열처리 공정 과정에 따라 형성되는 Cu2ZnSnSe₄ 박막 내 결함 조사

류혜선 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

Cu₂ZnSnSe₄ (CZTSe) 박막 태양전지는 Cu(In,Ga)Se₂나 CdTe 태양전지와는 달리 저렴하고 유해성이 낮은 재료로 주로 이루어져 있어, 저가ㆍ친환경 태양전지로 주목받아왔다. 그러나 본 태양전지의 개방전압 손실(Voc deficit)로 인해 다른 박막형 태양전지와 같은 ~20% 이상의 효율을 얻는 데에 어려움을 겪고 있다. 개방 전압 손실의 주 원인으로 CZTSe 박막 내 형성되는 antisite 결함들로 밝혀졌으며, 결함의 종류는 CZTSe 박막 내 금속 원소들의 비율에 따라 결정된다고 알려졌다. 본 연구에서는 CZTSe 박막을 형성하는 반응과정 또한 antisite 결함들의 종류에 영향을 미친다는 사실을 알아냈다. 동일한 전구체를 이용하여 각기 다른 열처리 공정과정을 거쳐 태양저지를 제조한 결과, CZTSe 박막의 특성은 비슷하나 제조된 태양전지의 효율이 8~10%로 상이하였으며, 그 이유로 CZTSe 박막 내 형성된 결함들이 열처리 공정과정에 따라 다르게 생성되는 것을 확인하였다.

A Study on the Performance Improvement of Machine LearningClassification Model by Resolving Imbalance in Financial Data: Focusing on Credit Card Accidents

류혜선,김상회,오경주 계명대학교 자연과학연구소 2023 Quantitative Bio-Science Vol.42 No.1

The advancement of innovative technologies such as artificial intelligence (AI) and big data has considerably increased in the amount of financial data. However, the quantity of abnormal data belonging to minority classes is relatively low, resulting in an exacerbation of data imbalance phenomenon. Data imbalance significantly impairs the performance of classifiers for minority classes. In this study, classification performance comparison experiments were conducted according to the data imbalance resolution methodology using credit card customer data, one of the financial data. Empirical analysis revealed that as the degree of data imbalance decreased, the performance of the classification model tended to improve, and applying the data imbalance resolution methodology led to performance enhancement. When SMOTETomek was applied, the deep neural network (DNN) showed the highest performance improvement, and the performance of the classification model could be improved using a conditional adversarial generative network (CGAN) for financial data. This study proposed solutions for data imbalance that could be applied to financial data, and the proposed methods contributed to the adoption and development of AI technology in the financial industry by making it more suitable for financial practices.

기린초(Sedum kamtschaticum Fisch.)의 자생지별 외부형태분석과 식생연구

류혜선,정지현,김상태,백원기 한국자원식물학회 2011 한국자원식물학회지 Vol.24 No.4

To address infra-specific relationships of Sedum kamtschaticum Fisch., and to provide the fundamental information for developing new horticultural variations, we analyzed the morphology of individuals in four natural populations (Mt. Gwangdeok, Mt. Samyeong, Mt. Yonghwa, Tongyeong) and investigated the vegetations of these area. Based on 50 morphological characters the principle component analysis (PCA) has been performed. Principle component axis 1, 2, and 3 explain 22.9%, 14.2%, and 7.4% of total variations, respectively. Dot plot of OTUs in PC2 by PC1 area showed that the areas of four populations are completely overlapped. The result of PCA and the statistics of each character indicate that all of morphological characters are overlapped in these four populations. The maximum deviations are found in the characters related in the size and shape of the leaf. In the vegetation analyses, eighteen community plots that we investigated were grouped into 10 subcommunities: subcomm. Boehmeria spicata, subcomm. Artemisia stolonifera, subcomm. Artemisia keiskeana, subcomm. Impatiens nolitangere, subcomm. Crepidiastrum chelidoniifolium, subcomm. Urtica thunbergiana, subcomm. Artemisia gmelini, subcomm. Commelina communis, subcomm. Erigeron annuus-Artemisia princeps, and typical subcommunity. 기린초 자생지 네 곳(광덕산, 사명산, 용화산, 통영지역)의 집단에 대하여 이들의 종내 유연관계를 알아보고 야생화의 원예화 또는 품종개량을 위한 기초자료를 제공하기 위하여 자생지별 식생조사 및 외부형태 형질을 측정하여 비교 분석하였다. 50개의 형태 형질을 이용한 주성분 분석 결과 주성분 1, 2, 3은 전체 변이에 대하여 각각 22.9%, 14.2%, 7.4%를 설명 하였으며, 주성분1에 대한 주성분2의 도시 결과 4개의 자생지 집단은 서로 중복되어 구별이 불가능하였다. 형태적 형질에 대한 주성분 분석은 여러 자생지들의 집단 간에 모든 외부 형태적 형질들이 연속적 양상을 나타냄을 보여주었고, 편차가 가장 큰 형질은 잎의 크기와 형태에 관여되는 형질들이었다. 식생은자생지에서 18개의 조사구를 선정하여 식생군락을 조사한 결과 좀깨잎나무하위군락, 넓은잎외잎쑥하위군락, 맑은대쑥하위군락, 노랑물봉선하위군락, 까치고들빼기하위군락, 쐐기풀하위군락, 더위지기하위군락, 닭의장풀하위군락, 개망초-쑥하위군락, 전형하위군락의 10개 하위군락으로 구분되었다.

