길경(桔梗)의 추출조건에 따른 사포닌 함량의 변화

최재석,유대석,최연희,연규환,홍경식,이병회,김혜진,김현기,김은주,노성환,정영철,김영섭,유시용,Choi, Jae-Seok,Yoo, Dae-Seok,Choi, Yeon-Hee,Yon, Gyu-Hwan,Hong, Kyung-Sik,Lee, Byung-Hoe,Kim, Hye-Jin,Kim, Hyun-Ki,Kim, Eun-Ju,Roh, Seong-Hwan,Jeong 한국생약학회 2007 생약학회지 Vol.38 No.2

We investigated the contents of crude saponin in the decoctions of Platycodi Radix prepared by the different extraction processes. Each lyophilized decoctions prepared by the different protocol were suspended in water and partitioned with ethylacetate (EtOAc) and n-butanol (BuOH), which gave the EtOAc fraction, BuOH fraction and the remaining water fraction, respectively. The content of crude saponin, which was estimated as the amount of BuOH fraction, and the HPLC profiles of the BuOH fraction were analyzed, and compared each others. The crude saponin content in the decoctions were increased proportionally to the increment of the extraction time, amount of water, extraction temperature and the number of repetition for extraction. Consequently, the optimized conditions were deduced to be suitable and recommendable for the preparation of Platycodi Radix ; the water amount needed for the extraction be 15-20 volumes to crude material, temperature for extraction be optimal at $85{\sim}100^{\circ}C$, extraction time be more than 5 hours and the repetition of extraction was 2 times.

데이터마이닝을 이용한 학자금 대출 부실 고위험군 예측모형 개발

최재석,한준태,김면중,정진아,Choi, Jae-Seok,Han, Jun-Tae,Kim, Myeon-Jung,Jeong, Jina 한국데이터정보과학회 2015 한국데이터정보과학회지 Vol.26 No.6

We develop the high risk group predictive model for loan default by utilizing the direct loan data from 2012 to 2014 of the Korea Student Aid Foundation. We perform the decision tree analysis using the data mining methodology and use SAS Enterprise Miner 13.2. As a result of this model, subject types were classified into 25 types. This study shows that the major influencing factors for the loan default are household income, national grant, age, overdue record, level of schooling, field of study, monthly repayment. The high risk group predictive model in this study will be the basis for segmented management service for preventing loan default. 본 연구는 한국장학재단의 2012-2014년간 일반 학자금 대출 자료를 활용하여 부실채권 보유 및 신용유의자로 분류될 수 있는 위험요인들을 파악하고, 부실 고위험군 예측모형을 개발했다. 예측모형 개발은 데이터마이닝 방법 중 의사결정나무 분석을 적용하였으며, 분석 패키지는 SAS Enterprise Miner 13.2를 활용했다. 개발된 모형은 25가지의 그룹으로 세분화 했으며, 부실 위험군에 영향을 미치는 주요 요인은 소득분위, 국가장학금 수혜유무, 나이, 연체계좌 보유 이력, 대학구분 (학부/대학원), 전공 계열, 월평균 상환액이 주요 요인으로 나타났다. 본 연구에서 개발된 부실 고위험군 예측모형은 장기연체로 인한 부실채권 발생 및 신용유의자 발생 예방을 위한 세분화된 관리서비스 제공을 위한 기초자료가 될 수 있을 것이다.

