• 천문학회지
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• 제51권4호
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• pp.89-110
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• 2018

Active Galactic Nucleus (AGN) variability can be used to study the physics of the region in the vicinity of the central black hole. In this paper, we investigated intra-night optical variability of AGN in the COSMOS field in order to understand the AGN instability at the smallest scale. Observations were performed using the KMTNet on three separate nights for 2.5 to 5 hours at a cadence of 20 to 30 min. We find that the observation enables the detection of short-term variability as small as ~ 0.02 and 0.1 mag for R ~ 18 and 20 mag sources, respectively. Using four selection methods (X-rays, mid-infrared, radio, and matching with SDSS quasars), 394 AGN are detected in the $4deg^2$ field of view. After differential photometry and ${\chi}^2$-test, we classify intra-night variable AGN. The fraction of variable AGN (0-8%) is statistically consistent with a null result. Eight out of 394 AGN are found to be intra-night variable in two filters or two nights with a variability level of 0.1 mag, suggesting that they are strong candidates for intra-night variable AGN. Still they represent a small population (2%). There is no sub-category of AGN that shows a statistically significant intra-night variability.

• 한국방재학회 논문집
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• 제8권5호
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• pp.23-33
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• 2008

최근 국내에서 케이블을 이용한 Extradosed 교 형식의 대교들이 건설되고 있다. 이러한 교량에서 자동차 충돌등으로 인한 화재에 의해 교량이 손상을 입는 사고가 발생되고 있어 화재에 대한 안정성해석이 필요하다. 본 연구에서는 케이블 교량형식 중 최근 국내에서 사용빈도가 높은 Extradosed 교 형식을 해석모델로 하였으며, 상용소프트웨어인 Solid Works 2007을 사용하여 모델링하고, COSMOS FloWorks 2007소프트웨어에 의한 열전달 해석 및 열응력 해석을 통하여 교량위 화재 발생시 와이어, 사재방재 파이프 및 그 주변에 대한 열유동 해석 및 사재방재 케이블의 안전을 검토하였다. 열원의 온도가 일정한 경우에 대해 다음 3개의 중요변수를 해석변수로 사용하였다. : (1)방호책과 열원사이의 거리, (2)풍속, (3) 스테인레스 강관의 끝단의 높이.

• 한국항공우주학회지
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• 제40권1호
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• pp.78-85
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• 2012

우주파편이란 지구궤도에 있는 인간이 만든 물체 중 더 이상 유용한 목적으로 사용할 수 없는 물체를 말한다. 우주파편은 1957년 인류가 우주에 위성을 보내기 시작한 이후로 그 숫자가 증가하고 있으며, 현재 미 전략사령부(USSTRATCOM, United States Strategic Command)에 의하면 10cm 이상의 우주파편이 15,000개 이상이라고 알려지고 있다. 최근에는 중국이 자국의 위성을 미사일로 요격시킨 사건과 미국 Iridium 33 위성 및 러시아 Cosmos 2251 위성이 우주상공에서 서로 충돌한 사건이 발생함에 따라 아리랑 2호가 운영중인 저궤도에서의 우주파편 환경이 나빠졌다. 본 논문에서는 우주파편이 아리랑 2호에 근접하는 회수 및 최소근접거리에 따른 최대충돌확률의 분포를 분석하였다. 특히 아리랑 2호와 충돌할 가능성이 있는 우주파편을 식별 및 분석하여 해당 우주파편을 지속적으로 감시 할 수 있게 하였다.

• 대한한의학원전학회지
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• 제25권4호
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• pp.39-55
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• 2012

Objective : In order to find the decision system in differentiation of syndromes and treatments, I paid attention to divination by Achillea sibireca. Method : I pulled out the elements of differentiation of syndromes and treatments in Zh$\bar{o}$ng y$\bar{i}$n$\grave{e}$i k$\bar{e}$ xu$\acute{e}$(中醫內科學), Uihagipmun Sanghan(醫學入門 傷寒), Donguibogam Japbyeong(東醫寶鑑 雜病) and compared them with the horoscope in The Book of Changes(周易) from the relativity of both eight principles(八綱) etc and subdivision in the entity of the cosmos (太極內 分化). Result : From this viewpoint, the decision system that has relative references in differentiation of syndromes & treatments on cold diseases(傷寒病) and complexed diseases(雜病) by eight principles etc can be compared with the decision system in divination by Achillea sibireca that the entity of the cosmos(太極) gradually can be breakdown into the positive and negative(陰陽), the positive and negative can be breakdown into four phases(四象), four phases can be breakdown into eight signs of divination(八卦), eight signs of divination can be breakdown into 64 divination signs(64卦). Conclusion : I had found that differentiation of syndromes and treatments and divination by Achillea sibireca have similarity to each other in side of decision system. Those decision systems for clinical use and telling the future has many relative references and are made of multiple structures. Clinician can easily, exactly distinguish similar syndromes of many another diseases through this way.

