• 한국산학기술학회논문지
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• 제13권10호
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• pp.4762-4767
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• 2012

열차의 위치를 검지하고 열차내연산(DTG)을 위한 각종 열차제어데이터를 차상으로 전송하는 AF궤도회로장치는 단일계로 구성되어 있다. 만약, 고장이 발생할 경우 선로전환기 및 신호기제어가 불가능하여 시스템이 복구되기까지 기관사에 의해 수동으로 열차를 운전하여야 한다. 이 과정에서 인적 오류는 열차지연, 충돌, 탈선 등 치명적인 안전사고 발생요인으로 작용한다. 따라서, 본 논문에서는 고장모드마다 시스템과 열차에 미치는 영향을 분석하였으며, 고장평점 및 고장등급을 계량화하였다. 계량화된 분석결과를 토대로 전원장치 독립설치, 증폭PCB의 결함콘덴서 원인분석 및 교체, 저항자 냉각시스템설치, 작업방법개선을 통해 고장발생건수 감소 및 신뢰성의 척도인 평균고장간격(MTBF)의 증가와 평균복구간격(MTTR)이 감소되었다. 그리고, 지금까지 경험에 의한 유지보수체계를 계량화된 방법에 의해 예측정비를 수행토록 하여 AF 궤도회로에 대한 신뢰성을 향상할 수 있도록 하였다.

• 수산해양교육연구
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• 제25권3호
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• pp.564-579
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• 2013

The purpose of Maritime Safety Tribunal is that experts about ship operation investigate and reveal causes of marine disasters and suggest plans to prevent recurrence in Korean Maritime Safety Tribunal which is a kind of administrative court. Despite the fact that 72% of marine disasters is fishing vessel accidents and 75% of collision accidents between vessels which most occur is related to fishing boats, it is the very serious problem that there is no any person with licenses of marine technicians for fishing vessels in judges and investigators of Korean Maritime Safety Tribunal. The operational characteristics of fishing vessels, their sizes, and shift patterns of duties in wheelhouses are completely and incommensurably different from those of merchant vessels. By the way, if the investigators and judges who just consist of merchant vessel experts investigate and judge marine accidents about fishing vessels, there could be errors in establishment of policies to investigate and reveal their causes and prevent recurrence of accidents. Especially, in case of collision accidents between fishing vessels and merchant vessels, it is thought that the marine accident interested provides causes which can be doubtful about fairness of judges. Therefore, it is thought that the ratio of judges and investigators is most desirable to compose it to be similar to the occurrence frequency of marine accidents. For this, the following solution plans are suggested. First, qualification for appointment requires first class marine technicians. But there is the only one vessel which needs the first class in fishing vessels. Therefore, it is thought that the provisory clause should be added so that the second class marine technicians can be used instead of the first class ones. Second, the marine accidents of fishing vessels reach 72% but the fact that there is no any judge and investigator with licenses of marine technicians for fishing vessels is thought to go against the purpose of establishment of Korean Maritime Safety Tribunal. Therefore, it is thought that there is, at least, one more judges and investigators in the central and local Korean Maritime Safety Tribunals. The same method should be applied to judge assistants and investigation assistants.

• 한국해양공학회지
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• 제28권5호
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• pp.411-422
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• 2014

A helideck is a very valuable offshore structure for the take-off and landing of a helicopter. In order to design a helideck, the design parameters and various loads defined by the regulations related to the design of a helideck should be applied. In this study, a risk analysis was performed based on the helicopter accidents for seven years, and the frequency and possible reasons for accidents involving helidecks were investigated. In addition, a finite element analysis of a steel helideck mounted on the upper deck of a ship (shuttle tanker) was performed with the load that should be considered when designing a helideck. Based on the results, a parametric study of helideck was carried out by applying a variety of design parameters, and an improved helideck design was presented. This improved helideck reduced the steel used by up to 24% compared to the initial helideck design, and the results of a finite element analysis were analyzed and compared with those of the initial analysis.

