• 한국기계가공학회지
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• 제19권6호
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• pp.67-72
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• 2020

Life tests are essential in reducing the catastrophic damage caused by the accidents of large machinery such as aircraft and ships. However, life tests are challenging to implement due to the high costs and time required to test the life of large machinery parts. Therefore, it is advantageous and convenient to apply accelerated life test techniques for key components to reduce costs and time. In fact, extensive research has already been conducted on these techniques. However, recently, there have been cases in which an experimental value was applied to the shape parameter of the Weibull distribution used in the reliability test, but the test time was not significantly reduced. Therefore, in this paper, the shape parameters are estimated from the probability density function of the Weibull distribution for the analysis of an accelerated life test for bladder accumulators, which are core components of military helicopters. The test time was derived based on the number of samples and confidence level by substituting it into the test time equation. Next, the accelerated life test time was calculated using the steady-state test time with an acceleration factor obtained from the Arrhenius model. The steady-state life test required approximately 15,000 H, whereas the accelerated life test time for one sample at 100 ℃ was 34% shorter than that of the steady-state life test.

• Journal of Yeungnam Medical Science
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• 제5권1호
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• pp.17-22
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• 1988

1984년 6월 부터 1987년 8월까지 영남대학교 의과대학 부속병원 정형외과에서 체험한 9예의 대퇴골 결부골절에 대한 분석결과는 아래와 같다. 골절의 원인은 교통사고가 대부분(5예)이었으며, 성별로는 여자 6예, 남자 3예였다. 골절의 유형은 제 2형(transcervical)이 6예로 가장 많았다. 치료는 4예에서 도수정복후 내고정하였으며 3예에서는 관혈적정복 및 내고정했고, 2예에서 견인과 석고붕대 고정하였다. 치료결과는 6예에서 우수하였으나, 3예에서 불량하였다. 불량한 예는 모두 고관절, 대퇴경부 및 대퇴골두에 합병증이 생긴 경우였다. 교통사고 등 사고예방에 관심을 높여야 하고, 빠른 진단과 적절한 내고정방법들이 중요한 것으로 생각되었다.

• 대한두개안면성형외과학회지
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• 제19권2호
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• pp.108-113
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• 2018

Background: The aim of our retrospective study is to evaluate the management of isolated orbital floor fractures considering the clinical, functional and aesthetic results according to the surgical approach and the type of materials used. Methods: Retrospectively, clinical, radiological, surgical, and ophthalmological data from 79 patients were collected from January 2010 to December 2016. Furthermore, included patients were interrogated on functional and aesthetic satisfaction. Results: The main causes of trauma were physical aggression followed by accidents. The median time between trauma and surgery was 4 days. The most common surgical approaches were the subciliary and the transconjunctival ones. Alloplastic materials were used in 75 patients. In two patients, we used a combination of two grafts. Patients experienced minor immediate complications. On follow-ups, none of our patients suffered from ocular movement restrictions. Patients treated by subciliary approach had higher risk of retractile scaring compared to other surgical approaches. In our study, patients agreed to complete a questionnaire assessing functional and aesthetic outcomes with a high satisfaction score. No association between the implant material used and the results has been assessed. Conclusion: This study describes the results of orbital floor reconstructions. Despite a variety of materials used and surgical approaches performed, we believe that the transconjunctival approach is the most suitable option with a high satisfaction score.

• 한국화재조사학회학술대회
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• 한국화재조사학회 2011년도 제21회 춘계학술대회
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• pp.77-97
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• 2011

본 논문에서 옥외용 LED 조명의 전기화재 및 감전 위험성 평가에 대하여 연구하였다. 옥외용 LED 조명관련 법 규정에 대하여 검토하였으며, LED 조명의 외형과 구조에 대하여 분석하였다. 또한, LED 조명에 대한 주수실험, DC 전로의 선간 단락, 손상된 피복의 선간 절연파괴, 과전압 유입, 건전상 및 수중에서의 DC 전로의 누전 실험을 수행하였다. 실험 결과로부터, LED 조명에서의 이상 조건에 의한 전기화재나 감전사고의 위험성이 있음을 확인할 수 있었으며, 전기안전을 위한 보호장치와 절연형 컨버터의 사용이 요구된다. 본 연구결과는 LED 조명의 전기안전 확보를 위한 제 규정의 개선과 전기사고의 조사에 도움이 될 것으로 기대된다.

• Safety and Health at Work
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• 제12권2호
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• pp.147-153
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• 2021

Background: In this study, the association of work and demographic characteristics with different traffic offenses committed by food delivery riders in Greece was examined. Previous research has identified various factors related to risky driving however, there is a need for exploring the complex interrelationship of work-related factors underlying risky driving behavior. Materials and Methods: A 2-items uestionnaire was used exploring delivery riders demographic characteristics, terms of employment, issues of concern during work and type of traffic offenses committed. In total, uestionnaires were analyzed using logistic regression in order to identify characteristics independently associated with serious traffic offenses, namely, red-light running and helmet non-use. Results: The analysis showed that: (i) typical health and safety measures had no effect on serious traffic offenses, (ii) young age was related to both offenses however (iii) different sets of work conditions were associated with reports of red-light running (i.e. low work experience, use of personal vehicle for work, and payment by hour) and helmet non-use respectively (i.e. intense work pace, high tip income per day and low concern about vehicle condition). Conclusion: The above findings provide evidence that serious traffic offenses are manifestations of underlying conflict experienced by the riders between safety and various performance criteria. Each one of the two offenses is related to different rider profiles aiming to satisfy different goals, namely, those mainly trying to maximize profit non-helmet users and those, mostly inexperienced ones, trying to cope with work pressure red light runners. Potential regulatory measures to alleviate risky practices are discussed.

