Peeling Mode in Experimental Equilibrium Conditions

ohjin Kwon 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.III

The peeling mode, driven by finite edge current, is strongly associated with edge localized modes (ELMs) when the pressure gradient is not large. The stability boundary of the peeling mode for circular plasma in the large aspect-ratio limit is staraight in jk/ < j > . space in the low limit. We have generated equilibria, which can be realized in SND experiments, with pressure profiles having an edge pedestal. Ideal MHD stability has been determined by using linearlized 2-D code, ELITE. The stability boundary of the peeling mode in experimental equilibrium conditions also remains almost straight.Gzm-G

Vertical Instability in Standard Aspect Ratio Tokamak

Ohjin Kwon 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.1

The vertical instability, which is intrinsic to an elongated plasma, can be a serious problem in tokamak operations. We numerically found the limiting equilibrium conditions, such as the elongation of plasma, for a standard aspect ratio tokamak like KSTAR, to have a stable vertical mode in the presence of a conformal stabilizing wall. We found that the simple analytical model fails when the triangularity is large for small elongation. The overall vertical stability improves with the triangularity.

Halo Current in JET /

Kwon, Ohjin 大邱大學校 基礎科學硏究所, 2003 基礎科學硏究 Vol.20 No.1

거대 희소 행렬을 이용한 특허정보 유통 모형에 대한 연구

권오진(OhJin Kwon),서진이(Jinny Seo),김정호(J.H. Kim),노경란(K.R. Noh),김완종(W.J. Kim),김진석(J.S. Kim) 한국정보과학회 2006 한국정보과학회 학술발표논문집 Vol.33 No.2A

최근 특정 주제의 지적 구조를 파악하기 위한 저자 동시인용분석, 동시단어분석, 서지결합법 등 계량정보분석에 대한 연구가 활발히 진행되고 있다. 그러나 국내의 경우 계량정보분석 기법을 활용한 정보 유통 프레임웍을 갖추고 있는 연구기관이나 대학이 아직 없는 실정이다. 그 이유는 특허나 과학문헌에 대한 인용정보를 보유한 곳이 없고, 거대 인용정보 행렬을 계산하기 위한 컴퓨팅 자원을 확보하지 못하고 있기 때문이다. 본 연구는 미국 특허 데이터베이스를 대상으로 인용 피인용 행렬을 생성한 후, 클러스터 컴퓨터를 사용하여 동시인용과 서지결합빈도를 계산하고 그 결과를 이용자에게 제공하는 정보 유통 서비스 모델을 제시하고자 한다.

A Model Equilibrium and ELITE

권오진 大邱大學校附設 基礎科學硏究所 2004 基礎科學硏究 Vol.21 No.1

ELITE code has previously been written to analyze MHD stability of large toroidal mode number especially in the tokamak edge region. We present a brief description of the code and variables in input files. We have generated up-down symmetric, circular cross-section plasma equilibrium with HELENA and tested MHD stability of n=6. Important outputs are described and two graphic outputs are also shown. This case will serve as a test case when installing ELITE to other computers or when other MHD codes are written.

Early identification of emerging technologies: A machine learning approach using multiple patent indicators

Lee, Changyong,Kwon, Ohjin,Kim, Myeongjung,Kwon, Daeil Elsevier 2018 Technological forecasting social change Vol.127 No.-

<P><B>Abstract</B></P> <P>Patent citation analysis is considered a useful tool for identifying emerging technologies. However, the outcomes of previous methods are likely to reveal no more than current key technologies, since they can only be performed at later stages of technology development due to the time required for patents to be cited (or fail to be cited). This study proposes a machine learning approach to identifying emerging technologies at early stages using multiple patent indicators that can be defined immediately after the relevant patents are issued. For this, first, a total of 18 input and 3 output indicators are extracted from the United States Patent and Trademark Office database. Second, a feed-forward multilayer neural network is employed to capture the complex nonlinear relationships between input and output indicators in a time period of interest. Finally, two quantitative indicators are developed to identify trends of a technology's <I>emergingness</I> over time. Based on this, we also provide the practical guidelines for implementation of the proposed approach. The case of pharmaceutical technology shows that our approach can facilitate responsive technology forecasting and planning.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Proposing a machine learning approach to identifying emerging technologies at early stages </LI> <LI> Defining 18 input and 3 output variables from the United States Patent and Trademark Office database </LI> <LI> Employing feed-forward multilayer neural networks to capture nonlinear relationships between input and output variables </LI> <LI> Developing two quantitative indicators to identify trends of a technology's <I>emergingness</I> </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

