• 한국관광식음료학회지:관광식음료경영연구
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• 제15권2호
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• pp.123-150
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• 2004

The purpose of this study is to prove that the approprlate fit between service failure and recovery strategy can effciently maximize customer satisfaction and behavioral intention, by using prepared scenario through comprehensive approach concerning how the expectation level about service recovery has influences on perceived fairness, satisfaction and behavioral intention of servlce recovery based upon size in case of service failure. This study has been conducted by way of selection of filling-up type questionnaires for customers themselves who have experience in service failure out of customers who can easily visit family and hotel restaurants, that is, domestic restaurants in Seoul area, June ~ August 2004, by setting factorial design of 2(control, severeness) ${\times}$ 3(distributive fairness, procedural fairness, mutual relational fairness) ${\times}$ 2(customer satisfaction, customer behavior). The survey was performed on the customers who visited common restaurants, family restaurants, hotel restaurants, etc. mainly in Seoul, and total 600 sheets of questionnaires were distributed and 496 sheets of them were returned(82.67% of return ratio).

• Clinical and Experimental Reproductive Medicine
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• 제50권3호
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• pp.185-191
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• 2023

Objective: Although intracytoplasmic sperm injection (ICSI) is a way to deal with in vitro fertilization failure, 3% of couples still experience repeated fertilization failure after attempted ICSI, despite having sperm within normal parameters. These patients are a challenging group whose sperm cannot fertilize the egg during ICSI. Unfortunately, no test can predict the risk of fertilization failure. Phospholipase C zeta (PLCζ) and transition nuclear proteins (TNPs) are essential factors for chromatin packaging during sperm maturation. This study aimed to assess PLCζ1 and TNP1 expression in the sperm of patients with fertilization failure and the correlations among the DNA fragmentation index, PLCζ1 and TNP1 gene and protein expression, and the risk of fertilization failure. Methods: In this study, 12 infertile couples with low fertilization rates (<25%) and complete failure of fertilization in their prior ICSI cycles despite normal sperm parameters were chosen as the case group. Fifteen individuals who underwent ICSI for the first time served as the control group. After sperm analysis and DNA fragmentation assays, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blot analyses were performed to compare the gene and protein expression of PLCζ and TNP1 in both groups. Results: DNA fragmentation was significantly higher in the fertilization failure group. The qRT-PCR and Western blot results demonstrated significantly lower PLCζ and TNP1 gene and protein expression in these patients than in controls. Conclusion: The present study showed that fertilization failure in normozoospermic men was probably due to deficient DNA packaging and expression of TNP1.

• Journal of Chest Surgery
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• 제17권1호
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• pp.3-11
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• 1984

Prosthetic valve replacement has resulted in marked improvement in the functional status of many patients with valvular heart disease. But valve failure from various causes has necessitated re-replacement of prosthetic valve in some of these patients. This selective group of patients has many inherent problems. This report presents our experience with seven patients who received re-replacement of prosthetic valve in the Seoul National University Hospital from 1981, to 1983. The patients included one woman and six men in the range of 9 and 49 years old. As the first valve operations, there were five MVR using tissue valves, one DVR [Bjork-Shiley and Ionescu-Shiley valve] and one case of modified Bentall operation with composite graft [Ionescu-Shiley valve]. Reoperations on prosthetic valve failure were performed 17 to 54 months after the first operation [mean 34 months]. Amon8 seven patients, there were two cases of prosthetic valve endocarditis and five cases of primary tissue failure. Gross calcification of the xenograft was found in two children with Ionescu-Shiley valve. All except one had relatively successful operative results. The unsuccessful one died intraoperatively from low output syndrome.

• 한국압력기기공학회 논문집
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• 제5권2호
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• pp.40-44
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• 2009

In this study, Event Corrective Action Supporting System (ECAS) is developed for the accident evaluation in nuclear power plant. The ECAS system can be used in supporting regulator and/or operator under event situation in nuclear power plants. The ECAS system consists of 5 modules including failure location module, failure analysis module, failure integrity evaluation module, system vulnerability evaluation module, and reporting and operating experience feedback module. The ECAS system will be used as sub module of Knowledge-Based Event Evaluation Network (K-EvENT) which is developing for the against the accident in nuclear power plants.