해상 이동형 담수화 플랜트 실증화 기술 개발

최재석(Jae-Seok Choi) 대한토목학회 2018 대한토목학회지 Vol.66 No.10

2007년 현재 일본 고교 일본사 교과서의 내용분석

최재석(Choi Jae-Seok) 고려대학교 아세아문제연구소 2007 亞細亞硏究 Vol.50 No.2

Throughout the sixth century Yamato-Wa (Japan) was virtually governed by the Yamato-Wa administering teams by turns dispatched by Paekche or Paekche kings, and the notoriously poor shipbuilding and navigation skills or the Japanese kept them from having free contact with neighboring peoples on their own, so that only with the help of Silla who had the command of the sea in the Far East could the Japanese go to Korea or China. These two indisputable facts are indirectly or directly mentioned in the Nihon shoki (Chronicles of Japan). In addition, it is now common knowledge that relocation of Japan's capitals (Fujiwarakyo and Heijokyo) and construction of Buddhist temples (the Horyuji temple and the reconstructed Horyuji temple) were carried out either by Korean experts themselves or with the technical cooperation of Korean professionals versed in expertise. Moreover, the origins of all cultures of ancient Japan, that is, in the sixth century through the early seventh century, were Korea, not China, so astutely observed a senior Japanese (mind you, not Korean) Buddhist historian, and another Japanese tumulus researcher points out, presenting indisputable evidence, that so many tumuli existing in Japan are related to Korea. Even so, the current highschool textbooks on the history of Japan reflect without exception only the biased assertions of those who grossly distorted actual history, in total disregard of conscientious scholars who spoke up on the true history of ancient Japan. In brief, current Japanese history textbooks allege that ancient Korea was Japan's colony and that Japanese culture resulted from sucking up Chinese culture, not Korean. Such historical falsification seems to take over the tradition of history distortion which was started by the General Staff Office of Imperial Japanese Army in the nineteenth century. I remember reading a long time ago in an American history textbook that the United States of America started from being a British colony. Now, textbooks published by private persons are also under the jurisdiction of the government. But, I believe, only when Japanese history textbooks?whether they are published by private individuals or by the government?record with a good conscience historical facts as they were and are will Japan be justly called a democratic country with good-neighbor policy that has entirely outgrown pre-1945 polity, ever having a high regard for factual historical facts.

A Criticism of Edwin O. Reischauer’s Pronouncements on Ancient Korea-Japan Relations

Choi Jae-seok(최재석) 고려대학교 한국사연구소 2011 International Journal of Korean History Vol.16 No.1

이 논문은 하버드대학교 교수와 주일미국대사를 역임했던 라이샤워(Edwin O. Reischauer)의 The Japanese(Tokyo: Charles E. Tuttle, 1977)에 서술되어 있는 고대한일관계를 고찰하는 것을 목적으로 한다. 이 책은 고대한일관계사를 잘못 전달하는 일본 역사가들의 왜곡된 견해를 반영하고 있다. 따라서 이 책을 비판적으로 살펴보는 것은 고대한일관계사를 객관적으로 이해하는 데에 일조할 것이다. 이 논문에서는 The Japanese에 서술되어 있는 왜곡된 고대한일관계사에 대해 다섯 가지 측면, 즉 일본의 고분, 6세기까지의 일본의 정치적 상황, 쇼토쿠타이시(聖德太子), 일본과 중국 관계, 한국과 일본 관계의 측면에서 살펴보았다. 라이샤워는 일본 내에서 자생한 반자치적인 부족국가가 존재했다고 주장했다. 그리고 일본의 고분이 일본 특권계급의 무덤이라고 설명했다. 그러나 이는 한국에서 일본으로 이주한 한국인 무덤인 것으로 입증되었다. 이와 더불어 쇼토쿠타이시가 허구의 인물임에도 불구하고, 라이샤워는 그가 호류지(法隆寺)를 창건한 역사적 인물이라고 주장했다. 또한 일본이 당나라 문화와 문명을 광범위하고 충실하게 받아들였다고 설명했다. 그러나 6세기 전부터 8세기 말까지의 한일관계를 살펴보면, 668년 이전까지 일본은 백제의 지배하에 있었으며, 그 이후에는 신라의 지배하에 놓여있었다. 그리고 고도의 문명과 문화를 지닌 한민족이 대량 이주하여 물고기와 해산물을 먹고사는 문맹의 토착민들이 살고 있는 일본에 정착한 것은 공공연한 사실이다. 그것은 새로운 영토를 찾기 위해 일본에 정착한 한민족 이주민들에 대한 『일본서기』(日本書紀) 기록에서 입증된다. 그리고 일본의 고대 지명은 한국의 지명을 본 따 이름 지어졌다. 그것의 대다수는 최근에 개칭되었고, 단지 소수만이 여전히 남아있다. This paper aims to examine the ancient Korea-Japan relations as mentioned in the book entitled The Japanese, (Tokyo: Charles E. Tuttle, 1977). The book was written by Edwin O. Reischauer, University Professor at Harvard, who was United States Ambassador to Japan from 1961 to 1966. The book reflects the distorted view of Japanese historians who misrepresent the history of ancient Korea-Japan relations. He insists that there were semi-autonomous tribal units of natural growth in Japan and the ancient burial mounds belonged to privileged Japanese aristocracy. But they were proven to be the tombs of the influential immigrants from the Korean Peninsula to Japanese islands. Notwithstanding that Prince Shotoku was a fictitious figure, Reischauer maintains that he was a historical person who founded the Horyuji Temple. Also he declares that the Japanese absorbed Tang culture and civilization extensively and single-mindedly. But from before the sixth century until the end of the eighth century, Japan was under the dominion of Korea-Baekje (Paekche) in pre-668 years and Unified Silla after that. And it is now an open secret that massive influxes of immigrants with highly advanced civilization and culture from Korea settled in the Japanese islands among unlettered natives living off fish and marine products. They can be proven to the accounts in the Nihonshoki on Korean immigrants settling in the Japanese islands to found a new state. And ancient place-names of Japan were named after Korean kingdoms, most of which were renamed in recent ages, only a few still remaining.