예측치의 낙관적 편향, 라운딩 및 예측정확도

강내철(Kang, Naechul),권오진(Kwon, Ohjin) 韓國公認會計士會 2016 회계·세무와 감사 연구 Vol.58 No.1

국내 분석가들의 예측정확도는 자본시장의 규모에 비해 초라한 수준이다. 그 주된 원인은 분석가의 낙관적 편향(optimistic bias)에서 찾을 수 있다. 대기업과 투자자의 눈치를 봐야 하는 분석가는 비관적 의견을 쉽게 낼 수 없다는 것이다. 예측치의 낙관적 편향에 관해서는 많은 연구들에서 확인되고 있다. Das et al.(1998)는 경영자의 비공개 정보에 접근하기 위해 분석가가 낙관적 편향을 가진 예측치를 선택한다고 보고하였다. 본 연구는 낙관적 편향이 있는 예측치를 선택한 분석가는 음의 예 측오차를 완화하기 위해 끝자리를 절사하는 라운딩을 시도할 것이라는 예측을 바탕으로 예측치의 라운딩이 낙관적 편향을 완화하는지, 그리고 그 결과 예측정확도가 개선되는지를 분석한다. 분석결과에 따르면 라운딩은 예측치에 만연한 낙관적 편향을 완화하는 역할을 함으로써 예측정확도를 개선하는 것으로 확인되었다. 그리고 라운딩된 예측치는 이익공시일의 이익반응계수가 유의하게 크다는 점이 확인되었다. 이것은 시장의 기대치 형성에 라운딩된 예측치가 반영되는 비중이 더 크다는 것을 의미한다. The forecasts accuracy of Korean analysts is poor for capital market size. We can find main reason from optimistic bias in analysts' forecast. Analysts are not free from firms and investors, so they can not lay out negative opinion without burden. There are so many research on optimistic bias in analysts' forecast. Das et al.(1998) reports that analyst select optimistically biased forecast to obtain a private information from management. We examine whether optimistic forecasts helps explaining the behavior of analysts’ rounding behavior of forecasts, i.e. the occurrence of zeros or fives in the last place. We expected that a rounding off the last digit of forecasts helps decreasing the negative forecasting error from optimistic forecasts. Based on this expectation, we examine whether rounded forecasts relieve optimistic bias and therefore improve the forecasting accuracy. We find evidence that rounded forecasts improve the forecasting accuracy through decreasing prevalent optimistic bias in analyst forecasts. We also find evidence that the earnings response coefficient of analyst forecast that is rounded is significantly higher. That means investors place higher weight on analyst forecast when the forecast is rounded.

Soft, curved electrode systems capable of integration on the auricle as a persistent brain–computer interface

Norton, James J. S.,Lee, Dong Sup,Lee, Jung Woo,Lee, Woosik,Kwon, Ohjin,Won, Phillip,Jung, Sung-Young,Cheng, Huanyu,Jeong, Jae-Woong,Akce, Abdullah,Umunna, Stephen,Na, Ilyoun,Kwon, Yong Ho,Wang, Xiao- National Academy of Sciences 2015 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.112 No.13

