• Communications for Statistical Applications and Methods
• /
• 제4권1호
• /
• pp.33-39
• /
• 1997

Tsutakawa(1988) proposed a mixed model for using empirical Bayes method to study the geographic variability in mortality rates of a disease. In particular cases of the analysis in mortality rate, we need to consider the effect of time. If observed data are collected annually for the time period, then time effect will be emphasized. Here, an extended model for estimating the geographic effect and the mortality rates of the disease with time effect is proposed.

• 한국초등수학교육학회지
• /
• 제22권3호
• /
• pp.221-240
• /
• 2018

본 연구는 그동안 선행연구에서 거의 다루어지지 않았던 초등학교 저학년 대상의 학교 통계교육 개선 방향을 살펴보기 위해, 현행 2015 개정 수학과 교육과정 중 초등학교 1~2학년군에서 다루고 있는 자료의 분류 및 표현 활동에 주목하였다. 구체적으로 통계적 소양 교육의 실천을 위한 핵심 개념으로서 통계적 문제해결과 변이성을 바탕으로 자료의 분류와 표현 활동이 지니는 의의를 분석하였다. 연구 결과자료의 분류 및 표현 활동은 통계적 문제해결을 위한 기능 외에, 변이성을 인식하고 분포를 표현하여 자료 정리 과정에서 자료의 의미를 구성하는 통계적 소양으로서 의의가 있음을 확인할 수 있었다. 이러한 의의는 실용 통계교육을 지향하는 2015 개정 수학과 교육과정 문서 및 교과서에도 반영되어 있었다. 이를 통해, 초등학교 저학년에서 다루어지는 자료의 분류 및 표현 활동을 통계적 소양 교육으로 구현하기 위한 제언을 도출하였다.

• Communications for Statistical Applications and Methods
• /
• 제7권3호
• /
• pp.773-788
• /
• 2000

Statistical process control (SPC) and engineering process control (EPC) are based on different strategies for processes quality improvement. SPC reduces process variability by detecting and eliminating special causes of process variation. while EPC reduces process variability by adjusting compensatory variables to keep the quality variable close to target. Recently there has been needs for a process control proceduce which combines the tow strategies. This paper considers a combined scheme which simultaneously applies SPC and EPC techniques to reduce the variation of a process. The process model under consideration is an integrated moving average(IMA) process with a step shift. The EPC part of the scheme adjusts the process back to target at every fixed monitoring intervals, which is referred to a repeated adjustment scheme. The SPC part of the scheme uses an exponentially weighted moving average(EWMA) of observed deviation from target to detect special causes. A Markov chain model is developed to relate the scheme's expected cost per unit time to the design parameters of he combined control scheme. The expected cost per unit time is composed of off-target cost, adjustment cost, monitoring cost, and false alarm cost.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 추계 학술발표회
• /
• pp.85-110
• /
• 2008

Ground investigation data to be used as a basis for geotechnical analysis and foundation design are usually troubled with large uncertainty, due to natural variability and limited number of data. Statistical methods can be a rational tool for handling such uncertain ground data, in particular with a view to the selection of characteristic values for estimating ground design parameters used in design. The characteristic values of soil properties for use in geotechnical design have oftenly based on not only a subjective judgment but also engineer's past acumulated experience. This paper discussed some statistical methods which can handle such intrinsic ground uncertainty data with a case design in a rational manner.

• 대한물리치료과학회지
• /
• 제10권1호
• /
• pp.206-211
• /
• 2003

The purpose of this study is the effect of massage therapy on the human autonomic nerve system by heart rate variability spectral analysis. This study were to effect autonomic nerve system before and after massage therapy in 12 health peoples. The effect of massage therapy were assessments through Heart Rate Variability (HRV; SA-2000E, Medicare, Korea) before and after the massage therapy by same massage therapist. Statistical techniques for data analysis were applied paired t-test. The 0.05 level of significance was used as the critical level for rejection of the null hypotheses for the study. On the basis of the results analyzed in this study, conclusions were drawn as follows; Rest Heart Rate was significantly decreased before and after massage therapy, but other variable were no statistical significances. These results suggest that massage therapy maybe be effective in reducing heart rate and activity in valgal tone.