대도시 중심지역의 재난 피해 저감을 위한 재난위험도 평가에 관한 연구

류혜선,홍원화 대한건축학회 2005 대한건축학회논문집 Vol.21 No.11

Presently, metropolises have a possibility of disaster occurrence, because of overcrowding. Therefore, in order to protect unexpected disaster and to recover damage , we need to study a plan for preventing disaster throughout the assessment of city disaster risk. This study will be used to the essential data of city master plan to make for safe city. Disaster risk is estimated and analyzed around the Jung-gu in the Daegu city.We classify disaster risk by three parts. They are classified such as facility risk , fire risk , refuge risk. Each risk is divided into five rank. And, a method of estimation is not absolute comparison but relative comparison in the disaster risk volume of block.Thus, the result of disaster risk is expressed to five color on the map. According to this study, the potential figures of fire risk are higher Sam-duk block and Dong-sung block than others. The potential figures of facilities and refuge risk are higher Sang-se block and Ha-se block than others.

脾兪(BL20) 大黃약침이 고지방식이로 유발된 肥滿白鼠에 미치는 영향

류혜선,김성필,김승만,이동근,이욱재,이주희,위통순 대한침구의학회 2012 대한침구의학회지 Vol.29 No.3

Objectives : This research was performed to investigate the effects of Rhei Radix et Rhizoma pharmacopuncture at Bi-Su(BL20) on weight change, food efficiency, concentration of serum lipid, liver function of rats fed high fat diet for 8 weeks. Methods : Subject groups were diveded into normal diet group(Normal), high fat diet group(Control), high fat diet and saline in BL20 treated group(Saline), high fat diet and Rhei Radix et Rhizoma pharmacopuncture in BL20 treated group(PT-1, 0.008mg/ml/g), high fat diet and Rhei Radix et Rhizoma pharmacopuncture in BL20 treated group(PT-2, 0.021mg/ml/g), and high fat diet and Rhei Radix et Rhizoma pharmacopuncture in BL20 treated group(PT-3, 0.042mg/ml/g). Pharmacopuncture was bilaterally treated at BL20 every 4 days, totally 14 times in 56 days. We observed the changes of body weight, food efficiency, ALT, AST, r-GTP, total cholesterol, triglyceride, HDL, LDL-cholesterol of each group. Results : 1. Body weight significantly decreased, as compared with the control group, in PT-1 from 2nd week to 8th week, in PT-2 from 4th week to 7th week. 2. Food efficiency decreased, as compared with the control group, in PT-1(0.05≤p<0.06). 3. HDL-cholesterol increased, as compared with the control group, in PT-1, PT-3, but not significantly. 4. In the changes of ALT, as compared with the control group, only in PT-1 group, the level of serum ALT decreased(0.05≤p<0.06). 5. As for the changes of r-GTP, as compared with control group, in every subject group, the levels of serum r-GTP significantly decreased. Conclusions : According to the above results, Rhei Radix et Rhizoma pharmacopuncture at BL20 can act on body weight, food efficiency and liver function. It also does not seem to be injurious on liver function. To use Rhei Radix et Rhizoma pharmacopuncture for obesity, further studies on its underlying mechanism and optimal dosage might be needed.

