• Journal of Advanced Research in Ocean Engineering
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• 제4권4호
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• pp.185-194
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• 2018

In this study, the extreme sloshing pressure was predicted using various statistical models: three-parameter Weibull distribution, generalized Pareto distribution, generalized extreme value distribution, and three-parameter log-logistic distribution. The estimation of sloshing impact pressure is important in design of liquid cargo tank in severe sea state. In order to get the extreme values of local impact pressures, a lot of model tests have been carried out and statistical analysis has been performed. Three-parameter Weibull distribution and generalized Pareto distribution are widely used as the statistical analysis method in sloshing phenomenon, but generalized extreme value distribution and three-parameter log-logistic distribution are added in this study. Additionally, statistical distributions are fitted to peak pressure data using three different parameter estimation methods. The data were obtained from a three-dimensional sloshing model text conducted at Seoul National University. The loading conditions were 20%, 50%, and 95% of tank height, and the analysis was performed based on the measured impact pressure on four significant panels with large sloshing impacts. These fittings were compared by observing probability of exceedance diagrams and probability plot correlation coefficient test for goodness-of-fit.

• Journal of Photoscience
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• 제12권2호
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• pp.101-107
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• 2005

Infrared multiphoton dissociation of $CHCl_2F$ was studied using $CO_2$ laser excitation. Three products, $C_2Cl_2F_2$, $C_2ClF_3$, and $C_2HClF_2$, were identified by the analysis of the gas mixture from the photoreaction of $CHCl_2F$. The dependence of the reaction probability on added Ar gas pressure and excitation laser pulse energy was investigated. At low pressure (< 10 torr), the reaction probability increased as Ar pressure increased due to the rotational hole-filling effect, while it diminished with the increase of Ar pressure at high pressure (> > 20 torr) due to the collisional deactivation. The ratio of two products $(C_2ClF_3/C_2Cl_2F_2)$ decreased at low pressure (< 10 torr) and increased at high pressure (> 20 torr) with the increase of Ar pressure. The log-log plot of the reaction probability vs. laser pulse energy (${\\phi}$) was found to have a linear relationship, and its slope decreased as the added Ar pressure was increased. The reaction mechanisms for product formation have been suggested and validated by experimental evidences and considering the energetics. Fluorine-chlorine exchange reaction in the intermediate complex has been suggested to explain the formation of $C_2ClF_3$.

• 한국세라믹학회지
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• 제36권10호
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• pp.1062-1068
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• 1999

상온 25$^{\circ}C$의 증류수에 단일 열충격을 시행한 후 ball-on-3 ball test로 강도를 측정하고 강도의 변화를 관찰하였다. 시편은 상용 알루미나 시편을 사용하였고, disc 형태의 시편에 대하여 열충격 후의 균열의 모양과 강도 시험 후의 균열의 모양을 잉크 침투법에 의해 관찰하였다. 통계적인 파괴 확률방법을 제시하였으며, thermal shock Weibull plot을 이용하여 3점 꺾임 강도와 비교하였다. ball-on-3 ball test 강도에 미치는 인자에 대해 통계학적인 접근을 통해 관찰한 결과, 시편중심에서 균열까지의 거리가 균열 밀도보다 더 큰 영향을 미치고 있음을 알 수 있었다.

• Journal of Photoscience
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• 제10권3호
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• pp.225-229
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• 2003

The fluorescence quenching of 5-methyl-3-phenyl-2-[s-oxadiazol-2'-thionen5'-yl] indole by carbon tetrachloride ($CCl_4$) and aniline in different solvents viz., dioxane, benzene, toluene, methanol, propanol has been carried out at room temperature to understand the role of quenching mechanisms. The Stern-Volmer plots have been found to be linear. As probability of quenching per encounter 'p' is less than unity, and the activation energy for quenching 'E$_{a}$' is greater than the activation energy of diffusion 'E$_{d}$', it is inferred that the fluorescence of quenching mechanism is not due to material diffusion alone.e.e.

• 품질경영학회지
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• 제40권1호
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• pp.15-24
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• 2012

For the construction of fractional factorial designs, the various arrays can be widely used. In this paper we review the statistical properties of fractional designs constructed by two arrays such as orthogonal array and partially balanced array, and develop a quick and easy method for analyzing unreplicated saturated designs. The proposed method can be characterized that we control the error rate by experiment-wise way and exploit the multivariate Student $t$-distribution. Especially the proposed method can be used efficiently together with some exploratory analysis methods, such as half normal probability plot method.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.366-368
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• 2007

In this paper, the Time-varying Failure Rate (TFR) of power distribution system equipment is extracted from the recorded failure data of Korea Electric Power Corporation (KEPCO). For TFR extraction, it is used that the fault data accumulated by KEPCO during 10 years. The TFR is approximated to bathtub curve using the exponential (random failure) and Weibull (aging failure) distribution function. In addition, Kaplan-Meier estimation is applied to TFR extraction because of incomplete failure data of KEPCO. Finally, Probability plot and regression analysis is applied. It is presented that the extracted TFR is more effective and useful than Mean Failure Rate (MFR) through the comparison between TFR and MFR.

