• 품질경영학회지
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• 제31권3호
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• pp.126-135
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• 2003

A basic assumption in standard applications of control charts is that the observations are statistically independent. However, this assumption is often violated from processes in many industries. The presence of autocorrelation has a serious impact on the performance of control charts, causing a dramatic increase in the frequency of false alarms. This paper considers a process in which the observations can be modeled as a first order autoregressive(AR(1)) process, and develops (equation omitted) charts with the variable sample size(VSS) scheme for monitoring the mean of this process.

• 한국국방경영분석학회지
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• 제22권2호
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• pp.126-138
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• 1996

The statistical control chart has been proven to be the effective tool most widely used in the manufacturing industry for monitoring and controlling the manufacturing processes. However, the Shewhart chart sometimes gives us false information when the distribution of quality characteristics is skewed. Therefore, it cannot serve as the universal quality control chart if there exist odd events in the manufacturing process. The objective of this study is thus to develop the new technique for constructing the limits of quality control chart based on a sample median and range when the distribution of the underlying population is skewed. This new control chart can effectively solve and manage the processes which have the non-normally distributed quality characteristics frequently occurring in the practical situation.

• 한국식생활문화학회지
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• 제36권2호
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• pp.218-225
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• 2021

The quality characteristics of sugar-reduced green tea cookies were tested, and there was no significant differences in density, spreadability, loss rate, and pH in all experimental groups (p<0.05). The sugar content of the sample with 100% sugar replaced was 0.96°Brix, which was significantly higher than the 0.80 °Brix of the control (p<0.05). The sample with 75% sugar substituted was 0.76°Brix, which was similar to that of the control (p>0.05). The calories per 100 g of cookies were reduced from 482 to 433 kcal in the sample groups, where the sugar content was reduced from 0 to 100%. Carbohydrates also decreased with decreasing sugar content. The protein was 5g in the sugar sample group reduced by 0-25%, and 6 g in the sugar sample group reduced by more than 50%. Dietary fiber was three times higher in the sugar sample group reduced by 75% than the control, and four times higher in the sugar sample group reduced by 100% than the control. No significant differences in the sweet sensory intensities were observed between the control and the 75% reduced sugar sample group (p>0.05). The brightness, savory, sweet, and aftertastes were similar in all experimental groups (p>0.05). Overall, high value-added green tea cookies with a more than 75% reduction in sugar were successfully developed with added functions of immunity, anti-cancer, antioxidant functions, preventing constipation and obesity, without deteriorating the sensory and physicochemical qualities tested.

• Child Health Nursing Research
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• 제14권4호
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• pp.396-404
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• 2008

Purpose: This study was conducted to identify the level of quality of family life, parental locus of control, and parental sense of competence, and to elucidate factors that influence family quality of life in the mothers of children with Attention Deficit/Hyperactive Disorder (ADHD). Method: A convenient sample of mothers from 6 child psychiatric clinics was used in this cross-sectional survey design. Questionnaires used for data collection included the following scales: Family Quality of Life, Parental Locus of Control-Short Form Revised, Parental Sense of Competence. Results: The level of family quality of life was mid-range. A positive relationship was found between Family Quality of Life and the research variables. The significant predictors of family quality of life were parental locus of control, parental sense of competence, and duration of medication and these variables accounted for 21.8% of the variance in family quality of life. Conclusions: These results indicate that family quality of life is an important factor which health care provider should assess and evaluate for children with ADHD and their families. The results of this study suggest that family quality of life is an important link with parental sense of competence and parental locus of control.

• 약학회지
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• 제41권5호
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• pp.539-546
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• 1997

Capillary electrophoresis (CE) is perceived as an attractive tool for the analysis of pharmaceuticals and biological materials because of their high separation efficiency, easy separation and low running cost. New concept of micellar electrokinetic capillary chromatography (MECC) expanded the application of CE to the separation of neutral molecules. Validation of CE as an analytical technique for quality control of pharmaceuticals should be confirmed by quantitative analysis and the peak confirmation. In this study, the quantitative analyses of various types of neutral, acidic and basic components (acetaminophen, caffeine, ascorbic acid, riboflavin, thiamine, chlorpheniramine, phenylpropanolamine, dl-methylephedrine and dextromethorphan) in complex cold medicines have been accomplished using CE. Combined methods of MECC using SDS and capillary zone electrophoresis lowering the pH of running buffer were adopted to determine the ingredients in capsule type or liquid formula complex medicines without particular sample pretreatment. The results indicate that CE is a promising technique for quality control analysis of pharmaceuticals as a validation method.

