracted much attention from many fields including business, economics, statistics, and mathematics. Early research on stock market prediction was based on random walk theory (RWT) and the efficient market hypothesis (EMH). According to the EMH, stock market are largely driven by new information rather than present and past prices. Since it is unpredictable, stock market will follow a random walk. Even though these theories, Schumaker [2010] asserted that people keep trying to predict the stock market by using artificial intelligence, statistical estimates, and mathematical models. Mathematical approaches include Percolation Methods, Log-Periodic Oscillations and Wavelet Transforms to model future prices. Examples of artificial intelligence approaches that deals with optimization and machine learning are Genetic Algorithms, Support Vector Machines (SVM) and Neural Networks. Statistical approaches typically predicts the future by using past stock market data. Recently, financial engineers have started to predict the stock prices movement pattern by using the SNS data. SNS is the place where peoples opinions and ideas are freely flow and affect others' beliefs on certain things. Through word-of-mouth in SNS, people share product usage experiences, subjective feelings, and commonly accompanying sentiment or mood with others. An increasing number of empirical analyses of sentiment and mood are based on textual collections of public user generated data on the web. The Opinion mining is one domain of the data mining fields extracting public opinions exposed in SNS by utilizing data mining. There have been many studies on the issues of opinion mining from Web sources such as product reviews, forum posts and blogs. In relation to this literatures, we are trying to understand the effects of SNS exposures of firms on stock prices in Korea. Similarly to Bollen et al. [2011], we empirically analyze the impact of SNS exposures on stock return rates. We use Social Metrics by Daum Soft, an SNS big data analysis company in Korea. Social Metrics provides trends and public opinions in Twitter and blogs by using natural language process and analysis tools. It collects the sentences circulated in the Twitter in real time, and breaks down these sentences into the word units and then extracts keywords. In this study, we classify firms' exposures in SNS into two groups: positive and negative. To test the correlation and causation relationship between SNS exposures and stock price returns, we first collect 252 firms' stock prices and KRX100 index in the Korea Stock Exchange (KRX) from May 25, 2012 to September 1, 2012. We also gather the public attitudes (positive, negative) about these firms from Social Metrics over the same period of time. We conduct regression analysis between stock prices and the number of SNS exposures. Having checked the correlation between the two variables, we perform Granger causality test to see the causation direction between the two variables. The research result is that the number of total SNS exposures is positively related with stock market returns. The number of positive mentions of has also positive relationship with stock market returns. Contrarily, the number of negative mentions has negative relationship with stock market returns, but this relationship is statistically not significant. This means that the impact of positive mentions is statistically bigger than the impact of negative mentions. We also investigate whether the impacts are moderated by industry type and firm's size. We find that the SNS exposures impacts are bigger for IT firms than for non-IT firms, and bigger for small sized firms than for large sized firms. The results of Granger causality test shows change of stock price return is caused by SNS exposures, while the causation of the other way round is not significant. Therefore the correlation relationship between SNS exposures and stock prices has uni-direction causality. The more a firm is exposed in SNS, the more is the stock price likely to increase, while stock price changes may not cause more SNS mentions.

• 한국항만경제학회지
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• 제35권2호
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• pp.61-76
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• 2019

본 연구의 목적은 BDI 변화가 한국 주가 변동성에 어떠한 영향을 미치는지를 분석하기 위하여 EGARCH 모형과 그랜저인과관계분석을 실시하였다. 주요 분석결과는 다음과 같이 요약할 수 있다. 첫째, 평균방정식을 보면, BDI 변화율은 대형주, 제조업, 서비스업과 화학에서 유의한 것으로 나타났으며, 다른 지수들은 유의하지 않은 것으로 나타났다. 그러나 음(-)의 값을 가지는 것으로 나타났으며, 이는 국내 주식시장이 해운시장 상황에 적절한 대응을 하지 못한다는 것을 의미할 뿐만 아니라, 원자재에 대한 수요의 증가가 실질적인 경기회복으로 이어지지 않고 있다는 것이다. 둘째, 분산방적식의 결과를 보면, BDI 변화율의 추정계수는 음(-)을 값을 가는지는 것으로 나타났으며, 규모별 변동성에서 BDI 변화율은 모든 지수에 유의한 것으로 나타났으며, 대형주에 비해 소형주 변동성에 미치는 영향이 더 큰 것으로 나타났다. 업종별 지수들의 분석결과에서는 제조업과 화학 부문을 제외하고 서비스업, 금융업, 건설업과 전기전자의 결과들에서는 통계적으로 유의하게 나타났다. BDI 변화가 건설업에 가장 큰 영향을 주는 것으로 나타났다. 셋째, 그랜저인과관계 검정결과를 보면, BDI 변화율이 금융업과 건설업을 선도하는 것으로 나타났다. BDI와 나머지 지수들 간에 선도관계가 나타나지 않았다. 따라서, 해상운임지수가 한국의 주식시장의 변동성의 움직임을 예측하는데 사용될 수 있다는 것을 보여주며, 투자자, 정책입안자에게 더 나은 결정을 할 수 있게 도움을 줄 수 있다.

