• 품질경영학회지
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• 제22권1호
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• pp.54-65
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• 1994

Multivariate exponentially weighted moving average (EWMA) control charts for monitoring the variance-covariance matrix are investigated. Two basic approaches, "combine-accumulate" approach and "accumulate-combine" approach, for using past sample information in the developement of multivariate EWMA control charts are considered. Multivariate EWMA control charts for monitoring the variance-covariance matrix are compared on the basis of their average run length (ARL) performances. The numerical results show that multivariate EWMA control charts based on the accumulate-combine approach are more efficient than corresponding multivariate EWMA control charts based on the combine-accumulate approach.

• 품질경영학회지
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• 제25권1호
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• pp.100-115
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• 1997

Shewhart control chart is a basic technique to monitor the state of a process. We observe samples of size four or five and plot some statistic(e.g., mean or range) of each sample on the chart. When setting up the chart, we need to obtain u, pp.r and lower control limits. It is common practice that those limits are calculated from the preliminary 20-40 samples presumed to be homogeneous. However, it may ha, pp.n in practice that the samples are contaminated by outlying observations caused by various reasons. The presence of outlying observations make the control limits wider and hence decrease the sensitivity of the charts. In this paper, we introduce robust control charts with tighter control limits when outlying observations are present in the preliminary samples. Examples will be given via simulation study.

• Journal of applied mathematics & informatics
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• 제3권2호
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• pp.253-264
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• 1996

The generalized logit model of nominal type with random regressors is studied for bootstrapping. We assess the accuracy of some estimators for our generalized logit model using a Monte Carlo simu-lation. That is we study the finite sample properties containing the consistency and asymptotic normality of the maximum likelihood es-timators. Also we compare Newton Raphson algorithm with BHHH algorithm.

• 한국조리학회지
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• 제23권3호
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• pp.29-37
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• 2017

This study investigated the physicochemical and sensory characteristics of white bean paste prepared with various amounts of aronia powder (as ratios of 0%, 2%, 4%, 6%, 8%, 10%). The result shows that the pH of white bean paste decreased significantly with the addition of aronia powder. From chromatography, the brightness, L-value was decreased by increasing the adding rate of aronia powder. The a-value of sample group adding 2% of aronia powder was the highest and that of sample group adding 8% was the lowest (p<0.01). Sample group adding 8% of aronia powder achieved the highest appraisal from many factors, such as springiness, cohesiveness, chewiness, brittleness, and adhesiveness. The total polyphenols and anthocyanin contents were proportionally increased with increasing the level of aronia powder added in white bean paste. The antioxidant activity measured by DPPH and NSA radical scavenging activities was significantly higher than control and increased proportionally to the aronia powder concentration. The result of sensory test shows that sample group adding 6% of aronia powder achieved the highest. Based on the above results, this study suggests that the addition of 6% aronia powder may be the best substitution ratio for white bean paste of the improvement of sensory preference and antioxidant.

• 대한임상검사과학회지
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• 제52권4호
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• pp.381-388
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• 2020

정확한 분자병리검사를 위해 검체에 대한 질관리의 중요성이 강조되고 있다. 본 연구에서 BRAF, EGFR, KRAS 돌연변이 검사에 대해, 검체 종류 및 처리과정 중 DNA 품질에 영향을 미치는 인자를 알아보고자 하였다. 모두 1,772건의 분자병리검사에 대해, 검체의 종류, 포르말린 고정시간, 재검기록 등 DNA 품질에 영향을 미칠 수 있는 임상병리학적 요소를 조사하였다. 세포검체는 고정액으로 처리를 한 검체보다 생리식염수에 보관한 검체가 DNA 품질이 좋았다. 조직검체는 10% 중성 포르말린에 24시간 이내에 고정된 검체가 그 이상 고정된 검체보다 DNA 품질이 좋았다. 검체 종류 중 신선조직검체, 그리고 종양세포밀도가 높은 조직검체가 파라핀포매조직 및 세침흡인액상 세포검체보다 상대적으로 DNA 품질이 좋았다. 10% 중성 포르말린에 24시간 이상 오래 고정된 검체일수록 Non-PNA Ct값이 비례 증가하여, 포르말린 고정시간이 검체 DNA 품질에 영향을 준다는 것을 확인하였다. 결론적으로 종양세포의 밀도 및 적절한 포르말린 고정시간이 DNA 품질을 유지하는데 가장 중요한 요소이며, 신속하고 정확한 분자병리진단을 위해 이들 요소를 적절히 관리하여 최적의 DNA 품질을 유지하도록 해야 한다.

• 품질경영학회지
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• 제32권1호
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• pp.92-101
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• 2004

Tris paper present an economic statistical design which have statistically constraints for the optimal design of an EWMA control charts with variable sampling interval. Cost function use that proposed by Lorenzen and Vance, and the optimal design parameters include the sample size, control limit width, sampling interval, EWMA weight value. Comparisons between VSI EWMA control charts optimal economic design and optimal economic statistical designs show the following fact. Although have demerits which are more costly than economic design, have merits which to detect shifts more efficiently and to improve statistical performance.