• 천문학회지
• /
• 제48권5호
• /
• pp.313-323
• /
• 2015

Active galactic nuclei (AGN) are known for irregular variability on all time scales, down to intra-day variability with relative variations of a few percent within minutes to hours. On such short timescales, unexplored territory, such as the possible existence of a shortest characteristic time scale of activity and the shape of the high frequency end of AGN power spectra, still exists. We present the results of AGN single-dish fast photometry performed with the Korean VLBI Network (KVN). Observations were done in a “anti-correlated” mode using two antennas, with always at least one antenna pointing at the target. This results in an effective time resolution of less than three minutes. We used all four KVN frequencies, 22, 43, 86, and 129 GHz, in order to trace spectral variability, if any. We were able to derive high-quality light curves for 3C 111, 3C 454.3, and BL Lacertae at 22 and 43 GHz, and for 3C 279 at 86 GHz, between May 2012 and April 2013. We performed a detailed statistical analysis in order to assess the levels of variability and the corresponding upper limits. We found upper limits on flux variability ranging from ~1.6% to ~7.6%. The upper limits on the derived brightness temperatures exceed the inverse Compton limit by three to six orders of magnitude. From our results, plus comparison with data obtained by the University of Michigan Radio Astronomy Observatory, we conclude that we have not detected source-intrinsic variability which would have to occur at sub-per cent levels.

• Journal of the Korean Data and Information Science Society
• /
• 제18권3호
• /
• pp.645-657
• /
• 2007

Several statistical procedures for assessment of bioequivalence of variabilities between two drug formulations in bioequivalence trials are reviewed and modified methods for assessing total variability are suggested. The problem of the current US FDA aggregate criterion for population bioequivalence and the necessity of disaggregate criterion are discussed with an illustrated example.

• Journal of the Korean Statistical Society
• /
• 제33권4호
• /
• pp.381-399
• /
• 2004

Statistical process control (SPC) and engineering process control (EPC) are based on different strategies for process quality improvement. SPC re-duces process variability by detecting and eliminating special causes of process variation, while EPC reduces process variability by adjusting compensatory variables to keep the quality variable close to target. Recently there has been need for an integrated process control (IPC) procedure which combines the two strategies. This paper considers a scheme that simultaneously applies SPC and EPC techniques to reduce the variation of a process. The process model under consideration is an IMA(1,1) model with a step shift. The EPC part of the scheme adjusts the process, while the SPC part of the scheme detects the occurrence of a special cause. For adjusting the process repeated adjustment is applied according to the predicted deviation from target. For detecting special causes the exponentially weighted moving average control chart is applied to the observed deviations. It was assumed that the adjustment under the presence of a special cause may increase the process variability or change the system gain. Reasonable choices of parameters for the IPC procedure are considered in the context of the mean squared deviation as well as the average run length.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1996년도 춘계학술대회
• /
• pp.27-30
• /
• 1996

PR interval variability has been proposed as a noninvasive tool for in-vestigating the autonomic nervous system as welt as heart rate variability. The goal of this paper is to determine whether PR interval variability is generated from deterministic nonlinear dynamics. The data used in this study is a 24-hour bolter ECGs of 20 healthy adults. We developed an automatic PR interval measurement algorithm, and tested it using MIT ECG Databases. The general discriminants of nonlinear dynamics, such as, correlation dimension and phase space reconstruction are used. Surrogate data is generated from simpler linear models to have similar statistical characteristics with the original data. Nonlinear discriminants are applied to both data, and compared for any significant results. It was concluded that PR interval variability shows non-linear characteristics.

• 한국수자원학회논문집
• /
• 제43권5호
• /
• pp.483-493
• /
• 2010

본 연구에서는 국내 기상관측소 중 관측년수가 30년 이상인 관측소 63개 지점에 대한 5개의 수문기상수문인자 즉, 연강수량, 연강수일수, 연평균기온, 연평균상대습도, 연일조시간 자료를 각 지점별로 수집하고, 통계학적 기법인 Wald-Wolfowitz 검정, Mann-Whitney 검정을 이용하여 변동성 분석과 Wavelet Transform을 이용하여 주기성을 분석하였다. 변동성 분석결과 연평균상대습도, 연평균기온에서 공통적으로 변동성이 나타났으며, 연강수량, 연강수일수, 연일조시간은 지역에 따라 상이한 결과를 보였다. 주기성 분석에서는 연강수량, 연강수일수에서 각 지점별로 주기가 나타났으나, 연평균기온, 연평균상대습도, 연일조시간에서는 뚜렷한 주기가 나타나지 않았다.