• 한국안전학회지
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• 제33권3호
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• pp.15-20
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• 2018

There have been a number of major fatal fire accidents in Korea recently. The number of fires in 2017 were 44,178, which is not only increasing number of fires but also increasing in casualties. Particularly, the fire at Jecheon Sports Center, which suffered many casualties, is expected to have a huge impact. The cause of the fire has not been determined yet, but heat waves on the ceiling have also been pointed out. As such, the copper heating waves, which are used as a preventive measure against damage of pipes due to freezing of pipes, etc., always have a fire hazard. To determine the possibility of a flame-resistant heated fire, a positive electric cable product was used to artificially ignite and analyze the results. In case of a short circuit, the external covering of the positive electric cable is damaged, but not short circuit unless the heating material surrounding the wire is damaged. Due to the characteristics of heating cable for preventing copper waves, the chances of insulation becoming more severe due to moisture and temperature changes are higher than normal wires. If the internal heating system is carbonized by insulating deterioration without damage to the outer coating, it is likely to cause trekking, to form a winding loop in the heating materials, and to cause short circuit in the heated materials. For the positive temperature line, if the middle is shorted, the current continues to flow to the short circuit unless the breaker disconnects. Consequently, a heated fire that does not cut off the power immediately may leave multiple marks or cuts.

• 한국도로학회논문집
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• 제6권4호
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• pp.35-43
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• 2004

미끄럼저항은 자동차의 타이 어 와 포장노면 사이에서 발생하는 미끄러짐을 방지하여 제동거리를 제어하고 주행 안전성을 확보하는데 중요한 역할을 한다. 우천시의 미끄럼저항 감소는 치명적인 교통사고를 유발할 수 있다. 노면위에 남은 토사 및 겨울철 제설재는 미끄럼저항을 감소시킬 수 있는 요소가 될 수 있다. 본 연구에서는 노면상의 잔류하는 이물질이 타이어와 포장노면사이에서 발생하는 미끄럼저항에 미치는 영향을 다양한 콘크리트 노면조직 형태 (횡방향타이닝, 종방향타이닝, 골재노출) 및 노면조직의 마모조건(신설노면, 마모된 노면)에 대하여 검토하였다. 노면상의 이물질로는 모래, 염화칼슘과 자동차에서 발생하는 폐 오일을 사용하였으며 각 경우별로 이물질의 양을 달리하여, 모래의 경우는 입도 및 양을 달리해가며 미끄럼저항에 미치는 영향을 검토하였다.

• Safety and Health at Work
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• 제6권3호
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• pp.227-232
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• 2015

Background: In comparison with other industries, the construction industry still has a higher rate of fatal injuries, and thus, there is a need to apply new and innovative approaches for preventing accidents and promoting safe conditions at construction sites. Methods: In this study, the effectiveness of a new incentive system-the surprising incentive system-was assessed. One year after the implementation of this new incentive system, behavioral changes of employees with respect to seven types of activities were observed. Results: The results of this study showed that there is a significant relationship between the new incentive system and the safety performance of frontline employees. The new incentive system had a greater positive impact in the first 6 months since its implementation. In the long term, however, safety performance experienced a gradual reduction. Based on previous studies, all activities selected in this study are important indicators of the safety conditions at workplaces. However, there is a need for a comprehensive and simple-to-apply tool for assessing frontline employees' safety performance. Shortening the intervals between incentives is more effective in promoting safety performance. Conclusion: The results of this study proved that the surprising incentive would improve the employees' safety performance just in the short term because the surprising value of the incentives dwindle over time. For this reason and to maintain the surprising value of the incentive system, the amount and types of incentives need to be evaluated and modified annually or biannually.

