• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.745-748
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• 2020

국민연금이 2056 년 고갈될 수 있다는 전망이 나오면서 연금소득에 대한 국민들의 불안감이 커졌다. 노후를 위해 미리 대비해야한다는 인식이 커지며 자동으로 투자해주는 '로보어드바이저'에 대한 사회적 관심이 함께 높아졌다. 본 연구에서는 기존 시중 은행들의 펀드 기반 로보어드바이저가 아닌 기업 재무 정보, 수정 종가 데이터를 이용한 직접 투자를 고안하였다. LGBM 알고리즘으로 포트폴리오를 구현해본 결과 실제 퀀트 투자에서 사용되는 지표들이 주식의 변화를 예측하는데 효과가 있음을 확인할 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.440-442
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• 2022

2017년 가치가 급상승하며 전 세계적으로 큰 이슈를 끈 비트코인은 최근 많은 사람들의 재태크 수단으로 이용되고 있다. 그러나 비트코인은 비슷한 재태크 수단인 주식과 다르게 24시간 내내 거래되고, 기사 하나하나에 의해 가격변동의 폭이 굉장히 크다. 이는 가격이 급변하는 비트코인 시장에서 가격을 예측하는데 어렵게 작용한다. 본 논문에서는 직접적인 가격 예측은 어렵다고 판단해 비트코인 가격변동에 영향을 주는 요소들을 딥러닝 모델을 통해 일일 단위 종가 가격의 등락을 예측해 위의 요소들이 비트코인 가격변동과 상관관계를 가지는지 확인한다.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.5
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• pp.59-66
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• 2020

Recently, cultivation and management technologies have been needed to adapt due to climate change, which is causing abnormal weather conditions. One technique is to increase the utilization of evergreen broad-leaved species with high ornamental value. A total of five treatments were installed (1m×22.5m), including 60g/㎡ and 80g/㎡ using two types mulching material with an overlapping and hole-drilling mulching method and these were compared to un-mulching treatment a total of planted 92㎡ attheWol-aTestSiteForestattheForestforBiomaterialsResearchCenterinJinju-si, Gyeongsangnam-dofor 10monthsusing3-years-oldQuercusglaucaThunb. In comparison with the control site, the 60g/㎡ overlapping method was about 1.9 times higher than the root collar diameter, but there was no statistical significance between the treatments. Healthy seedlings were found to meet these conditions due to high biomass values and below and T/R ratios of 3.0 or lower and H/D ratios of 7.0 or lower. Comparing the values of LWR, SWR, and RWR, which can be evaluated for seedling due to the mulching treatments, as compared to the control, the growth of the ground areas including leaves and stems was enhanced, but the growth of the underground areas containing roots tended to have high control values. Based on this, the SQI value, which can be evaluated for the comprehensive quality of seedlings, was found to be significantly different between the control site and the mulching treatment sites, confirming that the growth and growth improvement effects were achieved with mulching treatments. The chlorophyll content analysis showed that there was a significant difference from the control site, and it was judged that weed generation in the control acted as an environmental stress, causing a decrease in chlorophyll content. It was found that the overlapping 80g/㎡ of polypropylene mulching material generated about 4 times fewer weeds than the control, and the manpower required for the mulching test field and weeding were equal at 3.3 people/100㎡/1 day. Mulching treatments have demonstrated a significant difference in the promotion of growth and quality of the seedlings and are judged as an alternative that can reduce the economic burden incurred by the purchase of the supplies and the manpower required to weed forestry plantations.

• Journal of Wetlands Research
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• v.16 no.2
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• pp.245-250
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• 2014