• 산업기술연구
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• 제31권B호
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• pp.107-112
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• 2011

Recently, climate change around the world due to global warming has became an important issue and damages by climate change have a bad effect on human life. Changes of Sea Surface Temperature(SST) is associated with natural disaster such as Typhoon and El Nino. So we predicted daily future SST using Statistical Downscaling Method and CGCM 3.1 A1B scenario. 9 points of around Korea peninsular were selected to predict future SST and built up a regression model using Multiple Linear Regression. CGCM 3.1 was simulated with regression model, and that comparing Probability Density Function, Box-Plot, and statistical data to evaluate suitability of regression models, it was validated that regression models were built up properly.

• 한국정밀공학회지
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• 제19권12호
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• pp.179-184
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• 2002

In this study, we developed a portable device which can monitor and analyze vibration signals from machines. This system consists a PDA loading the program for vibration analysis and A/D board for vibration acquisition. A PDA is smaller than the palm of the hand, but it has a powerful computing ability as much as an IBM compatible PC with a Pentium 100MHz CPU. The A/D board developed in this study supports LAN interface using TCP/IP communication protocol. The application program for vibration analysis includes signal processing module, fault diagnosis module, data store module, and plot display module. MS visual embedded C＋＋ 3.0 was used to developed the program.

• Communications for Statistical Applications and Methods
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• 제30권1호
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• pp.21-35
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• 2023

Metabolic syndrome is a serious disease that can eventually lead to various complications, such as stroke and cardiovascular disease. In this study, we aimed to identify the risk factors related to metabolic syndrome for its prevention and recognition and propose a nomogram that visualizes and predicts the probability of the incidence of metabolic syndrome. We conducted an analysis using data from the Korea National Health and Nutrition Survey (KNHANES VII) and identified 10 risk factors affecting metabolic syndrome by using the Rao-Scott chi-squared test, considering the characteristics of the complex sample. A naïve Bayesian classifier was used to build a nomogram for metabolic syndrome. We then predicted the incidence of metabolic syndrome using the nomogram. Finally, we verified the nomogram using a receiver operating characteristic curve and a calibration plot.

• Weed & Turfgrass Science
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• 제7권3호
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• pp.275-282
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• 2018

억새(Miscanthus spp.)는 경관성이 우수하고 환경친화적이며 저관리가 가능한 종 들로 알려져 있다. 플러그묘를 통한 대량번식을 위해 4가지 품종의 억새(M. sinensis 'Andersson', 'Strictus', 'Gracillimus', 'Variegatus')와 삽목번식을 위한 3가지 품종의 억새(M. sinensis 'Gracillimus', M. xgiganteus, M. sacchariflorus)를 예비실험을 통해 선발하여 플러그 형성, 정식 후의 생육, 그리고 삽목 활착률 실험을 2015-2016년에 온실과 실험포장에서 실시하였다. 2가지 관수방법과 3가지 플러그 셀 크기로 종자로부터 플러그묘 형성과정 실험에서는 매트를 이용한 저면관수와 작은 크기의 플러그 셀이 양호한 결과를 보였다. 삽목실험에서 삽수채취 시기, 마디 부위, 삽수의 직경이 활착율에 미치는 영향을 분석한 결과 억새 공시 3종 모두 하부 마디에서 채취한 삽수가 높은 활착율을 보였으며 삽수 채취 시기는 화서가 발생 하기 전 그리고 목질화가 진행되어 삽수의 직경이 작은 하부마디가 높은 활착율을 보였다. 생존율의 차이가 뚜렷한 M. xgiganteus는 삽수채취 시기와 삽수 부위 및 삽수 직경에 따른 삽목의 성공여부(생존 혹은 고사)는 이분형 로지스틱 회귀모델(dichotomous logistic regression model)을 이용하여 분석 판정하였다. 그 결과 삽목 시기는 7월이 6월에 비하여 1.64배 정도 활착 성공률이 높았으며, 삽수 채취 마디부위는 1번째 마디를 기준으로 승산비(성공율/실패율)는 3번째 마디와 5번째 마디는 0.12와 0.02로, 각각 8배와 50배의 활착 실패율을 보였다. 즉 늦게 발달한 상대적으로 굵은 신생 줄기 마디는 목질화가 진행된 묵은 마디에 비해 직경은 크지만 생존율은 낮아졌다. 따라서 억새속 삽목번식은 화서가 분화되기 시작하는 9월 이전에 아래쪽 묵은 마디로 삽수로 사용하여 대량 번식을 하는 것이 바람직하다고 판단된다.