• 사상체질의학회지
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• 제9권1호
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• pp.245-253
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• 1997

The methodology of the Oriental philosophy is deductive and that of the of Occidental philosophy is inductive. Therefore study on the Oriental philosophy must start from right comprehension of fundamental premise before detailed analysis. The writer studied the meaning of the cosmology which forms the basis of Sa-sang constitutional philosophy and the propriety of visceral assignment by Sa-sang constitution which forms the theoletiacal basis of Sa-sang constitutional medicine. The results are following ; 1. The cosmology of Lee jae-ma has the existent principle but don't have the side of the formative principie. 2. The cosmology of Lee jae-ma is not that searchs for the objective rule of nature but that centers around a human being by subjective understanding system. 3. The cosmology consists of four elements, that is mind(心), body(身), events(事), and nature(物). Among them mind and body means a human being, nature means the natural environment containing time and space, events means not that of nature but that of human being. 4. The mind and body as Yin-yang(陰陽) means the state which objects and self become one. 5. The mind as the Great-Absolute(太極) has the possibility of two interpretation, Firstly it means the state of the source of life which nature and human being become one, and secondly it means that the mind of a human being becomes the cosmos or the center of the cosmos. 6. In the visceral assignment by Sa-sang constitution the position of heart, the Great-Absolute in center is immanent within four viscera and the function of it is that the undifferentiated unitary organic body, after it is diffrentiated still serves as the unitary organic whole by mutual connection, adjustment, unification and supervision. 7. The Great-Absolute in center is divided into the Great-Absolute of mind and that of body. And the Great-Absolute of body consists of the heart and the system of blood vessel, that of mind means the self-consciousness(自我).

• 복식문화연구
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• 제11권3호
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• pp.367-374
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• 2003

When analyzing forms in the human body and clothes, we conceptualize each part into a cone, sphere, and cylinder, and the esthetic characteristics of our fashion culture and esthetic fashion characteristics of Koreans are composed by expressing with universal images such as circle, square, and triangle when forms are expressed in a plane. To determine how the structural principle of shapes that are the shapes of all things and basic to geometry, i.e., circle, square, and triangle, applies to clothes that cloth our body called the small cosmos, we discussed the symbolic meaning hidden inside the structure of Korean clothes based on the basic pattern drafting method of Korean men’s traditional trousers. We drew the conclusion that Korean men's trousers composed of circles, triangles, and squares express the five elements diagram through their plane structure, are designed in circles with cones and pyramids, and are made to well express the principle of the small cosmos of our body. Moreover, when the basic pattern of Korean men’s trousers explained with the antipathy diagram is viewed to create all things while maintaining opposite and complementary relationship with Sangsang (mutually benefitting factor), it would be correct to say that the principle of the top verse the bottom is viewed as conflicting. From the structural point of view, since the philosophy of the Samsu principle (the principle of 1, 2 and 3 in which 1 represents the heaven, 2 represents the earth, and 3 represents the people) is hidden in Korean men's trousers in which Hurimalgi (the part of trousers corresponding to the waist band of Western pants) is the circle representing the heaven, Marupok is the square representing the earth, and Sapok is the triangle representing the people, we could look at deep meaning of our ancestors expressed in our clothes.

• 한국항공우주학회지
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• 제41권2호
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• pp.164-171
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• 2013

우주파편은 1957년 인류가 우주에 위성을 보내기 시작하면서 그 숫자가 급격하게 증가하고 있으며, 현재 미합동우주전략사령부(JSpOC, Joint Space Operations Center)에 의하면 지름 10cm 이상의 우주파편이 22,000개 이상이라고 알려지고 있다. 최근에는 중국이 자국의 위성을 미사일로 요격시킨 사건과 Iridium 33 및 Cosmos 2251 위성이 우주상공에서 서로 충돌한 사건이 발생함에 따라 아리랑 2호가 운영 중인 저궤도의 우주환경이 급격히 악화되고 있다. 미합동우주전략사령부는 15,000개 이상의 우주파편의 궤도정보를 이용하여 운영위성과의 충돌분석을 수행하고 있으며, 충돌 위험이 발생할 경우 해당 위성의 운영자에게 CSM(Conjunction Summary Message)이란 형식의 메시지를 제공하여 충돌분석 시 활용할 수 있도록 지원하고 있다. 본 논문은 JSpOC에서 제공하는 CSM의 아리랑2호 궤도데이터와 항우연이 관리하는 아리랑 2호의 정밀궤도 데이터와 비교하였으며, 아리랑 2호와 우주파편과의 충돌분석 결과를 도시하였다.