• 한국철도학회논문집
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• 제10권2호
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• pp.231-242
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• 2007

As railroad industry faces the new Renaissance era, effective and efficient maintenance methods for rolling stock operation are required with advanced railroad technology. All kinds of railroad systems such as high-speed long-distance train, metropolitan mass transit and light rail require systematic maintenance technology in order to maintain the safe railroad operation. Simulation models for regular operations of the example maintenance center are developed. In this study, standard maintenance procedures, layout, equipments, and number of workers of Siheung Metropolitan Railroad Maintenance Rolling Stock Depot are considered. The proposed simulation models are developed using simulation package ARENA. After simulation, four types of observations are analyzed. First, the bottleneck operation is identified. Second, the relationship between maintenance center size, number of workers and cycle time is analyzed. Third, the scheduling performances between PERT/CPM and Critical Chain Project Management(CCPM) are compared. Lastly, the simulation results according to worker's working coverage shows expanding the worker's coverage decreases the cycle time and increases throughput per train. However, workers are to be fully trained to do multiple skill work.

• The Journal of Asian Finance, Economics and Business
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• 제7권2호
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• pp.107-117
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• 2020

The research objective of the paper is to clarify the factors influencing system risks of listed companies in Vietnam, with a focus on clarifying the relationship and quantifying the impacts of ownership structure on systemic risk of listed companies. The data used in this study included financial statements and stock price data of listed companies on the Ho Chi Minh City Stock Exchange and Hanoi Stock Exchange of Vietnam stock market in the period from 2010 to 2017. The paper used the method of estimation in establising the regression models to choose among three models: Random Effect Model, Fixed Effect Model or Pooled OLS for regression using Stata statistical software. The research results showed that state ownership and ownership by foreign investors were positively related to systemic risk, while ownership by domestic investors had a reverse relationship with systemic risk of listed companies in Vietnam. In addition, as a control variable, both company size and profitability had an effect on the systemic risk of listed companies in the research sample. Based on the research results, the authors interpreted some of the implications in order to minimize systemic risks in the operation of listed companies in Vietnam.

• International journal of advanced smart convergence
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• 제12권2호
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• pp.193-200
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• 2023

This paper selects 100 IT companies listed on the Shenzhen Stock Exchange from 2016 to 2020, and the public announcement in Hwajung collects ESG integrated ratings and grades for each sector and empirically verifies the relationship between ESG ratings and stock returns. Huazheng ESG level data and QIANZHAN database Using corporate financial data, a total of 500 samples were selected through correlation analysis and linear regression analysis with SPSS23 to analyze the effect of ESG on Return. As a result of the analysis, first, the impact on stock returns was found to be a significant positive (+) value for ESG integrated ratings and ratings by E (environment), S (social), and G (governance) sectors, confirming that ESG ratings have a positive mold of corporate stock returns. Currently, the world's major economies have proposed sustainable development strategies and "carbon neutral" goals. Development strategies are very consistent with ESG concepts, and companies that agree and execute ESG concepts may have higher ratings than other companies in the same industry, resulting in certain evaluation premiums. In addition, capital market performance in recent years shows that companies with ESG concepts or "carbon neutrality" concepts are generally considered to have higher growth potential and stronger anti-risk capabilities in the market. For listed companies, they should focus on ESG investment, improve ESG performance, and actively disclose related information to investors. Improving ESG performance should deliver positive information to society, enhance corporate image, increase market confidence in the future development of listed companies, and positively improve corporate value to actively increase financial, financial, trading, and other aspects of negotiation.

