• 한국측량학회지
• /
• 제13권1호
• /
• pp.13-20
• /
• 1995

수평위치 결정에서 오차해석은 중요하다. 오차해석의 경우 표준오차타원이 정밀도의 척도로써 사용되나, 오차한계의 설정이나 측정치의 합격기준과 상대오차를 비교하는데 한계가 있어, 캐나다나 미국에서는 작업규정 에 95%신뢰타원을 오차한계로 설정하고 있다. 본 연구에서는 수평위치 결정시 신뢰타원을 오차해석에 적용하여 분석하였다. 최소제곱법과 오차해석이론에 대해 검토하였으며 , 컴퓨터 프로그램으로 E.D.M 삼변망에 대해 오차분석을 하였다. 본 연구결과 오차한계의 설정 , 측정치의 합격기준, 상대오차를 비교할 때 95%신뢰타원이 합리적이므로 작업규정에 95％신뢰타원을 도입하는 것이 필요하다. 또한 경제성있는 최적망 설계를 위해 측량망의 예비분석에도 95%신뢰타원이 효과적으로 적용될 수 있다고 사료된다.

• Genomics & Informatics
• /
• 제18권4호
• /
• pp.45.1-45.5
• /
• 2020

With the ongoing rise of coronavirus disease 2019 (COVID-19) pandemic across the globe, interests in COVID-19 antibody testing, also known as a serology test has grown, as a way to measure how far the infection has spread in the population and to identify individuals who may be immune. Recently, many countries reported their population based antibody titer study results. South Korea recently reported their third antibody formation rate, where it divided the study between the general population and the young male youths in their early twenties. As previously stated, these simple point estimates may be misinterpreted without proper estimation of standard error and confidence intervals. In this article, we provide an updated 95% confidence intervals for COVID-19 antibody formation rate for the Korean population using asymptotic, exact and Bayesian statistical estimation methods. As before, we found that the Wald method gives the narrowest interval among all asymptotic methods whereas mid p-value gives the narrowest among all exact methods and Jeffrey's method gives the narrowest from Bayesian method. The most conservative 95% confidence interval estimation shows that as of 00:00 November 23, 2020, at least 69,524 people were infected but not confirmed. It also shows that more positive cases were found among the young male in their twenties (0.22%), three times that of the general public (0.051%). This thereby calls for the quarantine authorities' need to strengthen quarantine managements for the early twenties in order to find the hidden infected people in the population.

• Journal of Radiation Protection and Research
• /
• 제29권4호
• /
• pp.221-230
• /
• 2004

방사선작업종사자에게 발생한 암의 방사선 인과도를 평가하기 위한 통계적 측도로 인과확률(Probability of Causation)이 주로 이용된다. 인과확률의 계산 과정에는 다양한 형태의 불확실성이 존재하며, 따라서 인과확률은 하나의 점추정치(point estimate)가 아니라 여러 불확실성을 반영한 분포 또는 신뢰구간으로 평가되어야 한다. 본 연구에서는 국내 방사선작업종사자에게서 발생한 암의 방사선 인과도를 평가하기 위하여, 한국인의 기저자료를 반영하며 가장 최근에 발표된 NCI-CDC 모형에 근거하여 인과확률의 분포를 계산하도록 개발된 전산 프로그램 RHRI-PEPC를 소개한다. 또한 방사선작업종사자의 가상 피폭시나리오에 대한 모의실험을 통해, 인과확률의 점추정치와 불확실성 분포에 의한 방사선 인과도 평가 결과의 차이를 살펴보고 분포에 의한 평가의 경우 적절한 신뢰도 선택의 필요성을 제시한다.

