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

• International Journal of Reliability and Applications
• /
• v.2 no.4
• /
• pp.241-251
• /
• 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 Korean Academy of Nursing
• /
• v.17 no.3
• /
• pp.227-240
• /
• 1987

Infection has assumed increased importance as a cause of death among thermally injured individuals. Decreased treatment effectiveness and an increase in mortality are the hallmarks of nosocomial infection. Infection control is a monumental task that must be achieved to reduce mortalities. This was a retrospective study to survey the epidemiological features of nosocomial infections in a burn unit and to identify the possibilities for infection control. During the past 6 year 2 month period from July, 1981 to August, 1987, 306 burn patients were treated in the burn unit of university hospital. Among of these, 290 cases were the subjects of this study. The data were collected from the patients' records after discharge. All data collected were analyzed using percent, x$^2$-test, t-test with SPSS program. The results of this study are summariged as follows: 1) Infection rate was 40%. According to site, there were 67 cases of wound infection, 60 cases of post-operative skin graft infection, 20 cases of septicemia and 20 cases of donor site infection. As far as the burn size was concerned, the infection rate for patients whose burn size ranged 61 to 70%, was shown to be 100%, followed by the infection rate of 93.8%, for patients whose burn size ranged from 41~50%. As far as the period of time over which the infection developed, 5 to 7 days showed the highest frequency. Further infection was the main cause of deaths and complications. 2) Based upon the results obained by comparing the general characteristics, between a hospital infection-group and non-hospital infection group, there was a significant defference according to age, the time of the year when the accident happened, the place of accident or length of hospital-admission. And according to the result obtained by comparing the general characteristics of the burn, there was a significant difference according to burn size, burn depth, burn type, and burn site. And also based upon the result obtained by comparing the two groups according to method of treatment, there was a significant difference according to the use of antibiotics and to the type of wound-treatment, and for the 8 different binds of treatment related to infection, there was a significant difference for all. In conclusion, age, length of hospital-admission, burn size, burn type, burn site, burn depth, type of woundtreatment and the 8 different binds of treatment, which are related to burns, were shown to be the factors which affect the infection rate in burn patients.

• Journal of the Korean Data and Information Science Society
• /
• v.17 no.3
• /
• pp.861-869
• /
• 2006

Burn-in is a widely used method to improve the quality of products or systems after they have been produced. In this paper, the problem of determining optimal burn-in time for a system which performs given mission is considered. It is assumed that the given mission time is not a fixed constant but a random variable which follows an exponential distribution. Assuming that the underlying lifetime distribution of a system has an eventually increasing failure rate function, an upper bound for the optimal burn-in time which maximizes the probability of performing given mission is derived. The obtained result is also applied to an illustrative example.

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

• Archives of Plastic Surgery
• /
• v.33 no.5
• /
• pp.581-586
• /
• 2006

Purpose: Pediatric burn still generates social problem leading to physical and mental sequelae for ages. We studied to help make a program for the prevention of pediatric burn. Methods: We analyzed retrospectically 2759 acute burn patients under the age of 15 years in recent 5years (January 2000 - December 2004). Results: 1553 males and 1226 females were investigated, with a male to female ratio of 1.25 : 1. The greatest number of burn patients were those with an age of 1 - 2 years(1435, 52%). Scalding burn was the most common cause of injury, which accounted for 1980 (71.8%) patients, followed by contact burns(286, 10.4%), flame burn(229, 8.3%), steam burn(141, 5.1%). Especially steam burn was the second cause of injury in the age under 1 year, while flame burn was the same in the age over 3 years. During recent 5 years, incidence of contact burn increased over twofold despite the others did not changed substantially. Variation of seasonal incidence is minimal and most of the patients(2545 cases, 92.2%) had burns of ${\leq}20%$ TBSA. The median hospital stay was 18.3 days, and the rate of operation was 35.4% with an high rate in electrical burn(70.6%), steam burn(68.8%), contact burn(65%). 27 patients died in this series, which yielded a mortality rate of 1%. Conclusion: We expect that these data will be used as a basis for prevention of pediatric burn.