• 미생물학회지
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• 제44권1호
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• pp.43-48
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• 2008

정도관리는 분석 결과의 신뢰성을 높이기 위해 필수적인 과정이며, 이를 위해서는 일정한 농도의 표준시료가 필요하다. 본 연구에서는 정도관리의 정략분석을 위해 실온에서도 일정시간 개체수가 유지되는 미생물 정도관리용 표준시료를 제작하였다. 대장균으로 조제한 미생물 시료에 세포 분열을 억제하기 위해 nalidixic acid ($100\;{\mu}g/ml$)와 cephalexin ($50\;{\mu}g/ml$)을 첨가하였다. 이후 12시간 간격으로 acridine orange로 염색 후 현미경으로 계수하는 방법과 한천 배지에 배양하여 집락을 계수하는 평판집락계수법으로 개체수 변화를 측정하였다. 현미경 계수 결과 초기간이 $3.7{\times}10^5\;cells/ml$이었을 때 대장균의 개체수는 48시간 동안 $3.5{\sim}4.2{\times}10^5\;cells/ml$의 범위를 보였고, 평판집락법 결과 초기값이 $1.2{\times}10^4\;CFU/ml$ 이었을 경우에는 $1.0{\sim}1.2{\times}10^4\;CFU/ml$로 조사되어 냉장 및 냉동의 필요 없이 실온에서도 48시간 동안 개체수가 비교적 안정적으로 유지되는 미생물 표준시료를 제작할 수 있었다. 따라서 본 연구에서 제작된 표준시료는 현재 상업적으로 판매되고 있는 표준균주 제품과 함께 정도관리의 정략분석을 위해 사용될 수 있을 것이다.

• Journal of Biosystems Engineering
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• 제33권2호
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• pp.130-135
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• 2008

The purpose of this study was to develop a preprocessor for real-time portable quality evaluation system of milk. The preprocessor consisted of two flow pump to supply milk sample and reaction reagent at given volume, a fan to mix milk with reaction reagent, a thermoelectric device to maintain sample temperatures of $40^{\circ}C$, and I/O interface to control signals. The tests conducted with different level of flow rate of pump, fan speed, ambient temperature, and intial temperature of mixtures. To evaluate performance of the preprocessor, the supplied volumes, color changes, and temperatures were measured and analyzed. The results showed that the preprocessor could control supplying volumes, mixing, temperatures of samples automatically. The preprocessor showed good performance to be used for portable quality evaluation system of milk.

• 품질경영학회지
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• 제35권2호
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• pp.37-44
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• 2007

Today, the statistical process control (SPC) in manufacture environment is an important role at the process by the productivity improvement of the manufacturing systems. The control chart in this statistical method is widely used as an important statistical tool to find the assignable cause that provoke the change of the process parameters such as the mean of interest or standard deviation. But the traditional SPC don't grasp the change of process according to the points fallen the near control limits because of monitoring the variance of process such as the fixed sampling interval and the sample size and handle the cost of the aspect of these sample point. The control chart can be divided into the statistical and economic design. Generally, the economic design considers the cost that maintains the quality level of process. But it is necessary to consider the cost of the process improvement by the learning effects. This study does the economic design in the VSI $\bar X$ control chart and added the concept of loss function of Taguchi in the cost model. Also, we preyed that the VSI $\bar X$ control chart is better than the FSI $\bar X$ in terms of the economic aspects and proposed the standard of the process improvement using the VSI $\bar X$ control chart.

• 산경연구논집
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• 제11권12호
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• pp.39-45
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• 2020

Purpose: The stock price delay phenomenon refers to a phenomenon in which stock prices do not immediately reflect corporate information and the reflection is delayed. A prior study reported that the stock price delay phenomenon appears strongly when the quality of corporate information is low (Callen, Khan, & Lu, 2013). The purpose of the internal accounting control system is to improve the reliability of accounting information. Specifically, the more professionals such as certified public accountants are placed in the internal accounting control system, the more information is prevented from being distorted, so the occurrence of stock price delay will decrease. Research design, data and methodology: In this study, companies listed on the securities market from 2012 to 2016 were selected as a sample to analyze whether the stock price delay phenomenon is alleviated as accounting experts are assigned to the internal accounting control system. The internal control personnel data were collected in the "Internal Accounting Control System Operation Report" attached to the business report of each company of the Financial Supervisory Service's Electronic Disclosure System(DART). The measurement method of the stock price delay phenomenon was referred to the study of Hou and Moskowitz (2005). The final sample used in the study is 2,641 firm-years. Results: It was found that companies with certified accountants in the internal accounting control system alleviate the stock price delay phenomenon. This result can be interpreted as increasing the speed at which corporate information is reflected in the stock price by improving the reliability of information disclosed in the market by the placement of experts in the system. Conclusions: The results of this study suggest that accounting professionals assigned to the internal accounting control system are playing a positive role in providing high-quality information to the market. In this study, focusing on the fact that the speed at which corporate information is reflected in the stock price is very important for the stakeholders in the capital market, we find that having a certified public accountant in the internal accounting control system alleviates the stock price delay phenomenon.

• 한국산업보건학회지
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• 제19권3호
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• pp.288-296
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• 2009

We conducted validation for asbestos quality control (QC) samples made by the developed method which was presented in our published paper. The main results of the validation study are as follows. The pooled coefficient variations of analytical results in three different concentrations (low, medium, and high concentration) for amosite and chrysotile were less than 20 %, which met the sample homogenicity criteria of NIOSH. Also we confirmed the homogenicity of asbestos samples by using the relocatable field slide. To evaluate the field applicability of the developed asbestos QC samples, the field validation was performed with four proficient asbestos analysts by using the statistical methods of AIHA asbestos PAT program. All analytical results from four asbestos analysts were located in the acceptable range.