• 한국산학기술학회논문지
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• 제12권12호
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• pp.5671-5676
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• 2011

변동성지수는 옵션가격에 내재된 미래 기초자산의 변동성을 나타내는 지수이며, 투자자들이 예상하는 향후 주가 변동 가능성을 측정한 시장의 기댓값이다. 현재 한국거래소(KRX)에서 한국시장구조에 맞는 변동성지수를 개발하여 2009년 4월 13일부터 변동성지수(VKOSPI)를 발표하고 있다. 본 연구는 2002년부터 2008년까지 일별 데이터를 이용하여 기업규모, 시장기치 대 장부가치 비율 및 베타의 특징들로 그룹화된 포트폴리오의 미래 수익률에 대한 변동성지수의 예측력을 검증하였다. 그 결과 VKOSPI의 변화율은 미래수익률에 대해 강한 음(-)의 예측력을 갖고 있는 것으로 나타났으며, 이러한 결과는 Ang et al.[2]의 결과와 일치하고, 이는 VKOSPI가 수익률 결정요인이라 할 수 있다. 시장총변동성 추정치의 부호에 대해 Ang et al.은 시장 총변동성위험과 개별주식 수익률간의 음(-)의 관계로 설명하였다. 이는 시장 총변동성위험이 높아질 때, 시장변동성과 상관관계가 높은 주식은 시장위험에 대한 주식의 민감도, 즉 베타가 낮아져 개별주식 수익률이 하락한다는 것이다. 또한 포트폴리오를 그룹화하는데 베타가 포함되어진다면, 미래 수익률에 대한 VKOSPI의 예측력이 강하다는 것으로 나타났다.

• 지능정보연구
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• 제27권1호
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• pp.65-82
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• 2021

주식시장에 참여하는 투자자들은 크게 외국인투자자, 기관투자자, 그리고 개인투자자로 구분된다. 외국인투자자 같은 전문투자자 집단은 개인투자자 집단과 비교하여 정보력과 자금력에서 우위를 보이고 있으며, 그 결과 시장 참여자들 사이에는 외국인투자자들이 좋은 투자 성과를 보이는 것으로 알려져 있다. 외국인 투자자들은 근래에는 인공지능을 이용한 투자를 많이 하고 있다. 본 연구의 목적은 투자자별 거래량 정보와 머신러닝을 결합하는 투자전략을 제안하고, 실제 주가와 투자자별 거래량 데이터를 이용하여 제안 모형의 포트폴리오 투자 성과를 분석하는 것이다. 일별 투자자별 매수 수량과 매도 수량 정보는 한국거래소에서 공개하고 있는 자료를 활용하였으며, 여기에 인공신경망을 결합하여 최적의 포트폴리오 전략을 도출하고자 하였다. 본 연구에서는 자기 조직화 지도 모형 인공신경망을 이용하여 투자자별 거래량 데이터를 그룹화하고 그룹화한 데이터를 변환하여 오류역전파 모형을 학습하였다. 학습 후 검증 데이터 예측결과로 매월 포트폴리오 구성을 하도록 개발하였다. 성과 분석을 위해 포트폴리오의 벤치마크를 지정하였고 시장 수익률 비교를 위해 KOSPI200, KOSPI 지수 수익률도 구하였다. 포트폴리오의 동일배분 수익률, 복리 수익률, 연평균 수익률, MDD, 표준편차, 샤프지수, 벤치마크로 지정한 시가총액 상위 10종목의 Buy and Hold 수익률 등을 사용하여 성과 분석을 진행하였다. 분석 결과 포트폴리오가 벤치마크 대비 2배 수익률을 올렸으며 시장 수익률보다 좋은 성과를 보였다. MDD와 표준편차는 포트폴리오와 벤치마크가 비슷한 결과로 성과 대비 비교한다면 포트폴리오가 좋은 성과라고 할 수 있다. 샤프지수도 포트폴리오가 벤치마크와 시장 결과보다 좋은 성과를 내었다. 이를 통해 머신러닝과 투자자별 거래정보 분석을 활용한 포트폴리오 구성 프로그램 개발의 방향을 제시하였고 실제 주식 투자를 위한 프로그램 개발에 활용할 수 있음을 보였다.