• 수산해양기술연구
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• 제58권1호
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• pp.19-31
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• 2022

Damages by jellyfish are occurring frequently around the world. Among them, accidents caused by jellyfish stings are serious enough to cause death. So we designed a jellyfish blocking net and analyzed its stability to prevent sting caused by jellyfish entering the beach. To this end, the dynamic behavior of the jellyfish blocking net according to the current speed (0.25-1.0 m/s) and the net type (50, 100 and 150 mm) on the upper part of the blocking net was modeled using the mass spring model. As a result of simulations for the model, the horizontal tension (horizontal component of the mooring tension) of the mooring line increased with the decrease in the mesh size on the upper part of the blocking net at all current speeds, but exceeded the holding force at high tides faster than 0.5 m/s and exceeded the holding force at all current speeds at low tide. Therefore, the jellyfish blocking nets showed poor stability overall. The depth of the float line had a little difference according to the upper mesh size and increased lineary proportional to the current speed. However, the float line sank too much to block the incoming jellyfish. These analysis results helped us find ways to improve the stability of the jellyfish blocking net, such as adjusting the length of the mooring line and improving the holding power. Therefore, it is expected that this technology will be applied us various underwater structures to discover the weaknesses of the structures and contribute to increasing the stability in the future.

• 대한교통학회지
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• 제29권4호
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• pp.53-62
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• 2011

본 연구는 운수업체에 대한 안전관리 시행에 따른 교통사고 감소효과 분석을 목적으로 수행되었다. 이를 위해 운수업체에 대한 안전관리 시행 전 후 비교 및 비교대상그룹과의 교통사고지수 변화량의 차이를 분석하였고, 안전관리를 통한 순수한 시행효과 분석을 위해 운수업체의 교통사고 사고지수 변화 트렌드 및 평균회귀량을 산출하여 제거해주는 방법을 이용하였다. 본 연구결과를 종합해 보면, 운수업체에 대한 안전관리는 전반적으로 운수업체의 교통사고예방에 기여효과가 있는 것으로 나타났으며, 이러한 효과는 안전관리 강도별, 운수업체 규모별로는 차이가 있는 반면 업종별로는 유의한 차이를 나타내지 않았고, 이들 조합에 따른 상호간 영향을 미치는 것으로 나타났다. 따라서 향후 운수업체에 대한 안전관리의 효율성을 높이기 위해서는 안전관리방식의 동일한 적용이 아닌 업체규모와 연계한 안전관리방식의 개발 및 적용이 필요하다.

• 한국항해항만학회지
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• 제43권6호
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• pp.437-443
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• 2019

항로표지는 선박에 대하여 등광, 형상, 색채, 음향, 전파 등을 수단으로 운항 선박에게 위치, 방향 및 장애물의 위치 등을 알려주는 항행보조시설 일체를 의미하며, 주야간 선박항행의 안전을 위한 기본 수단이다. 예인선은 안전을 위해 종류별 최소 설비요건을 마련하여 사고를 대비하고 있지만, 예인삭의 길이, 조류의 영향, 상대적으로 중량이 큰 부선의 타력으로 인한 영향 등으로 예인선과 선회권이 달라, 변침 시 부선이 예인선을 따라가지 못하여 등부표와 추돌하는 사고가 발생하기도 한다. 본 연구의 목적은 두 선박의 물리적 관계를 분석하여 예인선열을 식별하고 등부표와의 위험을 항로표지 관리운영 시스템을 통해 전파하는 기초 시스템을 제시하는데 있다. 연구를 통해 예부선의 사전 식별 가능성을 확인하였고, 위험 전파를 위한 메시지를 설계하고 모의 시스템을 통한 위험 전파 및 전자해도 상에 위험을 표시하였다.

• 한국기계가공학회지
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• 제15권6호
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• pp.83-88
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• 2016

Over the last five years, 568 people have died while hiking according to 2015 statistics from the public safety ministry. Among those deaths, approximately 33% were due to loss of footing or falling. In this respect, the highly advanced functions of hiking boots should be considered to prevent these unfortunate accidents. For example, by utilizing the Internet of Things (IoT) and Information and Communications Technology (ICT), hiking boots equipped with a Global Positioning System (GPS) or vital signs monitoring systems should be considered. In addition, many challenges remain for the production of 3D printed hiking boots, because the functions of hiking boots are variable, which is important when handling changing terrains and situations. The design of customized hiking boots was introduced in this paper, and 3D printing applications for midsoles using a Porous Polymer Printing (PPP) method was also suggested to verify the possibility of manufacturing hiking boots.

• 산업경영시스템학회지
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• 제46권spc호
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• pp.61-67
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• 2023

Special equipment used for snow removal is only used in the winter and must be moved into storage during non-winter seasons. However, when moving heavy equipment using a forklift within a limited space, safety accidents may occur due to deformation and damage due to the worker's limited visibility and excessive loading of heavy objects. In this study, the scissors boom of the developed heavy load transporter was conducted in two cases: link structural analysis and position-based structural analysis. In detail, the link structural analysis covers four cases of stress and safety factor according to material and thickness to optimize the specifications of the material selected during development, and the structural analysis according to position covers two cases before and after the lift, when maximum stress concentration is achieved. Safety was evaluated through finite element analysis. As a result of the study, when manufacturing a scissors boom type heavy load transporter that can withstand a load of 10 tons, the link showed safety at SS400 4.5mm or higher, and reinforcement is needed in the upper and lower structures, so it is judged to be useful in applying materials according to the load.