• 한국ITS학회 논문지
• /
• 제10권1호
• /
• pp.67-75
• /
• 2011

본 논문은 기존의 단일값(점추정)으로 제시하던 검지기 성능평가 결과를 통계적 신뢰구간(구간추정)으로 제시하기 위한 검지기 성능평가 방안을 제시했다. 일반적으로 구간추정은 점추정에 비해 표본 통계의 더 많은 정보를 제공하기 때문에 기존 단일값으로 제시해 오던 검지기 성능평가 결과의 신뢰성을 향상시킬 수 있다. 방법론은 크게 표본 추출, 평가척도 분석, 평가결과 제시의 세 부분으로 나누어진다. 표본추출 방법에는 다양한 통계적 표본 추출 방법이 있지만 교통, 조도, 기상조건에 따라 변화하는 차량검지기 성능의 특성상 층화추출법이 통계적 신뢰구간 제시를 위한 가장 적합한 방법론으로 간주되었다. 또한 기존에 널리 사용된 검지기 성능평가 척도들의 특징을 면밀히 분석하여 평가자로 하여금 해당 검지자료에 적합한 평가척도를 선택할 수 있는 프로세스를 정립하였다. 마지막으로 평가기간 전체(예. 30분)와 개별분석 단위(예. 1분) 평가결과의 통계적 신뢰구간을 반영하기 위한 방법론을 제시했다. 본 연구는 기존 검지기 성능평가 결과의 단일값 제시로 인해 불가능 했던 신뢰구간 제시를 가능하게 함에 따라 검지기 성능평가 결과의 신뢰성을 향상시킬 수 있을 것으로 판단된다.

• 한국수산과학회지
• /
• 제41권2호
• /
• pp.107-112
• /
• 2008

To evaluate uncertainty and risk in biological reference points, we applied a bootstrapping method and a Bayesian procedure to estimate the related confidence intervals. Here we provide an example of the maximum sustainable yield (MSY) of turban shell, Batillus cornutus, estimated by the Schaefer and Fox models. Fitting the time series of catch and effort from 1968 to 2006 showed that the Fox model performs better than the Schaefer model. The estimated MSY and its bootstrap percentile confidence interval (CI) at ${\alpha}=0.05$ were 1,680 (1,420-1,950) tons for the Fox model and 2,170 (1,860-2,500) tons for the Schaefer model. The CIs estimated by the Bayesian approach gave similar ranges: 1,710 (1,450-2,000) tons for the Fox model and 2,230 (1,760-2,930) tons for the Schaefer model. Because uncertainty in effort and catch data is believed to be greater for earlier years, we evaluated the influence of sequentially excluding old data points by varying the first year of the time series from 1968 to 1992 to run 'backward' bootstrap resampling. The results showed that the means and upper 2.5% confidence limit (CL) of MSY varied greatly depending on the first year chosen whereas the lower 2.5% CL was robust against the arbitrary selection of data, especially for the Schaefer model. We demonstrated that the bootstrap and Bayesian approach could be useful in precautionary fisheries management, and we advise that the lower 2.5% CL derived by the Fox model is robust and a better biological reference point for the turban shells of Jeju Island.

• 한국학교보건학회지
• /
• 제1권2호
• /
• pp.34-49
• /
• 1988

The purpose of this study is to identify the status of school health and analyze affecting factors of school nurses' self confidence and nursing activities of the secondary school in Seoul. The data was collected from 13th of August to 30th of October. The self reported questionairs were distributed during one of the school nurses seminars held in Seoul and 93 secondary school nurses answered. Analysis of the data was done utilizing SPSS for percentage, mean, T-test ANOVA and Pearson Correlation Coefficients. The results of study are summerized as follows; 1. General Characteristics The mean age of the subjects was 33.4 and mean length of experience as a school nurse was 7.3 years. 79.5 percent of them had clinical experiences and the mean clinic experience was 2.1 years. The majority of them were graduate of the baccalaureate nursing programs and 82.8 percent of them were married. 72.0 percent of the sample had religion, and 60.2 percent of them were in the national or public schools. 90.3 percent of them had independent duty. 2. The status of school health resources In average, there were 2,445 students, 37 classes and 63 teachers per school nurse. 48.4 percent of them were aware of the school budget. The budget for school health was 585,000 won per school in average. 30.0 percent of the schools had school health organization. The schools whose health clinics were on the first floor consisted of 79.3 percent, among them 42.9 percent were on the center of the building office. 3. Activities of school health nursing The average number of students using health clinic were 430 per month. The majority of the problem was digestive problem. There were 7.5 times of mean correspondences with parents per year. The activities of the school nurses were clinic management (29.0%), health care services (23.5%) and health education (14.1%). 4. The degrees of self confidence of the school nurse and nursing activities Self confidence measured by 6 items of self-reported questionaires scored by 4 point Likert Scale revealed. The nurses' self-confidence was 2.922 in clinic management, 2.909 in health education, 2.759 in program planning and evaluation, 2.757 in health care services, 2.692 in management of school environment, and 2.250 in operation of school health organization. The nursing activities scored by 2 point. The nursing activities was 1,870 in program planning and evaluation, 1.853 in health education, 1.843 in clinic management, 1.739 in health care services, 1.696 in management of school environment and 1.265 in operating of school health organization. 5. Factors affecting self confidence and nursing activities of school nurses The general characteristics of the school nurses and the school health resources were related to self confidence and nursing activities. The most significant variable to nurses' self confidence was type of the school ownership and the presence of school health organization was the most significant factor to nursing activities.