• 시스템엔지니어링학술지
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• 제12권1호
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• pp.41-58
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• 2016

Reliability Centered Maintenance (RCM) introduces a systematic method and decision logic tree for utilizing previous operating experience focused on reliability and optimization of maintenance activities. In this paper RCM methodology is applied on safety injection system for APR-1400. Functional Failure Mode Effects and Criticality Analysis (FME&CA) are applied to evaluate the failure modes and the effect on the component, system and plant. Logic Tree Analysis (LTA) is used to determine the optimum maintenance tasks. The results show that increasing the condition based maintenance will reduce component failure and improve reliability and availability of the system. Also the extension of the surveillance test interval of Safety Injection Pumps (SIPs) would lead to an improved pump's availability, eliminate the unnecessary maintenance tasks and this will optimize maintenance activities.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.191-196
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• 2007

This paper is reviewed RAM(Reliability, Availability and Maintainability) data table utilized for RAM data management to Urban Maglev Transit. As railway systems become more complex, the RAM requirements are reinforced to ensure that a design meets Reliability, Availability, Maintainability criteria. Therefore, it needs the efficient management for RAM data of railway system to meet RAM target. At this study, RAM data management format is suggested to ensure reliability and maintainability based on acquired experience for overseas rolling stock. This RAM data table and FMECA(Failure Mode Effect Criticality Analysis) table are useful to the calculation of MTBF(Mean Time Between Failure), MTBSF(Mean Time Between Service Failure) and Maintainability. Also, this RAM management table will be efficient to improve the RAM evaluation to Urban Maglev Transit.

• Nuclear Engineering and Technology
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• 제44권8호
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• pp.961-970
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• 2012

Often, probabilistic fracture mechanics (PFM) approaches have been adopted to quantify the failure probabilities of Ni-base alloy components, especially due to primary water stress corrosion cracking (PWSCC), in a primary piping system of pressurized water reactors. In this paper, the key features of an advanced PFM code, PINEP-PWSCC (Probabilistic INtegrity Evaluation for nuclear Piping-PWSCC) for such purpose, are described. In developing the code, we adopted most recent research results and advanced models in calculation modules such as PWSCC crack initiation and growth models, a performance-based probability of detection (POD) model for Ni-base alloy welds, and so on. To verify the code, the failure probabilities for various Alloy 182 welds locations were evaluated and compared with field experience and other PFM codes. Finally, the effects of pre-existing crack, weld repair, and POD models on failure probability were evaluated to demonstrate the applicability of PINEP-PWSCC.

• Journal of Chest Surgery
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• 제26권1호
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• pp.59-63
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• 1993

A clinical evaluation was performed with a population of 49 patients of chest trauma, who were diagnosed to undergo ventilator therapy, and had gone through ventilator therapy at the Department of Thoracic and Cardiovascular Surgery, Kyungpook University Hospital. One of most common causes of chest trauma was vehicle accidents [77.5%] with the prevalent age group being their forties. The common findings were multiple rib fractures [89.8%], hemopneumothrax [81.6%], lung contusion [61.2%] and flail chest [44.9%]. Their common combined injuries were the orthopedics and neurosugical injuries [86.7%]. Complications caused by chest trauma were pneumonia, respiratory failure, atelectasis, barotrauma and empyema. Pulmonary infections were commonly associated with mechanical ventilation in the long term group and were best prevented by using bronchial hygiene therapy.The mortality rate was 5.8% of the total patients and that was 38.8% of the patients, who needed ventilator therapy. The causes of death were pneumonia, respiratory failure, acute renal failure and hypovolemic shock. Mechanical ventilation has an important place in the treatment of patients with severe chest trauma.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.107-110
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• 2004

In this paper, a new structural health monitoring technique for composite laminates through the use of embedded fiber Bragg grating (FBG) sensors is presented. The method traces the ply stress states of a laminate and compares them with failure criteria during the service time of structures. The ply stress state of every ply composing the composite laminate can be obtained using classical lamination theory by embedded FBG sensors in the laminate. Graphite/epoxy laminate specimens, embedded with three FBG sensors, were fabricated. Tension tests were performed to evaluate the ply stress states tracing technique. Experimental results show that laminates experience fracture when the ply stress states are over the boundaries of failure criteria. In this method, critical damage can be detected by the ply stress states which are close to the boundaries of the failure criteria.

• Geomechanics and Engineering
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• 제33권1호
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• pp.53-63
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• 2023

Rock disturbance caused by blasting and stress relaxation is commonly observed during excavation. As the distance from the source of disturbance increases, the degree of disturbance decreases, and rock at a large depth does not experience disturbance. However, in stability analyses, a single value of disturbance is often applied to the entire rock mass, which leads to underestimated results. In this study, this modeling mistake is addressed by considering realistically varying rock disturbance. The safety of infinite slopes in a disturbed rock mass with a strength governed by the Hoek-Brown failure criterion is investigated based on the kinematic approach of limit analysis. The maximum disturbance is assigned to the outermost slope face because it is directly exposed to blasting damage and dilation, and the disturbance progressively decays with distance in the rock mass. The safety analysis results indicate that the assumption of uniform disturbance in the entire rock mass leads to underestimation of the rock strength and safety on infinite rock slopes. A critical slip surface appears to be within the disturbed rock layer as well as the interface between the disturbed upper rock and undisturbed lower rock.