• The Journal of Asian Finance, Economics and Business
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• 제8권2호
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• pp.759-770
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• 2021

Using a DCC - GARCH model analysis, this paper examines the existence of financial contagion from the U.S. stock market to the Vietnamese and the Philippine stock markets during the global financial crisis and the COVID-19 pandemic crisis. We use daily data from the S&P 500 (U.S.), VN-Index (Vietnam), and the PSEi (the Philippines). As a result, there is no evidence of contagion from the U.S stock market to the Philippine stock market that can be found during global financial crisis, while the Vietnamese market is influenced by this effect. Besides, both these developing stock markets (the Vietnamese and Philippine stock markets) are influenced by the contagion effect in COVID-19 pandemic crisis. Another finding is that the contagion effect during the coronavirus pandemic crisis in Vietnam is smaller than that during the global financial crisis, however, the opposite is the case for the Philippines. It is noticed that the Philippines seems to be more affected by the contagion effect from the COVID-19 pandemic than Vietnam at the time of this study. Because financial contagion is important for monetary policy, asset pricing, risk measurement, and portfolio allocation, the findings in this paper may give some useful information for policymakers and investors.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2000년도 춘계공동학술대회 논문집
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• pp.65-68
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• 2000

The problem of selecting a portfolio is to find Un investment plan that achieves a desired return while minimizing the risk involved. One stream of algorithms are based upon mixed integer linear programming models and guarantee an integer optimal solution. But these algorithms require too much time to apply to real problems. Another stream of algorithms are fur a near optimal solution and are fast enough. But, these also have a weakness in that the solution generated can't be guaranteed to be integer values. Since it is not a trivial job to tansform the scullion into integer valued one simutaneously maintaining the quality of the solution, they are not easy to apply to real world portfolio selection. To tackle the problem more efficiently, we propose an algorithm which generates a very good integer solution in reasonable amount of time. The algorithm is tested using Korean stock market data to verify its accuracy and efficiency.

• Journal of the Korean Data and Information Science Society
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• 제23권5호
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• pp.867-880
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• 2012

파론도 역설은 개별로는 지는 게임들이 결합하여 이기게 되거나 개별로는 이기는 게임들이 결합하여 지게 되는 역설적인 현상을 말한다. 본 논문에서는 주변의 투자 결과에 의해 매수 종목을 정하는 공간의존 파론도 게임의 규칙을 적용하여 매일 주식을 사고 파는 경우에 각 포트폴리오의 거래당 기대수익금을 계산하고, 2008년부터 2010년까지의 한국거래소의 주식 데이터를 이용하여 주식 투자에서도 파론도 역설 현상이 존재함을 확인한다.

• 경영과학
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• 제32권3호
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• pp.91-103
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• 2015

This study recognizes that there is a correlation between the movement of the financial market and the sentimental changes of the public participating directly or indirectly in the market, and applies the relationship to investment strategies for stock market. The concerns that market participants have about the economy can be transformed to the search terms that internet users query on search engines, and search volume of a specific term over time can be understood as the economic trend of big data. Under the hypothesis that the time when the economic concerns start increasing precedes the decline in the stock market price and vice versa, this study proposes three investment strategies using casuality between price of domestic stock market and search volume from Naver trends, and verifies the hypothesis. The computational results illustrate the potential that combining extensive behavioral data sets offers for a better understanding of collective human behavior in domestic stock market.