• Journal of the Korean Burn Society
• /
• v.23 no.2
• /
• pp.42-53
• /
• 2020

Purpose: It is important to consider both clinical factors and epidemiological factors in treating burn patients in emergency rooms. However, many emergency medical staffs happen to miss their chances of treating burns based on these considerations. This study is designed to find a better treatment for burn patients in emergency rooms along this approach. Methods: This study was conducted based on the data of the burn patients visiting the emergency room of a single general hospital from January 2015 to December 2019. The epidemiological and clinical factors were extracted out of the data, then the relationship between the prognosis and these factors were analyzed. Results: Most of burn accidents occurred at home, and were caused by hot water, soup, drinks, oil, etc. Especially, flame burns showed high hospitalization rate, surgical rate and mortality. In addition, their prognosis was poor when the affected area included facial, limb and perineal areas etc., or any inhalation burn co-existed. Also, the hospitalization rate and period increased when the treatment time was delayed or the pre-treatment was taken. There was a strong relationship between prognosis and the period of follow-up when patients were admitted during the period. Conclusion: It is difficult for medical staffs to evaluate prognosis of burns in emergency rooms due to progressive damages. Precise treatment and disposition are essential for patients' good prognosis. Therefore, medical staffs should establish treatment plans by identifying the patient's epidemiological and clinical factors, rather than giving prescriptions based on fragmentary and superficial symptoms.

• 한국전산유체공학회:학술대회논문집
• /
• 1998.05a
• /
• pp.1-14
• /
• 1998

Underwater explosion properties for TNT, an ideal explosive, and DXD-04, a nonideal explosive, were numerically modeled with a one-dimensional Lagrangian hydrodynamic code. The equation of state parameters for detonation products for TNT and DXD-04 were obtained from the BKW code, assuming complete reaction. Burn of TNT was modeled by using the Chapman-Jouguet(CJ) volume burn technique, a programmed-burn technique, assuming instantaneous detonation reaction. Burn of DXD-04 was modeled by using the same technique and by using the reaction rate calibrated from two-dimensional steady-state detonation experiments. The calculations for TNT reproduced the experimental peak pressure of the shock wave propagating through water with an error of $3.0\%$ and the experimental oscillation period of the bubble formed of detonation products with an error of $2.3\%$. For DXD-04, the CJ volume burn technique could not reproduce the experimental observations. When the reaction rate calibrated from two-dimensional steady-state detonation experimental data, the calculated peak pressure was slightly higher by $7.3\%$ than the experimental data, but the calculated shock profile was in good agreement. The bubble period was reproduced with an error of $1.8\%$. These results demonstrated that underwater explosion properties for an ideal explosive can be predicted by using a programmed burn technique, and that, however, those for a nonideal explosive can be predicted only when a well-calibrated reaction rate is used.

• The Journal of Korean Society for School & Community Health Education
• /
• v.20 no.2
• /
• pp.1-12
• /
• 2019

Objectives: The purpose of this study is to understand the factors affecting the dual smoking experience of conventional and heat-not-burn tobacco among adolescents with smoking experience. Methods: The study selected 8,691 people with experience in smoking. Data analysis used SPSS 25.0. Logistic regression was performed to identify the factors affecting the dual smoking experience. Results: In this study, the dual smoking experience rate of conventional and heat-not-burn tobacco was 16.3%. The dual smoking experience rate was 5.09 times higher than the number of smokers among friends. The lower the smoking age, the higher the smoking rate, and the longer the smoking days, the higher the dual smoking rate of heat-not-burn cigarettes. Conclusion: We need a peer-to-peer group arbitration program rather than a separate anti-smoking arbitration program for smokers.

• Journal of the Korea Safety Management & Science
• /
• v.1 no.1
• /
• pp.135-143
• /
• 1999

This paper discusses an optimal burn-in procedure to minimize total costs based on the assumption that the failure rate pattern follows a bimodal mixed Weibull distribution. The procedure will consider warranty period as a factor of the total expected bum-in cost. A cost model is formulated to find the optimal burn-in time that minimizes the expected burn-in cost. Conditional reliability for warranty period will be discussed. An illustrative example is included to show how to use the cost model in practice.