• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.383-386
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• 2006

The safety of the railway system is important because the system is a mass transit system and the results of the accident are inconceivable. The railway system is operated by train operation system such as train control system. So the train control system requires safety critical characteristics. In the European railway, ETCS (European Train Control System) project has been finished to accomplish the interoperability of each national railway signaling system. According to the interoperability degree, ETCS levels are suggested. As the highest level, ETCS level 3 suggests a radio communication. Also recently urban railway system is operated by driverless and automatic train control system. In this circumstance, more safety is required than before in the railway system. In order to accomplish the safety of a system, the requirements considering safety have to be suggested. The requirement is a set of several functions such as general function, environment, safety etc. For the safety critical system, safety function is more important than any other functions. The safety functions are deduced by safety analysis. In order to perform the safety analysis, the system hazards have to be identified and then risk analysis for each hazard should be performed. The risk is related to the frequency and the severity of each hazard. And then countermeasures for each risk have to be prepared. The summary of the countermeasures is about a kind of safety functions in a system. In this paper, the safety functions for a train control system are presented according to the above procedure.

• Journal of Korean Neurosurgical Society
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• 제60권1호
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• pp.67-74
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• 2017

Objective : The purpose of this study was to investigate the prevalence of and the relevant risk factors for lumbar spondylosis (LS) among middle-aged and elderly rural Korean residents and to explore the association between radiographic LS and lower back pain (LBP) in relation to age and gender. Methods : This community-based, cross-sectional study evaluated 1512 subjects with available radiograph. The prevalence of LBP was obtained using a questionnaire and disability resulting from LBP was measured using a validated Korean version of the Oswestry disability index (ODI). In lumbar spine radiographs, vertebral levels from L1/2 to L4/5 were evaluated for the presence of osteophytes and joint-space narrowing (JSN), and Kellgren-Lawrence (KL) grading was applied. Results : Of 4261 subjects aged 40-79 years, data from 1512 subjects were included. The prevalence of radiographic LS indicated by grade ${\geq}2$ osteophytes and JSN were 53.9 and 15.8%, respectively. Seventy-three percent of subjects had KL grade ${\geq}2$ spondylosis and LBP was present in 36.5% of subjects. Although LS was more common among males, the prevalence of LBP was higher among females. Age, male gender and history of hand or knee arthritis were risk factors for LS. LS was significantly associated with LBP mostly among females over 60 years old and correlated with the ODI after adjusting for age and gender. Conclusion : Our study among rural Korean residents revealed a high prevalence of LS and LBP. The association between LS and LBP was observed mostly among females and LS was significantly correlated with the severity of back pain.

• 보건행정학회지
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• 제31권4호
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• pp.451-461
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• 2021

Background: Readmissions related to lack of quality care harm both patients and health insurance finances. If the factors affecting readmission are identified, the readmission can be managed by controlling those factors. This paper aims to identify factors that affect readmissions of convalescent rehabilitation patients. Methods: Health Insurance Review and Assessment Service claims data were used to identify readmissions of convalescent patients who were admitted in hospitals and long-term care hospitals nationwide in 2018. Based on prior research, the socio-demographics, clinical, medical institution, and staffing levels characteristics were included in the research model as independent variables. Readmissions for convalescent rehabilitation treatment within 30 days after discharge were analyzed using logistic regression and generalization estimation equation. Results: The average readmission rate of the study subjects was 24.4%, and the risk of readmission decreases as age, length of stay, and the number of patients per physical therapist increase. In the patient group, the risk of readmission is lower in the spinal cord injury group and the musculoskeletal system group than in the brain injury group. The risk of readmission increases as the severity of patients and the number of patients per rehabilitation medicine specialist increases. Besides, the readmission risk is higher in men than women and long-term care hospitals than hospitals. Conclusion: "Reducing the readmission rate" is consistent with the ultimate goal of the convalescent rehabilitation system. Thus, it is necessary to prepare a mechanism for policy management of readmission.