This study developed allometry equation and estimated the aboveground-biomass of Quercus glauca, a warm-temperature, evergreen broad-leaved tree, growing in Kotzawal wetland located on Jeju Island. The allometric equations between DBH(diameter at breast height) and dry weights of stems (Ws), branches (Wb), leaves (Wl) and aboveground biomass (Wab) of Q. glauca were as follows: logWs=2.4042logDBH-1.3045, logWb=2.6436logDBH-1.6232, logWl =1.5428logDBH-1.3692 and logWab=2.3324logDBH-0.9181. The allometric equations between $D^2H$ and Ws, Wb, Wl, and Wab of Q.glauca were as follows : logWs=$0.853logD^2H-1.4252$, logWb=$0.8453logD^2H-1.5834$, logWl=$0.5328logD^2H-1.4073$ and logWab=$0.8453logD^2H-1.0327$. The $R^2$ between DBH and Ws, Wb, Wl and Wab were 0.9873, 0.9711, 0.7979 and 0.993, respectively. The $R^2$ between $D^2H$ and Ws,Wb,Wl and Wab were 0.9841, 0.9174, 0.7537 and 0.9876, respectively. There was no significant difference between observed and calculated values of the allomatric equations from DBH and $D^2H$(p>0.05, Kolmogorov-Smirnov test). Thus, to estimate the aboveground biomass of Q. glauca, use of DBH and $D^2H$ as an independent variables in the allometric equation is recommended.

• Korean Business Review
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• v.12
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• pp.119-138
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• 1999

In this study, we empirically investigate the relations between trading volumes and our proxies for information flows and differences of opnion. Econometric methods to analyze the relations in the equity and KOSPI 200 futures markets include Generalized Method of Moment(GMM) and Generalized Autoregressive Conditional Heteroscedasticity(GARCH) models. Major findings from our empirical analyses are summarized as follows; (i) Trading volume in both the equity and KOSPI 200 futures markets varies positively with proxies for information flows. We find that trading volumes in both markets are closely related to firm-specific information rather than market-wide information. (ii) Trading volumes in the equity and KOSPI 200 futures market have positive relations with our proxies for differences of opinion. (iii) Day-of-the-week effect is clear in both markets. Trading volumes in both the equity and KOSPI 200 futures markets tend to be relatively low early and late in the week. (IV) Futures contract life-cycle effect is clear. In other words, futures trading volume increses in the period around contract expiration. (V) In addition, ARCH effect on trading volumes is reported significant enough to take into account. The disturbance of trading volumes in both markets seem to be conditional heteroscedastic.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.572-578
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• 2020

The stock market is affected by unexpected factors, such as politics, society, and natural disasters, as well as by corporate performance and economic conditions. In recent days, artificial intelligence has become popular, and many researchers have tried to conduct experiments with that. Our study proposes an experiment using not only stock-related data but also other various economic data. We acquired a year's worth of data on stock prices, the percentage of foreigners, interest rates, and exchange rates, and combined them in various ways. Thus, our input data became diversified, and we put the combined input data into a nonlinear autoregressive network with exogenous inputs (NARX) model. With the input data in the NARX model, we analyze and compare them to the original data. As a result, the model exhibits a root mean square error (RMSE) of 0.08 as being the most accurate when we set 10 neurons and two delays with a combination of stock prices and exchange rates from the U.S., China, Europe, and Japan. This study is meaningful in that the exchange rate has the greatest influence on stock prices, lowering the error from RMSE 0.589 when only closing data are used.

• Korean Journal of Plant Resources
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• v.23 no.5
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• pp.465-479
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• 2010

This study was carried out to classify the regional folk plants in the inland of Gyeongsangbuk-do. According to the survey results from 582 survey sheets of 126 residents at 85 places of 17 counties and cities from March to October, 2009, the folk plants in the inland of Gyeongsangbuk-do consisted of a total 254 taxa; 76 families, 207 genera, 225 species, 2 subspecies, 26 varieties, and 1 form. The use by its usage was: 216 taxa; edible, 82 taxa; medicinal, 30 taxa; dye, 3 taxa; aroma, 4 taxa; spice, 4 taxa; ornamental, 1 taxa; fiber, 2 taxa; oil, 1 taxa; starch, 5 taxa; fuel, 9 taxa; others, respectively, so the edible use is the highest. The most useful part was the leaf, followed by stem and root. The folk plants of 3 head families from Yeongyang and Cheongsong were 42 taxa. The consistency comparison between the scientific name and the local name were the highest in the 50's and the lowest in 80's.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.61-61
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• 2018

