• Journal of Chest Surgery
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• 제31권5호
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• pp.494-501
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• 1998

From May 1, 1993 to May 31 1995, the authers studied retrospectively 211 patients who underwent cardiovascular operation with cardiopulmonary bypass(CPB). Because we were interested in new development of ARF(prevalence, mortality rate, and main risk factors), we performed a multivariate statistical analysis about data of patients with preoperative serum creatinine values of less than 1.5 mg/dL. Normal renal function before operation(serum creatinine level less than 1.5 mg/dL) was registered in 198(74%) patients. Of these, 27(14%) patients showed postoperative renal complication, including 20(10%) patients classified as renal dysfunction(serum creatinine level between 1.5 and 2.5 mg/dL) and 7(4%) patients as acute renal failure(serum creatinine level higher than 2.5 mg/dL). The mortality rate was 5.8% in normal patients, 5% in patients with renal dysfunction, and 43% when acute renal failure developed(p=0.036). Indeed, the renal impairment proved to be an independent predictor of mortality(odd ratio 2.52∼11.25), along with cardiovascular(odd ratio 4.20) and respiratory(odd ratio 2.18) complications. Multivariate analysis identified the following variables as independent risk factors for postoperative renal impairment : advanced age(odd ratio 1), need for emergency operation(odd ratio 3.78), low-output syndrome(odd ratio 3.66), respiratory complication(odd ratio 1.30), need for deep hypothermic circulatory arrest(odd ratio 1.4). The 13 patients(7%) with preoperative renal failure showed a significantly higher morbidity and mortality rate than those without renal complications before operation. We concluded that the likelihood of severe renal complications is resonably low in the patients undergoing cardiac operation without preexisting renal dysfunction, but associated mortality remains high. A prominant role of hemodynamic factor in the development of postoperative acute renal failure must be recognized during preoperative, intraoperative, and postoperative periods.

• Journal of Chest Surgery
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• 제30권10호
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• pp.973-978
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• 1997

We reviewed data of 64 patients who underwent reoperation because of prosthetic valve malfunction from January 1991 to December 1995. The indications for reoperation were prosthetic valve failure(primary tissue failure: 53 patients, 82.8%), prosthetic valve thrombosis(6 patients, 9.4%), paravalvular leak(3 patients, 4.7%), prosthetic valve endocarditis(2 patients, 3.6%). Prosthetic valve failure developed most frequently in mitral portion(40 patients, 75%), prosthetic valve thrombosis also in mitral portion(4 patients, 67%), paravalvular leak significantly in aortic portio (3 patients, 100%). Explant period was longest in prosthetic valve failure(mean 107.4 $\pm$ 24.6 months), shortest in prosthetic valve endocarditis with prosthetic valve thrombosis(1 patient, 1 month). Mean explant period, defined as from first valve replacement operation to redo-valve replacement operatopn, was 109.2$\pm$ 10.7 months in mitral portion, 97.8$\pm$ 10.4 months in aortic portion, 109.5$\pm$ 10.4 months in total. Overall hospital mortality was 9.38%. The most common cause of death was the low cardiac output(4 patients), other causes were bleeding(1 patient), CNS injury(1 patient). Preoperative NYHA class IV(P=0.011), emergency operation(P=0.011), prosthetic valve endocarditis(P=0.001) were the independent risk factors, but age, sex, explant period, ACC time, double valve replacement, valve position, second reoperation did not appear to be significant risk factors. Mean follow up period was 28.8 $\pm$ 17.8 months. Actuarial survival at 3 year was 92.0$\pm$6.2%, 2 year event-free survival w s 84.3$\pm$6.1%. We propose that patients undergoing reoperation because of prosthetic valve failure are carfully controlled and selected in regarding to above mentioned risk factors NYHA class IV, emergency operation, prosthetic valve endocarditis in preoperative state. About other risk factors possible, there is necessary of following study.

• Journal of Digital Contents Society
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• 제15권2호
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• pp.301-308
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• 2014

The mass storage of data and the importance of storage capacity lately has emerged. In this paper, we suggest the new method which estimate life cycle from acceleration life test about 2.5 inch hard disk driver as mass storage, which minimize the difference between real market annual failure rate and estimated failure rate. we obtain market transfer capacity per hours from returned 2.5inch hard disk drives about 309 numbers and accelerating transfer capacity per hours from acceleration life test. we calculate acceleration factor about duty cycle and estimate annual failure rate from failure rate and acceleration factors: temperature acceleration factor, duty cycle acceleration factor, the transfer capacity per hour represent the 93.4 % of user is 5.8 GB/hour, the transfer capacity per hour from acceleration life test is 81.4 GB/hour. the acceleration factor of duty cycle is 14.1. annual failure rate is stabilized at market one year after, annual failure rate is between 0.3 and 0.378. estimated annual failure rate is 0.4, so it is matched at 75~94 % between estimate annual failure rate and market annual failure rate. This study influence the estimate method of annual failure rate by the result of acceleration life cycle of manufacture.