와전류 브레이크의 영구자석배열 최적설계

최재석(Jae Seok Choi),유정훈(Jeonghoon Yoo) 대한기계학회 2009 大韓機械學會論文集A Vol.33 No.7

Eddy current is usually generated in the material with high conductivity by time-varying source such as AC current and also is induced by the moving source with relative velocity. The contactless magnetic brake makes use of the braking force from the eddy current generated by the moving source and currently used for the secondary brakes of heavy trucks, buses and rail vehicles. This study aims to design the magnetization pattern of the eddy current brake system of a permanent magnet type where the design aim is to maximize the braking force. The analysis of brake systems is based on the two-dimensional finite element analysis. We use the sequential linear programming as the optimizer and the adjoint variable method is applied for the sensitivity analysis.

A Study on the Reliability Evaluation for Interconnecting Power Systems in Northeast Asia

崔在錫(Jae-Seok Choi),車濬敏(Jun-Min Cha) 대한전기학회 2008 전기학회논문지 Vol.57 No.7

This paper proposes a reliability evaluation for interconnection planning using a tie line equivalent assisting generator model (TEAG) that considers the uncertainties of the interconnected transmission systems and the tie lines. Development of this model was triggered by the need to perform probabilistic reliability evaluations on the NEAREST (North East Asia Region Electric Systems Tied) interconnection. The TEAG is the basis for the newly developed interconnection systems reliability evaluation computer program, NEAREL. The model is capable of considering uncertainties associated with generators, tie lines, and the tied grids. Reliability evaluations for six interconnection scenarios involving the power systems of six countries in the Asian north eastern region were performed using NEAREL. Sensitivity analysis was used to determine reasonable tie line capacities for three interconnected country scenarios of the six countries. Test results and summarized comments of the scenarios are included in the paper.

볼 베어링을 이용한 Linear Motion Guide의 동적 특성에 관한 연구

최재석(Jae Seok Choi),유정훈(Jeong hoon Yoo),이용섭(Yong-sub Yi),김윤영(Yoon Young Kim),이동진(Dong Jin Lee),이성진(Sung Jin Lee) 한국소음진동공학회 2004 한국소음진동공학회 학술대회논문집 Vol.2004 No.5

최적설계법을 이용한 할바 영구자석 배열의 설계

최재석(Jae Seok Choi),유정훈(Jeonghoon Yoo) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

This study tries to design Halbach magnet array using numerical optimization techniques based on the two-dimensional finite element analysis. Optimization problems with various objectives are introduced and design variables are defined as the magnetization direction of each element in the design domain. It is interesting that the base magnet array of all optimized results is equivalent to the Halbach array without any exception. The optimal magnet arrays composed of two linear magnet layers are investigated to maximize the magnetic force between magnet layers. The optimization procedure is constructed by using the sequential linear programming and the adjoint variable method.

의암호의 어류군집

최재석 ( Jae Seok Choi ) 한국어류학회 2005 韓國魚類學會誌 Vol.17 No.1