• Journal of Cardiovascular Imaging
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• 제31권4호
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• pp.200-206
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• 2023

BACKGROUND: Right ventricular (RV) dysfunction is a significant risk of major adverse cardiac events in patients with acute heart failure (AHF). In this study, we evaluated RV-pulmonary artery (PA) coupling, assessed by tricuspid annular plane systolic excursion (TAPSE)/pulmonary artery systolic pressure (PASP) and assessed its prognostic significance, in AHF patients. METHODS: We measured the TAPSE/PASP ratio and analyzed its correlations with other echocardiographic parameters. Additionally, we assessed its prognostic role in AHF patients. RESULTS: A total of 1147 patients were included in the analysis (575 men, aged 70.81 ± 13.56 years). TAPSE/PASP ratio exhibited significant correlations with left ventricular (LV) ejection fraction(r = 0.243, p < 0.001), left atrial (LA) diameter(r = -0.320, p < 0.001), left atrial global longitudinal strain (LAGLS, r = 0.496, p < 0.001), mitral E/E' ratio(r = -0.337, p < 0.001), and right ventricular fractional area change (RVFAC, r = 0.496, p < 0.001). During the median follow-up duration of 29.0 months, a total of 387 patients (33.7%) died. In the univariate analysis, PASP, TAPSE, and TAPSE/PASP ratio were significant predictors of mortality. After the multivariate analysis, TAPSE/PASP ratio remained a statistically significant parameter for all-cause mortality (hazard ratio [HR], 0.453; p = 0.037) after adjusting for other parameters. In the receiver operating curve analysis, the optimal cut-off level of TAPSE/PASP ratio for predicting mortality was 0.33 (area under the curve = 0.576, p < 0.001), with a sensitivity of 65% and a specificity of 47%. TAPSE/PASP ratio < 0.33 was associated with an increased risk of mortality after adjusting for other variables (HR, 1.306; p = 0.025). CONCLUSIONS: In AHF patients, TAPSE/PASP ratio demonstrated significant associations with RVFAC, LA diameter and LAGLS. Moreover, a decreased TAPSE/PASP ratio < 0.33 was identified as a poor prognostic factor for mortality.

• Geomechanics and Engineering
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• 제23권3호
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• pp.261-273
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• 2020

This paper presents an efficient method utilizing user-defined computer functional codes to determine the reliability of an embankment slope with spatially varying soil properties in real time. The soils' mechanical properties varied with the soil layers that had different degrees of compaction and moisture content levels. The Latin Hypercube Sampling (LHS) for the degree of compaction and Kriging simulation of moisture content variation were adopted and programmed to predict their spatial distributions, respectively, that were subsequently used to characterize the spatial distribution of the soil shear strengths. The shear strength parameters were then integrated into the Geostudio command file to determine the safety factor of the embankment slope. An explicit metamodal for the performance function, using the Kriging method, was established and coded to efficiently compute the failure probability of slope with varying moisture contents. Sensitivity analysis showed that the proposed method significantly reduced the computational time compared to Monte Carlo simulation. About 300 times LHS Geostudio computations were needed to optimize precision and efficiency in determining the failure probability. The results also revealed that an embankment slope is prone to high failure risk if the degree of compaction is low and the moisture content is high.

• Journal of Korean Neurosurgical Society
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• 제30권sup1호
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• pp.79-84
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• 2001

목 적 : 뇌실 복강간 단락술 부전의 기여인자를 조사 및 분석하여 뇌실 복강간 단락술의 합병증 및 재수술의 가능성을 줄이는 데에 목적이 있다. 대상 및 방법 : 1995년 1월부터 1998년 12월까지 본원에서 뇌실 복강간 단락술을 시행 받은 237명의 수두증 환자를 후향적 방법으로 고찰하여 뇌실 복강간 단락 부전의 기여인자 및 단락기 생존율을 통계학적으로 분석하였다. 결 과 : 수두증의 원인은 종양, 출혈, 감염, 선천성 기형, 정상 뇌압 수두증, 외상 등이었다. 68명의 환자에서 109회의 재수술이 이루어졌다. 재수술의 이유는 폐색, 근위부 카세타의 위치이상, 감염 등이었다. 단락기 생존율은 1년, 2년, 3년에 각각 77.1%, 75.4%, 74.1%이었다. 10세 이하의 환자에서 재수술의 빈도가 통계학적으로 의의 있게 높았다. 그리고 수두증의 원인에 따라서 통계학적으로 의의 있게 재수술의 빈도 차이가 있었다. 결 론 : 대부분의 뇌실 복강간 단락 부전은 술후 1년내에 발생하였다. 환자의 나이 및 수두증의 원인이 뇌실 복 강간 단락 부전의 주요 기여인자였다.

