• Journal of Korea Water Resources Association
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• v.43 no.11
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• pp.967-976
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• 2010

AFDA (Approximate Full Distribution Approach) model of FORM (First-Order Reliability Model) which can quantitatively calculate the probability that storm sewer reach to performance limit state was developed in this study. It was defined as a failure if amount of inflow exceed the capacity of storm sewer. Manning's equation and rational equation were used to determine the capacity and inflow of reliability function. Furthermore, statistical characteristics and distribution for the random variables were analyzed as a reliability analysis. It was found that the statistical distribution for annual maximum rainfall intensity of 10 cities in Korea is matched well with Gumbel distribution. Reliability model developed in this study was applied to Y shaped storm sewer system to calculate the probability that storm sewer may exceed the performance limit state. Probability of failure according to diameter was calculated using Manning's equation. Especially, probability of failure of storm sewer in Mungyeong and Daejeon was calculated using rainfall intensity of 50-year return period. It was found that probability of failure can be significantly increased if diameter is decreased below the original diameter. Therefore, cleaning the debris in sewer pipes to maintain the original pipe diameter should be one of the best ways to reduce the probability of failure of storm sewer. In sewer system, two sewer pipes can flow into one sewer pipe. For this case, probability of system failure was calculated using multiple failure mode. Reliability model developed in this study can be applied to design, maintenance, management, and control of storm sewer system.

• Journal of Korean Neurosurgical Society
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• v.58 no.6
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• pp.539-546
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• 2015

Objective : To report the learning curve of percutaneous endoscopic lumbar discectomy (PELD) for a surgeon who had not been previously exposed to this procedure based on the period and detailed technique with a retrospective matched comparative design. Methods : Of 213 patients with lumbar disc herniation encountered during the reference period, 35 patients who were followed up for 1 year after PELD were enrolled in this study. The patients were categorized by the period and technique of operation : group A, the first 15 cases, who underwent by the 'in-and-out' technique; group B, the next 20 cases, who underwent by the 'in-and-out-and-in' technique. The operation time, failure rate, blood loss, complication rate, re-herniation rate, the Visual Analogue Scale (VAS) for back and leg were checked. The alteration of dural sac cross-sectional area (DSCSA) between the preoperative and the postoperative MRI was checked. Results : Operative time was rapidly reduced in the early phase, and then tapered to a steady state for the 35 cases receiving the PELD. After surgery, VAS scores for the back and leg were decreased significantly in both groups. Complications occurred in 2 patients in group A and 2 patients in group B. Between the two groups, there were significant differences in operative time, improvement of leg VAS, and expansion of DSCSA. Conclusion : PELD learning curve seems to be acceptable with sufficient preparation. However, because of their high tendency to delayed operation time, operation failure, and re-herniation, caution should be exercised at the early phase of the procedure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.2
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• pp.180-186
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• 2005

As a driving method of AC-PDP, Address-Display Separated(ADS) driving has been widely adopted for its simple architecture and low discharge failure rate. However, a high definition like a HDTV has defect of long addressing time by reason of a number of pixels. Priming effect isn't fully sustained because of long addressing time during the address period. Therefore, it has different wall charge and luminance of each addressing time in the sustain period. In this study, we suggest a new driving waveform on the address period to improve these defects. We applied a ramp waveform, instead of a square waveform, to an address period in ADS, for operating on the AC-PDP, which used the conventional gas [He-Ne-Xe]. When the ramp waveform is applied to the address period, we experimented for uniform wall charge and the improved luminance by sustained Priming effect at each addressing time in the sustain period.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.4
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• pp.123-132
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• 2020

Currently, there are two types of trainer in Korea : basic and advanced. Both models have been in operation for more than 10 years, and compared to the early stage of operation, reliability has gradually improved and failure rates have also entered a trend of stabilization. Therefore, it is necessary to extend the maintenance period considering economic feasibility. This study investigates the three maintenance period calculation methods: NAVAIR 00-25-403 [17], DOD, U.S. [4], CERL and US Army [3], with intention to extend the maintenance period of the trainer from current 200 hours to 400 hours. In addition, the maintenance period was calculated by the three methods with actual operational data. Common standards and procedures were established to apply operational data to the existing maintenance period calculation methods, the required reliability indicators were derived, and the maintenance periods was calculated based on the results, additionally, a review on the field applicability of the three maintenance cycles was conducted. An on-site interviews were conducted with the calculation results, and 11 out of the 15 items were expected to be extended by 400 hours. It was suggested that the remaining 4 items could be extended to 400 hours by supplementing the inspection method through additional analysis such as functional analysis, inspection content verification, and site connection.

• Journal of Haehwa Medicine
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• v.21 no.1
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• pp.163-174
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• 2012

Objective: The primary objective this study was to evaluate the effect of Paljeong-san (PJS) pharmacopuncture treatment on against the glycerol-induced acute renal failure in rats. Methods: Glycerol injection decreased GFR (glomerular filtration rate) and increased urine volume, serum creatinine, BUN level, urine albumine secretion and fractional excretion of Na+, K+. PJS was selected in the basis of invigorating kidney which can eliminate pathogens. Rats were treated with PJS pharmacopuncture on Shin-shu (BL23) and Chon-chu (ST25) point for 3 days, followed by 50% concentration of glycerol injection ($5m{\ell}/kg$ body weight). Results: After the 3 days treatment period, Paljeong-san (PJS) pharmacopuncture treatment improved renal function. In addition, Glycerol injection increased lipid peroxidation, and decreased Na-K-ATPase in renal cortex and which were prevented by PJS treatment. Conclusion: This study suggests that Paljeong-san (PJS) pharmacopuncture treatment show favorable effect on glycerol-induced acute renal failure in rats.

