• 응용통계연구
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• 제21권5호
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• pp.739-754
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• 2008

다중탈퇴모형 연구에서 연(year) 기준의 다중탈퇴율과 연 기준의 절대탈퇴율을 상호 전환하는 방법에 집중되어 있다. 실제 실무에서는 월(month) 기준의 다중탈퇴율이 필요한 경우가 많으므로 본 논문에서는 연 기준의 절대탈퇴율을 월 기준의 다중탈퇴율로 전환하거나 연 기준의 다중탈퇴율을 일 기준의 절대탈퇴율로 전환하는 공식을 유도한다. 유도된 공식은 월 기준 대신에 일(day) 기준 또는 분기(quarter) 기준 또는 반기(semiannual) 기준 등으로도 전환 가능한 공식이다. 또한 월 기준의 절대탈퇴율에서 월 기준의 다중탈퇴율로 전환 가능한 공식도 제시한다. 절대탈퇴율에서 다중탈퇴율로 전환하는 과정에서 절대탈퇴율이 균등분포 가정(UDD: Uniform Distribution of Decrements)을 따른다고 한다. 다중탈퇴율에서 절대탈퇴율로 전환하는 과정에서는 다중탈퇴율이 UDD를 가정하는 경우와 상수탈퇴력 가정 (Constant force assumption)을 따르는 경우로 나누어서 공식을 유도한다. 유도된 공식은 Bowers 등 (1997)에 있는 전환 공식의 일반적인 형태임을 확인할 수 있다. 또한 유도된 공식을 활용하여 수치 예를 통하여 자료를 이용하여 절대탈퇴율과 다중탈퇴율의 전환 과정을 설명하며 유도된 공식들의 차이점을 비교한다.

• 응용통계연구
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• 제26권3호
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• pp.549-568
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• 2013

보험상품의 보험료를 계산하거나 리스크 관리를 하는 과정에서 다중탈퇴율이 필요하지만 경험 자료의 부족으로 절대탈퇴율을 다중탈퇴율로 전환하여 많이 사용한다. 다중탈퇴율과 절대탈퇴율간의 전환에는 소수연령분포를 균등분포로 가정하거나 탈퇴력을 상수로 가정하여 전환하는 방법을 주로 사용한다. 하지만, 이러한 가정하에서는 전환 시 오차가 발생하므로 본 연구에서는 전환오차를 줄이기 위하여 소수연령분포를 삼차 스플라인 함수로 추정하여 전환하는 방법을 제안한다. 기존에 많이 사용하던 방법은 탈퇴력이 불연속적이라는 특징이 있었으나 새로이 제시하는 방법은 탈퇴력이 연속적이라는 측면에서 차이가 있다. 수치 예를 통하여 기존의 방법과 오차를 비교해 봄으로써 스플라인 추정법이 오차를 줄이는데 효과적임을 확인할 수 있다.

• 대한임상검사과학회지
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• 제38권1호
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• pp.1-8
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• 2006

The purposes of this study were to evaluate the changes in hematologic indices after plateletpheresis and to identify the preapheresis platelet count and clinical factors (age, gender, height, and weight) that showed some influence on the percentage of platelet decrement, yield and efficiency. Plateletpheresis was performed on 101 healthy donors in Bundang CHA general hospital. The data was analyzed using the SAS program with t-test, ANOVA test and Multiple regression. The mean percentage decrease after plateletpheresis was 2.0% in hemoglobin, 1.8% in hematocrit, and 29.7% in the platelet count, while a WBC count showed an increase of 2.6%. The mean percentage decrease of hemoglobin and hematocrit were 1.7% and 1.4%, in males and 3.6% and 3.7% in females, respectively. Particularly the percentage decrease of platelet count was significantly higher in females (40.0%) than in males (27.2%). The platelet decrementage and yield were significantly higher in females, but the efficiency did not differ significantly between males and females. The yield showed the lowest levels in subjects who were 40 years old or over but the platelet decrement and efficiency did not change according to age. The platelet decrement increased as height and weight increased. Also, the platelet decrement and yield increased as the initial platelet counts increased, but the efficiency did not. From multiple regression analysis, the platelet decrement was associated with gender, weight, and initial platelet count. The yield was related to the initial platelet count, but the efficiency was not related to gender, age, weight, height or initial platelet counts. This study has a limitation of the generality of the study results since this study was conducted only in a single university hospital. Further study would be necessary to find out a subpopulation that is sensitive to the hematologic change after plateletpheresis, and to determine the standard criteria for blood donation based on the subpopulation.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제17권1호
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• pp.31-36
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• 2014

Purpose: Infliximab (IFX) is considered safe and effective for the treatment of ulcerative colitis (UC) in both adults and children. The aim of this study was to evaluate the short- and long-term clinical course of IFX in Korean children with UC. Methods: Pediatric patients with UC who had received IFX infusions between November 2007 and May 2013 at Samsung Medical Center were retrospectively investigated. The clinical efficacy of IFX treatment was evaluated at 8 weeks (short term) and 54 weeks (long term) after the initiation of IFX treatment using the Pediatric Ulcerative Colitis Activity Index (PUCAI). The degree of response to IFX treatment was defined as complete response (PUCAI score=0), partial response (decrement of PUCAI score${\geq}20$ points), and non-response (decrement of PUCAI score <20 points). Adverse events associated with IFX treatment were also investigated. Results: Eleven pediatric patients with moderate to severe UC had received IFX. The remission rate after IFX treatment was 46% (5/11) and 82% (9/11) at 8 weeks and 54 weeks after IFX treatment, respectively. All patients who were steroid-dependent before treatment with IFX achieved remission at 54 weeks and were able to stop treatment with corticosteroids, while all steroid-refractory patients failed to achieve remission at 54 weeks after treatment with IFX. Conclusion: Response to IFX treatment after 8 weeks may predict a favorable long-term response to IFX treatment in Korean pediatric UC patients.