• 한국가스학회지
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• 제23권6호
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• pp.33-38
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• 2019

제조식 수소충전소에서 생산되는 수소가스는 일반적으로 석탄연료의 개질 및 부생가스 등을 활용하지만 순수물을 활용한 수전해 기술의 경우 청정한 기술로 각광 받고 있다. 전기에너지를 이용하여 순수한 물로부터 수소를 생산하는 기술 중에는 향후 가격 및 성능 경쟁에서 우수한 PEM(Polymer Electrolyte Membrane electrolysis)을 이용한 개발이 주로 이루어지고 있다. 이에 본 연구에서는 국내 수소충전소 중 개발단계에 있는 PEM 수전해 수소충전소에 대해 잠재된 유해위험요소를 확인하여 안전한 수소생산 및 수소충전소의 활성화를 도모하고자 한다. 유해위험요소를 도출하기 위해서는 수전해 수소충전소의 설비 및 장치의 안전성이 우선 확보되어야하기에 FMEA(Failure Mode & Effect Analysis)를 수행함으로써 수전해 및 수소충전소의 설비에서의 유해위험요인을 분석하였다.

• Radiation Oncology Journal
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• 제18권4호
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• pp.265-276
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• 2000

목적 : 1983년부터 1988년 사이에 유방암으로 진단받고 근치적 유방절제술을 시행한 환자로써 조직학적으로 액와림프절 전이가 확인된 218명의 환자에서 수술 후 보조적 방사선치료 및 항암약물치료를 시행하였으며 이들 환자를 대상으로 한 치료 결과를 후향적 연구를 통해 분석하고자 하였다. 대상 및 방법 : 대상환자는 3개 군으로 분류하였는데, 1군은 항암약물치료 단독으로 치료한 80명의 환자가 포함되었고 2군은 방사선치료 단독으로 치료한 52명을 포함하였으며 3군은 방사선치료 및 항암약물치료를 병용하여 치료한 86명의 환자를 포함하였다. 이들의 평균 연령은 44세, 27$\~$70세의 연령분포를 보였으며 추적관찰 기간의 중앙값은 51개월이었다. 결과 : 7년 무병생존율 및 전체생존율은 각각 56$\%$와 67$\%$이었으며, 각 치료군에 따른 생존율은 1군에서는 50$\%$와 56$\%$, 2군은 51$\%$와 65$\%$, 3군은 62$\%$와 75$\%$이었다. 국소재발율은 13$\%$이었으며 원격전이율은 33$\%$ 이었다. 방사선치료가 포함되었던 2군과 3군에서는 국소재발 위험이 낮았으나(p<0.05) 원격전이율의 차이는 없었다. 단변량분석에서 무병 생존율에 영향을 주는 인자로서는 액와 림프절 양성 비율이었으며 전체생존율에 있어서는 원발 병소 크기, 액와 림프절 전이 개수 및 양성 비율, 병기가 관련있는 인자임을 알 수 있었다. 그러나 다변량분석에서는 치료방법만이 의미있는 예후인자임을 알 수 있었다. 전체 치료실패율과 원격전이율에 영향을 주는 예후인자는 액와 림프절 양성 비율이었으며 국소재발율은 치료방법이 의미있는 예후인자임을 알 수 있었다. 결론 : 결론적으로 이러한 결과는 폐경전 환자, 액와 림프절 전이 개수가 4개 이상이거나 양성 비율이 1/3이상인 환자에서 수술 후 방사선치료가 시행된 경우 국소재발율을 감소시킨다는 사실을 보여주고 있다. 또한 종양의 크기가 2$\~$5 cm, IIB 병기 및 액와 림프절 전이 개수가 4개 이상이거나 양성 비율이 1/3이상인 환자에서 수술후 보조적 치료로써 방사선치료/항암약물치료 병용요법이 가장 효과적인 치료방법임을 알 수 있었다.

