• Journal of Korean Society for Quality Management
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• v.31 no.1
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• pp.109-122
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• 2003

This paper presents a robust process capability index(PCI) based on the expected loss derived from the empirical distribution function(EDF). We propose the EDF expected loss in order to develop a PCI that does not depends on the underlying process distribution. The EDF expected loss depends only on the sample data, so the PCI based on it is robust and it does nor require complex calculations. The inverted normal loss function(INLF) is employed in order to overcome the drawback of the quadratic loss which may Increase unboundedly outside the specification limits. A comprehensive simulation study was performed under various process distributions, in order to compare the accuracy and the precision of the proposed PCI with those of the PCI based on the expected loss derived from the normal distribution. The proposed PCI turned out to be more accurate than the normal PCI in most cases, especially when the process distribution has high kurtosis or skewness. It is expected that the proposed PCI can be utilized In real processes where the true distribution family may not be known.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.117-132
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• 2018

There always exist nonzero inspection errors whether inspectors are humans or automatic inspection machines. Inspection errors can be categorized by two types, type I error and type II error, and they can be regarded as either a constant or a random variable. Under the assumption that two types of random inspection errors are distributed with the "uniform" distribution on a half-open interval starting from zero, it was proved that inspectors overestimate any given fraction defective with the probability more than 50%, if and only if the given fraction defective is smaller than a critical value, which depends upon only the ratio of a type II error over a type I error. In addition, it was also proved that the probability of overestimation approaches one hundred percent as a given fraction defective approaches zero. If these critical phenomena hold true for any error distribution, then it might have great economic impact on commercial inspection plans due to the unfair overestimation and the recent trend of decreasing fraction defectives in industry. In this paper, we deal with the same overestimation problem, but assume a "symmetrical triangular" distribution expecting better results since our triangular distribution is closer to a normal distribution than the uniform distribution. It turns out that the overestimation phenomenon still holds true even for the triangular error distribution.

• Journal of Distribution Science
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• v.20 no.7
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• pp.57-64
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• 2022

Purpose: The government of India has initiated the Covid-19 Vaccination drive from early January 2021. Vaccination is identified to be best option to protect the people across the globe. However, owing to fast wide spread of the Covid-19, the Vaccine Distribution is a major challenge owing various issues like temperature control, infrastructure, hesitancy, geographical diversity, and other critical factors. Various research is carried out globally to understand and study the Vaccine Distribution issues based on the respective country issues and factors. Research Design, Data, and Methodology: This research paper attempts to explore prominent factors that could be taken up on priority for better and effective vaccination program. The study tries to rank various factors and sub-factors affecting vaccine distribution in India. AHP methodology based on feedback from 22 experts from the Vaccine industry has been deployed to get the desired results. Result: The results show that factors vaccine approval process, geographical prioritization, power supply, infrastructure maintenance costs for vaccine storage, and vaccine pricing are the prominent factors of effective vaccination in the country. Conclusion: The role and need for district-level health officers towards vaccine storage has been brought forward. A long-term effective vaccination policy is needed for optimum vaccine distribution.

• Wind and Structures
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• v.34 no.6
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• pp.469-482
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• 2022

The generalized extreme value distribution (GEVD) is frequently used to fit the block maximum of environmental parameters such as the annual maximum wind speed. There are several methods for estimating the parameters of the GEV distribution, including the least-squares method (LSM). However, the application of the LSM with the expected order statistics has not been reported. This study fills this gap by proposing a fitting method based on the expected order statistics. The study also proposes a plotting position to approximate the expected order statistics; the proposed plotting position depends on the distribution shape parameter. The use of this approximation for distribution fitting is carried out. Simulation analysis results indicate that the developed fitting procedure based on the expected order statistics or its approximation for GEVD is effective for estimating the distribution parameters and quantiles. The values of the probability plotting correlation coefficient that may be used to test the distributional hypothesis are calculated and presented. The developed fitting method is applied to extreme thunderstorm and non-thunderstorm winds for several major cities in Canada. Also, the implication of using the GEVD and Gumbel distribution to model the extreme wind speed on the structural reliability is presented and elaborated.