• 한국경영과학회지
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• 제31권3호
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• pp.127-143
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• 2006

While e-learners' satisfaction would be determined by qualify of e-learning environment including learning management systems, learning contents and interactions, the influence of quality on satisfaction can be changed by e-learners' self-regulated efficacy The objective of this study is to show difference of the relationship between qualify and satisfaction In e-learning by self-regulated efficacy. For this purpose, we propose a research model which consists of five quality factors in e-learning as explaining variables, satisfaction as a result variable and self-regulated efficacy as a control variable. For empirical test of this model, the sample is collected from e-learning classes in a college and divided into two groups by self-regulated efficacy in order to analyze the effects of control variable. By multi-group analysis, we show two groups are different from each other in the relationship between quality and satisfaction of e-learning environment.

• 품질경영학회지
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• 제15권2호
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• pp.10-19
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• 1987

Statistical control charts are useful tools to monitor and control the manufacturing processes and are widely used in most Korean industries. Many Korean companies, however, do not always obtain desired results from the traditional control charts by Shewhart such as the $\overline{X}$-chart, X-chart, $\widetilde{X}$-chart, etc. This is partly because the quality charterstics of the process are not distributed normally but are skewed due to the intermittent production, small lot size, etc. In the Shewhart $\overline{X}$-chart, which is the most widely used one in Korea, such skewed distributions make the plots to be inclined below or above the central line or outside the control limits although no assignable causes can be found. To overcome such shortcomings in nonnormally distributed processes, a distribution-free type of confidence interval can be used, which should be based on order statistics. This thesis is concerned with the design of control chart based on a sample median which is easy to use in practical situation and therefore properties for nonnormal distributions may be easily analyzed. Control limits and central lines are given for the more famous nonnormal distributions, such as Gamma, Beta, Lognormal, Weibull, Pareto, and Truncated-normal distributions.

• 한국식생활문화학회지
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• 제21권3호
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• pp.290-296
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• 2006

본 연구에서는 난소화성 전분의 대체비율을 0%, 10%, 20% 및 30%로 하여 호두 빵을 제조하고 이화학적 검사, 관능검사 및 기호도 검사를 통하여 품질 특성을 조사하였다. 반죽의 pH는 10% 시료군과 대조군이 높은 값을 나타내었다. 반죽의 수분함량은 난소화성 전분을 대체한 시료군이 대조군에 비해 유의적으로 높은 값을 나타내었다. 완성된 빵의 부피는 대조군이 가장 큰 것으로 평가되었으나 10%와 20% 시료군과는 유의적인 차이를 보이지 않았다. 빵의 밝은 정도는 난소화성 전분을 대체한 비율이 높을수록 유의적으로 낮게 평가되었다. 빵의 경도는 10%와 20% 시료군이 대조군보다 유의적으로 낮은 특성을 나타내었다. 빵의 검성과 깨짐성은 비슷한 경향을 보이며 대조군과 30% 시료군이 강하게 평가되었다. 빵의 관능검사를 실시한 결과 고소한 맛은 대조군이 가장 특성이 강하게 평가되었고 떫은맛은 난소화성 전분의 대체비율이 높아짐에 따라 유의적으로 증가하는 것으로 나타내었다. 난소화성 전분의 대체비율이 높아질수록 떫은맛이 강해지므로 향후 떫은맛을 개선시키는 연구가 필요하다고 사료된다. 빵의 질긴 정도는 10%와 20% 시료군이 대조군보다 유의적으로 낮은 특성을 나타내어 부드럽게 평가되었다. 빵 내부의 조밀성은 대조군이 높게 평가되었으나 30% 시료군과는 유의적인 차이를 보이지 않았다. 빵의 기호도 검사 결과 조직감의 기호도는 10% 시료군이 대조군보다 유의적으로 높은 기호도를 나타내었다. 난소화성 전분으로 10%와 20%로 대체된 빵은 대조구와 비교하였을 때 유의적인 차이가 없거나 유의적으로 높은 기호도를 나타내어 개발 가능성을 보여주었으며, 아울러 품질 향상을 위한 체계적인 후속 연구가 계속 이루어져야 할 것으로 사료된다.

• 대한가정학회지
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• 제30권3호
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• pp.119-129
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• 1992

Black soybeans were gamma-irradiated at dost levels of 0, 2., 5, 10 and 20 kGy, and stored at room temperature for the experiments associated with cooking quality. The degree of cooking of soybeans in boiling water at 98-10$0^{\circ}C$ has been determined by measuring the maximum cutting force of cotyledon. The cutting force to reach a complete cooking was about 120~130g/g. Irradiation at 2.5~20kGy caused the reduction of cooking time in black soybeans by 30~60% compared to the nonirradiated control, and the cooking rate constant of the irradiated samples was higher than that fo the nonirradiated control sample. These results were similarly found in the stored samples for one year at room temperature after irradiation. Color characteristics of cooked samples showed no significant difference between the nonirradiated control and 5 kGy-irradiated sample. After complete cooking of black soybeans, there were not significant in the organoleptic qualities between the nonirradiated and irradiated samples.