• 한국학교보건학회지
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• 제2권1호
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• pp.131-146
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• 1989

This study was conducted for the development of recording system of students' health problems, and for the application of International Classification of Health Problem in Primary Care(ICHPPC) as a tool of morbidity classification in school health care. The data were collected from 12th of September to 24th of September in 1988. The objects were composed of health problems written by 10 school nurses who take service in the elementary school. The results were as follows: 1. The features of students' health problmes. The health problems of students were 68 problems from the total numbers of 361 codes of ICHPPC. The 93.4% of health problems was contained in 20 descriptive diagnoses and 97.0% was contained in 30 descriptive diagnoses. According to frequency of main health problems, There were abrasion, scratch and blister(26.7%); disorder of stomach function, other disease of stomach and duodenum (20.4%); headache(10.6%); bruise and contusion (5.3%); acute URI (5.0%); laceration and open wound(4.6%); Insect bite and sting(4.0%); epistaxis(3.4%): abdominal pain(2.6%): superficial tissue(1.7%). Out of all health problems, Category 17(accident, injury and poisoning was 44.7%. and Category 9(digestive system Disease) was 22.2%. 2. Applicability of ICHPPC by the school nurses. School nurses used 68 codes, among the total number of 361 codes from ICHPPC. According to ICHPPC method, school nurses can classified more diverse health problems systematically and objectively than that in other studies on school nurses activities. ICHPPC was found as a useful and applicable tool of morbidity classification in the practice of school nurses.

• 성인간호학회지
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• 제14권1호
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• pp.15-25
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• 2002

Purpose: This study was performed to identify the prevalence and type of urinary incontinence (UI) after a stroke, to find the differences in urinary symptoms according to continence or incontinence, and to find the degree of impact of UI on daily life. Method: For data collection, we had a structured interview with a questionnaire. The subjects were 239 post stroke patients. Results: Among the subjects(mean age: $65{\pm}10$), 66.1 percent had an infarction, and 25.5 percent had a hemorrhage. And 26.4 percent of subjects were within 2 weeks and 28.9 percent from 1 year to 5 years since their episodes of a stroke. Forty five point six percent of subjects had various types of UI: urge 25.7 percent, stress 14.7 percent, functional 20.2 percent, and mixed 39.4 percent. There were significant differences in frequency, nocturia, decreased stream, and incomplete emptying between the incontinent and continent groups. Subjects reported UI influenced various aspect of daily life, 54.1 percent as cause of distress, 53.2 percent on overall quality of life, and 40.4 percent on sleep. The Mixed UI, including urge UI, had higher impact on daily life than others. Conclusion: There was a high prevalence of UI, mixed, urge, and functional type as most prevalent, and it had a strong impact on daily life of post stroke patients.

• 한국가스학회지
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• 제20권3호
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• pp.12-21
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• 2016

화석연료의 의존도를 줄이고자 대체에너지 연구가 활발하게 이루어지고 있는 현재, 산업에서 가장 많이 사용하고 있는 대체에너지 중 하나가 수소이다. 수소의 수요는 매년 꾸준히 증가하고 있으며, 수소의 생산 및 이송을 위한 설비도 늘어나고 있는 실정이다. 이에 따른 수소설비에서 중대사고가 발생할 확률 또한 증가할 것으로 예상된다. 또한 산업현장에서 가장 사고를 많이 초래하는 물질은 LPG 61%, 수소 12%, LNG 10%로 세 가지 가연성가스의 사고 빈도는 높은 축에 속한다. 따라서 산업용으로 많이 사용되며 사고다발성 가연성 가스인 수소, LNG, LPG가 제한된 공간에서 폭발했을 때의 폭발위험성에 대하여 CFD 시뮬레이션을 이용하여 계산을 하였고, 그 결과들을 기반으로 비교분석하여, 제한된 공간에서의 각 가스별 폭발에 대한 위험성을 검토하였다.