한경 곶자왈 산림유전자원보호구역은 개가시나무와 백서향 등을 포함한 암괴지대의 상록활엽수림으로서 그 중요성이 인정되어 산림유전자원 생태보전지역으로 지정 관리되고 있다. 따라서 본 지역의 식물상을 조사하여 곶자왈의 분포식물을 파악하고자 실시하였다. 본 연구는 한라산 서쪽 곶자왈지역 중 곶자왈 산림유전자원 보호구역으로 지정된 지역을 2017년 6월부터 2017년 9월까지 20여 차례 현장조사를 통하여 표본을 수집하고 이를 기록 정리하였다. 조사지역의 식물은 총 83과 181속 236종 23변종 2품종 총 261종으로 조사결과 양치식물이 7과 18속 30종 2변종 32분류군, 나자식물이 1과 1속 2분류군, 피자식물은 74과 162속 204종 21변종 2품종 227분류군 이었다. 그 중 쌍자엽식물은 67과 139속 179종 16변종 1품종 196분류군이고, 단자엽식물이 7과 23속 25종 5변종 1품종 31분류군이었다. 조사에서 확인된 환경부 멸종위기야생식물은 개가시나무 1종 이었다. 식물 구계학적 특정식물로는 총 97분류군이 조사되었다. 등급별로는 V등급 검정개관중, 개가시나무로 2분류군, IV등급 백서향, 녹나무 등 12분류군, III등급 아왜나무, 호자나무 등 37분류군, II등급 올벚나무, 개산초 등 13분류군, I 등급 푸조나무, 자금우 등 33분류군으로 확인되었다. 한국의 적색목록 식물을 분석해보면 취약(VU)은 개가시나무, 섬다래 등 3분류군, 준위협(NT)은 백서향, 약난초로 2분류군, 관심대상종(LC)은 골고사리, 새우난초 등 9분류군, 미평가종(NE)은 빌레나무 1분류군으로 나타났다. 이 결과는 청수 저지 곶자왈 지역의 생태학적 자료로 제주도 내 곶자왈과 비교하였을 때 맹아가 발달한 종가시나무가 우점하는 지역으로 향후 상록수림 천이에 의해 상록수 아래에 자라는 식물로 낙엽활엽수가 대체될 것으로 추정되어 지속적인 조사가 요구된다.

• The Korean Journal of Financial Management
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• v.20 no.1
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• pp.163-190
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• 2003

This study tests the hypothesis of market efficiency through the information spillover effects over price and volatility across countries by using open-to-close(daytime) returns and close-to-open(overnight) returns of NASDAQ, KOSDAQ and JASDAQ data from January 3, 1997 to December 21, 2000. Based on Granger-causality and time-varying AR(1)-GARCH(1, 1)-M models we document that the evidence of statistically significant conditional mean and volatility spillovers effects from the daytime returns and volatility of NASDAQ to the overnight returns and volatility of KOSDAQ is observed both before and after the IMF foreign currency crisis but not to the close-to-open return before the IMF foreign currency crisis. We can understand the information spillover effect from NASDAQ to KOSDAQ on the overnight rather than the daytime grows more significantly after the IMF foreign currency crisis. We also find the interactive information spillover effect between NASDAQ and JASDAQ both before and after the IMF financial crisis, in particular, to close-to-open return. In addition, the market efficiency between KOSDAQ and NASDAQ is on an increasing trend through IMF foreign currency crisis.

• Management & Information Systems Review
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• v.31 no.4
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• pp.593-609
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• 2012

This study is designed to investigate whether the information spillover effect is existed between the foreign investors' unexpected volatility of net purchasing intensity and the volatilities of returns in terms of daily closing stock return, overnight return, and daytime return, before and after financial crisis in Korea. The result of this study shows that there is negative information spillover effect between the foreign investors' unexpected volatility of net purchasing intensity and the volatility of daily closing stock return for time t-1. However, there is an opposite result for time t, showing positive information transmission effect. For the overnight return, the test result provides there is no statistical significance between the foreign investor's unexpected volatility of net purchasing intensity and the volatilities of return. In addition, I found that the information transmission effect is existed between the foreign investor's unexpected volatility of net purchasing intensity and the volatilities of the daytime return for the entire timeline.