• 한국터널지하공간학회 논문집
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• 제20권6호
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• pp.931-946
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• 2018

도심지에서의 공동구의 활용성 증가에 따라 쉴드 TBM 공법이 적용된 터널식 공동구의 시공 및 연구개발이 활발히 진행되고 있다. 터널식 공동구는 지하굴착 공사로써 건설안전에 상대적으로 취약하지만, 건설업 재해율 감소를 위한 설계안전성 검토 제도 도입에도 불구하고 터널식 공동구 건설에 적합한 위험요소가 제대로 알려져 있지 않다. 따라서 본 연구에서는 터널식 공동구에 적합한 안전 위험요소를 발굴하고 이중에서 중점으로 관리되어야 할 핵심 안전 위험요소를 도출하였다. 도출된 핵심 안전 위험요소는 매트릭스 기법을 적용하여 위험성 평가를 실시함으로써 공동구 계획, 설계 및 시공 단계의 위험성 평가 및 주요 참고 자료로 사용될 수 있도록 하였다.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제8권6호
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• pp.223-234
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• 2019

첨단 무기체계들이 고도로 연동되어 수행되는 네트워크 중심전에서는 사이버 공격이 전쟁의 승패를 좌우하는 커다란 위협으로 대두되었다. 또한 최신예 전투기로 발전할수록 증가하는 소프트웨어 의존도는 사이버 공격에 대한 전투기 소프트웨어의 강화된 보안대책을 요구하고 있다. 본 논문에서는 항공기 감항 보안 인증 표준인 DO-326A를 적용함에 있어 전투기의 특성 및 운용환경을 반영하여 위험기반 보안위협 평가 프로세스를 설계한다. 이를 위하여 DO-326A의 감항 보안 인증 프로세스의 보안위협 평가 단계에서 전투기 보안위협을 도출하고 사이버 공격의 발생 가능성과 전투기에 미치는 영향력의 관점에서 위협을 점수화하며 보안위험 심각도를 결정하는 단계를 추가하여 적용한다.

• Clinical and Experimental Emergency Medicine
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• 제5권4호
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• pp.230-239
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• 2018

Objective The suicide rate in South Korea is very high and is expected to increase in coming years. Intoxication is the most common suicide attempt method as well as one of the common reason for presenting to an emergency medical center. We used decision tree modeling analysis to identify predictors of risk for suicide by intentional intoxication. Methods A single-center, retrospective study was conducted at our hospital using a 4-year registry of the institute from January 1, 2013 to December 31, 2016. Demographic factors, such as sex, age, intentionality, therapeutic adherence, alcohol consumption, smoking status, physical disease, cancer, psychiatric disease, and toxicological factors, such as type of intoxicant and poisoning severity score were collected. Candidate risk factors based on the decision tree were used to select variables for multiple logistic regression analysis. Results In total, 4,023 patients with intoxication were enrolled as study participants, with 2,247 (55.9%) identified as cases of intentional intoxication. Reported annual percentages of intentional intoxication among patients were 628/937 (67.0%), 608/1,082 (56.2%), 536/1,017 (52.7), 475/987 (48.1%) from 2013 to 2016. Significant predictors identified based on decision tree analysis were alcohol consumption, old age, psychiatric disease, smoking, and male sex; those identified based on multiple regression analysis were alcohol consumption, smoking, male sex, psychiatric disease, old age, poor therapeutic adherence, and physical disease. Conclusion We identified important predictors of suicide risk by intentional intoxication. A specific and realistic approach to analysis using the decision tree modeling technique is an effective method to determine those groups at risk of suicide by intentional intoxication.

• 한국식품영양학회지
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• 제34권1호
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• pp.88-95
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• 2021

This study compared the lifestyle patterns, dietary patterns, and health care practices of Korean middle-aged people by household type, and ultimately analyzed their relationship with different risk factors for the prevalence and severity of metabolic syndrome. We analyzed the data from 4,755 subjects who were from 40 to 64 years old, and gathered our sample from participants of the Korea National Health and Nutrition Examination Survey from 2013 to 2015. Our results showed that single-person households had lower economic income levels, lower subjective health statuses, and higher levels of food instability than households with two or more individuals. The incidence of metabolic syndrome was 1.64 times higher in single-person households than in households with two or more individuals. After adjusting for potential confounding factors (sex, age, education, household income, smoking status, health status, and dietary factors), single-person households showed 1.75 times higher hypertriglyceridemia ORs than non-single-person households. In the conclusion of our study, we suggest that middle-aged people in single-person households may be at greater risk for metabolic syndrome and hypertriglyceridemia.

