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

• Journal of Magnetics
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• 제17권3호
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• pp.206-209
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• 2012

Peak interval for reversible permeability is presented for nondestructively evaluating the remanent life of 1Cr-0.5Mo steel. The method to measure the peak interval of reversible permeability is based on the value of reversible permeability is the same as the differential value of the hysteresis loop. The measurement principle is based on the first harmonics voltage induced in a sensing coil using a lock-in amplifier tuned to a frequency of the exciting voltage. Results obtained for the peak interval of reversible permeability and Rockwell hardness on the aged samples decrease as aging time and the Larson-Miller parameter increase. We could estimate the remanent life of 1Cr-0.5Mo steel by using the relationship between the peak interval of reversible permeability and the Larson-Miller parameter, nondestructively.

• 품질경영학회지
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• 제26권4호
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• pp.124-142
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• 1998

It is essential to have a correct measurement system assessment to help improve process or quality. In this paper, we emphasize that a confidence interval a, pp.oach for the parameters of measurement error study and GR&R is crucial and a simple a, pp.oach for constructing them is presented. We also discuss on the issue of linearity of the gauge. Next, we try to reveal the relationship between measurement error and the process capability index. Finally some aspects of conducting the measuring experiment concerning the number of parts, number of measurements per part, and recommendations on how the experiment is to be performed will be considered.

• 품질경영학회지
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• 제35권1호
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• pp.10-19
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• 2007

ANOVA is widely, used for measurement system analysis. It assumes that the measurement error is normally distributed, which nay not be seen in some industrial cases. In this study the estimates of the measurement system variability and PTR (precision-to-tolerance ratio) are obtained by using weighted standard deviation for the case where the measurement error is non-normally distributed. The Standard Bootstrap method is used foy estimating confidence intervals of measurement system variability and PTR. The point and confidence interval estimates for the cases with normally distributed measurement error are compared to those with non-normally distributed measurement errors through computer simulation.

• Communications for Statistical Applications and Methods
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• 제11권1호
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• pp.181-187
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• 2004

One of objectives in epidemiologic studies is to detect the amount of change caused by a specific risk factor. Risk ratio is one of the most useful measurements in epidemiology. When we perform the inference for this measurement with rare events, the standard approach based on the normal approximation may fail, in particular when there are no disease cases observed. In this paper, we discuss and evaluate several existing methods for constructing a confidence interval of risk ratio through simulation when the disease of interest is a rare event. The results in this paper provide guidance with how to construct interval estimates for risk difference and risk ratio when there are no disease cases observed.

• 한국환경과학회지
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• 제21권3호
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• pp.289-296
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• 2012

The purpose of this study was to identify the irrigation intervals and the amount of suitable growing substrate needed to achieve the desired shallow-extensive green roof system during a dry summer in Korea. In terms of treatment, three types (SL, $P_6P_2L_2$, $P_4P_4L_2$) with varying soil mixture ratios and two types (15 cm, 25 cm) with varying soil depths were created. The results have been analyzed after measuring growth and soil water contents. The difference of growth by treatment was significant in terms of green coverage, height, leaf width and photosynthesis. In measurement of chlorophyll content, no difference was detected when measured against soil depth. According to the growth measurement of Zoysia japonica with respect to differing soil mixture ratios in the 15 cm-deep treatment, a statistical difference was detected at the 0.05 significance level in photosynthesis. In case of green coverage, height, chlorophyll content and leaf width, no statistical significance was observed. In case of the 25 cm-deep treatment, a statistical significance was observed in height and photosynthesis. In terms of green coverage, chlorophyll content and leaf width, no statistical significance was detected. In comparisons of soil moisture tension and soil water contents, the irrigation interval and amount were 8 days and 14.9 L in the SL (15 cm) treatment, respectively. The irrigation interval showed for 10 days a 1.3-fold increase, and the irrigation amount was 27.4 L 1.8-fold more than SL (25 cm), respectively. For $P_6P_2L_2$ (15 cm) treatment, the irrigation interval and amount were 12 days and 20.7 L, respectively. However, an irrigation interval under $P_6P_2L_2$ (25 cm) was for 15 days 1.3 times longer than $P_6P_2L_2$ (15 cm), and an irrigation amount of 40 L was 1.9 times more than that under $P_6P_2L_2$ (15 cm). In $P_4P_4L_2$ (15 cm) treatment, it was indicated that the irrigation interval was 15 days, and the irrigation amount was 19.2 L. It was not needed to irrigate for 16 days under $P_4P_4L_2$ (25 cm) treatment during the dry summer and the longest no-rain periods. The irrigation interval and amount under $P_4P_4L_2$ were 1.8-fold and 1.3-fold, respectively, more than SL treatment as affected by soil mixture ratio. Comparatively $P_4P_4L_2$ had more 1.3-fold and 0.9-fold in irrigation interval and amount more than $P_6P_2L_2$. Therefore, it can be noted that different soil depth and soil mixture ratios had a significant effect on the irrigation interval and amount.

