임의중단자료에서의 조건부 평균잔여수명함수 추정

이원기,송명언,정성화,Lee, Won-Kee,Song, Myung-Unn,Jeong, Seong-Hwa 한국데이터정보과학회 2011 한국데이터정보과학회지 Vol.22 No.1

본 연구에서는 Buckley와 James의 방법을 이용하여 중도절단된 자료를 보완한 조건부생존함수 추정량으로부터 조건부평균잔여수명함수를 추정하는 방법을 제안하고, 모의실험을 통하여 제안된 방법의 효율성을 평가하였다. 모의실험 결과 비례위험모형이 아닌 경우 제안된 방법으로 추정한 조건부 평균잔여수명함수의 평균제곱오차가 Cox모형이나 Beran의 비모수적 방법을 이용하여 구한 추정치의 평균제곱오차보다 작게 나타났으며, 비례위험모형인 경우에는 제안된 방법으로 추정한 결과들이 Cox 모형을 이용하여 얻은 결과들과 비슷하게 나타났다. 또한 K대학교병원 외과에서 위암 수술을 받은 1,192명의 환자 자료를 이용하여 제안된 방법의 임상적 적용의 적절성을 평가하였다. The aims of this study were to propose a method of estimation for mean residual life function (MRLF) from conditional survival function using the Buckley and James's (1979) pseudo random variables, and then to assess the performance of the proposed method through the simulation studies. The mean squared error (MSE) of proposed method were less than those of the Cox's proportional hazard model (PHM) and Beran's nonparametric method for non-PHM case. Futhermore in the case of PHM, the MSE's of proposed method were similar to those of Cox's PHM. Finally, to evaluate the appropriateness of practical use, we applied the proposed method to the gastric cancer data. The data set consist of the 1, 192 patients with gastric cancer underwent surgery at the Department of Surgery, K-University Hospital.

후천성면역결핍환자의 삶의 질 측정을 위한 한국판 WHOQOL-HIV BREF 개발

이원기,김신우,김혜인,장현하,이종명,김윤주,이미영,Lee, Won Kee,Kim, Shin-Woo,Kim, Hye-In,Chang, Hyun-Ha,Lee, Jong-Myung,Kim, Yoon-Joo,Lee, Mi-Young 한국데이터정보과학회 2014 한국데이터정보과학회지 Vol.25 No.2

세계보건협회에서 인간후천성면역결핍환자 (human immunodeficiency virus; HIV)의 삶의 질을 측정하기 위해 개발한 WHOQOL-HIV BREF (World Health Organization's quality of life - human immunodeficiency virus, brief scale)를 한국판으로 번역 개발하였다. 설문 문항은 전반적 삶의 질과 건강상태를 묻는 두 문항과 6개의 도메인을 포함한 29문항을 합하여 총 31문항으로 구성되어 있다. 자료수집은 국내 14개 병원에 내원한 220명의 인간면역결핍바이러스 양성환자를 대상으로 전문조사원이 무기명 자가 기입식으로 조사하였다. 대상자 중 남성이 202명 (91.8%), 평균 나이는 40.6세, 평균 CD4+ T 세포수는 1ml당 414.9개였다. 삶의 질은 평균 53.2점이었고 도구의 크론바흐 ${\alpha}$ 신뢰계수는 0.942였다. 동일 도구로 측정한 포르투칼의 경우 54.8점으로 유사하였으며 전반적인 삶의 질과 건강상태와의 상관관계는 각각 0.747 (p <0.01)과 0.651 (p <0.01)이었다. 한국판 도구의 내적신뢰도와 구성타당도도 만족스러웠다. 후천성면역결핍증후군과 인간면역결핍바이러스 환자의 지속적인 관찰은 필요하며 이러한 도구의 개발은 이들의 삶 삶의 질 향상에 기여할 뿐만 아니라 다른 나라 환자들과의 비교를 가능하게 해 줄 것이다. There is no known publication about assessment of quality of life (QOL) in Korean HIV patients. We aimed to assess the QOL of HIV patients. We developed Korean version of the WHOQOL-HIV BREF (short forms of WHOQOL-HIV, 31 questions with 6 domains). Survey data from 220 HIV-positive adults were obtained in 14 centers in South Korea. Male were dominant (202/220, 91.8%). Mean age was $40.6{\pm}12.1$. Mean CD4+ T-cell count was $414.9{\pm}226.6/ml$. Overall of WHOQOL-HIV BREF were $53.2{\pm}14.9$ (perfect score=100) (Cronbach's ${\alpha}$ = 0.942). It is similar score comparing to another country (Portugal: 54.75/100, measured by WHOQOL-HIV). Correlations of WHOQOL-HIV BREF score with patients' subjective QOL and with subjective satisfaction were 0.747 (p <0.01) and 0.651 (p <0.01), respectively. WHOQOL-HIV BREF have internal reliability. There is in need of monitoring for QOL of HIV patients in the clinical practice and trials. This survey tool could be used to assess the effect of intervention. Additionally, comparison across countries would be possible and promising.

