• East Asian Economic Review
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• 제27권3호
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• pp.213-242
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• 2023

This paper investigates whether the price of cryptocurrency is determined by the US dollar index, the price of investment assets such gold and oil, and the implied volatility of the KOSPI. Overall, the returns on cryptocurrencies are best predicted by the trading volume of the cryptocurrency both in-sample and out-of-sample. The estimates of gold and the dollar index are negative in the return prediction, though they are not significant. The dollar index, gold, and the cryptocurrencies seem to share characteristics which hedging instruments have in common. When investors take notice of the imminent market risks, they increase the demand for one of these assets and thereby increase the returns on the asset. The most notable result in the out-of-sample predictability is the predictability of the returns on value-weighted portfolio by gold. The empirical results show that the restricted model fails to encompass the unrestricted model. Therefore, the unrestricted model is significant in improving out-of-sample predictability of the portfolio returns using gold. From the empirical analyses, we can conclude that in-sample predictability cannot guarantee out-of-sample predictability and vice versa. This may shed light on the disparate results between in-sample and out-of-sample predictability in a large body of previous literature.

• East Asian Economic Review
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• 제23권4호
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• pp.333-351
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• 2019

We use a data-mining bootstrap procedure to investigate the predictability test in the eight Asia-Pacific regional stock markets using in-sample and out-of-sample forecasting models. We address ourselves to the data-mining bias issues by using the data-mining bootstrap procedure proposed by Inoue and Kilian and applied to the US stock market data by Rapach and Wohar. The empirical findings show that stock returns are predictable not only in-sample but out-of-sample in Hong Kong, Malaysia, Singapore, and Korea with a few exceptions for some forecasting horizons. However, we find some significant disparity between in-sample and out-of-sample predictability in the Korean stock market. For Hong Kong, Malaysia, and Singapore, stock returns have predictable components both in-sample and out-of-sample. For the US, Australia, and Canada, we do not find any evidence of return predictability in-sample and out-of-sample with a few exceptions. For Japan, stock returns have a predictable component with price-earnings ratio as a forecasting variable for some out-of-sample forecasting horizons.

• KDI Journal of Economic Policy
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• 제37권4호
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• pp.1-20
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• 2015

We examine the validity of popular exchange rate models such as the purchasing power parity (PPP) hypothesis and the monetary model for Korean won/US dollar exchange rate. Various specification tests demonstrate that Korean data are more favorable for both models based on time-varying cointegration coefficients as compared to those based on constant cointegration coefficients. When the abilities to predict future exchange rates between those models based on time-varying cointegration coefficients are compared, an in-sample analysis shows that the time-varying PPP (monetary model) has better predictive power over horizons shorter (longer) than one year. Results from an out-of-sample analysis indicate that the time-varying PPP outperforms models based on constant cointegration coefficients when predicting future exchange rate changes in the long run.

• 대한치과교정학회지
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• 제27권3호
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• pp.457-471
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• 1997

본 연구는 치열궁 길이 부조화(Arch length discrepancy : 이하 ALD)의 원인요소간의 상대적 중요성과 혼합치열기에서의 예측가능성을 알아보고자 시행되었다. Angle씨 I급 대구치관계이며 근기능 이상이나 골격형태의 이상이 없다고 판단되는 142명의 진단모형을 이용하여 성별과 ALD의 양에 따라 여섯군으로 나누어 각 치아의 크기와 치열궁 각 부위의 크기를 계측하였다. SPSS통계처리 프로그램을 이용하여 각군의 평균, 표준편차를 구하고 Student t-test, 상관관계 분석, 요인분석, 다중회귀분석을 실시하였으며 혼합치열기에서 얻을 수 있는 자료들을 이용한 ALD의 예측가능성을 평가하여 다음과 같은 결과를 얻었다. 1. 성별에 따른 차이는 정상군에서는 거의 보이지 않았으며 spacing군은 대부분의 계측치에서, crowding군은 몇가지 치열궁의 크기에 관한 계측치에서 유의한 차이를 보였다. 2. 남자crowding군과 여자 spacing군은 해당 정상군에 비해 주로 치아크기에 관한 계측치에서 유의한 차이를 보였다. 3. 남자 spacing군과 여자crowding군은 해당 정상군에 비해 치열궁의 크기에 관한 계측치에서 유의한 차이를 보였다. 4. 상관관계분석과 요인분석결과에서는 주로 치열궁의 크기에 관한 계측치들이 ALD와 큰 연관성을 나타내었다. 5. 혼합치열기에서 얻을 수 있는 정보인 중절치, 측절치, 제1대구치의 폭경과 제1대구치간 폭경, 치열궁 장경 을 이용한 ALD의 다중회귀분석은 최소 $63\%$에서 최대 $80\%$의 예측도(R square)를 보였다.