단순 요통환자에 대한 침치료와 중성어혈-녹용 혼합약침 병행치료의 효과비교연구

류혜선,김성필,천혜선,류미선,신정철,위통순 대한침구의학회 2011 대한침구의학회지 Vol.28 No.6

Objectives : The purpose of this study is to investigate the effect of mixed pharmacopuncture of Jungsongouhyul and Cervi Pantotrichum Cornu on low back pain patients. Methods : 83 patients with Low back pain who were treated in Dept. of Acupuncture and Moxibusion, Dongshin University Hospital in Suncheon from Sep. 1st, 2010 to August 31th, 2011, were divided into two groups. One group (52 patients) was treated with conservative treatments (acupuncture, herb med, cupping therapy and physical therapy) and mixed pharmacopuncture of Jungsongouhyul and Cervi Pantotrichum Cornu theraphy (PG) and the other group (31 patients) was treated with conservative treatments alone(NPG). To estimate the effects of treatments, visual analog scale(VAS) and Oswestry disability index(ODI) were checked. Results : 1. In VAS, both of PG and NPG shows statistically significant improvement rate after 3rd treatment and 5th treatment. 2. In ODI, both of PG and NPG shows statistically significant improvement rate after 3rd treatment and 5th treatment. 3. In comparing VAS of PG and NPG, there was more significant improvement in PG than NPG after 3rd treatment and 5th treatment. 4. In comparing ODI of PG and NPG, there was more significant improvement in PG than NPG after 3rd treatment but no significant improvement between PG and NPG after 5th treatment. Conclusions : According to the study, it is thought that mixed pharmacopuncture of Jungsongouhyul and Cervi Pantotrichum Cornu theraphy is effective to low back pain patients, and further study is needed for the confirmation of the effect of mixed pharmacopuncture of Jungsongouhyul and Cervi Pantotrichum Cornu.

고효율 케스터라이트계 박막 태양전지와 열처리 공정과정과의 상관관계에 관한 연구

류혜선,손대호,김승현,김성연,성시준,황대규,양기정,김대환,강진규 한국에너지학회 2021 한국에너지공학회 학술발표회 Vol.2021 No.4

대면적 칼코지나이드 태양전지 제조를 위한 열처리 조건 및 금속 그리드 구조 최적화

류혜선,김승현,손대호,황반쿠이,이인표,조승택,노종욱,홍태의,김준호,김대환,강진규 한국공업화학회 2023 한국공업화학회 연구논문 초록집 Vol.2023 No.1

선 열처리 공정이 케스터라이트 박막 형성 및 이의 태양전지 특성에 미치는 영향 조사

류혜선,김승현,손대호,김성연,김대환,강진규 한국공업화학회 2021 한국공업화학회 연구논문 초록집 Vol.2021 No.0

공매도의 형평성·공정성 제고 방안에 관한 소고 - 핀테크 서비스 연계를 중심으로

류혜선 ( Ryu Heasun ),류혁선 ( Ryu Hyeuksun ) 한국지급결제학회 2021 지급결제학회지 Vol.13 No.2

국내 주식시장에서 개인투자자가 차지하는 거래비중은 작지 않음에도, 공매도 시장에의 참여 기회는 매우 제한적이다. 이로 인해 주식시장이 하락국면으로 접어들 때마다 매번 기울어진 운동장에 비유되며 공매도의 공정성 문제가 제기되곤 한다. 이에 금융당국도 지속적으로 제도를 개선해 왔지만, 공매도 참여 기회의 형평성 및 거래의 공정성을 제고하기 위해서는 보다 실천적이고 근본적인 개선 방안이 논의되어야 한다. 본고는 공매도의 전제인 주식의 차입 방식에서 투자자간 차등이 존재하는 문제를 해결하고, 대여대차 프로세스를 보다 투명하게 개선하기 위하여 디지털금융 혁신의 일환으로 도입된 마이데이터와 마이페이먼트 개념을 원용한 핀테크 서비스 연계 방식의 오픈 API 기반주식 대여대차 통합플랫폼 서비스의 구축을 제안한다. 이를 통해 대여자, 차입자 모두 투명한 가격과 거래정보를 제공받고, 선입선출에 의한 공정한 체결 방식의 구현으로 그동안 장외시장 특성으로 인해 거래가 불투명하고, 참여 기회가 불공평했던 대여대차시장에서의 관행이 근본적으로 개선될 것으로 기대된다. Although the share of retail investors in the stock market is not small, their opportunities to participate in the short-selling market are very limited. As a result, whenever the stock market enters a downward phase, it is compared to a tilted playground, and the issue of fairness in short selling is often raised. Accordingly, the financial authorities have also continuously improved the system, but more practical and fundamental measures should be discussed to enhance the fairness of short selling. In this paper, we propose a security lending and borrowing (SLB) scheme using financial innovation technology to solve the problem of differences between investors in the borrowing mechanism of stocks. In other words, the establishment of an open API-based SLB integrated platform service (‘Open SLB Scheme’) that uses MyData and MyPayment concepts will provide transparent prices and transaction processes to participants, and improve the practice of SLB market, which has been opaque due to over-the-counter market characteristics.