• 한국산업정보학회논문지
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• 제22권1호
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• pp.105-116
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• 2017

본 연구에서는 콜라우드 서비스의 높은 실패율에 대하여, 어떠한 위험이 존재하는지 살펴보고, 이러한 위험을 제거하기 위한 실물 옵션, 특히 포기 옵션의 채택에 영향을 끼칠 수 있는 위험의 종류에 대하여 실증 분석을 실시하였다. 특히 개인 차원에서 인식하는 위험의 정도가 포기 옵션의 채택에 어떠한 영향을 끼치는 지에 더하여, 조직 차원의 변수 (CEO의 혁신성, 밴드웨건 효과)가 개인 차원의 효과들을 어떻게 조절하는지에 대하여 실증 분석을 실시한다. 수도권 소재 중소기업의 IT 담당자들을 대상으로 설문조사한 내용을 바탕으로, 기술적 위험과 경제적 위험이 포기 옵션의 채택에 유의한 영향을 끼치며, CEO의 혁신성이 기술적 위험의 효과를 억제하는 조절 효과가 검증되었다. 그러나, 밴드웨건 효과는 개인 차원의 영향을 억제하는 조절 효과는 실증적으로 유의하지 않았다.

• 품질경영학회지
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• 제49권3호
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• pp.299-312
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• 2021

Purpose: We provide a condition-based maintenance policy where a surrogate variable is used for monitoring system performance. We constructed a risk function by taking into account the risk and losses accompanied with erroneous decisions. Methods: Assuming a unique degradation process for the performance variable and its specific relationship with the surrogate variable, the maintenance policy is determined. A risk function is developed on the basis of producer's and consumer's risks accompanied with each decision. With a strategic safety factor considered, the optimal threshold value for the surrogate variable is determined based on the risk function. Results: The condition-based maintenance is analyzed from the point of risk. With an assumed safety consideration, the optimal threshold value of the surrogate variable is provided for taking a maintenance action. The optimal solution cannot be obtained in a closed form. An illustrative numerical example and solution is provided with a source code of R program. Conclusion: The study can be applied to situation where a sensor signal is issued if the system performance begins to degrade gradually and reaches eventually its functional failure. The study can be extended to the case where two or more performance variables are connected to a same surrogate variable. Also estimation of the distribution parameters and risk coefficients should be further studied.

• 대한임상독성학회지
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• 제19권2호
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• pp.93-99
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• 2021

Purpose: Nutritional status and support in critically ill patients are important factors in determining patient recovery and prognosis. The aim of this study was to analyze the early nutritional status and the methods of nutritional support in critically ill patients with acute poisoning and to evaluate the effect of nutritional status on prognosis. Methods: A retrospective study was conducted in tertiary care teaching hospital from January 2018 to December 2020. in an emergency department of university hospital, 220 patients who were stayed more than 2 days of poisoning in intensive care unit were enrolled. Results: 155 (70.5%) of patients with acute poisoning had low-risk in nutritional risk screening (NRS). Patients with malignancy had higher NRS (low risk 5.2%, moderate risk 18.5%, high risk 13.2%, p=0.024). Patients of 91.4% supplied nutrition via oral route or enteral route. Parenteral route for starting method of nutritional support were higher in patients with acute poisoning of herbicide or pesticide (medicine 3.2%, herbicide 13.8%, pesticide 22.2%, p=0.000). In multivariate logistic regression analysis, herbicide or pesticide intoxication, higher risk in NRS and sequential organ failure assessment over 4.5 were affecting factor on poor recovery at discharge. Conclusion: NRS in patients intoxicated with herbicide or pesticide were higher than that in patients intoxicated with medicine intoxication. Enteral nutrition in patients intoxicated with herbicide or pesticide was less common. Initial NRS was correlated with recovery at discharge in patient with intoxication. It is expected to be helpful in finding patients with high-risk nutritional status in acute poisoning patients and establishing a treatment plan that can actively implement nutritional support.