• IMMUNE NETWORK
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• 제6권1호
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• pp.43-51
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• 2006

Background: The DR-$70^{TM}$ immunoassay is a newly developed cancer diagnostic test which quantifies the serum fibrin degradation products (FDP), produced during fibrinolysis, by antibody reaction. The purpose of this study was to evaluate the potential of DR-$70^{TM}$ Immunoassay in screening malignant tumor. Methods: Sample subjects were 4,169 adults, both male and female, who visited the health promotion center of a general hospital from March 2004 to April 2005 and underwent the DR-$70^{TM}$ immunoassay test and other tests for cancer diagnosis. The patient group was defined as 42 adults out of the sample subjects who were newly diagnosed with cancer during the same time period when the DR-$70^{TM}$ immunoassay test was performed. Final confirmation of a malignant tumor was made by pathological analysis. Results: The mean DR-$70^{TM}$ level was $0.83{\pm}0.65{\mu}g/ml$ (range: 0.00 (0.0001)${\sim}7.42{\mu}g/ml)$ in the control group (n=4,127) as opposed to $2.70{\pm}2.33{\mu}g/ml$ (range: $0.12{\sim}9.30{\mu}g/ml)$ in the cancer group (n=42), and statistical significance was established (p<0.0001, Student t-test). When categorized by the type of malignant tumor, all cancer patients with the exception of the subgroups of colon and rectal cancer showed significantly higher mean DR-$70^{TM}$ levels compared with the control group (p<0.0001, Kruscal-Wallis test). The receiver operating characteristic (ROC) curve analysis revealed ${\geq}1.091{\mu}g/ml$ as the best cut-off value. Using this cut-off value, the DR-$70^{TM}$ immunoassay produced a sensitivity of 71.4%, a specificity of 70.1%, a positive predictability of 69.4%, and a negative predictability of 69.2% (1). Conclusion: A significant increase in the mean DR-$70^{TM}$ value was observed in the cancer group (thyroidal, gastric, breast, hepatic and ovarian) com pared with the control group. In particular, the specificity and sensitivity of the DR-$70^{TM}$ immunoassay was relatively high in the subgroups of breast, gastric, and thyroidal cancer patients. There is need for further studies on a large number of malignant tumor patients to see how the DR-$70^{TM}$ level might be changed according to the differentiation grade and postoperative prognosis of the malignant tumor.

• Journal of Biosystems Engineering
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• 제29권1호
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• pp.65-70
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• 2004

This study was carried out to verify and predict the soil informations such as the contents of organic matter(OM) and Mg and pH of the soil. The predictability of spacial variation in the paddy field was examined by analyzing the various soil information. The prediction models for the OM pH, and Mg, were developed using inverse distance weighted (IDW), triangulated irregular network(TIN) and Kriging model. The determination of coefficients of linear and spherical Kriging models were 0.756 and 0.578, respectively, and were very low in comparison with other soil information. For IDW and TIN model, the determination of coefficients were 1.000 and hence the performance of the models was found to be excellent. The developed models were validated using unknown soil sample obtained In 2000 and 2001. From the analysis of relationship between the measured pH and predicted 0.9353. For prediction of Mg, the determination of coefficient is more than 0.8. Since the determination of coefficients of developed models for OM were relatively low, it may be difficult to predict the content of OM using the developed models. For further study, the additional works to enhance the performance of the prediction models for soil information are required.