• 대한수의학회지
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• 제44권4호
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• pp.649-653
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• 2004

To estimate the source of variance components for some hematological parameters and assess the utility of the conventional population-based reference interval, this study computed index of individuality for blood samples, which were from 13 dogs drawn once weekly for 4 consecutive weeks. Results were subjected to nested analysis of variance. For all parameters measured between-dog variations were greater than within-dog variation. Except for the parameters RBC and MCHC the index of individuality was <1.4. The low reliability coefficient and high index of individuality of ${\leq}0.8$ were found for the majority of hematological parameters. In practical term, the present study indicated that use of hemogram profiles alone in the evaluating clinical state of a single patient should be avoided because of their physiological or natural random variations, and that comparing a single measurement on the blood analytes from an individual dog to the conventional population-based reference range may be too insensitive to detect any significant changes in the blood components of that particular dog. A single measurement may not characterize an individual's average concentration of the parameters even shortterm period.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 1997년도 한국감성과학회 연차학술대회논문집
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• pp.85-89
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• 1997

We present several biosignal measurement results and analysis algorithms for the visual stimulus from International Affective Picture Sytem. Sine human body is nonlinear dynamic system, we investigated both linear and nonlinear methods. We found that the alpha wave of EEG, the chaos of peripheral blood pressure, the LF/HF of HRV and thd retutn map of RR interval were good parameters for the measuremet of human sensibility. These can be used as the parameters for the measurement of human sensibility.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2006년도 추계 학술대회
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• pp.199-204
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• 2006

ANOVA is widely used for measurement system analysis. It assumes that the measurement error is normally distributed, which may not be seen in some industrial cases. In this study, the estimates of the measurement system variability and PTR (precision-to-tolerance ratio) are obtained by using weighted standard deviation for the case where the measurement error is non-normally distributed. The Standard Bootstrap method is used for estimating confidence intervals of measurement system variability and PTR. The point and confidence interval estimates for the cases with normally distributed measurement error are compared to those with non-normally distributed measurement errors through computer simulation.

• 대한기계학회논문집B
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• 제40권10호
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• pp.653-658
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• 2016

본 연구에서는 비정상 열전도 역산문제의 해석이 가능한 프로그램을 이용하여 온도측정의 시간간격, 측정위치가 분무냉각 열유속의 측정결과에 미치는 영향에 대한 연구를 수행하였다. 그 결과 다음과 같은 결론을 얻을 수 있었다. CHF 부근에서는 온도측정의 시간간격이 커질수록 비정상 열전도 역산법을 이용하여 계산한 열유속은 점차 감소하고 있음을 알 수 있었다. CHF 부근에서는 열유속이 매우 빠르게 변화하기 때문에 시간간격을 일정 값 이하로 작게 측정하여 열유속을 계산하는 것이 매우 중요할 것으로 판단된다. 온도측정위치는 비정상 열전도 역산법을 이용한 CHF 부근의 계산결과에 큰 영향을 미치지 않는 것으로 파악되었다. 실험결과로부터 CHF 과열도는 열전대의 측정위치가 전열면 표면에 가까울수록 약간 고온으로 이동하는 경향이 있음을 알 수 있었다.