<P><B>Significance</B></P><P>Conventional electroencephalogram (EEG) recording systems, particularly the hardware components that form the physical interfaces to the head, have inherent drawbacks that limit the widespread use of continuous EEG measurements for medical diagnostics, sleep monitoring, and cognitive control. Here we introduce soft electronic constructs designed to intimately conform to the complex surface topology of the auricle and the mastoid, to provide long-term, high-fidelity recording of EEG data. Systematic studies reveal key aspects of the extreme levels of bending and stretching that are involved in mounting on these surfaces. Examples in persistent brain–computer interfaces, including text spellers with steady-state visually evoked potentials and event-related potentials, with viable operation over periods of weeks demonstrate important advances over alternative brain–computer interface technologies.</P><P>Recent advances in electrodes for noninvasive recording of electroencephalograms expand opportunities collecting such data for diagnosis of neurological disorders and brain–computer interfaces. Existing technologies, however, cannot be used effectively in continuous, uninterrupted modes for more than a few days due to irritation and irreversible degradation in the electrical and mechanical properties of the skin interface. Here we introduce a soft, foldable collection of electrodes in open, fractal mesh geometries that can mount directly and chronically on the complex surface topology of the auricle and the mastoid, to provide high-fidelity and long-term capture of electroencephalograms in ways that avoid any significant thermal, electrical, or mechanical loading of the skin. Experimental and computational studies establish the fundamental aspects of the bending and stretching mechanics that enable this type of intimate integration on the highly irregular and textured surfaces of the auricle. Cell level tests and thermal imaging studies establish the biocompatibility and wearability of such systems, with examples of high-quality measurements over periods of 2 wk with devices that remain mounted throughout daily activities including vigorous exercise, swimming, sleeping, and bathing. Demonstrations include a text speller with a steady-state visually evoked potential-based brain–computer interface and elicitation of an event-related potential (P300 wave).</P>

Beneficial effect of Gyejibokryeong-hwan on climacteric syndrome with blood stasis pattern: A randomized, double-blinded, placebo-controlled clinical pilot trial

Kyungsun Han,Jeong-Eun Yoo,Jung-Eun Kim,Ohjin Kwon,Ae-Ran Kim,Hyo-ju Park,So-Young Jung,Mikyung Kim,Changsop Yang,Jung-Hyo Cho,Jun-Hwan Lee 한국한의학연구원 2023 Integrative Medicine Research Vol.12 No.2

Background: Gyejibokryeong-hwan (GBH), a herbal mixture that is widely used for climacteric syndrome, is studied for its efficacy; however, no study evaluated the GBH indication, which is a blood-stasis pattern based on traditional Chinese medicine theory. Methods: This was a randomized, double-blinded, placebo-controlled clinical pilot trial. Fifty subjects with climacteric syndrome were recruited and randomly assigned to GBH group or placebo group. Subjects were administered GBH or placebo granules for 4 weeks followed by 4 weeks of observation period. For the primary outcome, the Menopause Rating Scale (MRS) was evaluated. For the secondary outcomes, quality of life, degrees of abdominal resistance and tenderness, blood-stasis pattern questionnaire and degree of upward movement of Qi were evaluated. Results: After 4-week intervention, the mean change of total MRS score significantly decreased in the GBH group compared to the placebo group (p = 0.037). The quality of life related to physical health (p = 0.008) and blood-stasis pattern (p = 0.018) significantly improved in the GBH group but not in the placebo group. Conclusion: Our findings provide evidence of the feasibility of recruiting subjects with GBH indications and show that GBH may have clinical efficacy for the treatment of menopausal symptoms, especially urogenital symptoms, without any significant adverse events. Trial registration: This trial was registered at Clinical Research Information Service (CRIS identifier: KCT0002040).

무선 메쉬 네트워크 장비의 실험적인 성능 검증

이옥환(Okhwan Lee),김성관(Seongkwan Kim),이희영(Heeyoung Lee),이성우(Sungwoo Lee),권오진(Ohjin Kwon),김웅찬(Eungchan Kim),최성현(Sunghyun Choi) 한국통신학회 2008 한국통신학회 학술대회 및 강연회 Vol.2008 No.4