• 한국철도학회논문집
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• 제12권3호
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• pp.342-347
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• 2009

고장모드, 영향 및 임계분석(FMECA)은 시스템의 구성요소가 갖는 잠재적인 고장모드와 각 고장모드가 시스템에 미치는 영향을 평가하는 도구로 활용된다. 일반적으로 FMECA는 관련 전문가들의 의견에 따라 고장모드의 심각도와 치명도를 평가하여 이를 위험도 매트릭스의 양축으로 나타냄으로써 중요한 고장모드에 대한 분석을 수행한다. 그러나 이러한 절차는 평가가 전문가의 주관에 의해 이루어져 결과에 불확실성이 포함될 수밖에 없다. 따라서 본 논문에서는 최소절단집(MCS)와 퍼지이론을 이용한 새로운 FMECA 절차를 제안한다. 심각도 평가에 있어서는 MCS를 이용함으로써 객관적인 구조적 중요도를 평가할 수 있게 하였고, 치병도의 평가에서는 설비의 대표적인 고장률을 이용하였다. 그리고 두 지수를 종합하기 위해 퍼지 전문가 시스템을 구성하여 종합적인 위험도를 평가하였다.

• 한국안전학회지
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• 제36권4호
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• pp.80-87
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• 2021

Risk assessment techniques are processes used to evaluate hazardous risk factors in construction sites, facilities, raw materials, machinery, and equipment, and to estimate the size of risk that could lead to injury or disease, and establish countermeasures. The most important thing in assessing risk is calculating the size of the risk. If the size of the risk cannot be calculated objectively and quantitatively, all members who participated in the evaluation would passively engage in establishing and implementing appropriate measures. Therefore, this study focused on predicting accidents that are expected to occur in the future based on past occupational accident statistics, and quantifying the size of the risk in an overview. The technique employed in this study differs from other risk assessment techniques in that the subjective elements of evaluators were excluded as much as possible by utilizing past occupational accident statistics. This study aims to calculate the size of the risk, regardless of evaluators, such as a manager, supervisor, safety manager, or employee. The size of the risk is the combination of the likelihood and severity of an accident. In this study, the likelihood of an accident was evaluated using the theory of Bud Accident Chainability, and the severity of an accident was calculated using the occupational accident statistics over the past five years according to the accident classification by the International Labor Organization.

• 한국도로학회논문집
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• 제11권2호
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• pp.195-203
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• 2009

본 연구는 교통사고의 발생 유형과 교통사고 심각도(Severity)와의 관계를 규명함으로써 위험유형을 제시하고, 운전자 특성과 교통사고의 관계를 규명하고자 하였다. 교통사고 유형을 여덟 가지로 세분하고, 결과의 객관성 확보를 위해 안전벨트 착용여부를 추가하여 상해정도와의 관계를 분석하였으며, 위험그룹의 분류를 위한 운전자의 특성은 성별, 차종, 연령 등을 대상으로 하였다. 카테고리 자료의 분석을 위하여 로그-선형 모형 및 로짓 모형을 사용하였다. 분석결과 사고유형과 심각도와의 관계에서는 정면충돌 사고와 앞지르기시, 우회전시 사고가 부상 또는 사망사고에 연루될 가능성이 높았다. 위험그룹 분석에서는 20세 미만의 이륜차 운전자, 41세에서 50세까지의 택시 운전자가 가장 위험한 집단으로 분석되었으며 또한 남자보다는 여자가 승용차와 중형화물 등에 관계되었을 때 더 위험한 것으로 분석되었다. 따라서 교통사고 발생시 인명 피해를 줄이기 위해서는 정면충돌 사고와 앞지르기시, 우회전시 발생하는 사고를 줄일 수 있는 방안이 연구되어야 하고, 교통사고 취약계층으로 분석된 위험그룹에 대한 교통안전 교육 및 단속이 강화되어야 할 것이다.