임의중도절단된 자료에서 생존함수의 동시신뢰대 구성

이원기,송명언,송재기,박희주,Lee, Won-Kee,Song, Myung-Unn,Song, Jae-Kee,Park, Hee-Joo 한국데이터정보과학회 1998 한국데이터정보과학회지 Vol.9 No.1

임의중도절단된 생존시간자료에서 생존함수에 대한 동시신뢰대를 근사식이나 표없이 구성하는 간단한 방법을 제안하였다. 그리고 모의실험을 통하여 기존의 동시신뢰대와 포함확률측면에서 서로 비교하고, 실제자료에 적용하여 보았다. We consider the problem of obtaining the confidence bands for the survival function with incomplete data. It is a rather simple procedure for constructing confidence bands of survival function. This method uses the weak convergence of normalized cumulative hazard estimator to a mean zero Gaussian process whose distribution can be easily approximated through simulation. Finally, we compare the performance of the proposed confidence bands through Monte Carlo simulation and we applied to construct the proposed bands with the Leukemia patient data.

부검체 두발과 장기의 중금속 오염농도 관련성

이원기,송명언,송재기,이성국,박성화,Lee, Won-Kee,Song, Myung-Unn,Song, Jae-Kee,Lee, Sung-Kook,Park, Sung-Hwa 한국데이터정보과학회 1999 한국데이터정보과학회지 Vol.10 No.1

많은 역학조사에서 두발을 이용하여 체내 중금속 오염 정도를 알아보는 방법이 유용한 것으로 보고 있다. 본 논문에서는 61구의 부검체를 이용하여 다변량기법으로 두발과 장기의 수은 및 카드늄 축적정도를 측정하여 상호간 관련성을 밝히고자 하였다. 그 결과 수은의 경우 두발에서의 축적정도와 2차 축적장기와는 통계적으로 유의한 상관성이 있는 것으로 나타났다. It is well known to use scalp hair as a signal of strengths of heavy metals contamination. In this paper, using the multivariate methods we examine the relationship between strengths of cadmium and mercury in scalp hair and cerebellum, cerebrum, heart, kidney, liver, lung and spleen from 61 korean autopsy subjects. As a result, there is statistically singnificant relationship between strengths of mercury contamination in scalp hair and secondary contaminated organs.

흡연이 치과 외래 이용 및 치과 외래 의료비에 미치는 영향

정선락 ( Sun Rak Jeong ),김영희 ( Young Hee Kim ),장지언 ( Ji Eon Jang ),이원기 ( Won Kee Lee ) 대한예방치과·구강보건학회 2015 大韓口腔保健學會誌 Vol.39 No.4

Objectives: The objectives of this study were to evaluate the effect of smoking on utilization of and expenses in ambulatory dental care. Methods: The subjects of this study were 5,751 men aged over 20 years selected from the Korea Health Panel data collected during 2010-2012. Pack-years of smoking were calculated based on the survey data. Dental utilization was defined as dental outpatient clinic use least once in three years. The expenses in ambulatory dental care were summed to determine total dental health care spending for three years. To detect the effect of smoking, we used multiple logistic regression analysis for dental utilization and multiple linear regression for expenses in ambulatory dental care after changing log. Results: The pack-years had a significant effect on dental utilization and expenses in participants aged 40-59 years. After controlling for income level, bedtime brushing, and the presence of chronic disease, dental care utilization rates in the over 10 to less than 25 pack-year and the over 25 pack-year groups were about 1.4 (OR=1.37, (P =0.007)) and 1.6 times (OR=1.59, (P =0.001)) those in the 0 pack-year group. In comparison with the 0 pack-year group, the over 10 to less than 25 pack-year group spent 50,000 won more over dental expenses, while the corresponding number for the over 25 pack-year group was about 100,000 won. Thus, the ambulatory dental care expenses increased with the packyears of smoking. Conclusions: Smoking significantly influenced the utilization and expense in ambulatory dental care in men aged 40-59 years.

