• 한국식생활문화학회지
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• 제18권5호
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• pp.437-442
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• 2003

This study was conducted to confirm the effect of drying method on quality of popped rice for making salyeotgangjung(popped rice lump with malt syrup) in process of drying gelatinized rice. The drying were performed at dry oven or convection oven, at $30^{\circ}C,\;50^{\circ}C\;and\;105^{\circ}C$, respectively. There were not significant differences in the hardness of popped rice among the drying methods. The dry at $30^{\circ}C$ constant in dry oven showed higher popping rate, good external surface, uniformed and well developed internal cell size. The dry at $30^{\circ}C$ in convection oven and $50^{\circ}C$ constant temperature in dry oven showed low expansion and poor external surface, respectively. In conclusion, the drying at $30^{\circ}C$ in non-convection oven had the highest quality of popped rice for salyeotgangjung.

• 한국생산제조학회지
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• 제6권1호
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• pp.77-83
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• 1997

In this paper, we have studied internal quality including chemical compositions, microscopic structure and nonmetalic inclusion of test materials. We have analyzed dynamic characteristics of cutting force of milling including tensile strength value, hardness etc. Test materials are used in the tempered carbon steel and the non-tempered carbon steel. The obtained results are as follows: 1. In analyzing internal quality, the tempered carbon steel have typical martensite structure and the non-tempered carbon steel have ferrite + pearlite structure. 2. Yield strength, tensile strength and hardness value are in the non-tempered carbon steel but elongation is maximum value in the tempered carbon steel. 3. Cutting force is smaller non-tempered carbon steel than tempered carbon steel when feed speed and depth on cut is constant. 4. Cutting force is smaller non-tempered carbon steel than tempered carbon steel when cutting speed and depth of cut is constant.

• Agricultural and Biosystems Engineering
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• 제1권1호
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• pp.38-42
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• 2000

Though the freshness for agricultural products is an important factor related to their quality management, this terminology is being used restrictedly because it is very subjective. In this study, a dimensionless index which had the span of the maximum of 1 through the minimum of 0 was proposed to describe freshness of the product with time-variant quality and was applied to Tsugaru and Fuji apples. First, the compressive properties having the linearity in their change regarding time elapsed after harvest were selected. For Tsugaru apple, bio-yield and rupture forces had high correlation with time while for Fuji, bio-yield and rupture deformations had high correlations. When the slope, or ratio of force to deformation, was considered, the effect of cultivar could be neglected. When the linearly time-variant compressive properties for Tsugaru and Fuji apples were involved in the freshness indices, they described well freshness of apples. Also, the freshness decay constant depicted a characteristic which related to freshness decay rate. Therefore, the freshness index can be utilized to manage the quality during storage and distribution of apples.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.405-408
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• 1997

The microwave dielectric properties of CuO and CdO addition of BiNbO$_4$ceramics were investigated. As the content of CdO increased, sintered density and quality factor is decreased. With increase in sintering temperature, the dielectric constant and quality factor is increased. In case of specimen sintered at 96$0^{\circ}C$ with 0.03 wt% CuO and CdO, the microwave dielectric properties obtained were dielectric constant of 41.2, quality factor (Q$\times$f) of 6, 500, temperature coefficient of resonant frequency of ppm/$^{\circ}C$.

• Communications for Statistical Applications and Methods
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• 제13권3호
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• pp.651-656
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• 2006

Wu and Clements-Croome (2005) investigate the optimization problem of PM policies for situations where the quality of PM is a random variable with a certain probability distribution. However, they assume that the cost of preventive maintenance is constant, not depending on the quality of PM. Thus, this paper considers a periodic PM model when PM cost depends on the quality of PM activity. The optimal PM policy are presented for the extended PM model and the numerical examples are presented for illustrative purpose.

• 품질경영학회지
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• 제38권4호
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• pp.540-548
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• 2010

We consider the problem of selecting the most profitable initial process mean and length of production cycle for manufacturing processes subject to a constant linear trend during the same cycle that varies after resetting the processes. Assuming that the quality characteristic of interest is normally distributed, the optimum initial process mean and the length of production cycle are jointly obtained by minimizing the expected loss per unit time. We assume that the quality loss function due to the deviation from the target value is quadratic and resetting loss is constant. We consider both cases of symmetric and asymmetric quality loss function. An illustrative example is given and sensitivity analysis performed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.139-142
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• 2003

Microwave dielectric properties of $Ca(Li_{1/4}Nb_{3/4})O_3-CaTiO_3$ ceramic systems were investigated with calcination temperatures and amounts of $CaTiO_3$ in the range of 0.2 to 0.4mol. $Ca(Li_{1/4}Nb_{3/4})O_3$ ceramics having orthorhombic crystal structure could be synthesized at $750^{\circ}C$ and sintered well at $1250^{\circ}C$. They showed the dielectric constant of 26, quality factor($Q{\times}f_o$) of 13,000 and temperature coefficient of resonant frequency(${\tau}_f$) of $-49{\pm}2ppm/^{\circ}C$ With adding the $CaTiO_3$ amount the dielectric constant and ${\tau}_f$ increased due to the solute of $CaTiO_3$ but the quality factor decreased. The 0.7$Ca(Li_{1/4}Nb_{3/4})O_3-0.3CaTiO_3$ ceramic showed the dielectric constant of 44, quality factor($Q{\times}f_o$) of 12,000 and ${\tau}_f$ of $-9{\pm}1ppm/^{\circ}C$.

• 한국환경보건학회지
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• 제31권4호
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• pp.260-265
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• 2005

Indoor air quality might be affected by source strength of indoor pollutants, ventilation rate, decay rate, outdoor level, and so on. Although technologies measuring these factors exist directly, direct measurements of all factors are not always practical in most field studies. The purpose of this study was to develop an alternative method to estimate the source strength and deposition constant by application of multiple measurements. For the total duration of 60 days, indoor and outdoor $NO_2$ concentrations every 3 days were measured in 30 houses in Seoul, Asan and Daegu. Using a compartment model by mass balance and linear regression analysis, penetration factor (ventilation divided by sum of air exchange rate and deposition constant) and source strength factor (emission rate divided by sum of air exchange rate and deposition constant) were calculated. Subsequently, the source strength and deposition constant were estimated. Natural ventilation was $1.80{\pm}0.42\;ACH,\;1.11{\pm}0.50\;ACH,\;0.92{\pm}0.26\;ACH$ in Seoul, Asan and Daegu, respectively. Calculated deposition constant(K) and source strength of $NO_2,$ in this study were $0.98{\pm}0.28\;hr^{1}\;and\;16.28{\pm}7.47\;ppb/h,$ respectively.

• 품질경영학회지
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• 제26권2호
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• pp.51-60
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• 1998

Exponetially weighted moving average(EWMA) control chart to simultaneously monitor correlation coefficients of several correlated quality variables under multivariate normal process are proposed. Performances of the proposed control charts are measured in terms of average run length(ARL) by simulation. Numerical results show that smaller values of smoothing constant are more efficient in terms of ARL.

• 품질경영학회지
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• 제11권2호
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• pp.37-41
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• 1983

Nine different rectification inspection policies are considered. For each variation, the cost breakeven points between acceptance without inspection, 100% inspection and sampling inspection are evaluated in both cases where process average is constant and varies as a beta distribution.