• Journal of Chest Surgery
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• v.16 no.2
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• pp.184-189
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• 1983

Between 1958 and 1982, 70 patients have undergone pericardiectomy for constrictive pericarditis at the Thoracic Department of Seoul National University Hosp. 58 males and 12 females, with an average age of 27 years [ranging 3 to 60 years], of which 55% were between 10 and 30 years old, were treated. Eight patients died, of whom 4 were in the immediate postoperative period, less that 24 hours after operation. The cause of death was myocardial failure in 3 patients and hypotension during operation in one patient. The remaining four deaths occurred between the fifth and eighteenth postoperative day, and the causes of death varied: bilateral phrenic nerves injury, congestive heart failure, dissemination of tuberculosis, and cardiac arrest. Two patients suffered from congestive heart failure pre-and postoperatively due to the associated valvular heart disease. There were 8 wound infections on which resulted in perichondritis of costal cartilages requiring segmental resection 2 months later. There was one postoperative bleeding requiring immediate reopening for bleeding control. Tuberculosis was confirmed as the cause of constrictive carditis in 27 patients [39%]. Acute pyogenic pericarditis was precursor in 8 patients [11%]. In 2 patients [2.9%], the constrictive pericarditis developed following OHS. Both suffered from congestive heart failure postoperatively due to the residual valvular heart disease. In the others, the cause of the constrictive pericarditis was considered idiopathic or non-specific inflammation.

• Journal of Power Electronics
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• v.3 no.3
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• pp.145-150
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• 2003

Reliability, availability, and cost have been the major concerns for photovoltaic hybrid systems since their beginning as primary sources for much critical applications like communication units and repeaters. This paper descnbes the performance of two hybrid systems, photovoltaic-battery, wind-turbine coupled with the public-grid (PVBWG) hybrid system and photovoltaic-battery, wind-turbine coupled With the diesel generator (PVBWD) hybrid system The systems are sized to power a typical 300W/48V de telecommunication load continuously throughout the year Such hybrid systems consist of subsystems, which in turn consist of components Failure of anyone of these components may cause failure of the entire system. The reliability and availability basics, and estimation procedure for the two proposals are introduced also in this paper. The PVBWG and PVBWD system configurations are shown with the relevant mean-time-between-faIlure (MTBF) and failure rate (${\lambda}$) of each component. The characteristics equations of the two systems are deduced as a function of operating hours and the percentage of sun and wind availabilities per day. The system probability failure as well as the reliability is estimated based on the fault tree analysis technique. The results show that, by using standard or normal components MTBF, the PVBWG is more reliable and the time of periodic maintenance period is more than one year especially in the rich sites of both sun and wind, but PVBWD competes else Also, in the first five years from the system installation, the system is quit reliable and may not require any maintenance. The results show also, as the sun and wind are available, as the system reliable and available.

• Journal of Korean Biological Nursing Science
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• v.19 no.4
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• pp.227-240
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• 2017

Purpose: The purpose of this review was to identify the current status of nursing studies on heart failure (HF) patients in South Korea and to suggest future study direction. Methods: A literature review of databases such as KoreaMed, KERIS and nursing and allied health journal were searched with key terms 'heart failure' and 'nursing' for the period from January 2000 to February 2017. A total of 35 studies including 28 articles and 7 theses met the inclusion criteria. Results: Twenty-seven out of 35 studies were observational studies on outpatients and most of the studies did not mention the ejection fraction and New York Heart Association functional classification class (NYHA class) in the inclusion criteria. Self-care and health-related quality of life as psychological factors, and physical activity as a biological factor, were used as main variables. However, we found it difficult to understand how much score indicates better quality of life because of an inconsistent and wide score. In quality assessment, 8 intervention studies had no serious flaws. Conclusion: Further studies should consider more biological and social factors influencing HF. The quality assessment with respect to nursing intervention studies in HF showed that randomized and double-blind trials are needed.

• Journal of Korean Society for Quality Management
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• v.39 no.2
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• pp.217-233
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• 2011

This paper introduces service failure management on internet shopping environment. The purpose of this study is to find and improve service failure modes at the time of customer's complaint thereby reducing that. To achieve this purpose, this study combines the Service Blueprint which describes the online shopping process and FMEA which finds each encounter of service failures and proposes how to recover them. First of all this study generates internet shopping process using Service Blueprint then matches customer's purchase decision making process and company's service provide process. After this process customer complaint types in real purchasing process are fell in according to their occurrence and more frequently occurred complaint is more risky. Finally 6 Risk Priority Numbers(unfair exchange/return policies, slow response/poor customer service support, purchase arrived later than promised/deliverly service dissatisfaction, dissatisfaction short period to take back/exchange/cancels order, A/S or handle defective item) are extracted and suggest their improvement.

• Journal of Korean Academy of Nursing
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• v.54 no.1
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• pp.93-105
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• 2024

Purpose: The study aimed to understand the semantic structure and nature of the disease experience of kidney transplant recipients with kidney graft failure by applying phenomenological research methods. Methods: Data were collected between February and September 2021 through individual in-depth interviews with 12 kidney transplant recipients with kidney graft failure. Colaizzi's phenomenological analysis was used to analyze the meaning of the participants' illness experiences. Results: 5 theme clusters and 15 themes were derived. The five theme clusters are as follows: (1) First transplant giving me a second life; (2) Body and mind becoming sick again; (3) Waiting for a re-transplant with hope and worry; (4) Life supported by gratefulness; (5) Having control over my own life. Conclusion: This study shows that kidney transplant recipients with kidney graft failure experience physical and psychological difficulties during the long disease period and require help from many people, including family members, friends, colleagues, and health care providers, to overcome their difficulties.