• 한국IT서비스학회지
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• 제19권2호
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• pp.109-124
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• 2020

Facing the 4^th Industrial Revolution era, researches on artificial intelligence have become active and attempts have been made to apply machine learning in various fields. In the field of finance, Robo Advisor service, which analyze the market, make investment decisions and allocate assets instead of people, are rapidly expanding. The stock price prediction using the machine learning that has been carried out to date is mainly based on the prediction of the market index such as KOSPI, and utilizes technical data that is fundamental index or price derivative index using financial statement. However, most researches have proceeded without any explicit verification of the prediction rate of the learning data. In this study, we conducted an experiment to determine the degree of market prediction ability of basic indicators, technical indicators, and system risk indicators (AR) used in stock price prediction. First, we set the core parameters for each financial indicator and define the objective function reflecting the return and volatility. Then, an experiment was performed to extract the sample from the distribution of each parameter by the Markov chain Monte Carlo (MCMC) method and to find the optimum value to maximize the objective function. Since Robo Advisor is a commodity that trades financial instruments such as stocks and funds, it can not be utilized only by forecasting the market index. The sample for this experiment is data of 17 years of 1,500 stocks that have been listed in Korea for more than 5 years after listing. As a result of the experiment, it was possible to establish a meaningful trading strategy that exceeds the market return. This study can be utilized as a basis for the development of Robo Advisor products in that it includes a large proportion of listed stocks in Korea, rather than an experiment on a single index, and verifies market predictability of various financial indicators.

• 한국직업건강간호학회지
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• 제9권1호
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• pp.39-48
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• 2000

Hyperlipemia is the most leading risk factor of cardiovascular disease which is the main cause of death in Korea. However, there is a tendency to neglect the prevention and treatment since it has no specific symptoms. It has been reported that the level of serum-lipid can be lowered by the improvement of eating habits. Therefore, it is highly likely that the development of programs on the improvement of eating habits through behavioral theory is required to the community nursing practice. The theory of planned behavior, which assumes that human behaviors are determined by one's intention to carry out the behavior, can be characterized by the point that behaviors are not only individual factors but also social behaviors relating to subjective norms. It is widely recognized that this theory has a high predictability on health behavior due to it's simplicity clearness, and measurability as well as high quality of being general. Thus, the theory of planned behavior could be useful in developing a model of a health promotion program to the change of behaviors of the risk group of cardiovascular disease. Consequently, based on the theory of planned behavior, the purpose of this study is to develop an intention promotion program of the diet, and then to testify the effects. The sample of this study consisted of 26 industrial workers who had proved hyperlipemia from a medical examination in 1996 (experimental group 13, control group 13). The intention promotion program, which includes education, monitoring, pressure, counselling on the level of individuals, families and organizations, was conducted for 10 weeks The purpose of this program was to promoting intention of the diet through changes of the prerequisite factors of intention such as behavioral belief, outcome evaluation, normative belief and control belief. When it came to data analysis, the ${\chi}^2$-test and Fisher's Exact test were used to compare the general characteristics between the experimental and the control group, an independent t-test for the other variables. ANOVA was used to the test hypothesis, and the Pearson correlation test for variable's correlation. The results of this study can be summarized as follows ; 1) There was a significant increase in the intention(F=18.51, p=.00) of diet in the experimental group. 2) Diets(F=32.51, p=.001) in the experimental group were better carried out than in the control group. 5) There was a moderate correlation between the intention of diet and performance (r=.587. p=.003). From the results, it can be concluded that the intention promotion program is very effective, leading to the change of health promotion behavior. Above all, it is really valuable that the intention promotion program in this study regards health promotion behavior as a social behavior and that intervention was done on the level of family and organization. Consequently, when performing a health promotion program, social approach elevating the intention should go hand in hand in order to make the program effective.

