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팬텀투과계수와 유효조사면 개념을 이용한 종양선량 확인에 관한 연구
김유현,여인환,권수일,Kim, You-Hyun,Yeo, In-Hwan,Kwon, Soo-Il 대한방사선기술학회 2002 방사선기술과학 Vol.25 No.1
The aim of this study Is to develop a simple and fast method which computes in-vivo doses from transmission doses measured doting patient treatment using an ionization chamber. Energy fluence and the dose that reach the chamber positioned behind the patient is modified by three factors: patient attenuation, inverse square attenuation. and scattering. We adopted a straightforward empirical approach using a phantom transmission factor (PTF) which accounts for the contribution from all three factors. It was done as follows. First of all, the phantom transmission factor was measured as a simple ratio of the chamber reading measured with and without a homogeneous phantom in the radiation beam according to various field sizes($r_p$), phantom to chamber distance($d_g$) and phantom thickness($T_p$). Secondly, we used the concept of effective field to the cases with inhomogeneous phantom (patients) and irregular fields. The effective field size is calculated by finding the field size that produces the same value of PTF to that for the irregular field and/or inhomogeneous phantom. The hypothesis is that the presence of inhomogeneity and irregular field can be accommodated to a certain extent by altering the field size. Thirdly, the center dose at the prescription depth can be computed using the new TMR($r_{p,eff}$) and Sp($r_{p,eff}$) from the effective field size. After that, when TMR(d, $r_{p,eff}$) and SP($r_{p,eff}$) are acquired. the tumor dose is as follows. $$D_{center}=D_t/PTF(d_g,\;T_p){\times}(\frac{SCD}{SAD})^2{\times}BSF(r_o){\times}S_p(r_{p,eff}){\times}TMR(d,\;r_{p,eff})$$ To make certain the accuracy of this method, we checked the accuracy for the following four cases; in cases of regular or irregular field size, inhomogeneous material included, any errors made and clinical situation. The errors were within 2.3% for regular field size, 3.0% irregular field size, 2.4% when inhomogeneous material was included in the phantom, 3.8% for 6 MV when the error was made purposely, 4.7% for 10 MV and 1.8% for the measurement of a patient in clinic. It is considered that this methode can make the quality control for dose at the time of radiation therapy because it is non-invasive that makes possible to measure the doses whenever a patient is given a therapy as well as eliminates the problem for entrance or exit dose measurement.
Statistical Interpretation of Economic Bubbles
Yeo, In-Kwon 한국통계학회 2012 응용통계연구 Vol.25 No.6
In this paper, we propose a statistic to measure investor sentiment. It is a usual phenomenon that an asymmetric volatility (referred to as the leverage effect) is observed in financial time series and is more sensitive to bad news rather than good news. In a bubble state, investors tend to continuously speculate on financial instruments because of optimism about the future; subsequently, prices tend to abnormally increase for a long time. Estimators of the transformation parameter and the skewness based on Yeo-Johnson transformed GARCH models are employed to check whether a bubble or abnormality exist. We verify the appropriacy of the proposed interpretation through analyses of KOSPI and NIKKEI.
Determination of metabolic enzymes involved in biotransformation of IN-1130, an ALK5 inhibitor
Yeo Woon KIM(김여운),Kyung Nan MIN(민경난),Jung In JEE(지정인),Kyoung Jin KWON(권경진),Seo Youn GO(고서운),Yong Kook KIM(김용국),Il Young CHO(조일영),Youn Jee CHUNG(정연지),Dae-kee KIM(김대희),Yhun Yhong SHEEN(신윤용) 환경독성보건학회 2007 한국독성학회 심포지움 및 학술발표회 Vol.- No.-
변환-역변환을 통한 자기회귀이동평균모형에서의 예측값 추정
여인권,조혜민,Yeo, In-Kwon,Cho, Hye-Min 한국통계학회 2008 응용통계연구 Vol.21 No.3
시계열자료 분석에 있어 주요 목적 중에 하나는 미래에 대한 예측 값을 추정하는 것이다. 이 논문에서는 정상자기회귀이동평균 모형에서 변환-역변환 방법을 이용하여 예측값을 구하는 과정에서 발생하는 문제에 대해 알아보고 회귀분석에서 제안되었던 smearing 추정방법을 시계열분석에서 사용할 수 있도록 붓스트랩을 이용하여 수정한 추정법을 소개한다. Yeo-Johnson 변환 (2000)을 이용한 KOSDAQ지수의 수익률 실증분석을 통해 기존에 사용되고 있는 방법의 문제점과 제안된 방법의 적절성에 대해 고찰해 보았다. One of main goals of time series analysis is to estimate prediction of future values. In this paper, we investigate the bias problem when the transformation and back- transformation approach is applied in ARMA models and introduce a modified smearing estimation to reduce the bias. An empirical study on the returns of KOSDAQ index via Yeo-Johnson transformation was executed to compare the performance of existing methods and proposed methods and showed that proposed approaches provide a bias-reduced estimation of the prediction value.