권역심뇌혈관질환센터 사업의 비용-편익 분석

김병호 ( Byung Ho Kim ),감신 ( Sin Kam ),배상근 ( Sang Geun Bae ),김건엽 ( Keon-yeop Kim ),이원기 ( Won Kee Lee ),홍남수 ( Nam-soo Hong ),박형근 ( Hyeung-keun Park ),이혜진 ( Heyjean Lee ),조은정 ( Eun-jung Cho ),채성철 ( Shung C 한국보건정보통계학회(구 한국보건통계학회) 2017 보건정보통계학회지 Vol.42 No.1

Objectives: This study was conducted to investigate economic feasibility of operating Regional Cardiocerebrovascular Centers using cost-benefit analysis. Methods: The current study assessed cost and benefit data collected from nine hospitals which were designated as Regional Cardiocerebrovascular Centers between 2008 and 2010. Results: The operation of Regional Cardiocerebrovascular Centers reduced mortality rate and length of stay due to acute myocardial infarction and stroke and also decreased disability occurred after stroke. The total calculated cost of operating nine Regional Cardiocerebrovascular Centers was 19.85-22.30 billion won and the minimum benefit calculated was 23.98 billion won. Applying the maximum cost and the minimum benefit, the net benefit was 1.68 billion won, which is estimated to 190 million won per Regional Cardiocerebrovascular Center. Conclusions: The present study revealed that the operation of Regional Cardiocerebrovascular Centers was economically beneficial. The benefit would be larger if intangible benefit such as the long-term effects to community hospitals and enhancement of quality of life of patients and their families are considered.

중앙은행 커뮤니케이션의 시장금리에 대한 영향

이원기 ( Won Kee Lee ),강삼모 ( Sammo Kang ) 한국금융연구원 2021 금융연구 Vol.35 No.2

본 논문에서는 중앙은행의 커뮤니케이션이 시장금리에 실질적인 영향을 주는지 여부를 분석하고자 하였다. 한국은행이 금리중시 운용목표를 본격적으로 도입, 운용하기 시작한 이후를 분석기간으로 설정하였다. 커뮤니케이션 변수는 통화정책 결정회의 직후 공표되는 결정문의 경제상황 및 전망기술을 근거로 수치화하였다. 실증분석 결과, 콜금리, CD 및 CP 금리, 만기 1년물 통안증권 및 국고채 금리 등 단기금리에 대해서만 커뮤니케이션 효과가 나타나는 것으로 추정되었다. 또한 정책금리 목표가 상승한 시기, 불변인 시기, 하락한 시기로 구분하여 추정한 경우에는 하락기의 만기 1년 이내의 금리에 대해서만 유의적으로 추정되었다. 이와 같이 커뮤니케이션 변수에 대하여 단기 금리만이 유의적인 반응을 보이고 중장기 금리는 유의적인 반응을 보이지 않는 점은 커뮤니케이션의 역할이 본래 미래의 단기금리 경로에 관한 예상, 향후 경기상황 및 인플레이션 예상 등과 연관되어 장기금리에도 영향을 줄 수 있다는 점을 감안할 때 우리나라에서는 그 역할이 미흡하였음을 의미한다. 한편 정책금리 목표의 조정 여부에 따라 구분하여 추정한 결과에서는 금리목표가 인하된 경우에는 만기 10년물 금리에 이르기까지 유의적인 양의 반응을 보였으나 인상된 경우에는 시장금리가 커뮤니케이션 변수에 별다른 반응을 보이지 않았다. 이는 정책금리조정이 다소 상방 경직적으로 운영되어 긴축 기조로의 변경 신호가 실제 실현될 가능성을 시장에서는 크게 평가하지 않았음을 시사한다. In the case of Korea, the Bank of Korea changed its monetary policy operation method from the money volume to the interest rate after the full amendment of the Bank of Korea Act at the end of 1997. In addition, the policy signaling function of decision statements, such as expansion of the content of monetary policy statements, has been steadily strengthened. In addition, with the introduction of the price stabilization target system, communication efforts are being reinforced through various channels, such as reinforcing responsibility for explaining the operation situation. In this paper, we analyzed whether central bank communication has a real impact on market interest rates. Central bank communication is meant to encompass a series of communication with individual economic actors and markets in the course of monetary policy operation. However, we measured communication by limiting it to the domestic economic situation and prospects shown in the statements released by the Bank of Korea immediately after monetary policy decision. In general, we set the analysis period after the Bank of Korea started operating its interest-oriented management target in earnest. Looking at the analysis results, communication effects were found only on short-term interest rates such as call rate, CD and CP rates, and 1-year maturity rate. In addition, we classified the timing into a period when the policy interest rate target rose, a constant period, and a decreased period and then conducted an empirical analysis. As a result of the analysis, only short-term interest rates showed a significant response to communication variables, and mid- to long-term interest rates did not. Central bank communication can have an effect on the future short-term interest rate pathway, future economic conditions and inflation forecasts, and ultimately long-term interest rates. Therefore, the above results mean that the role of central bank communication in Korea is still insufficient. On the other hand, an empirical analysis was conducted by categorizing whether the policy interest rate target rises or falls. As a result of the analysis, when the interest rate target was lowered, even the 10-year maturity interest rate was affected. However, when the interest rate target was raised, the market interest rate did not show a significant reaction to the communication variable. This implies that the possibility of realization of a change signal to an interest rate hike was not greatly assessed in the market because policy interest rate had been mainly adjusted toward the direction of the cut.

