• Earthquakes and Structures
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• 제24권4호
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• pp.303-316
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• 2023

Rapid post-earthquake damage estimation of subway stations is particularly necessary to improve short-term crisis management and safety measures of urban subway systems after a destructive earthquake. The conventional Performance-Based Earthquake Engineering (PBEE) framework with constant earthquake occurrence rate is invalid to estimate the aftershock risk because of the time-varying rate of aftershocks and the uncertainty of mainshock-damaged state before the occurrence of aftershocks. This study presents a time-varying probabilistic seismic risk assessment framework for underground structures considering mainshock and aftershock hazards. A discrete non-omogeneous Markov process is adopted to quantify the time-varying nature of aftershock hazard and the uncertainties of structural damage states following mainshock. The time-varying seismic risk of a typical rectangular frame subway station is assessed under mainshock-only (MS) hazard and mainshock-aftershock (MSAS) hazard. The results show that the probabilities of exceeding same limit states over the service life under MSAS hazard are larger than the values under MS hazard. For the same probability of exceedance, the higher response demands are found when aftershocks are considered. As the severity of damage state for the station structure increases, the difference of the probability of exceedance increases when aftershocks are considered. PSDR=1.0% is used as the collapse prevention performance criteria for the subway station is reasonable for both the MS hazard and MSAS hazard. However, if the effect of aftershock hazard is neglected, it can significantly underestimate the response demands and the uncertainties of potential damage states for the subway station over the service life.

• 한국환경보건학회지
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• 제49권4호
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• pp.228-235
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• 2023

Background: As the public interest in chemical substances found in daily life has increased, environmental health education content has been developed and related studies have been conducted. However, there is still insufficient research on methodologies for environmental health education. Objectives: This study aimed to explore risk communication strategies by focusing on N-nitrosamines in rubber balloons. Methods: In this study, two different health messages were composed: a gain-framed message emphasizing the advantages of practicing the health behavior and a loss-framed message emphasizing the negative consequences of not practicing the health behavior. The effect of the message containing risk information was evaluated by measuring the health beliefs and health behavior potential for female caregivers. As the Environmental Health Act defines a child as "a person under the age of 13," a total of 131 women with children under the age of 13 were studied. Results: The age, awareness, and interest of the participants in the gain frame group and these in the loss frame group were similar. In terms of message framing effect, the gain-framed message was more effective in terms of health belief and potential health behavior than was the loss-framed message. As a result of an independent t-test, among the six variables of health belief model the message effect was statistically significant at the level of p<0.05 in three variables: perceived severity (t=2.287, df=129, p=0.024), self-efficacy (t=2.123, df=129, p=0.036), and health behavior potential (t=2.094, df=129, p=0.038). Conclusions: This study presented a direction for effective environmental health education by studying the effects of risk communication messages based on scientific evidence. It is necessary to extend the scope of environmental health education research by expanding research into various household products.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.304-311
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• 2022

Construction inspection is a crucial stage that ensures that all contractual requirements of a construction project are verified. The construction inspection capabilities among state highway agencies have been greatly affected due to budget reduction. As a result, efficient inspection practices such as risk-based inspection are required to optimize the use of limited resources without compromising inspection quality. Automated prioritization of textual requirements according to their criticality would be extremely helpful since contractual requirements are typically presented in an unstructured natural language in voluminous text documents. The current study introduces a novel model for predicting the risk level of requirements using machine learning (ML) algorithms. The ML algorithms tested in this study included naïve Bayes, support vector machines, logistic regression, and random forest. The training data includes sequences of requirement texts which were labeled with risk levels (such as very low, low, medium, high, very high) using the fuzzy logic systems. The fuzzy model treats the three risk factors (severity, probability, detectability) as fuzzy input variables, and implements the fuzzy inference rules to determine the labels of requirements. The performance of the model was examined on labeled dataset created by fuzzy inference rules and three different membership functions. The developed requirement risk prediction model yielded a precision, recall, and f-score of 78.18%, 77.75%, and 75.82%, respectively. The proposed model is expected to provide construction inspectors with a means for the automated prioritization of voluminous requirements by their importance, thus help to maximize the effectiveness of inspection activities under resource constraints.

• 우울조울병
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• 제9권2호
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• pp.57-63
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• 2011

Objectives : This study aimed to investigate the prevalence and risk factors of depression within two weeks after stroke. Methods : A total of 362 stroke patients were recruited. Depression (major and minor depressive disorders) was diagnosed by applying DSM-IV criteria. Data on socio-demographic characteristics (age, gender, education, marital state, living state, religion, occupation, income, life event, and social support), stroke severity (NIHSS), disability (BI), stroke hemisphere and location, vascular risk and disease, and previous history of stroke and depression were obtained. Results : Depression was present in 90 (24.9%) patients: major depression 29 (8%) and minor depression 61 (16.9%) patients. In the univariate analyses, depression was associated with older age, higher number of stressful life event, poorer social support, severe disability, anterior stroke location, previous history of stroke and depression. In the multivariate analyses, depression was independently associated with higher number of stressful life events and poorer social support. Conclusion : Depression was common and was determined by premorbid levels of stress and social support in stroke patients at acute stage. More intensive psychiatric care and intervention is needed for the high risk group.