• The Journal of Asian Finance, Economics and Business
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• 제7권9호
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• pp.125-134
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• 2020

This study examines the nominal price anomaly in the Vietnamese stock market, that is, whether stocks with low nominal price outperform stocks with high nominal price. Using a sample of all 351 companies listed on the Ho Chi Minh Stock Exchange (HOSE) from June 2009 to March 2018, we confirm our hypothesis and document that cheaper stocks yield higher subsequent abnormal returns. The results are robust after controlling for various stock characteristics that have been documented to be value-relevant in prior literature, including firm size, book-to-market ratio, intermediate-term momentum, short-term reversal, skewness, market risk, idiosyncratic risk, illiquidity and extreme daily returns, using both the portfolio analysis and the Fama-MacBeth cross-sectional regression. The negative effect persists in the long term (i.e., after up to 12 months), implying a slow adjustment of stock prices to their intrinsic value. Further analysis show that the observed nominal price anomaly is mainly driven by mispricing but not a latent risk factor proxied by stock price, thus the observed anomaly reflects a mispricing but not a fundamental risk. The study highlights the irrational behaviour of investors and market inefficiency in the Vietnamese stock market and provides important implication for investors in the market.

• The Journal of Asian Finance, Economics and Business
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• 제9권5호
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• pp.1-9
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• 2022

The study examines stock prices (LOGKSE) and exchange rate (LOGPK)-Pakistani Rupee vis-à-vis US Dollar- interactions in Pakistan. This study employs a multivariate VAR-GARCH model using monthly data from January 2012 to October 2020. The results of the Johansen cointegration test show that there is no relationship between Foreign Exchange Market and Stock Market in the long run. In the short-run, stock exchange returns are affected slightly negatively by the changes in the foreign exchange market, but the foreign exchange market does not seem to be affected by the ups and downs of the stock exchange. The VAR model and Granger Causality show that both markets are strongly influenced by their own lagged values rather than by the lagged values of one another and show weak or no correlation between the two markets. Volatility persistence is observed in both the stock and foreign exchange markets, implying that shocks and past period volatility are major drivers of future volatility in both markets. Thus greater uncertainties today will induce panic and consequently generate higher volatility in the future period. This phenomenon has been observed many times on Pakistan Stock Exchange especially. The results have important implications for local international investors in portfolio diversification decisions and risk hedging strategies.

• 대한가정학회지
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• 제41권9호
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• pp.105-120
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• 2003

This study has conducted to develop the computer program for households portfolio management to enhance their financial well-being. The study has divided into two parts. First, descriptive statistics has used to analyze as a basis of computer program and it includes the comparison of household asset allocations between households in Korea and U. S. A., Second, it shows the components of the portfolio program developed to manage households efficiently. For both two countries, recent four years data has been used and in part two, total sample size of households in Korea is 2155. From the statistical analysis, households in U. S. A. tend to invest more on the stock & bonds as their net-asset is increased. However households in Korea tend to have less financial assets and it might be found the fact that they prefer to own real-estate because of the inflation. In the part of computer program, it is included the average financial asset responding to the demographic variables and households could refer those average amount as a reference planning their asset portfolio.

• Journal of applied mathematics & informatics
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• 제15권1_2호
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• pp.109-126
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• 2004

This paper deals with two problems of optimal portfolio strategies in continuous time. The first one studies the optimal behavior of a firm who is forced to withdraw funds continuously at a fixed rate per unit time. The second one considers a firm that is faced with an uncontrollable stochastic cash flow, or random risk process. We assume the firm's income can be obtained only from the investment in two assets: a risky asset (e.g., stock) and a riskless asset (e.g., bond). Therefore, the firm's wealth follows a stochastic process. When the wealth is lower than certain legal level, the firm goes bankrupt. Thus how to invest is the fundamental problem of the firm in order to avoid bankruptcy. Under the case of different lending and borrowing rates, we obtain the optimal portfolio strategies for some reasonable objective functions that are the piecewise linear functions of the firm's current wealth and present some interesting proofs for the conclusions. The optimal policies are easy to be operated for any relevant investor.