• 한국안전학회지
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• 제26권6호
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• pp.104-110
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• 2011

In FMEA, the risk priority number(RPN) is used for risk evaluation on each failure mode. It is obtained by multiplying three components, i.e., severity, occurrence, and detectability of the corresponding failure mode. Each of the three components are usually determined on the basis of the past experience and technical knowledge. But this approach is not strictly objective in evaluating risk of a given failure mode and thus provide somewhat less scientific measure of risk. Assuming a homogeneous Poisson process for occurrence of the failures and causes, we propose a more scientific approach to evaluation of risk in FMEA. To quantify severity of each failure mode, the mission period is taken into consideration for the system. If the system faces no failure during its mission period, there are no losses. If any failure occurs during its mission period, the losses corresponding to the failure mode incurs. A longer remaining mission period is assumed to incur a larger loss. Detectability of each failure mode is then incorporated into the model assuming an exponential probability law for detection time of each failure cause. Based on the proposed model, an illustrative example and numerical analyses are provided.

• The Journal of Advanced Prosthodontics
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• 제3권1호
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• pp.25-32
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• 2011

PURPOSE. The purpose of this study was to assess the prevalence and extent of clinical attachment loss of periodontal tissue and to find out variables related to clinical attachment loss (CAL) in Korean adults older than 40 years of age. MATERIALS AND METHODS. Data were collected from 2,519 subjects who were part of a cohort study conducted in Ansan city by Korea University Medical School for Korean Genome project. Age, sex, smoking, drinking, fast glucose, blood pressure, obesity and total cholesterol levels were examined. The oral examination included probing pocket depth, gingival recession and CAL of Ramford's teeth. The severity of periodontitis was classified based on the mean value of CAL. The relationship between each risk factor and the severity of CAL was independently estimated using the chi-square test, the test or one-way ANOVA. Multiple regression analysis was used to determine the significance of each factor in the periodontal disease. RESULTS. The prevalences of clinical attachment between 1 and 3 mm, between 3 and < 5 mm, and ${\geq}$ 5 mm were 80.27%, 16.75% and < 1%, respectively. Although the univariate analysis showed age, gender, smoking, fasting glucose, blood pressure and total cholesterol levels were significantly related to the severity of CAL, multiple regression analysis indicated that age (P < .0001), gender (P < .0001) and smoking (P < .05) were only significantly related. CONCLUSION. Older age, male gender and smoking were significant risk factor for the increase of CAL, and these may be useful indicators of periodontitis high-risk groups.

• Journal of Chest Surgery
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• 제52권2호
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• pp.91-99
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• 2019

Background: The relationship between the size of bullae and pneumothorax recurrence is controversial. The aim of this study was to retrospectively evaluate the role of blebs or bullae in predicting ipsilateral recurrence in young patients experiencing their first episode of primary spontaneous pneumothorax (PSP) who underwent conservative treatment. Methods: A total of 299 cases of first-episode PSP were analyzed. The status of blebs or bullae was reviewed on high-resolution computed tomography (HRCT). The dystrophic severity score (DSS; range, 0 to 6 points) was calculated based on HRCT. Results: The 5-year recurrence rate was 38.2%. In univariate analysis, age (<20 years), body mass index (<$20kg/m^2$), a unilateral lesion, and intermediate risk (DSS 4 and 5) were associated with recurrence. Sex; smoking history; and the presence, number, and maximal size of blebs or bullae were not related to recurrence. In Cox regression, age and intermediate risk were independent risk factors for recurrence. High risk (DDS 6) was not an independent risk factor. Conclusion: The presence, number, and size of blebs or bullae did not affect ipsilateral recurrence. DSS failed to show a positive correlation between severity and recurrence. The decision to perform surgery in patients experiencing their first episode of PSP should not be determined by the severity of blebs and bullae.

• Architectural research
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• 제24권2호
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• pp.21-27
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• 2022

