• Investigative and Clinical Urology
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• v.59 no.6
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• pp.376-382
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• 2018

Purpose: The authors performed this study to investigate the risk factors for predicting stent failure and to evaluate its impact on prognosis. Materials and Methods: Between January 2002 and March 2017, we retrospectively reviewed 117 consecutive patients who underwent retrograde ureteral stenting and exchanging at least once every 3 months for malignant ureteral obstruction. The patients were classified according to their pre-stenting chronic kidney disease (CKD) stage. The factors affecting stent failure were analyzed using a logistic regression model. Overall survival (OS) was estimated, and the prognostic significance of each variable was estimated using Cox proportional-hazards regression modeling. Results: Before stenting, 91 patients were CKD stages 1-3 and 26 patients were CKD stages 4-5. These two groups differed significantly only in pre-stenting estimated glomerular filtration rate (eGFR), bilateral obstruction, and pre-stenting pyuria. Among the 117 patients, stent failure occurred in 30 patients (25.6%), and there were no differences between the groups. Pre-stenting pyuria and post-stenting complications were significant predictors of stent failure. There were 79 deaths in total, including 56 in the CKD stages 1-3 group and 23 in the CKD stages 4-5 group. In the multivariate analysis predicting patient OS, pre-stenting eGFR and post-stenting disease progression were significant factors. Conclusions: Internal ureteral stenting was effective for maintaining renal function in malignant ureteral obstruction. However, it did not restore renal function, which is related to the prognosis of the patients. Therefore, to improve patients' renal function and prognosis, patients who require stenting must be quickly recognized and treated.

• Journal of Yeungnam Medical Science
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• v.24 no.2
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• pp.275-286
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• 2007

Background : Acute renal failure is one of the leading causes of postoperative morbidity and mortality. The purpose of this study was to determine the risk factors that are associated with acute renal failure after colorectal surgery. Materials and Methods : Five hundred seventy patients who operated colorectal surgery at the Yeungnam University Medical Center over three years from 2004 to 2006 were enrolled in this study. The effects of gender, age, ASA classification, concomitant disease, surgery type and duration, reoperation, urogenital manipulation, medication, hypotension, hypovolemia, transfusion, and postoperative ventilatory care on the occurrence of acute renal failure after colorectal surgery were studied. Results : The major risk factors of acute renal failure after colorectal surgery were age of patients (P=0.003), ASA classification (P<0.001), concomitant disease (P<0.001), duration of the time surgery (P=0.034), reoperation (P=0.001), use of intraoperative diuretics (P=0.005), use of postoperative diuretics (P<0.001), intraoperative hypotension (P=0.018), intraoperative transfusion (P<0.001), postoperative transfusion (P<0.001), and postoperative ventilatory care (P=0.001). Conclusion : Multiple factors cause synergistic effects on the development of acute renal failure after colorectal surgery. Therefore, efforts to reduce the risk factors associated with acute renal failure are needed. In addition, intensive postoperative care should be provided to all patients.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.54
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• pp.167-177
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• 2000

The problem of system reliability is very important issue in the nuclear power plant, because the failure of its system brings about extravagant economic loss, environment destruction, and quality loss. This paper therefore proposes a normalized scoring model by the qualitative factors order to evaluate the robust reliability of nuclear power plants under uncertainty. Especially, the qualitative factors including risk, functional, human error, and quality function factors for the robust justification has been also introduced. Finally, the analytical reliability and safety assessment model developed in this paper can be used in the real nuclear power plant.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.2
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• pp.257-268
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• 1994

An experimental study was carried out to elicit important factors causing cracks and rupture of steel members and their elements under imposed large repeated deformations, and of the quantitative relationships among the important physical factors leading to failure. Each of twenty-eight angles and nine thin-plates served as the specimen and was subjected to repeated axial load after undergoing inelastic buckling. Particular attention was paid to the effects of loading pattern, failure mode and cross-sectional shape on the very-low-cycle failure behavior under loading repetitions of the order of a few to twenty. The experimental results show that energy dissipation capacity depends heavily on the entire history of loading, the failure mode, the slenderness ratio and the width-to-thickness ratio. No simple quantitative relations were observed between the initiation of the visible cracks or rupture and the energy dissipation capacity. The maximum values of residual "net" strains are found to range from 25% to 40%, independent of the test parameters.

• Journal of Korean Neurosurgical Society
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• v.49 no.4
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• pp.217-221
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• 2011