• International Journal of Contents
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• 제14권3호
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• pp.53-60
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• 2018

Based on the previous studies on sinkholes and ground subsidence conducted until date, the factors affecting the occurrence of sinkholes can be divided into natural environmental factors and human environmental factors in accordance with the purpose of the study. Furthermore, to be more specific, the human environment can be classified into the artificial type and the social type. In this study, the assessment indices for assessing risks of sinkholes and ground subsidence were developed by performing AHP analysis based on the results of the study by Lee et al. (2016), who selected the risk factors for the occurrence of sinkholes by performing Delphi analysis targeting relevant experts. Analysis showed that the artificial environmental factors were of significance in affecting the occurrence of sinkholes. Explicitly, the underground factors were found to be of importance in the natural environment, and among them, the level of underground water turned out to be an imperative influencing factor. In the artificial environment, the underground and subterranean structures exhibited similar importance, and in the underground structures, the excessive use of the underground space was found to be an important influencing factor. In the subterranean ones, the level of water leakage and the erosion of the water supply and sewage piping system were the influential factors, and in the surface, compaction failure was observed as an imperative factor. In the social environment, the regional development, and above all, the groundwater overuse were found to be important factors. In the managemental and institutional environment, the improper construction management proved to be the most important influencing factor.

• Journal of Korean Neurosurgical Society
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• 제64권5호
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• pp.791-798
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• 2021

Objective : The period of mechanical ventilator (MV)-dependent respiratory failure after cervical spinal cord injury (CSCI) varies from patient to patient. This study aimed to identify predictors of MV at hospital discharge (MVDC) due to prolonged respiratory failure among patients with MV after CSCI. Methods : Two hundred forty-three patients with CSCI were admitted to our institution between May 2006 and April 2018. Their medical records and radiographic data were retrospectively reviewed. Level and completeness of injury were defined according to the American Spinal Injury Association (ASIA) standards. Respiratory failure was defined as the requirement for definitive airway and assistance of MV. We also evaluated magnetic resonance imaging characteristics of the cervical spine. These characteristics included : maximum canal compromise (MCC); intramedullary hematoma or cord transection; and integrity of the disco-ligamentous complex for assessment of the Subaxial Cervical Spine Injury Classification (SLIC) scoring. The inclusion criteria were patients with CSCI who underwent decompression surgery within 48 hours after trauma with respiratory failure during hospital stay. Patients with Glasgow coma scale 12 or lower, major fatal trauma of vital organs, or stroke caused by vertebral artery injury were excluded from the study. Results : Out of 243 patients with CSCI, 30 required MV during their hospital stay, and 27 met the inclusion criteria. Among them, 48.1% (13/27) of patients had MVDC with greater than 30 days MV or death caused by aspiration pneumonia. In total, 51.9% (14/27) of patients could be weaned from MV during 30 days or less of hospital stay (MV days : MVDC 38.23±20.79 vs. MV weaning, 13.57±8.40; p<0.001). Vital signs at hospital arrival, smoking, the American Society of Anesthesiologists classification, Associated injury with Injury Severity Score, SLIC score, and length of cord edema did not differ between the MVDC and MV weaning groups. The ASIA impairment scale, level of injury within C3 to C6, and MCC significantly affected MVDC. The MCC significantly correlated with MVDC, and the optimal cutoff value was 51.40%, with 76.9% sensitivity and 78.6% specificity. In multivariate logistic regression analysis, MCC >51.4% was a significant risk factor for MVDC (odds ratio, 7.574; p=0.039). Conclusion : As a method of predicting which patients would be able to undergo weaning from MV early, the MCC is a valid factor. If the MCC exceeds 51.4%, prognosis of respiratory function becomes poor and the probability of MVDC is increased.