For the past decade, South Korea had experienced catastrophic building fires, which resulted in consider-ably high number of casualties. This motivated research to develop fire-safe wall assemblies. In this study Fire Risk Analysis (FRA) is conducted as part of the project designing phase to ensure fire safety of the final product. Traditional approach was to consider fire performance at the end of the designing stage, when PASS/FAIL fire test results are required to be submitted to the Authority Having Jurisdiction (AHJ). By applying a fire risk analysis to guide the designing phase, overall fire safety of a wall assembly can be achieved more systematically as conducting FRA allows designers to clearly identify elements that are more vulnerable to fire and simply replace them with other practical options. Severity of fire risk is determined by considering the fire hazards of a wall assembly such as the exterior layer, insulation, vertical connectivity, and external ignition sources (e.g., photovoltaic panels). Frequency of fire risk is assessed based on the factors affecting fire likelihood, which are air cavity and fire-stopping applied in the design, and random design changes occurring during on-site construction. Fire risk matrix is proposed based on these fire risk factors and efforts to reduce the fire risk level associated with the wall assembly are given by systematically assessing the fire risk factors identified from fire risk analysis. Current study demonstrates how fire risk analysis can be applied to develop fire-safe walls by reducing the relevant fire risks- both severity and frequency.

• 대한교통학회지
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• 제34권6호
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• pp.535-547
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• 2016

본 연구는 고속도로의 공사구간의 사고 심각도에 영향을 미치는 주요인들을 파악하고 사고 심각도와의 관계를 규명하는 것을 목적으로 한다. 2011년부터 2015년까지 국내 고속도로에서 발생한 교통사고 자료를 공사구간 사고와 일반구간(비공사구간) 사고로 구분하였으며, 이 중 물피사고를 제외하고 분석에 활용하였다. 의사결정나무(Decision Tree)기법을 적용하여 공사구간과 일반구간의 사고 심각도에 영향을 끼치는 요인들을 파악한 뒤 사고 특성 및 영향요인의 차이점을 비교하였다. 특히 공사구간에서는 교통량이 많고 중차량 비율이 높을 경우 전반적인 구간속도 저하로 사고 심각도가 낮아지는 반면, 교통량이 적고 중차량 비율이 낮을수록 구간속도가 증가하여 심각도가 높은 사고로 이어지는 경향을 확인할 수 있었다. 본 연구를 통해 도출한 공사구간 사고심각도 영향 요인들은 공사구간 안전 관리 대책 마련에 도움을 줄 수 있을 것으로 기대한다.

• 대한불안의학회지
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• 제16권2호
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• pp.91-97
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• 2020

Objective : The suicide mortality rate among Koreans was ranked first among the OECD countries in 2018. Alcohol consumption is a significant risk factor for suicidal behavior. This study examined the relationship between the severity of subjects' drinking habits and the suicidal ideation among Koreans according to gender and age. Methods : The data of 113,602 people who visited the Kangbuk Samsung Hospital Health Screening Center from January 2013 to December 2014 were used. The severity of subjects' harmful drinking habits was assessed using the Korean version of the Alcohol Use Disorders Identification Test (AUDIT-K). The relationship between the severity of harmful drinking and suicidal ideation was compared using logistic regression analyses. We also examined the tendency through p for trend to identify a trend. Results : Of the 113,602 study subjects, 6,586 (5.8%) responded that they had thought of committing suicide. After controlling for gender, marriage, education, body mass index (BMI), depression and anxiety, the results showed that the higher the level of harmful drinking, the higher the suicidal ideation. Conclusion : This study found that, even after controlling depression and anxiety, the severity of drinking could be a significant risk factor for suicidal ideation.

• 한국병원경영학회지
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• 제19권4호
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• pp.21-33
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• 2014

This study was conducted to propose an insight into the appropriateness of hospital length of stay(LOS) by developing a severity-adjusted LOS model for patients with pneumonia, organism unspecified. The pneumonia risk-adjustment model developed in this paper is based upon the 2006-2010 the Korean National Hospital Discharge in-depth Injury Survey. Decision tree analysis revealed that age, admission type, insurance type, and the presence of additional disorders(pleural effusion, respiratory failure, sepsis, congestive heart failure etc.) were major factors affecting the severity-adjusted model using the Clinical Classifications Software(CCS). Also there was a difference in LOS among the regional hospitals, especially the hospital LOS has not been efficiently managed in Gyeongsangbuk-do, Jeollanam-do, Jeollabuk-do, Daejeon, and Busan. To appropriately manage hospital LOS, reliable statistical information about severity-adjusted LOS should be generated on a national level to make sure that hospitals voluntarily reduce excessive LOS and manage main causes of delayed discharge.