• 대한안전경영과학회지
• /
• 제10권2호
• /
• pp.205-210
• /
• 2008

The research interprets the principles of sampling error design for quality statistics models such as hypothesis test, interval estimation, control charts and acceptance sampling. Introducing the proper discussions of the design of significance level according to the use of hypothesis test, then it presents two methods to interpret significance by Neyman-Pearson and Fisher. Second point of the study proposes the design of confidence level for interval estimation by Bayesian confidence set, frequentist confidential set and fiducial interval. Third, the content also indicates the design of type I error and type II error considering both productivity and customer claim for control chart. Finally, the study reflects the design of producer's risk with operating charistictics curve, screening and switch rules for the purpose of purchasing and subcontraction.

• 한국유기농업학회지
• /
• 제21권4호
• /
• pp.487-500
• /
• 2013

The purpose of this study is to estimate efficiency of environmental-friendly agricultural product by using Data Envelopment Analysis. A proposed method employs a bootstrapping approach to generating efficiency estimates through Monte Carlo simulation resampling process. The technical efficiency, pure technical efficiency, and scale efficiency measure of strawberry by pesticide-free certification is 0.967, 0.995, 0.968 respectively. However those of bias-corrected estimates are 0.918, 0.983, 0.934. We know that the DEA estimator is an upward biased estimator. In technical efficiency, average lower and upper confidence bounds of 0.807 and 0.960. According to these results, the DEA bootstrapping model used here provides bias-corrected and confidence intervals for the point estimates, it is more preferable.

• 산업공학
• /
• 제22권3호
• /
• pp.214-222
• /
• 2009

In the early design stage, system reliability must be estimated from life testing data at the component level. Previously, a point estimate of system reliability was obtained from the unbiased estimate of the component reliability after assuming that the number of failed components for a given time followed a binomial distribution. For deriving the confidence interval of system reliability, either the lognormal distribution or the normal approximation of the binomial distribution was assumed for the estimator of system reliability. In this paper, a new estimator is used for the component level reliability, which is biased but has a smaller mean square error than the previous one. We propose to use the beta distribution rather than the lognormal or approximated normal distribution for developing the confidence interval of the system reliability. A numerical example based on Monte Carlo simulation illustrates advantages of the proposed approach over the previous approach.

• International Journal of Quality Innovation
• /
• 제6권2호
• /
• pp.31-45
• /
• 2005

The target costing technique, mathematically discussed by Sauers, only uses the $C_p$ index along with Taguchi loss function and ${\bar{X}}-R$ control charts to set up goal control limits. The new specification limits derived from Taguchi loss function is linked through the $C_p$ value to ${\bar{X}}-R$ control charts to obtain goal control limits. This study further considers the reflected normal loss function as well as the $C_{pk}$ index along with its lower confidence interval in forming goal control limits. With the use of lower confidence interval to replace the point estimator of the $C_{pk}$ index and reflected normal loss function proposed by Spiring to measure the loss to society, this modified and improved target costing technique would become more robust and applicable in practice. Finally, an example is provided to illustrate how this modified and improved target costing technique works.