• International Journal of Advanced Culture Technology
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• 제11권2호
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• pp.389-396
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• 2023

This paper selects 100 IT companies listed on the Shenzhen Stock Exchange from 2016 to 2020, and the public announcement in Hwajung collects ESG integrated ratings and grades for each sector and empirically verifies the relationship between ESG ratings and stock returns. Huazheng ESG level data and QIANZHAN database Using corporate financial data, a total of 500 samples were selected through correlation analysis and linear regression analysis with SPSS23 to analyze the effect of ESG on Return. As a result of the analysis, first, the impact on stock returns was found to be a significant positive (+) value for ESG integrated ratings and ratings by E (environment), S (social), and G (governance) sectors, confirming that ESG ratings have a positive mold of corporate stock returns. Currently, the world's major economies have proposed sustainable development strategies and "carbon neutral" goals. Development strategies are very consistent with ESG concepts, and companies that agree and execute ESG concepts may have higher ratings than other companies in the same industry, resulting in certain evaluation premiums. In addition, capital market performance in recent years shows that companies with ESG concepts or "carbon neutrality" concepts are generally considered to have higher growth potential and stronger anti-risk capabilities in the market. For listed companies, they should focus on ESG investment, improve ESG performance, and actively disclose related information to investors. Improving ESG performance should deliver positive information to society, enhance corporate image, increase market confidence in the future development of listed companies, and positively improve corporate value to actively increase financial, financial, trading, and other aspects of negotiation.

• 무역학회지
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• 제45권1호
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• pp.173-201
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• 2020

As the US's trade deficit with China and China's manufacturing industry has risen rapidly, the US has begun to regulate trade items as part of China's checks. Four rounds of reprisal measures have greatly altered the trade structures of both countries. In particular, Korea, which is highly dependent on the US and China, has been directly affected by US-China trade disputes. The purpose of this study was to analyze the effects of US-China trade disputes on the stock price of Korean export firms by performing an event study. This study analyzed stock price fluctuations for 7 days before and after entry into forced [Please check] retaliatory tariffs on Korean exporters' export items subject to retaliatory tariffs. According to the analysis results, among companies that produce goods with major tariffs imposed on China by the US, such as electronic appliances, semiconductors, machinery, and automobiles, those producing electronics and semiconductor products were positively affected by the tariff incident. Secondly, among the companies producing steel, chemicals, and machinery, which the main tariffs imposed by the United States, companies producing steel and chemicals were negatively affected by the incident due to the stagnation of trade between China and the US. The results of this study suggest future trade policy directions for Korea and help to establish an export strategy for major industries.

• 한국환경보건학회지
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• 제27권2호
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• pp.51-59
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• 2001

Song stream is located in the upstream of the Namhan River. Normal times, the stream flows down to the east sea through the drainage pipe but at rainy season, it flows to the Namhan River. There are large stock farm, leisure town and cultivated land in this basin. The pollutants from these contamination source cause eutrophication at lake Doam and deterioration of water quality in namdai stream. In this case, this study was carried out to evaluate water quality and environmental capacity as well as economical efficiency of each industry. The basin shape factor of subject stream was 0.315, slope is higher than usual basin. The BOD, T-N and T-P productive contamination loading from each contamination source was 2,690, 974 and 194 kg/day, respectively, and major contamination source was stock farm and cultivated land. Annual BOD, T-N, T-P distribution(median value) of Song stream showed 1.0~2.2 mg/L, 3.16~5.85 mg/L and 0.024~0.197 mg/L Doam lake showed 1.1~1.9, 2.51~3.89 and 0.042~0.114 mg/L, respectively. Being compared of water quality at main stream between past and present, it showed that the water quality has improved since last five years. BOD improvement rate was 8~50%. Run off loading of BOD, T-N, T-P was 366, 1129, 17.2 kg/day, and run off rate was 13.6%, 86.2%, 11.3% respectively. Finally, the result of productivity survey of each industry, leisure town, cultivated land and large stock farm was 118, 46, 50 billion won, per T-P 1kg productive, and productivity portion was 100, 39, 42% respectively, and the highest economical efficiency industry was leisure facilities.