• 한국조사연구학회지:조사연구
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• 제13권1호
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• pp.135-158
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• 2012

국내 선거여론조사에서 면접대상인 가구(또는 개인) 표본을 추출하기 위해 유선전화 전화번호부 또는 임의번호걸기(RDD) 방식이 주로 이용되고 있다. 하지만 유선전화를 보유하지 않은 가구가 늘어나고 있고, 유선전화가 있더라도 전화번호부 등재를 꺼리는 가구가 점차 많아지고 있다. 또한 젊은 층이나 직장인의 경우 여론조사가 실시되는 낮 시간대에 주로 외부에서 활동하므로 유선전화를 통한 접촉이 매우 어려운 실정이다. 상술한 문제들로 인하여 선거 여론조사의 예측력이 점점 떨어지고 있으며, 특히 조사시간대에 주로 외부에서 활동하는 사람들에 대한 낮은 접근성은 보수 성향 후보에게 긍정적인 예측결과를 내놓는 편향으로 이어지고 있다. 이러한 문제점을 해소할 수 있는 한 가지 방법으로 이동전화를 함께 활용하는 조사를 생각해 볼 수 있다. 즉, 낮 시간대 재택성향이 높은 사람들에 대해서는 유선전화를 활용한 조사를 수행하고, 부재성향이 높은 사람들에 대해서는 이동전화조사를 수행한 후, 두 결과를 혼합하는 방식(유 무선전화 병행조사)이다. 유 무선전화 병행조사를 실시하기 위해서는 1)유선전화와 이동전화 조사를 위한 표집틀이 확보되어야 하고, 2)유선전화와 이동전화로 조사할 비중을 사전에 결정해야 한다. 본 연구에서는 유 무선전화 병행조사를 실시하기 위한 경험적(heuristic) 방법론을 제안한다. 제안된 방법에서는 유선전화조사를 위해 임의번호걸기 방식을 이용하고, 이동전화조사를 위해 조사회사에서 모집한 조사패널을 활용한다. 또한, 유선전화와 이동전화로 조사할 표본의 비중은 통계청 생활시간조사 결과를 이용해서 계산한 재택율과 부재율을 활용한다. 제안된 조사방법을 활용하여 10.26 서울시장 보궐선거에 대한 여론조사를 실시하였다. 총 4회의 여론조사가 실시되었는데, 처음 3회의 조사는 판세분석용 조사이고, 최종 조사는 선거결과 예측용 조사이다. 판세분석조사의 경우 조사시점에 발생된 이슈에 대한 반응이 타당성 있게 조사되었고, 선거예측조사의 경우 실제 선거결과에 매우 근접한 예측능력을 보였다.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제12권1호
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• pp.138-148
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• 2001

본 연구는 생태계 이론에 근거하여 비계획적인 청소년기 성행동의 위험 요인을 파악하고자 실시되었다. 1996년 9월 12월까지 13~18세 연령 범위의 청소년 2326명에게 설문을 실시하였다. 미혼모 보호소에 있는 대상을 제외하였을때 응답자외 8.8%가 과거 성행동 경험이 있다고 보고하였다. 그 글 남자는 13.4% 여자는 5.0%로서 남자가 2.7배 더 많았고 13세(3.2%)보다 18세(19.2%)에서 약 6배 더 많았다. 연령과 성별을 맞추어 성행동 경험군과 비경험군을 비교한 결과 다섯가지의 위험요인이 발견되었다. 첫째 개인요소로서 자신의 잠재된 능력에 대한 고려가 부족하고 음주, 흡연, 약물 복용, 가출등의 경력이 있거나 포르노에 노출된 경우 그리고 자신이 성에 대해서 많이 알고 있다고 생각하는 것들이 포함된다. 둘째 요인은 가족 요인으로서, 가족의 중요성을 덜 느끼고 가족의 지시를 덜 받는 경우, 수입이 높고 평균보다 많거나 적은 경우 등이 포함된다. 셋째 요인은 또래 문제로써, 친구들이 실제보다 더 많은 문제 행동을 하고 있다고 믿는 경향이 포함된다. 넷째, 학교 요인으로는 학교의 중요성을 느끼지 못하고 학업 능력이 좋지 않을 경우에 성행동 위험이 높아졌다. 자아가 형성되는 시기인 사춘기에 예기치 않은 성행동을 예방하기 위해서는 가족관계와 학교생활에 주목해야 하며, 본 연구에서 밝혀진 위험 요인들이 향후 성행동에 미치는 영향에 대한 전향적 연구가 필요하다고 할수 있다.