• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.80-89
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• 2014

A stochastic optimal power flow (S-OPF) model considering uncertainties of load and wind power is developed based on chance constrained programming (CCP). The difficulties in solving the model are the nonlinearity and probabilistic constraints. In this paper, a limit relaxation approach and an iterative learning control (ILC) method are implemented to solve the S-OPF model indirectly. The limit relaxation approach narrows the solution space by introducing regulatory factors, according to the relationship between the constraint equations and the optimization variables. The regulatory factors are designed by ILC method to ensure the optimality of final solution under a predefined confidence level. The optimization algorithm for S-OPF is completed based on the combination of limit relaxation and ILC and tested on the IEEE 14-bus system.

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

• 품질경영학회지
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• 제35권3호
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• pp.107-117
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• 2007

The fatigue has been considered the most failure mode of metal, ceramic, and composite materials. In this paper, numerical experiments to asses the usefulness of two Dixon's methods(small and large samples) and 14 S-N methods on assumptions of lognormal fatigue limit distribution under RFL(Random Fatigue Limit) model are conducted for staircase(or up-and-down) test and compared by MSE(Mean Squared Error) and bias for estimates of mean log-fatigue limit. Also, guidelines for staircase test plans to choose initial stress level and step size are recommended from numerical experiments including sensitivity analyses. In addition, the parametric bootstrap method to construct a confidence interval for the mean of log-fatigue limit by the percentile method using a transition probability matrix of Markov chain is presented and illustrated with an example.

• Structural Engineering and Mechanics
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• 제67권6호
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• pp.587-601
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• 2018

Elevated water tanks are inverted pendulum type structures where drift limit is an important criterion for seismic design and performance evaluation. Explicit drift criteria for elevated water tanks are not available in the literature. In this study, probabilistic approach is used to determine maximum drift limit for damage state of yielding and damage state of collapse for the elevated water tanks supported on RC frame staging. The two damage states are defined using results of incremental dynamic analysis wherein a total of 2160 nonlinear time history analyses are performed using twelve artificial spectrum compatible ground motions. Analytical fragility curves are developed using two-parameter lognormal distribution. The maximum allowable drifts corresponding to yield and collapse level requirements are estimated for different tank capacities. Finally, a single fragility curve is developed which provides maximum drift values for the different probability of damage. Further, for rational consideration of the uncertainties in design, three confidence levels are selected and corresponding drift limits for damage states of yielding and collapse are proposed. These values of maximum drift can be used in performance-based seismic design for a particular damage state depending on the level of confidence.

• Journal of Radiation Protection and Research
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• 제24권3호
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• pp.171-184
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• 1999

본 논문에서는 저준위 환경방사능 측정시 이용되는 검출한계에 대한 기본개념 및 수식을 통계학적 이론을 기초로 서술하였다. 방사능을 정확하게 검출할 신뢰도를 95%로 설정하여 알파 베타 및 감마선 측정기에 대한 검출한계치값을 계산하였다. 또한 환경 방사능 계측에 많이 사용되는 방사능 핵종에 대해 최소 검출 방사능 농도값을 검출한계치 개념을 근거로 계산하여 저준위 환경 방사능 분석시 환경방사능 측정결과에 대한 신뢰도 평가에 활용 가능 하도록 하였다.

• Structural Engineering and Mechanics
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• 제82권3호
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• pp.271-282
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• 2022

The active learning surrogate model based on adaptive sampling strategy is increasingly popular in reliability analysis. However, most of the existing sampling strategies adopt the trial and error method to determine the size of the Monte Carlo (MC) candidate sample pool which satisfies the requirement of variation coefficient of failure probability. It will lead to a reduction in the calculation efficiency of reliability analysis. To avoid this defect, a new method for determining the optimal size of the MC candidate sample pool is proposed, and a new structural reliability analysis method combining polynomial chaos-based Kriging model (PC-Kriging) with adaptive sampling region is also proposed (PCK-ASR). Firstly, based on the lower limit of the confidence interval, a new method for estimating the optimal size of the MC candidate sample pool is proposed. Secondly, based on the upper limit of the confidence interval, an adaptive sampling region strategy similar to the radial centralized sampling method is developed. Then, the k-means++ clustering technique and the learning function LIF are used to complete the adaptive design of experiments (DoE). Finally, the effectiveness and accuracy of the PCK-ASR method are verified by three numerical examples and one practical engineering example.