Objective : This paper presents data from a retrospective study of endoscopic third ventriculostomy (ETV) in patients with shunt malfunction and proposes a simple and reasonable post-operative protocol that can detect ETV failure. Methods : We enrolled 19 consecutive hydrocephalus patients (11 male and 8 female) who were treated with ETV between April 2001 and July 2010 after failure of previously placed shunts. We evaluated for correlations between the success rate of ETV and the following parameters : age at the time of surgery, etiology of hydrocephalus, number of shunt revisions, interval between the initial diagnosis of hydrocephalus or the last shunt placement and ETV, and the indwelling time of external ventricular drainage. Results : At the time of ETV after shunt failure, 14 of the 19 patients were in the pediatric age group and 5 were adults, with ages ranging from 14 months to 42 years (median age, 12 years). The patients had initially been diagnosed with hydrocephalus between the ages of 1 month 24 days and 32 years (median age, 6 years 3 months). The etiology of hydrocephalus was neoplasm in 7 patients; infection in 5; malformation, such as aqueductal stenosis or megacisterna magna in 3; trauma in 1; and unknown in 3. The overall success rate during the median follow-up duration of 1.4 years (9 days to 8.7 years) after secondary ETV was 68.4%. None of the possible contributing factors for successful ETV, including age (p=0.97) and the etiology of hydrocephalus (p=0.79), were statistically correlated with outcomes in our series. Conclusion: The use of ETV in patients with shunt malfunction resulted in shunt independence in 68.4% of cases. Age, etiology of hydrocephalus, and other contributing factors were not statistically correlated with ETV success. External ventricular drainage management during the immediate post-ETV period is a good means of detecting ETV failure.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.324-337
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• 2010

For the development of load and resistance factor design, reliability analysis is required to calibrate resistance factors in the framework of reliability theory. The distribution of measured-to-predicted pile resistance ratio was constructed based on only the results of load tests conducted to failure for the assessment of uncertainty regarding pile resistance and used in the conventional reliability analysis. In other words, successful pile load test (piles resisted twice their design loads without failure) results were discarded, and therefore, were not reflected in the reliability analysis. In this paper, a new systematic method based on Bayesian theory is used to update reliability index of driven steel pile piles by adding more pile load test results, even not conducted to failure, into the prior distribution of pile resistance ratio. Fifty seven static pile load tests performed to failure in Korea were compiled for the construction of prior distribution of pile resistance ratio. Reliability analyses were performed using the updated distribution of pile resistance ratio and the total load distribution using First-order Reliability Method (FORM). The challenge of this study is that the distribution updates of pile resistance ratio are possible using the load test results even not conducted to failure, and that Bayesian update are most effective when limited data are available for reliability analysis or resistance factors calibration.

• The Journal of the Korea Contents Association
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• v.21 no.5
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• pp.182-199
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• 2021

This study was designed by paying attention to the negative aspects of the performing arts service. As interest in performing arts increases, various studies on services are being conducted in the performing arts field as well. However, although research on the positive side of performing arts services is steadily increasing, research on the negative side is insufficient. In this study, the limitations of existing studies were supplemented and the study was conducted by applying the Stimulus-Organism-Response (S-O-R) model for empirical research. The effect of failure of performing arts service as a stimulus variable on the response to complaint behavior through negative emotion as an organism was verified. As a result of the analysis, it was found that among the factors of failure in performing arts services, performance works and personal services had a significant influence on negative emotions. In addition, the influence of negative emotions on public and private complaints was confirmed. Lastly, this study will have academic significance in that it analyzed consumers by converting the factors of service failure of performing arts into variables.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.347-353
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• 2022

In the restaurant industry, start-ups are active due to high demand from consumers and low entry barriers. However, the restaurant industry has a high closure rate, and in the case of franchises, there is a large deviation in sales within the same brand. Thus, research is needed to prevent the closure of food franchises. Therefore, this study examines the factors affecting franchise sales and uses machine learning techniques to predict the success and failure of franchises. Various factors that affect franchise sales are extracted by using Point of Sale (PoS) data of food franchise and public data in Gangnam-gu, Seoul. And for more valid variable selection, multicollinearity is removed by using Variance Inflation Factor (VIF). Finally, classification models are used to predict the success and failure of food franchise stores. Through this method, we propose success and failure prediction model for food franchise stores with the accuracy of 0.92.

• Journal of Chest Surgery
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• v.23 no.2
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• pp.275-284
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• 1990

A serious problem after cardiovascular surgery known as Multiple Organ Failure[MOF] whereby several vital organs successively demonstrate dysfunction in spite of intensive postoperative treatment has recently arisen. We have made a retrospective study of the clinical records of 137 patients who underwent cardiovascular surgery during past two years [1987-1988]. Fourteen patients [10%] developed multi-organ failure postoperatively with the results of seven death [50%]. In fatal group, preoperative poor cardiac function [Cardiac Index<2.0L/min/m2] was considered important prognostic factor and infection 5 disseminated intravascular coagulation complicating gastrointestinal bleeding were the leading cause of death. In conclusion, evaluation of multiple factors concerning multi-organ failure demonstrates preoperative poor functional preservation of vital organs is the main factor. So early diagnosis k management for each of the failing organs & prevention of infection are mandatory of the treatment of these critically ill patients.

• Korean Journal of Head & Neck Oncology
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• v.6 no.1
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• pp.1-10
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• 1990

This review will be discussed the various causes of radiation failure for head and neck cancers from radiobiologic perspective and also provided a few clinical data to illustrate the basic principle. A knowledge about multiplicity of factors that may underlie failure of radiation treatment is essential for rational application of new treatment strategies. Furthermore, it is important to distinguish causes of failure that can be reduced or minimized by application of conventional treatment from one are potentially remediable by new treatment strategies, and one that are not amenable to some modification of radiotherapeutic approach.