電氣火傷患者 171例에 對한 觀察

이원기(Lee Won Kee),이선호(Lee Sun Ho) 대한정형외과학회 1973 대한정형외과학회지 Vol.8 No.1

연령대별 인적자본스톡 추정 : 1993∼2015

이원기(Lee, Won Kee),강삼모(Kang, Sam Mo) 동국대학교 사회과학연구원 2018 사회과학연구 Vol.25 No.2

1993∼2015년을 대상으로 우리나라의 인적자본스톡을 10개 연령대별로 평균 교육기간과 실질 생애소득으로 추정하였으며, 그 주요 결과는 다음과 같다. 첫째, 그 동안의 경제발전과 교육수준의 향상 등에 힘입어 1인당 실질 인적자본스톡은 전반적으로 증가하는 추세이다. 둘째, 1인당 실질 생애소득은 2015년 기준으로 물적 자본스톡의 약 2.4배에 달하는 것으로 나타났으나 주요국에 비해서는 낮은 수준이다. 셋째, 연령대별로는 모든 연령대에서 증가하는 가운데 대체로 핵심적인 생산연령계층인 30대에서 50대 전반까지의 연령대에서 빠르게 증가하였다. 넷째, 1인당 인적자본스톡의 크기는 25∼29세 또는 30∼34세에서 최고수준을 보이는 보편적인 역 U자 형태로 나타났다. 다섯째, 산업별로는 1인당 급여수준이 많은 전기·가스·수도업, 금융 및 보험업 등에서 1인당 인적자본이 전반적으로 높은 수준이었다. 여섯째, 저학력자보다 고학력자의 인적자본 수준이 높고 그 격차는 학력 격차가 커질수록 더욱 확대되었다. Human capital stock per employee will be becoming issues of growing importance with the rapid progress of population ageing. In this paper, it is estimated by 10 age groups yearly from 1993 to 2015 on the basis of average years of schooling or real lifetime income. The results are summarized as follows. Firstly, it tends to increase due to economic development and educational progress. Secondly, per capita real lifetime income amounts to be about 2.4 times as much as physical capital stock as of 2015, which is lower than other major countries. Thirdly, it increases in all age groups, especially rapidly from the thirties to the early fifties - the core productive age groups. Fourthly, it takes an inverted U-shape of the highest point at the late twenties or the early thirties on the age groups(X)- and per capita human capital stock(Y)- axes. Fifthly, as compared by industry, it is mostly higher in the electricity, gas and water supply, finance and insurance etc. because of higher per capita wages. Lastly, as compared by school career, it is higher in the well-educated workers than in the low-educated and its differences expand as educational gap widens.

개체명 인식과 단어 정렬을 이용한 통계적 기계번역의 성능 향상

이원기(Won-Kee Lee),김영길(Young-Gil Kim),조승우(Seung-Woo cho),권홍석(Hong-Seok Kwon),이의현(Eui-Hyun Lee),조형미(Hyung-Mi Cho),이종혁(Jong-Hyeok Lee) 한국정보과학회 2017 한국정보과학회 학술발표논문집 Vol.2017 No.06