• 한국응급구조학회지
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• 제15권2호
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• pp.43-54
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• 2011

Purpose: The purpose of this study was to explore EMT-paramedic students' experience of simulation education and analyze the confidence before and after education, learning attitude and course evaluation. Method: Research survey was conducted on 38 EMT-paramedic students during November, 2011 and EMT-paramedic students' experience of simulation education was analyzed after applying head, spinal, and chest injury scenario. The confidence before and after education, learning attitude and course evaluation in gender were analyzed by Mann-Whitny U test and the difference of confidence before and after education was analyzed by Wilcoxon signed rank test and learning attitude & course evaluation were analyzed by evaluating frequency, percentage, mean, standard deviation by using SPSS WIN 17.0 program. Results: 1. Students experienced various advantages such as increasing interest and self-reflection on learning, critical thinking ability, and EMT-paramedic-role experience and recognition of importance of teamwork. Students also pointed out disadvantages such as gap between real situation and simulation, limit of time and equipments, and burden of demonstration. 2. The confidence between before and after education, learning attitude and course evaluation in gender were not significant different statistically. 3. Confidence mean score elevated from 5.53(before education) to 5.87(after education), but the difference in their confidence did not show significant difference statistically. 4. Total mean score in learning attitude after simulation education was 3.70 out of 5.00, which is considerably very high. 5. Total mean score in course evaluation was 3.89 with score of 3.83 in evaluation in learning environment and 3.99 in evaluation of debriefing. Conclusion: The finding of this study demonstrate that the simulation education can provide a safe and repetitive practice environment, improve problem-solving ability and critical thinking, and increase the confidence in prehospital emergency care; therefore, simulation may be the new effective EMT-paramedic education strategy.

• 한국정보시스템학회지:정보시스템연구
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• 제23권2호
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• pp.1-23
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• 2014

Companies are required to have adequate understanding and awareness of a partner company within the supply chain, together with the understanding of the imbalance consequent on power types. Therefore, this study intends to look into the power types and make clear their influence on confidence & commitment and causal relationship that is linked to SCM user satisfaction. The concrete research results are as follows. First, the result showed that none of the behavioral coercive, high-handed reward, and relative legitimacy in terms of Mediated power had a significant influence on confidence and commitment. Like this, the result explains that there is a limit to forcibleness power in forming a continuous, long-term relationship. Second, business expertise, professional information and value reference in terms of Non-Mediated power were all found to have a significant influence on confidence and commitment. This could be judged as having an intention of aggressively accepting a partner company's expertise, information strength and imitable culture, etc. Third, both confidence and commitment was found to have a significant influence on SCM user satisfaction.

• 한국대기환경학회지
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• 제22권1호
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• pp.117-126
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• 2006

The purpose of this study is to develop a badge-type passive sampler for the measurement of short-term nitrogen dioxide and to evaluate its performance. The principle of the method is a colorimetric reaction of nitrogen dioxide with sulfanilic acid, N-1-naphthylethylendiamine, and phosphoric acid. First, it has been shown that the filter paper should be rinsed with ultrapure water and ultrasound, and then dried in a vacuumed desiccator. The concentration and volume of absorption reagent (triethanolamine) were $20\%$ and 100 ${\mu}L$, respectively. The extraction time was determined as 60 min. Second, duplicate measurements (n= 116) were carried out for evaluating the precision of the passive sampler. The relative error and the correlation coefficient between duplicates are $3.4\pm 3.0\%$ and 0.994, respectively. In addition, the $95\%$ confidence interval of intraclass correlation coefficient and the estimated value are 0.992$\sim$0.996 and 0.994, respectively. Third, a paired t-test was carried out for evaluating the accuracy of the passive sampler (n=40). In the result of the test, the $95\%$ confidence interval of the difference was -1.710 ppb <$\gamma$< 0.788 ppb. Finally, the average concentration of blanks, measurement detection limit, limit of detection, and limit of quantification are $2.4\pm 0.4$ ppb, 104 ppb, 3.8 ppb, and 7.0 ppb, respectively.

• 한국환경농학회지
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• 제36권3호
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• pp.184-192
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• 2017

BACKGROUND: This study was performed to evaluate the residue dissipation of boscalid and spinetoram on crown daisy and sweet pepper affected by the morphology of the crop. The half-lives and dissipation rate constants for boscalid and spinetoram on crown daisy and sweet pepper were calculated. And then lower limit of 95% confidence interval for dissipation rate constant could be used to propose the pre-harvest residue limit. METHODS AND RESULTS: The pesticide products diluted according to the pesticide label were applied one time on crown daisy and sweet pepper at 2 field sites, respectively. Initial concentration of boscalid and spinetoram on crown daisy after application were in the range of 72.80~117.15 mg/kg and 2.82~4.67 mg/kg, respectively. And Initial concentration of boscalid and spinetoram on sweet pepper were in the range of 1.58~1.62 mg/kg and 0.10~0.21 mg/kg, respectively. Boscalid and spinetoram for crown daisy dissipted below the maximum residue limit(MRL) at 10 and 2 days after application, respectively. All residues concentration of boscalid and spinetoram for sweet pepper below the MRL at 0 day after application. The half-lives based on dissipation rate constant for boscalid and spinetoram on crown daisy were 4.2~4.9 days and 3.0~2.4 days respectively. And the half-lives for boscalid and spinetoram on sweet pepper were 6.7~7.0 days and 2.8~4.0 days respectively. CONCLUSION: The difference in initial concentration of boscalid and spinetoram among crop commodities were due to different crop morphology with larger surface areas. This study was suggested that pre-harvest residue limit would be calculated from lower limit of 95% confidence interval for dissipation rate constant and would be useful to protect consumers by controlling the pesticide residues in crop.