• 대한치과교정학회지
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• 제53권2호
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• pp.106-115
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• 2023

Objective: To evaluate the null hypothesis that there is no difference in a set of clinical predictors of potentially impacted canines between low-risk patients with and without displaced canines. Methods: The normal canine position group consisted of 30 patients with 60 normally erupting canines ranked in sector I (age, 9.30 ± 0.94 years). The displaced canine group comprised 30 patients with 41 potentially impacted canines ranked in sectors II to IV (age, 9.46 ± 0.78 years). Maxillary lateral incisor crown angulation, inclination, rotation, width, height, and shape, as well as palatal depth, arch length, width, and perimeter composed a set of clinical predictors, which were evaluated on digital dental casts. Statistical analyses consisted of group comparisons and variable correlations (p < 0.05). Results: There was a significant association between sex and mesially displaced canines. Unilateral canine displacement was more prevalent than bilateral displacement. The crown of the maxillary lateral incisors was significantly angulated more mesially and rotated mesiolabially in low-risk patients with displaced canines, who also had a shallower palate and shorter anterior dental arch length. Lateral incisor crown angulation and rotation, as well as palatal depth and arch length, were significantly correlated with the canine displacement severity. Conclusions: The null hypothesis was rejected. Maxillary lateral incisor angulation inconsistent with the "ugly duckling" stage as well as a shallow palate and short arch length are clinical predictors that can significantly contribute to the early screening of ectopic canines in low-risk patients.

• Communications for Statistical Applications and Methods
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• 제15권5호
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• pp.697-708
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• 2008

본 논문은 금융기관에서 활용하고 있는 운영리스크 측정모형에 대한 적합성검증 방법 중 안정성 검증에 관한 것이다. 신용리스크와는 달리 운영리스크는 손실자료의 특징, 과거 자료의 부족 그리고 적합성검증을 위한 이론적 도구의 부족 등으로 인해 현재 적절한 적합성검증 방안에 제시되지 못하고 있다. 본 논문에서는 운영리스크 VaR(Value at Risk) 추정값의 안정성을 평가하는 적합성검증 방법을 제시하고 이를 활용한 실증분석을 통해 제안된 방법에 대한 실제적 활용 가능성을 확인해 보고자 한다. 구체적으로 본 논문에서는 붓스트랩 방법을 활용하여 운영리스크 VaR의 신뢰구간을 생성함으로써 운영리스크 VaR 추정값의 안정성을 검증하는 기법을 제안하였으며, 이를 토대로 적합에 따른 운영리스크 VaR 추정값의 안정성을 측정하는 방안도 제시하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권7호
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• pp.3147-3153
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• 2016

Background: Many strategies are required for cervical cancer reduction e.g. provision of education cautious sexual behavior, HPV vaccination, and early detection of pre-invasive cervical lesions and invasive cancer. Basic health data for cervical cytology/ HPV DNA and associated factors are important to make an appropriate policy to fight against cervical cancer. Aims: To assess the prevalence of abnormal cervical cytology and/or HPV DNA and associated factors, including sexual behavior, among Bangkok Metropolitan women. Materials and Methods: Thai women, aged 25-to-65 years old, had lived in Bangkok for ${\geq}5$ years were invited into the study. Liquid-based cervical cytology and HPV DNA tests were performed. Personal data were collected. Main Outcomes Measures: Rates of abnormal cytology and/ or high-risk HPV (HR-HPV) and factors associated with abnormal test (s) were studied. Results: Abnormal cytology and positive HR-HPV were found in 6.3% (279/4442 women) and 6.7% (295/4428), respectively. The most common abnormal cytology was ASC-US (3.5%) while the most common HR-HPV genotype was HPV 16 (1.4%) followed by HPV 52 (1.0%), HPV 58 (0.9%), and HPV 18 and HPV 51 at equal frequency (0.7%). Both tests were abnormal in 1.6% (71/4428 women). Rates of HR-HPV detection were directly associated with severity of abnormal cytology: 5.4% among normal cytology and 13.0%, 30.8%, 40.0%, 39.5%, 56.3% and 100.0% among ASC-US, ASC-H, AGC-NOS, LSIL, HSIL, and SCC, respectively. Some 5% of women who had no HR-HPV had abnormal cytology, in which 0.3% had ${\geq}$ HSIL. Factors associated with abnormal cytology or HR-HPV were: age ${\leq}40$ years, education lower than (for cytology) or higher than bachelor for HR-HPV), history of sexual intercourse, and sexual partners ${\geq}2$. Conclusions: Rates for abnormal cytology and HR-HPV detection were 6.3% and 6.7% HR-HPV detection was directly associated with severity of abnormal cytology. Significant associated factors were age ${\leq}40$ years, lower education, history of sexual intercourse, and sexual partners ${\geq}2$.