• Diabetes and Metabolism Journal
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• 제42권6호
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• pp.496-512
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• 2018

Background: This study aimed to investigate the association between the presence and severity of cardiovascular autonomic neuropathy (CAN) and development of long-term glucose fluctuation in subjects with type 2 diabetes mellitus. Methods: In this retrospective cohort study, subjects with type 2 diabetes mellitus who received cardiovascular autonomic reflex tests (CARTs) at baseline and at least 4-year of follow-up with ${\geq}6$ measures of glycosylated hemoglobin (HbA1c) were included. The severity of CAN was categorized as normal, early, or severe CAN according to the CARTs score. HbA1c variability was measured as the standard deviation (SD), coefficient of variation, and adjusted SD of serial HbA1c measurements. Results: A total of 681 subjects were analyzed (294 normal, 318 early, and 69 severe CAN). The HbA1c variability index values showed a positive relationship with the severity of CAN. Multivariable logistic regression analysis showed that CAN was significantly associated with the risk of developing higher HbA1c variability (SD) after adjusting for age, sex, body mass index, diabetes duration, mean HbA1c, heart rate, glomerular filtration rate, diabetic retinopathy, coronary artery disease, insulin use, and anti-hypertensive medication (early CAN: odds ratio [OR], 1.65; 95% confidence interval [CI], 1.12 to 2.43) (severe CAN: OR, 2.86; 95% CI, 1.47 to 5.56). This association was more prominent in subjects who had a longer duration of diabetes (>10 years) and lower mean HbA1c (<7%). Conclusion: CAN is an independent risk factor for future higher HbA1c variability in subjects with type 2 diabetes mellitus. Tailored therapy for stabilizing glucose fluctuation should be emphasized in subjects with CAN.

• 한국건설관리학회논문집
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• 제2권2호
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• pp.68-80
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• 2001

건설시장의 세계화, 다양한 조달시스템의 부각 및 정보기술의 발전 등에 따라 해외건설사업을 겨냥한 건설업체들의 시장확대 및 수익창출의 기회가 증가하고 있다. 하지만 방대한 량의 계약문서, 장기적인 투자회수기간 및 자금조달 등의 부담과 더불어 환율, 이자율, 물가상승, 신용 등의 다양한 해외건설사업의 리스크 또한 현저하게 증가하고 있어 이들을 사업대상으로 하는 종합건설업체에게는 상기 리스크들에 대한 적극적인 관리가 요구된다. 본 연구는 다수의 해외건설사업을 수행하는 종합건설업체의 측면에서 최적의 사업포트폴리오 선정을 위한 의사결정모델을 제안한다. 여기에는 프로젝트 레벨과 기업레벨의 리스크를 통합적으로 관리하기 위한 기업수준의 리스크 관리 시스템을 대상으로 하여 건설산업에 포트폴리오 및 VaR(Value at Risk) 개념을 소개하고 기업의 전략적 목적에 근거하여 의사결정을 위한 다기준(Multi-criteria)이 제안된다. 의사결정 과정에서 정량적 분석과 더불어 의사결정자의 리스크 태도에 의한 정성적 평가가 가능하도록 해당 건설기업의 효용개념을 도입하였다. 또한 수집된 해외공사 실적자료를 기반으로 시나리오 분석을 통하여 상기 의사결정 방법론에 대한 검증을 실시하였다.

• Journal of Trauma and Injury
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• 제19권1호
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• pp.47-53
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• 2006

Purpose: Recently, the American Heart Association recommended that routine cervical spine protection in submerged patients was not necessary, except in high-energy injury situations. However, until now, this recommendation has few supportive studies and literatures. This retrospective study was performed to demonstrate the risk of cervical spine injury in patients who had been submerged in a river. Methods: Seventy-nine submerged patients who visited St. Mary's Hospital between January 2000 and December 2005 were included in this retrospective study. We investigated and analyzed the victim's age, sex, activity on submersion, mental status and level of severity at admission, prognosis at discharge, associated injuries, and risk group by using the medical records and cervical spine lateral images. According to the activity on submersion, victims were classified into three groups: high risk, low risk, and unknown risk. The reports of radiologic studies were classified into unstable fracture, stable fracture, sprain, degenerative change, and normal. Results: The patients' mean age was 36.8 yrs, and 54% were males. Of the 79 patients, adult and adolescent populations (80%) were dominant. Jumping from a high bridge (48%) was the most common activity on submersion and accounted for 52% of the high-risk group. The Glasgow coma scale at admission and the cerebral performance scale at discharge showed bimodal patterns. The results of the radiologic studies showed one stable fracture, one suspicious stable fracture, and 18 sprains. The incidence of cervical spine fracture in submerged patients was 2.5% in our study. The incidence of cervical spine injury was higher in the high-risk group than it was in the low-risk group, especially in the jumping-from-high-bridge subgroup; however this observation was not statistically significant. No other factors had any significant effect on the incidence of cervical spine injury. Conclusion: Our study showed that even submerged patients in the high risk group had a low incidence of cervical spine fracture and that the prognosis of a patient did not seem to be influenced by the cervical spine fracture itself.