• 한국가스학회지
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• 제20권5호
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• pp.17-26
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• 2016

현대 화학플랜트 및 석유 가스 산업 시설은 다양한 잠재위험으로 인하여 위험물질의 누출 및 화재가 빈번히 발생하고 있다. 그 중 특히 화재는 직접적인 화염의 접촉 또는 복사열로 인하여 인명피해는 물론 건물, 설비에 대한 피해 발생으로 domino effect가 발생하여 2차, 3차 피해까지도 발생하기도 한다. 따라서 본 연구에서는 발생가능한 화재를 파악하여 사고피해영향과 빈도를 낮추어 화재 위험성을 관리하는 FRA(Fire Risk Assessment)기법의 절차를 제시하였으며, 사고피해영향으로 화염의 직접적인 접촉과 복사열로 인한 주요건물(제어실, 창고, 변전소)의 물리적 특성이 변형되는 시간을 고려하였다. 사례연구를 통하여 수행한 FRA기법으로 국내외 화학공장의 위험성을 경감시킬 수 있었으며, Protection 설정을 통한 사고의 빈도와 피해영향의 감소를 정량적으로 파악할 수 있었다.

• 한국산학기술학회논문지
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• 제16권12호
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• pp.8812-8819
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• 2015

콘크리트 궤도 건설의 증가로 인한 레일 체결장치의 중요성이 커지고 있는 상황에서 최근 레일 체결장치의 부속품인 텐션클램프가 절손되는 사고가 발생되었다. 이는 현장상태, 운영기관, 열차운행조건 및 빈도 등 다양한 요인에 의한 것으로 텐션클램프의 거동관련 연구가 필요하다. 본 논문에서는 실내실험 및 유한요소해석을 통해 텐션클램프의 역학적 거동을 분석하였다. 실내실험을 수행하여 텐션클램프 체결력에 따른 응력 및 변위를 도출하고 이를 유한요소해석 결과와의 비교를 통해 해석 모델을 검증하였다. 또한 검증된 모델을 적용하여 열차 하중에 따른 텐션클램프의 변형과 응력을 도출하고, 응력 분석을 통해 텐션클램프의 피로에 대한 취약도를 파악하였다.

• 대한교통학회지
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• 제18권1호
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• pp.35-43
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• 2000

본 연구는 평면곡선부의 자유속도변화와 교통사고에 대한 영향을 분석하기 위해 수행되었으며, 이를 위해 곡선반경별로 진입부 직선도로-곡선부도로-진출부 직선도로로 구분하여 각 차량의 속도를 산출하였다. 평면곡선부의 자유속도변화와 기하구조의 영향을 분석하기 위해 선행차량에 의해 영향을 받지 않는 속도를 이용하였다. 이러한 곡선부에서 주행하는 차량의 자유속도를 통해 곡선반경별 최저속도와 그 속도가 나타나는 위치를 분석하였고, 해당 도로구간의 교통사고자료를 비교·분석하여 평면곡선 내의 속도변화와 교통사고발생간의 관계를 규명하였다 연구 결과는 다음과 같다. 첫째, 운전자들은 곡선시작지점에 도착하기 전에 충분히 속도를 줄이고, 곡선부에서 가장 낮은 속도가 나타나는 위치는 곡선내에서 나타난다. 이는 운전자의 시거에 의한 영향이다 둘째, 곡선부에서의 속도변화폭이 클수록 사고위험성은 크고, 실제 교통사고 발생건수도 높다. 본 연구의 결과를 통해 도로 주행의 안전성을 고려한 평가지표를 개발할 수 있으며, 이는 일관성 있는 도로설계를 이루게 한다.

• 한국전기전자재료학회논문지
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• 제19권10호
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• pp.947-952
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• 2006

It has been confirmed that the inner defect of insulator and the perfect diagnosis for aging are closely related to safe electric power transmission system and that the detection of accident and diagnosis technique turn out to be very important issues. But perfect diagnosis is difficult because discharge pattern is irregular. Thus, we investigated discharge pattern using the new distribution statistical models with cross-inked polyethylene(XLPE) specimens. Voltage was applied to power frequency by step method, and calibration of discharge was set to 50 pC. After the voltage was applied, it measured the discharge occurring during 10s. We investigated discharge pattern using the K-means analysis and Weibull function. We also investigated variation of centroid and shape parameter due to variation of voltage. As a result of analyzing K-means, it was confirmed that cluster including many object numbers was formed by the presence of void. And result of Weibull distribution, it was confirmed that shape parameter of discharge varied from 1.28 to 1.62 in no void specimens, and that shape parameter of discharge number varied from 1.28 to 1.62. In the void, shape parameter of discharge varied from 5.66 to 6.43, and shape parameter of discharge number varied from 5.05 to 5.08.