• Journal of Distribution Science
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• v.21 no.2
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• pp.91-102
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• 2023

Purpose: to explore more deeply the variables of knowledge construction in influencing performance, through entrepreneurial leadership, motivation, organizational learning, and commitment to the performance of midwives in providing maximum service to patients and the community. Research design, data and methodology: using quantitative methods with hypothesis testing, data was obtained through direct visits and surveys to midwife practice locations through coordination with the Indonesian Midwives Association (IBI) regarding surveys to be carried out and needed. Results: there are 3 direct paths that have significant value. The path between the motivation variable to commitment was found to be significant, then the effect of organizational learning on commitment was found to be significant and finally the effect of the path variable from commitment to distribution performance was found to be significant. The indirect effect was found to be insignificant for the influence of entrepreneurial leadership through commitment to distribution performance, but different results found a significant indirect effect for the relationship between motivation through commitment to performance and organizational learning through commitment to distribution performance. Conclusion: there is a high commitment to the work of midwives, commitment as a good mediation in influencing distribution performance between organizational learning and work motivation.

• Journal of the Semiconductor & Display Technology
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• v.20 no.1
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• pp.18-24
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• 2021

The current settlement and distribution used in theme, background and signal music market other than conventional music is being carried out with either the comprehensive settlement method or the measured meter-rate settlement method in the payment process of collected user fees and compensation depending on the use-permission types. In this settlement and distribution process, however, the reliability issues are often being raised because of the difficulty of tracking rights due to changes in music source rights management information, etc, and the opaque settlement and distribution method itself. This paper proposes a new settlement and distribution platform using a blockchain for the reliable collection and distribution of copyright fees among music user group, monitoring organization group, trust organization group and copyright holders, based on the monitoring information of the theme, background and signal music usage. This platform also provides the transparency in settlement and distribution process among stakeholders through smart contract system.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2208-2218
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• 2017

To resolve overload in a distribution system, a distribution system operator (DSO) often performs a load transfer using normally open tie points and switches in the distribution line. During this process, the distribution system is momentarily operated in closed-loop operation. A closed-loop current in the distribution system can cause a power failure due to excess breaking current in the circuit breakers and reclosers. Therefore, it is necessary to calculate the closed-loop current exactly. However, if there are a large number of distributed generation (DG) systems in the distribution system, such as energy storage systems (ESS), they might obstruct the closed-loop operation based on bidirectional power flow. For quick and precise operation of a closed-loop system, the ESS has to regulate the power generation while satisfying closed-loop operation in the worst cases. We propose a strategy for balanced power regulation of an ESS. Simulations were carried out using PSCAD/EMTDC, and the results were compared with calculation results.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.477-480
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• 1996

The main objective of this research is to develop the optimal control method for a Distribution Center - multi Branch inventory distribution system. With the continuous review policy, the distribution center places an order for specific order quantity to an outside supplier, and the order quantity is replenished after a certain lead time. Also, each branch places an order for particular order quantity to the distribution center to satisfy the customer demands, and receives the replenishment after a lead time. When an out of stock condition occurs during an order cycle, a backorder is placed to the upper level to fill the unfilled demands. With these situation, variable demand and variable lead time are used for better industrial practice. Futher, actual lead times with a generic lead time distribution are used in developing the control model. Under the actual lead time model, the customer service measures actually attained for the distribution center and each branch are explained as the effective customer service measures. Thus, throughout the optimal control (using computer search procedures), we can set the desired service levels for the distribution center and each branch to produce the effective service level for each branch which is consistent with the goal level of service for each branch. At the same time, the entire distribution system keeps minimum inventories.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.2
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• pp.123-130
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• 1992

The model of k-out-of n : G repairable system with identical components is extended to a repairable system with n different components. The objective is to analytically derive the mean time of the busy period for a k-out-of-n : G system with unrestricted repair. Then, the lower and upper bounds on the average time of the busy period of the n-component system with restricted repair are also shown.

• Journal of Environmental Health Sciences
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• v.12 no.2
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• pp.27-37
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• 1986

This study was carried out to investigate inflow stream of Chungju intake reservoir and in catchment area, run-off loading amount, distribution of Nitrogen and phosphorus, N/P ratio, correlationship between T-N and chlorophyll a, correlationship between T-P and chlorophyll a, and study of trophic state. Field survey was carried out from June to August, 1985, for the purpose of finding out the nitrogen and phosphorus concentration in Chungju intake reservoir.