• Journal of Korean Society for Quality Management
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• v.23 no.4
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• pp.148-156
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• 1995

The past approach to burn-in optimization have been focused mainly in cost minimization problem during entire product life cycle. But in the case of practical application, burn-in optimization under reliability restriction might be preferred to burn-in optimization by cost minimization. Accordingly this paper shows real examples which estimate the practical burn-in period through application of heuristic method and select the best reliability model through comparison of reliability performance measures.

• Communications for Statistical Applications and Methods
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• v.16 no.5
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• pp.871-880
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• 2009

Recently, there has been much development on burn-in models in reliability area. Especially, the previous burn-in models have been extended to more general cases. For example, (i) burn-in procedures for repairable systems have been developed (ii) an extended assumption on the failure rate of the system has been proposed and (iii) a stochastic model for burn-in procedure in accelerated environment has been developed. In this paper, recent extensions and advances in burn-in models are introduced and some issues to be considered in the future study are discussed.

• Archives of Plastic Surgery
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• v.35 no.4
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• pp.373-378
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• 2008

Purpose: In full thickness burn, the depth of burn is known to increase until around 1-3 days after the burn. However, no study on how the depth increase during the first 24 hours has been conducted. Therefore, the authors investigated how the depth of burn changes within the first 24 hours after the burn by using the standardized burn model. Methods: A total of four experiments on pigs were carried out for this study. Experiment 1 was performed to examine how temperature affects the depth of burn. The digitally controlled aluminum thermal block was set at different temperatures-80, 90 and 100 degrees in Celsius, respectively. Then the pig was exposed to the block for 15 seconds each time. The time exposed to heat was set as a variable for the Experiment 2. The temperature was maintained at 80 degrees Celsius, and the pig was contacted with the thermal block for 5, 10 and 20 seconds, respectively. The biopsy of the tissues were performed in one hour, 6 hours, 24 hours, and 7 days after the burn. After hematoxylin and eosin staining a percentage of the depth from a basement membrane of epidermis to the deepest tissue damaged by the burn against total dermal thickness was measured. Results: In Experiment 1, the depth of burn increased considerably as time passed by. At all three temperatures, differences in depths measured in 6 and 24 hours, and in 1 hour and 7 days were both significant. In addition, the depth deepened as the temperature went higher. In the case of Experiment 2, the depth of burn also increased significantly as time passed by. At all three times, differences in depth measured in 6 and 24 hours, and in 1 hour and 7 days were also significant. Moreover, the depth extended with longer contact time when it was compared according to the time. Conclusion: Full thickness burn progressed rapidly from 6 to 24 hours after the burn and the depth of burn was almost decided within the first 24 hours after the burn. On the other hand, partial thickness burn also advanced from 6 to 24 hours after the burn but the depth deepened at slower level.

• Journal of Korean Society for Quality Management
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• v.21 no.2
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• pp.102-108
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• 1993

The purpose of burn-in is to eliminate the early failures of the products before they are delivered for customer use. Therefore burn-in should he continued until one is reasonally sure that all the weak items have failed, thus leaving the remaining items in a healthy state of reliability. From this point of view, burn-in time dependent costs such as a cost per product per burn-in time, and cost of repair of the product per failure occurred during burn-in time will he increased. Conversely, the cost of field repair of the product per failure occurred during the guarantee period will be decreased since the early failure of the product is fully eliminated during burn-in. Hence, this paper intend to determine optimal burn-in time which minimize the total of above costs associated with burn-in.

• Journal of the Korean Chemical Society
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• v.39 no.10
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• pp.763-768
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• 1995

The theory previously proposed to simulate hole depth in the weak burn intensity limit is extended to examine the hole depth at arbitrary burn intensity using 3-level system model. The hole spectrum simulated using constant fluence gives different hole depth for strong burn intensity while it gives same hole depth for weak burn intensity region. The calculated hole growth curves are compared with published experimental data for oxazine720 in glycerol and tetracene in MTHF glass.

• Korean Journal of Adult Nursing
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• v.17 no.1
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• pp.100-108
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• 2005

Purpose: The purpose of this study was to identify predictors of quality of life in burn patients. The predictors of quality of life were the subject's characteristics(marriage, income, burn size, burn site, pain and functional limitation) and personal resources(self esteem and social support). Method: 96 burn subjects who were hospitalized participated in the study. The data analysed was with descriptive analysis, ANOVA, Pearson correlation coefficient and multiple regression. Result: Burn patients who had a spouse and had higher levels of income, with smaller size of burn, no arm burn, with lower levels of pain and functional limitation, plus higher levels of self esteem and social support reported higher levels of quality of life(R2=0.5229). Conclusion: Based on the finding of this study, development of nursing intervention programs including reduction of pain and functional limitation, enhancing self esteem and social support can be suggested.