조혜민,오승언,여인권,Cho, Hye-Min,Oh, Sung-Un,Yeo, In-Kwon 한국통계학회 2007 응용통계연구 Vol.20 No.3
시계열자료를 분석하는데 있어 중요한 목적 중에 하나가 미래값에 대한 예측이다. 일반적으로 자기회귀이동평균모형에서는 백색잡음이 정규분포를 따른다는 가정 하에서 모수의 추론과 예측 및 예측구간의 추정이 이루어지고 있다. 그러나 자료가 이러한 가정을 만족하지 않는 경우, 자료를 가정에 맞게 변환시킨 후 분석하는 방법을 생각해 볼 수 있다. 이 논문에서는 변환된 자료를 분석하여 얻은 결과를 이용하여 본래의 척도에서의 미래값에 대한 예측구간을 추정하는 문제에 대해 알아본다. 제안하는 방법에서는 먼저 적절한 변환을 이용하여 자료를 정규가정을 만족하도록 변환시키고 변환된 자료를 이용하여 미래값에 대한 예측구간을 추정한 후, 역변환을 이용하여 예측구간을 추정한다. 이 논문에서는 시계열분석에서 모델링이 상대적으로 어려운 왜도의 문제를 해결하기 위해 Yeo-Johnson 변환을 중심으로 한 방법론을 소개한다. 모의실험 결과 제안된 방법에 의한 단측예측구간의 포함확률이 변환을 사용하지 않은 구간보다 명목수준에 가까운 것을 확인하였다. One of main aspects of time series analysis is to forecast future values of series based on values up to a given time. The prediction interval for future values is usually obtained under the normality assumption. When the assumption is seriously violated, a transformation of data may permit the valid use of the normal theory. We investigate the prediction problem for future values in the original scale when transformations are applied in ARMA models. In this paper, we introduce the methodology based on Yeo-Johnson transformation to solve the problem of skewed data whose modelling is relatively difficult in the analysis of time series. Simulation studies show that the coverage probabilities of proposed intervals are closer to the nominal level than those of usual intervals.
"이수헌", "여인권", "정재성", "박종대" 배재대학교 자연과학연구소 2015 自然科學論文集 Vol.26 No.1
PVDF(Polyvinylidene Fluoride)를 사용하여 진동에너지를 전기적 에너지로 수집할 수 있는 소형 발전시스템을 개발하였다. 개발된 시스템은 온도, 진동, 압력 등의 데이터를 수집하고 무선으로 전송하는 센서 네트워크의 전원으로 사용될 수 있다. We have developed a small electrical energy harvesting system using PVDF(Polyvinylidene Fluoride) which can convert vibrational energy into electrical energy. The developed system can be used as a power source for sensor network which acquire data such as temperature, vibration, pressure, etc and transmit data to a data center
장순자,김형중,여인권 강원대학교 석재복합신소재제품연구센터 2001 석재연 논문집 Vol.6 No.-
영상검색은 문자위주의 검색의 한계로, 그 내용에 기반 한 특징벡터를 이용하여 검색을 수행한다. 특징벡터간의 거리를 계산하고 그 값들에 순위를 매긴다. 이렇게 얻어진 순위 값들을 가지고 사용된 검색방법의 유효성을 검사하는데 Recall/Precision방법이 이용되고 있다. 질의영상과 같은 군에 속하는 영상이 얼마나 검출되었는지를 검출된 영상에 기반 하여 계산하거나, 영상 군에 기반 하여 계산하는 방법들이다. 그러나, 검출되는 순위 값의 범위를 정하고, 그 범위 내에 속하는 만족하는 값의 개수를 세는 방법을 이용한다. 따라서 주어진 두 샘플의 전체적인 경향을 비교하지는 못한다. 본 연구에서는 순위를 이용하여 비교하고자하는 두 샘플의 순위들을 결합하여 순위를 매기고 각 샘플들에 매겨진 순위값들의 평균과 분산을 이용하여 각 샘플들을 전체적으로 비교할 수 있다. Retrieval effectiveness of content-based image is usually measured by "recall and precision" method. The method has disadvantages such that it depends on the number of considered images among retrieved ones. We propose the Wilcoxon rank test for measuring retrieval effectiveness instead of the recall and precision.
( In Kwon Yeo ),( In Pyeong Son ),( Kap Sok Li ),( Chang Kwun Hong ) 대한피부과학회 2013 대한피부과학회 학술발표대회집 Vol.65 No.2
Background: Severe alopecia areata (AA) is resistant to conventional treatment. Although systemic oral corticosteroids are an effective treatment for patients with severe AA, they have many adverse effects. Corticosteroid pulse therapy has been introduced to increase therapeutic effects and reduce adverse effects. However, there is still controversy about treatment modality in severe alopecia areata. Objectives: To evaluate the effectiveness of corticosteroid pulse therapy in patients with severe AA compared to a group treated with oral cyclosporine with corticosteroid. Methods: A total of 82 patients with severe AA were treated with corticosteroid pulse therapy, and 60 patients were treated with oral cyclosporine with corticosteroid. Both groups were retrospectively evaluated for therapeutic efficacy according to AA type and disease duration. Results: In 82 patients treated with corticosteroid pulse therapy, 53 patients (64.6%) were good responders (regrowth greater than 50%). AA patients with plurifocal (PF) type and those with short disease duration (≤ 3 months) showed better responses. In 60 patients treated with oral cyclosporine with corticosteroid, 30 patients (50.0%) showed a good response. AA type or disease duration, however, did not significantly affect the response to treatment. Conclusion: Corticosteroid pulse therapy may be a more successful treatment option than combination therapy in severe AA patients with PF type.