• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 1998년도 The 12th Asia Quality Management Symposium* Total Quality Management for Restoring Competitiveness
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• pp.133-142
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• 1998

This paper is a brief review of the different procedures that are available for fitting theoretical distributions to data. The use of each technique is illustrated by reference to a distribution system which including the Pearson, Poission approximation of Gamma distribution and Burr functions. These functions can be used to calculate percent out of specification. Therefore, in this paper a new methods for estimating a measure of non-normal process capability for Gamma distributed variable data proposed using the percentage nonconforming. Process capability indices combines with the percentage nonconforming information can be used to evaluate more accurately process capability.

• 대한안전경영과학회지
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• 제9권2호
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• pp.215-233
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• 2007

Even though the ad hoc Shewhart methods remain controversial due to various mathematical flaws, there is little disagreement among researchers and practitioners when a set of process data has a skewness distribution. In the context and language of process control, the error related to the process data shows that time to signal increases when a control parameter shifts to a skewness direction. In real-world industrial settings, however, quality practitioners often need to consider a skewness distribution. To address this situation, we developed an enhanced design method to utilize advantages of the traditional attribute control chart and to overcome its associated shortcomings. The proposed design method minimizes bias, i.e., an average time to signal for the shift of process from the target value (ATS) curve, as well as it applies a variable sampling interval (VSI) method to an attribute control chart for detecting a process shift efficiently. The results of the factorial experiment obtained by various parameter circumstances show that the VSI c control chart using nearly unbiased ATS design provides the smallest decreasing rate in ATS among other charts for all experimental cases.

• 한국수자원학회논문집
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• 제35권1호
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• pp.109-124
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• 2002

본 연구는 간헐 수문사상인 시간강수계열의 구조적 특성을 고찰하여 강수발생의 군집성을 고려한 강수발생과정에 대한 추계학적 모의발생 모형을 개발한 것이다. 먼저 강수사상의 발생패턴을 기술하기 위해 Poisson 군집과정을 사용하였고, 이 과정에서 군집간의 시간과 군집내의 사상 수는 지수분포로 기술하였다. 둘째로 사상의 지속기간과 군집내에서 사상간의 시간은 음대수혼합분포로 기술하였다. 마지막으로 이상과 같은 시간강수사상의 발생패턴과 사상기간내의 강수의 종속구조를 구명하기 위해 서울을 대상으로 하여 실적강수자료를 분석하였다. Monte Carlo 모의결과는 모형이 강수발생의 계절적 패턴, 사상특성의 주변 및 조건부 분포를 잘 재현하고 있음을 보여주었다.

• Journal of the Korean Data and Information Science Society
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• 제8권2호
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• pp.119-125
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• 1997

We handle the stochastic processes of independent and identically distributed random variables. But random variables are usually dependent among themselves in actual life. So in this paper, we find out a new process not satisfying Markov property. We investigate the probability mass functions and study on the probability of the first-passage time. Also we find out the average frequency of continuous successes in from 0 to n time.

• 한국정밀공학회지
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• 제13권10호
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• pp.130-138
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• 1996

In general, the scattler is observed in fatigue test data due to the nonhomogeneity of a material. Consequently. It is necessary to use the statistical method to describe the fatigue crack growth process precisely. Bogdanoff and Kozin suggested and developed the B-model which is the probabilistic models of cumulative damage using the Markov process in order to describe the damage process. But the B-model uses only constant probability ratior(r), so it is not consistent with the actual damage process. In this study, the r-decreasing model using a monotonic decreasing function is introduced to improve the B-model. To verify the model, thest data of fatigue crack growth of A12024-T351 and A17075-T651 are used. Compared with the empirical distribution of test data, the distribution from the r-decreasing model is satisfactory and damage process is well described from the probabilistic and physical viewpoint.

• Journal of the Korean Data and Information Science Society
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• 제11권2호
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• pp.217-223
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• 2000

In this paper, we develop optimal decision interval exponentially weighted moving average(EWMA) scheme for the process mean and the reciprocal measure of dispersion of the inverse Gaussian distribution.

• 산업경영시스템학회지
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• 제44권3호
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• pp.1-9
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• 2021

This research examines deep learning based image recognition models for beef sirloin classification. The sirloin of beef can be classified as the upper sirloin, the lower sirloin, and the ribeye, whereas during the distribution process they are often simply unified into the sirloin region. In this work, for detailed classification of beef sirloin regions we develop a model that can learn image information in a reasonable computation time using the MobileNet algorithm. In addition, to increase the accuracy of the model we introduce data augmentation methods as well, which amplifies the image data collected during the distribution process. This data augmentation enables to consider a larger size of training data set by which the accuracy of the model can be significantly improved. The data generated during the data proliferation process was tested using the MobileNet algorithm, where the test data set was obtained from the distribution processes in the real-world practice. Through the computational experiences we confirm that the accuracy of the suggested model is up to 83%. We expect that the classification model of this study can contribute to providing a more accurate and detailed information exchange between suppliers and consumers during the distribution process of beef sirloin.

• Journal of the Korean Statistical Society
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• 제31권4호
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• pp.509-518
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• 2002

This paper is concerned with semiparametric Bayesian analysis of the proportional intensity regression model of the Poisson process for multiple event time data. A nonparametric prior distribution is put on the baseline cumulative intensity function and a usual parametric prior distribution is given to the regression parameter. Also we allow heterogeneity among the intensity processes in different subjects by using unobserved random frailty components. Gibbs sampling approach with the Metropolis-Hastings algorithm is used to explore the posterior distributions. Finally, the results are applied to a real data set.

• 품질경영학회지
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• 제31권1호
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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.

• 동아시아경상학회지
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• 제9권4호
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• pp.69-80
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• 2021

Purpose - This study investigated the development process of the Chinese distribution industry and analyzed the current status of China's offline and online distribution industries under the development process of the Chinese distribution industry. In addition, the current status of offline distributors in China and representative companies were analyzed as case studies. Research design, data, and methodology - This study analyzed the overall environment of the Chinese distribution industry by using literature data. Then, this study conducted a case analysis using RT Mart and Jingdong, major companies in the distribution industry. Result -The main research results of this study show that the Chinese distribution market has already matured, and retailers are fiercely competing to secure sales and operating profits through various methods such as finding new management methods, improving awareness and customer loyalty by expanding the number of stores. Conclusion -Recently, the characteristic of China's distribution industry is that the boundaries of distribution are breaking down. Chinese retailers are taking strategies to expand the scope of services by erasing the boundaries of distribution. In other words, distribution companies are promoting a borderless distribution strategy in which consumers purchase products online and offline without restrictions on time and space. In addition, small stores in residential areas are on the rise compared to large-scale stores in the city center. The existing distribution industry operates various types of distribution stores to prepare for the post-COVID-19 crisis.