• International Journal of Reliability and Applications
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• v.2 no.4
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• pp.241-251
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• 2001

In this paper, optimal bum-in time to minimize the total mean cost, which is the sum of manufacturing cost with burn-in and cumulative warranty-related cost, is obtained. When the products with cumulative pro-rata warranty have high failure rate in the early period (infant mortality period), a burn-in procedure is adopted to eliminate early product failures. After burn-in, the posterior product life distribution and the warranty-related cost are dependent on burn-in time; long burn-in period may reduce the warranty-related cost, but it increases the manufacturing cost. The paper provides a methodology to obtain total mean cost under burn-in and cumulative pro-rata warranty. Property of the optimal burn-in time is analyzed, and numerical examples and sensitivity analysis are studied.

• Journal of the Korean Burn Society
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• v.22 no.2
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• pp.38-44
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• 2019

Purpose: The immature granulocyte count has been reported to be a marker of infection and sepsis. The difference in leukocyte subfractions (delta neutrophil index, DNI) in ADVIA 2120 reflects the fraction of circulating immature granulocytes in the blood. This study evaluated the clinical utility of DNI as a severity and prediction marker in critically ill patients with burn sepsis. Methods: One hundred and sixty nine patients admitted to the burn care unit were studied. DNI (the difference in leukocyte subfractions identified by myeloperoxidase and nuclear lobularity channels) was determined using a specific blood cell analyzer. Results: Seventy one patients (42 %) were diagnosed with burn sepsis. DNI was significantly higher in patients with burn sepsis than in patients without (P<0.01). Delta neutrophil index was a better indicator of burn sepsis than C-reactive protein, lactate, white blood cell count, HCO3, base excess, lactate, procalcitonin (odds ratio, 6.31; confidence interval 2.36~16.90; P<0.01). And the receiver operating characteristic curves showed that delta neutrophil index, AUC 0.795 (95% confidence interval, 0.721~0.869; P<0.05) was a better predictor of burn sepsis than lactate, procalcitonin, white blood cell, base excess and abbreviated burn severity index. Conclusion: Delta neutrophil index may be used as a early marker of patients with burn sepsis.

• Archives of Plastic Surgery
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• v.38 no.4
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• pp.445-450
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• 2011

Purpose: The objective of this study is to analyze the epidemiological characteristics of pediatric burn patients and to determine the targets for a pediatric burn prevention program. Methods: A retrospective review of all medical records of acute pediatric burn patients (age < 15 years old) admitted to our hospital between January 2005 and December 2009 was performed. Results: 1472 males and 1323 females were investigated, with a male to female ratio of 1.11 : 1. The greatest number of burn patients were those with an age of 1~2 years (1,463, 52.3%). Scalding burn was the most common cause of injury, which accounted for 2183 (78.1%) patients, followed by contact burns (10.5%), flame burn (4.9%), steam burn (3.6%). Especially steam burn was the second cause of injury in the age under 1 year, while flame burn was the second cause of injury in the age over 7 years. During recent 5 years, incidence of flame burn, steam burn, electrical burn gradually decreased. Variation of seasonal incidence is minimal and most of the patients (2,716 cases, 97.2%) had burns less than 20% TBSA (Total body surface area). The median hospital stay was 18.79 days, and the rate of operation was 28.6% with a high rate in electrical burn (76.2%), flame burn (50.0%), steam burn (46.1%). 6 patients died in this series, which yielded a mortality rate of 0.2%. Conclusion: Prevention efforts should reflect recent study results. Focused prevention program and campaign to make people aware of risk factors and their avoidance is required to reduce the number of burn accidents in children.

• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.544-555
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• 1998

Although the bimodal mixed weibull distribution is used to developing burn-in model widely, the failure times for a component or a system is often truncated at some time, T, due to the obsolescence in the electronics industry. In this paper, we will determine minimum total cost and burn-in time by using the bimodal mixed weibull distribution and the truncated bimodal mixed weibull distribution under the free warranty policy. The results of this study are summarized as follows. First, when products or system is not repairable, the width of the change of burn-in time can be larger by ${\beta}_1,\;{\beta}_2$ Second, if burn-in time become longer, it will be impossible to consider the bum-in in a long time, and in this case, the burn-in time should be shorten by the acceleration burn-in. Third, in case that opportunity loss cost or repair cost is exceed the warranty cost, or the total cost of considering burn-in is larger than that of not considering burn-in, it is not existed burn-in time which makes total cost to minimize. Forth, the shorter life-cycle of product, the more burn-in times will be decreased and the cost in considering burn-in will be increased