• 해양환경안전학회지
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• 제29권2호
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• pp.238-247
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• 2023

선박 연료로서 LPG는 현재의 기술과 경제성 등을 고려하였을 때 매력적인 연료이다. 하지만, 아직 LPG 연료 선박의 안전 지침을 개발 중에 있고, 국내에서는 중소형 선박에 LPG 추진 시스템을 적용한 사례가 없다. 본 연구에서는 국내 최초 개발된 해상용 LPG 엔진 시스템에 대해 보다 객관적인 위험성 평가를 수행하고 안전 운용 기준을 제안하고자 한다. 우선, 위험과 운전 분석 기법을 통해 동 엔진 시스템을 5개의 검토 구간으로 분할하고 총 58가지의 위험요소를 식별하였다. 그다음 정성적 평가인 HAZOP 기법의 주관성을 보완하기 위해 퍼지 이론을 사용하고 검출도, 민감도 등 위험 요인을 추가하여 퍼지 분석적 계층 과정을 통해 위험 요인의 상대적 가중치를 비교하였다. 그 결과, 5가지의 위험 요인 중, 위험성에 가장 큰 영향을 미치는 위험 요인은 발생 빈도와 심각도로 평가되었다. 마지막으로, 위험 요인에 대한 가중치를 고려하여 위험 순위를 세밀하게 선정하기 위해 퍼지 TOPSIS 기법을 적용하였다. 그 결과, 위험 등급은 47개 그룹으로 구분할 수 있었고, 동 엔진 시스템의 운용 중 가장 위험도가 높은 위험요소는 LPG 공급 라인 유지 보수 중 가스 누출로 분석되었다. 본 연구에 제안된 기법을 LPG 공급계통 등 다양한 설비에도 적용하여, 향후 LPG 추진 선박의 안전 기준 마련을 위한 위험성 평가의 표준절차로 활용할 수 있기를 기대한다.

• Journal of Korean Biological Nursing Science
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• 제13권1호
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• pp.61-71
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• 2011

Purpose: The purpose of the present study was to investigate the prevalence, subtypes and risk factors of irritable bowel syndrome by ROME-III among Korean university students. Methods: This study was descriptive survey research. The sampls were 796 and variables were measured by structured questionaire. Rome-III criteria was used for diagnosis of IBS. The gathered data were analyzed with %, $x^2$-test, t-test, logistic regression by SPSS win 17.0. Results: The students with IBS were 61 (7.7%) and the most of the subtype was IBS-M (42.6%). Meal (times/day), breakfast, stress, quality of sleep, neuroticism, bodily pain, general health, social function, role emotional restriction, mental health, somatization, obcessive-compulsive state, depression, anxiety, hostility, global severity index, positive symptom distress index, positive symptom were significantly different between IBS group and non-IBS group. The prevalence of IBS was low in the higher score of role emotional in general health state. There were more 2 times students who had score of the obsessive-compulsive in psychological health over the 50 than below the 50 in IBS group. Conclusion: 7.7% of students were diagnosed by Rome-III criteria and the most of the sybtype was IBS-M. The risk factors of IBS were role emotional restriction, obsessive-compulsive state.

• 벤처창업연구
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• 제9권1호
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• pp.177-186
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• 2014

FMEA는 실패로 인한 위험을 최소화하기위해 실패의 요인과 그로인한 영향을 사전에 평가하는 체계적인 방법이다. 이 방법은 제품의 신뢰도 문제를 해결하기 위해 제조산업 분야에서 주로 사용되어 왔으나, 서비스의 역할과 중요성이 커지면서 최근에는 이를 서비스의 신뢰도 문제에도 사용하고 있다. 하지만, 서비스에서는 고객이 서비스 전달 프로세스에 참여하며 고객마다의 이질성 등으로 인해 제조업을 위해 개발된 FMEA를 직접 사용할 수은 없다. 이러한 이유로 인해, FMEA를 서비스에 적용하기위한 여러 연구가 이루어지고 있다. 본 논문에서는, 심각도, 발생빈도, 검출력으로 우선순위를 평가하던 기존의 RPN 대신에, 서비스 특성을 고려하여 심각도, 발생빈도, 회복력 3가지로 평가하는 새로운 지수 S-RPN을 제시하였으며, 기존연구의 사례를 통해 제시된 방법의 효용성을 평가하였다.