• 한국항해항만학회지
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• 제44권2호
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• pp.128-135
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• 2020

Long-term shipping contracts represent the cooperative and coexisting relationships between the shipping and steel industries. Yet, differences between the contract forms for iron ore and steel products have emerged. Specifically, the large proportion of consecutive voyage charters (CVC) is being applied in the iron ore trade, whereas the contract of affreightment (COA) is proportionally higher for shipping steel products. The literature review and in-depth interviews in this study identified through the research model, the characteristics of the shipping and market structure in both markets have significantly contributed to the preference of different long-term contracts. It has been determined that the mutual oligopoly market structure and the characteristics of shipping such as, the small number of suitable vessels in the market, the single fixed load/discharge ports, the long-distance voyages, and the potential risks for fatal accidents because of cargo liquefaction, for the iron ore trade, provide higher contribution to the preference of CVC contracts. In contrast, the consignor oligopoly market structure and the shipping characteristics, such as the greater number of suitable vessels available in the market, the variation in ports, the cargo quantity per shipment, the various load/discharge ports, and the need for experienced carriers for steel product loading in the steel product trade has shown higher preference on the COA contracts as the consignors with superiority over the shipowners, resulting in favorable contract types and conditions for the consignors.

• 한국항공우주학회지
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• 제45권9호
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• pp.724-733
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• 2017

비정상 비행(Upset) 상황으로 인한 항공기 사고는 유인항공기와 무인항공기 모두에 치명적인 피해를 발생시킨다. 본 논문은 항공기의 비정상 비행상황에 대한 실시간 대처와 추가적인 위험상황을 방지하기 위한 기법을 연구한다. 먼저 확장칼만필터(Extended Kalman Filter) 방법을 이용해 얻게 되는 예측값과 센서를 통해 실제로 얻게 되는 측정값 사이의 차이를 모니터링하여 현재 항공기의 비정상 비행 진입 여부를 판단한다. 또한, 확장칼만필터의 시간 업데이트를 반복 연산하여 얻은 수 초 후의 예측값을 통해 항공기의 상태가 비정상 비행상황으로 진입할 것인지를 예측하여 사전에 판단할 수 있게 된다. 본 연구결과는 차세대 유무인 항공기의 비정상 비행 상태 진입 방지 시스템 구축을 위한 가교 역할을 할 것으로 사료된다.

• 대한교통학회지
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• 제20권5호
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• pp.163-174
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• 2002

최근 국내에 확대 설치되고 있는 자동과속단속시스템의 핵심은 주행차량의 지점속도를 측정하는 속도검지부의 정확도라 할 수 있다. 우리나라 속도검지부의 경우 대부분 2중 루프검지기를 이용하여 속도를 측정하고 있는 데 속도측정정확도는 루프검지기의 하드웨어 성능뿐 아니라 루프검지기 발생신호를 처리하는 알고리즘에 상당부분 의존한다. 따라서 본 연구에서는 2중 루프검지기의 속도측정 정확도를 높이기 위한 신호처리 알고리즘을 개발하고 이를 현장에서 평가하였다. 먼저 이론 및 현장실험에서 밝혀진 문제점들을 분석하여 원인별로 개선방향을 분류한 뒤 알고리즘을 개발하였다. 이를 위해서 첫째, 검지기의 2개의 진입시점 신호 뿐 아니라 진출시점 신호까지 포함시켜 정확도를 높이는 2중 처리 알고리즘을 개발하였다. 둘째, 속도측정 오차의 허용범위인 $\pm$5%를 초과하는 원인이 되는 검지영역내 비정상적인 주행궤적차량 즉, 대자선주행과 동시진입차량을 걸러내는 필터링알고리즘을 개발하였다. 현장실험을 통하여 개발 알고리즘의 정확성을 평가한 결과 속도측정정확도가 대폭적으로 개선됨을 확인할 수 있었다. 또한 패각선 주행차량, 동시진입차량 등 검지영역 내에서 비정상적 주행궤적을 발생시켜 심각한 오차를 발생시키는 차량들을 성공적으로 제거할 수 있었다.