• Tuberculosis and Respiratory Diseases
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• 제57권5호
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• pp.439-442
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• 2004

Background : Extubation failure and reintubation increase the morbidity and the mortality rate. Several extubation criteria and risk factors for extubation failure have been recommended. However, some patients present with extubation failure even after a planned extubation. The aim of this study was to evaluate the clinical characteristics of patients with extubation failure after a planned extubation. Methods : Thirty one patients who presented with planned extubation were included. Extubation failure was defined as reintubation within 48 hours after extubation. The clinical, respiratory and hemodynamic parameters between extubation success and failure group were compared. Results : Six patients were included in the failure group. The extubation failure rate was 19.4%. The age, periods of intubation and heart rates were significantly different between the extubation success and failure group. In the success and failure group, the mean age were $60.4{\pm}15.65$ vs. $80.3{\pm}7.17$ year, the intubation periods were $7.12{\pm}2.47$ vs. $13.83{\pm}2.4$ day and the heart rates were $94.32{\pm}5.77$ vs. $110.67{\pm}3.78/min$, respectively. Conclusion : Old age and patients intubated for periods will require a will careful assessment before extubation. Extensive cardiac evaluations before extubation will also be needed.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 한국지진공학회 2002년도 춘계 학술발표회 논문집
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• pp.228-235
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• 2002

As the response spectrum method generally used in the earthquake resistant design is a linear method, the nonlinear behavior of a structure is to be reflected with a specific factor. Such factors are provided in the "Design Criteria for Roadwaybridges"as response modification factors and in the Eurocode 8, Part 2 as behavior factors. In this study a 5-span steel box bridge with single column piers is selected and the behavior factor is determined. The linear time history analyses are carried out with a simple linear model, where the nonlinear behavior of piers leading to the ductile failure mechanism is considered as predetermined characteristic curves.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 한국산업경영시스템학회 2002년도 춘계학술대회
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• pp.25-30
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• 2002

The problem of qualitative reliability system is very important issue in the digitalized nuclear power plant, because the failure of its system brings about extravagant economic loss, extensive environment destruction, and fatal damage of human. Therefore this study is to develop the reliability evaluation model through the normalized scoring model by the quantitative and qualitative factors considering the advanced safety factors In the Advanced Pressurized water Reactor 1400MWe(APR 1400) under uncertainty Especially, the qualitative factors considering the information and human factors for the systematic and rational justification have been closely analyzed. The reliability evaluation model can be simply applied in real fields in order to minimize the industrial accident and human error in the digitalized nuclear power plant.

• Journal of Information Technology Applications and Management
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• 제17권4호
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• pp.127-156
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• 2010

Most companies in the IT service industry have suffered from low profitability although this industry is highly value added, which may result in losing the competitiveness of the industry. The purpose of this study is to identify the influencing factors on the profit improvement rate of IT service projects and suggest how to improve the profit improvement rate, thus recovering the competitiveness of the IT service industry. The 273 IT service projects conducted by an IT service company in Korea during the past three years were analyzed and the project managers who performed these projects responded to the questionnaire developed in this study. The result from the analysis of data collected shows that the influencing factors on the profit improvement rate of IT service projects include scheduling, experience in similar projects, the leadership of project leaders, the level of team skills, relationship with clients, and clients support.

• Proceedings of the KSR Conference
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1501-1507
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• 2006

The accidents are often resulted from multiple causes with hardware failure and human errors. So to ensure the safety of rail operation, human error should be prevented effectively. The purpose of this paper is to present an analysis system on factors of influencing human error in korean rail industry especially for engine driver and train despatcher. To achieve it, ESFs(error shaping factors) classification system was derived from several PSFs(performance shaping factors) classification system. Based on them, two kinds of questionnaires for engine driver and train despatcher each were developed. Then Analytic Hierarchy Process (AHP) methodology was used to evaluate what factors were critical to human error.

• Journal of Veterinary Clinics
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• 제31권3호
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• pp.163-169
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• 2014

Glucose metabolism abnormalities secondary to heart failure, including insulin resistance (IR) and impaired fasting glucose, have been gradually recognized as important prognostic factors in disease progression. However, to date, no study has investigated glucose abnormalities in dogs with chronic mitral valve insufficiency (CMVD). Thus, we hypothesized that glucose metabolism abnormalities due to heart failure may develop in dogs with CMVD. A prospective study was performed on 113 client-owned dogs with variable CMVD severities. Serum insulin, glucagon, fructosamine, and glucose concentrations were measured, and insulin resistance was determined using the homeostatic model assessment (HOMA) score. The serum insulin concentration had a significant inverse association with the heart failure severity. However, there was no significant association between the heart failure severity and fructosamine, HOMA score, and fasting blood glucose. Insulin, fructosamine, and HOMA had a significant positive association with body condition scores (BCS), whereas glucose had no association. This study found that insulin secretion in dogs with naturally occurring heart failure due to CMVD might be compromised as the disease worsens.

• Journal of Digital Convergence
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• 제13권12호
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• pp.143-149
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• 2015

This study aims to analyze the predict capability of some of the popular software NHPP reliability models(Goel-Okumo model, delayed S-shaped reliability model and Rayleigh distribution model). The predict capability analysis will be on two key factors, one pertaining to the degree of fitment on available failure data and the other for its prediction capability. Estimation of parameters for each model was used maximum likelihood estimation using first 80% of the failure data. Comparison of predict capability of models selected by validating against the last 20% of the available failure data. Through this study, findings can be used as priori information for the administrator to analyze the failure of software.