• Communications for Statistical Applications and Methods
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• v.14 no.1
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• pp.155-167
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• 2007

Knowing the time of the process change could lead to quicker identification of the responsible special cause and less process down time, and it could help to reduce the probability of incorrectly identifying the special cause. In this paper, we propose the maximum likelihood estimator (MLE) for the process change point when a control chart is used in monitoring the mean of a process in which the observations can be modeled as an AR(1) process plus an additional random error. The performance of the proposed MLE is compared to the performance of the built-in estimator when they are used in EWMA charts based on the residuals. The results show that the proposed MLE provides good performance in terms of both accuracy and precision of the estimator.

• Communications for Statistical Applications and Methods
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• v.10 no.3
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• pp.825-833
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• 2003

Knowing the time of the process change could lead to quicker identification of the responsible special cause and less process down time, and it could help to reduce the probability of incorrectly identifying the special cause. In this paper, we propose a maximum likelihood estimator of the process change point when a Shewhart $\bar{X}$ chart with variable sample size (VSS) scheme signals a change in the process mean. Also we build a confidence interval for the process change point by using the likelihood function.

• Journal of Digital Convergence
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• v.9 no.6
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• pp.13-25
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• 2011

The purpose of this study is to explore a characteristic for raising the percentage of employment of the special high-school. And consider the specialization concept appearing on the stage as these means and analysis the actual operation condition. There are various of the major cause factors of the special high-school and these factors were judged on having a negative effect of raising the percentage of employment of the special high-school. Also, the study were suggested various improvement plan for minimizing negative effect of these factors. Based on the findings, the study showed that grasp the situation of the special high-school and improving plan and present the political plan.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.2
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• pp.74-78
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• 2015

With the improvement of living standards and economic development, electricity consumption continues to grow. The electricity is a special energy which is hard to store, so its supply must be consistent with the demand. The objective of electricity demand forecasting is to make best use of electricity energy and provide balance between supply and demand. Hence, it is very important work to forecast electricity demand with higher precision. So, various forecasting methods have been developed. They can be divided into five broad categories such as time series models, regression based model, artificial intelligence techniques and fuzzy logic method without considering special-day effects. Electricity demand patterns on holidays can be often idiosyncratic and cause significant forecasting errors. Such effects are known as special-day effects and are recognized as an important issue in determining electricity demand data. In this research, we developed the power demand forecasting method using ELM(Extreme Learning Machine) for special day, particularly, lunar new year and Chuseok holiday.

• Journal of the Korea Safety Management & Science
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• v.24 no.1
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• pp.91-98
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• 2022

Since cranes are a kind of complex human-machine systems, it is almost impossible to completely secure safety with current technologies. Therefore, managerial interventions to prevent human errors are needed for safely operating a crane. The Occupational Safety and Health law states that cabin-type crane operators should have crane drivers' licence and crane-related operators (e.g., pendent-type crane operators, slinging workers) should take a special safety training. However, statistics on industrial accidents showed that fatalities due to crane accidents (185 accidents occurred during 2013~2017) were the highest among hazardous machinery and equipment. To effectively control the crane-related accidents, voices of crane workers need to be analyzed to investigate the current status. This study surveyed perceived causes of crane accidents and status of special safety training for crane workers of 387. The survey revealed that 24.3% of the respondents experienced crane accidents and 31.4% eye-witnessed crane accidents. 79% of the respondents pointed human errors such as improper crane operation and improper slinging as the first cause. Lastly, only 16.7% of the respondents took a professional special safety training; but the rest took lecture-based or incomplete education. The findings of the present study can be applied to improve crane-related policies and special safety training systems.

• Proceedings of the Korean Statistical Society Conference
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• 2004.11a
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• pp.179-184
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• 2004

Statistical process control (SPC) and engineering process control (EPC) are based on different strategies for process 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 need for an integrated process control (IPC) procedure which combines the two strategies. This article considers a scheme that simultaneously applies SPC and EPC techniques to reduce the variation of a process. The process disturbance model under consideration is an IMA(1,1) model with a location 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 by compensating the predicted deviation from target. For detecting special causes the two kinds of exponentially weighted moving average (EWMA) control chart are applied to the observed deviations: One for detecting location shift and the other for detecting increment of variability. It was assumed that the adjustment of the process under the presence of a special cause may change any of the process parameters as well as the system gain. The effectiveness of the IPC scheme is evaluated in the context of the average cost per unit time (ACU) during the operation of the scheme. One major objective of this article is to investigate the effects of the process parameters to the ACU. Another major objective is to give a practical guide for the efficient selection of the parameters of the two EWMA control charts.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.64-67
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• 2000

It is usual that the medical examination of human body need special knowledpe and equipments. Thus we have to spend Lime and energy on going to special place such as hospital where doctors and equipments are. Which often cause missing a good chance af medical treatment as well as giving us inconvenience. However many simple and convenient equipments were developed for checking our health conditions recently. O-ring test is accepted a3 one of useful methods to examine our heallb conditions. Also the test is recognized as a uscful means to judge, withoul any special equipment and medical knowledge, if some medical substances or foods are beneficial or harmful to our health. However, the judgement may be mcorrect because it depend on doctor's subjective point of view.In this study, we developed an automatic O-ring t a r mach~ne which enable us to check our health conditions objectively and quantitatively. The validity of the idea to develope the machine was proved by experiments.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.236-241
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• 2008

The Police are classed special service on civil service system. Most of special service officers are applied special personnal law. It is for this reason that organization and mission are different from general public officials. The police performance evaluation is enforced in dissimilar form with another civil services for these cause. This study proposed to verification formality about appraisal result to desirable operation of police performancce evaluation system. At system enforcement early, it may be desirable that verification is limited finally supervisors rating.

• Journal of the Korean Data and Information Science Society
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• v.20 no.2
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• pp.435-443
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• 2009

Knowing the time of the process change could lead to quicker identification of the responsible special cause and less process down time, and it could help to reduce the probability of incorrectly identifying the special cause. In this paper, we propose the maximum likelihood estimator (MLE) for the process change point when a control chart is used in monitoring the parameters of a process in which the observations can be modeled as a IMA(1,1).

• Journal of Convergence for Information Technology
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• v.11 no.7
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• pp.181-188
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• 2021

This study was performed to examine the strategy method for the sustainable stability and effectiveness of small and medium hospital, where the relationship between perceptual satisfaction and expectation factors for special hospital was analyzed. The structural questionnaire was given to the residents of Busan and Gyungnam over the age of 20 and the square contingency and the logistical regression were employed for the analysis of the results. First, the respondent with 68.0% has realized the hospital claiming to be characterization as the special hospital and the Ministry of Health and Welfare designated hospital was identified to the respondent of 21.3%. Second, perceptual satisfaction with expectation level was satisfied to the most visitor in case of visiting special hospitals with subjective perception and was confirmed to the intention of revisiting consistently. Third, for the perceptual satisfaction of visiting with expectation level, the safety and the quality of treatment affected significantly the cause-and-effect. The result has provided the useful information with the establishment of a strategy for the long-term and continued effect through the perceptual satisfaction and the emotional attachment.