• 동의생리병리학회지
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• 제24권4호
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• pp.571-579
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• 2010

The advancement of medical technology has made it possible to treat various incurable diseases. Especially organ transplantation can give another life to the patients who have organ failure and could not find any other ways to treat their diseases. According to the development of medical technology and immunosuppressive drugs, the rate and extent of organ transplantation is increasing these days. New medical technologies like organ transplantation brought on critical issues and these have changed the way of thinking and morals that has been the fundamental rules in our society. Bioethics is already an important field of medicine and oriental medicine should investigate the problem caused by the development of medical technology and life science and should form a view of life in oriental medicine. Oriental medicine is East Asian traditional medicine based on "Huangdi-Neijing", constructed by the system of Jangfu and meridian. The traditional therapies of oriental medicine have completed a scientific system on the point of view that looks on human and nature equally. This process continued to form a new medical theory as the environment was changed and the new diseases were appeared since "Huangdi-Neijing" and "Shoganron" showed a new scope to investigate human and diseases. Therefore, it is important to develop the point of view of oriental medicine as the medical situation was changed. Oriental medicine has a holistic view that considers human as a little cosmos resonated by a big cosmos and regards the possibility to recover and to regulate the energy in our body. This theory is a basic idea of oriental philosophy. Oriental medicine focuses on the balance of yin and yang of the body and tries to harmonize the imbalance of yin and yang caused by the life style and environment. This can solve many problems that cannot be settled by modern medicine and this can accomplish the new paradigm of oriental medicine that is needed these days.

• 대한교통학회지
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• 제25권5호
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• pp.33-42
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• 2007

현재 사용되고 있는 실시간 신호제어시스템의 좌회전 녹색시간 배분모형은 검지기 장애가 일정기간 동안 유지되는 경우에 장애가 발생한 좌회전 이동류의 포화도를 항시 작게 산출하여 최소녹색시간으로 운영하고, 정상적인 이동류에 불필요한 녹색시간을 배분하여 수요에 비합리적인 녹색시간을 배분하는 한계성을 가지고 있다. 본 논문에서는 이와 같은 문제점을 개선하기 위하여 해당 교차로 접근로의 검지기 정보 및 이력자료를 이용하는 8가지 모형을 검토하여 다양한 교통상황하에서 평가하였다. 평가 결과로부터 장애발생시 같은 요일 및 시간대의 4 주간 포화도를 평균하여 사용하는 모형이 최소의 오차를 나타내었고, 이를 개선모형으로 제시하였다. 개선모형의 실제적 효과에 대한 평가를 위하여 NETSIM 시뮬레이션 프로그램을 이용하여 기존모형과의 평균지체시간을 비교분석한 결과 개선모형이 기존모형보다 평균지체시간이 매우 감소된 결과를 얻었다. 그리고 산출된 평균지체시간의 차이에 대하여 t-검정을 실시한 결과, 통계적으로 유의하게 나타나 개선모형이 실제적으로 효과가 있음을 확인하였다.

• 천문학회지
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• 제39권2호
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• pp.41-50
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• 2006

We present the results of new multi-color CCD photometry for the contact binary XZ Leo, together with reasonable explanations for the period and light variations. Six new times of minimum light have been determined. A period study with all available timings confirms Qian's (2001) finding that the O-C residuals have varied secularly according to $dP/dt\;=\;+8.20{\times}10^{-8}\;d\;yr^{-l}$. This trend could be interpreted as a conservative mass transfer from the less massive cool secondary to the more massive hot primary in the system with a mass flow rate of about $5.37{\times}10^{-8}\;M_{\odot}\;yr^{-l}$. By simultaneous analysis of our light curves and the previously published radial-velocity data, a consistent set of light and velocity parameters for XZ Leo is obtained. The small differences between the observed and theoretical light curves are modelled by a blue third light and by a hot spot near the neck of the primary component. Our period study does not support the tertiary light but the hot region which may be formed by gas streams from the cool secondary. The solution indicates that XZ Leo is a deep contact binary with the values of q=0.343, $i=78^{\circ}.8$, ${\Delta}(T_1-T_2)=126\;K$, and f=33.6 %, differing much from those of Niarchos et al. (1994). Absolute parameters of XZ Leo are determined as follows: $M_1=1.84\;M_{\odot},\;M_2=0.63\;M_{\odot},\;R_1=1.75\;R_{\odot},\;R_2=1.10\;R_{\odot},\;L_1=7.19\;L_{\odot},\;and\;L_2=2.66\;L_{\odot}$.