• Journal of Chest Surgery
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• 제46권3호
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• pp.197-201
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• 2013

Background: Most traumatic tracheobronchial injuries are fatal and result in death. Some milder cases are not life threatening and are often missed at the initial presentation. Tracheobronchial rupture is difficult to diagnose in the evaluation of severe multiple trauma patients. We reviewed the traumatic tracheobronchial injuries at Konyang University and Eulji University Hospital and analyzed the clinical results. Materials and Methods: From January 2001 to December 2011, 23 consecutive cases of traumatic tracheobronchial injury after blunt trauma were reviewed retrospectively. We divided them into two groups by the time to diagnosis: group I was defined as the patients who were diagnosed within 48 hours from trauma and group II was the patients who diagnosed 48 hours after trauma. We compared the clinical parameters of the two groups. Results: There was no difference in the age and gender between the two groups. The most common cause was traffic accidents (56.5%). The Injury Severity Score (ISS) was 19.6 in group I and 27.5 in group II (p=0.06), respectively. Although the difference in the ISS was not statistically significant, group II tended toward more severe injuries than group I. Computed tomography was performed in 22 cases and tracheobronchial injury was diagnosed in 5 in group I and 6 in group II, respectively (p=0.09). Eighteen patients underwent surgical treatment and all four cases of lung resection were exclusively performed in group II (p=0.03). There were two mortality cases, and the cause of death was shock and sepsis. Conclusion: We believe that close clinical observation with suspicion and rigorous bronchoscopic evaluation are necessary to perform diagnosis earlier and preserve lung parenchyma in tracheobronchial injuries from blunt trauma.

• Tuberculosis and Respiratory Diseases
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• 제66권3호
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• pp.241-245
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• 2009

외상성 횡격막 손상은 대부분 교통사고와 관련되어 있다. 특히, 횡격막 파열은 그 진단이 지연되는 경우가 많다. 왜냐하면, 임상적 증상 및 징후가 특이적이지 않기 때문이다. 또한, 가슴 X-선 사진에서도 특징적 소견을 보이지 않으며, 더구나 동반된 다른 외상으로 인해 진단이 은폐될 수 있다. 그래서 다발성 외상 환자를 접근할 때는 횡격막 손상을 의심하고 적절한 검사를 택하는 것이 중요하다. 저자들은 교통사고로 인한 다발성 둔기외상으로 내원한 54세 남자 환자에서 입원 12 병일에 수술적 치료를 요하는 횡격막 파열을 경험하였기에 문헌고찰과 함께 보고하는 바이다.

• 한국실내디자인학회논문집
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• 제25권4호
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• pp.60-67
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• 2016

Falls are accidents that can happen throughout the overall period of human life and their results are very fatal and have a serious negative effect on individuals and society. In case of aged people, even though they live in places where dangerous risks of falls are prevalent, they cannot improve their residential environment for themselves. Therefore, this study intends to prove the effects of fall prevention education by providing fall prevention education to spatial design majoring students in order to improve their perception about the falls and fall prevention environments and their social responsibility as a designer. This study was designed as Quasi-experimental study, and 121 beginners to spatial design received the education. As a result, the effects of education was proved by showing improvements on their awareness about the fall risks, the importance of fall prevention environment and social responsibility as a designer. In addition, after the education students could know more about spatial elements for fall prevention and they specified the details of important environmental factors for fall prevention. Generally, fall prevention education has been given to aged people and this is a first example of fall prevention education that was given to younger generation. It is meaningful that fall prevention education has changed the awareness of the students to help them work in spatial environment design with a strong sense of responsibility as an expert of spatial designer in future.

• 대한기계학회논문집A
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• 제25권10호
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• pp.1551-1558
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• 2001

Recently, a number of underground pipelines have been drastically increased. The integrity of these buried pipelines, especially gas transmitting pipelines, is of importance due to an explosive characteristic of natural gas. The third party damage is known as one of the most critical factor which causes fatal accidents. For this reason, a number of systems detecting third party damage are under development. The major concern in the development of third party damage detection system is to transmit vibration signals out of accelerometer to signal conditioner and data acquisition system without any interference caused by noise. The objective of this paper is to develope a fiber optic accelerometer applicable to third party damage detection system. A fiber optic accelerometer was developed by use of combining principles of one degree of freedom vibration model and an extrinsic Fabry-Perot interferometer. The developed fiber optic accelerometer was designed to perform with a sensitivity of 0.06mVg, a frequency range of less than 6kHz and an amplitude range of -200g to 200g. The developed, accelerometer was compared with a piezoelectric accelerometer and calibrated. In order to verify the developed accelerometer, the field experiment was performed. From the field experiment, vibration signals and the location of impact were successfully detected. The developed accelerometer is expected to be used for the third party damage detection system which requires long distance transmission of signals.