• 한국안전학회지
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• 제36권2호
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• pp.18-25
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• 2021

Specialty contractor facilities, which involve a combination of welding and commissioning, face a high risk of serious accidents such as fire, explosion, and suffocation associated with welding work, nitrogen, and argon use. In such facilities, the organizational safety culture has considerable impact on the frequency of accidents. In this study, a safety culture evaluation was conducted on specialty contractors. NOSACQ-50, a standardized survey method on safety culture, was selected as an assessment tool to evaluate the safety culture in specialized construction companies that could not afford to invest heavily in safety. The self-administered questionnaire survey was conducted with 201 workers of four construction companies and the results were analyzed. It was found that in companies with low safety culture, the occurrence of irrationality was 66.0%, while in companies with high safety culture, the occurrence of irrationality was 42.6%. Thus, the difference in the occurrence of irrationality by safety culture was statistically significant. The difference in safety culture level according to the experience of occurrence of irrationality was also significant. It was also found that the higher the belief in safety management authorization, safety responsibilities of managers, worker safety priorities, and safety system effects, the lower the probability of irrationality.

• Advances in Computational Design
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• 제7권3호
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• pp.173-188
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• 2022

In modern buildings, glass is considered a structurally unsafe material due to its brittleness and unpredictable failure behavior. The possible use of structural glass elements (i.e., floors, beams and columns) is generally prevented by its poor tensile strength and a frequent occurrence of brittle failures. In this study an innovative modelling based on an equivalent thickness concept of laminated glass beam reinforced with FRP (Fiber Reinforced Polymer) composite material and of glass plates punched is presented. In particular, the novel numerical modelling applied to an embedding Carbon FRP-rod in the interlayer of a laminated structural glass beam is considered in order to increase both its failure strength, together with its post-failure strength and ductility. The proposed equivalent modelling of different specimens enables us to carefully evaluate the effects of this reinforcement. Both the responses of the reinforced beam and un-reinforced one are evaluated, and the corresponding results are compared and discussed. A novel equivalent modelling for reinforced glass beams using FRP composites is presented for FEM analyses in modern material components and proved estimations of the expected performance are provided. Moreover, the new suggested numerical analysis is also applied to laminated glass plates with wide holes at both ends for the technological reasons necessary to connect a glass beam to a structure. Obtained results are compared with an integer specimen. Experimental considerations are reported.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.261-268
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• 2022

In road work zones, pedestrian workers' habituated inattention to warning alarms from construction vehicles can lead to fatal accidents. Previous studies have theorized that human factors such as personality traits may affect workers' inattentiveness to workplace hazards. However, there has been no study that directly examined how road construction workers' personality traits affect their attention to warning alarms within a work zone and the likelihood of engagement in a struck-by accident. This study examines how workers' sensation-seeking (especially boredom susceptibility) is related to inattention to warning alarms while performing a task in road work zones. An experiment with actual road construction workers was conducted using a virtual road construction environment. Workers' attention to repeatedly presented warning alarms was measured using eye-tracking sensors. In response to workers' frequent inattentive behaviors, a virtual accident was simulated. Results revealed a significant association between boredom susceptibility and workers' engagement in the virtual accident, a consequence of inattentiveness to warning alarms. The findings suggest that workers' personality traits predispose them to tune out warning alarms and become vulnerable to accidents in road work zones. The findings of this study can be used to develop targeted interventions aimed at preventing workers' inattention to repeatedly exposed workplace hazards, thereby contributing to reducing fatal accidents in road work zones.

• 국제학술발표논문집
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• The 10th International Conference on Construction Engineering and Project Management
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• pp.367-374
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• 2024

The detection and tracking of construction workers in building sites generate valuable data on unsafe behavior, work productivity, and construction progress. Many computer vision-based tracking approaches have been investigated and their capabilities for tracking construction workers have been tested. However, the dynamic nature of real-world construction environments, where workers wear similar outfits and move around in often cluttered and occluded regions, has severely limited the accuracy of these methods. Herein, to enhance the performance of vision-based tracking, a new framework is proposed which seamlessly integrates three computer vision components: detection, tracking, and re-identification (DTR). In DTR, a tracking algorithm continuously tracks identified workers using a detector and tracker in combination. Then, a re-identification model extracts visual features and utilizes them as appearance descriptors in subsequent frames during tracking. Empirical results demonstrate that the proposed method has excellent multi-object-tracking accuracy with better accuracy than an existing approach. The DTR framework can efficiently and accurately monitor workers, ensuring safer and more productive dynamic work environments.

• 한국심리학회지 : 문화 및 사회문제
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• 제12권3호
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• pp.23-47
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• 2006

본 연구에서는 연령에 따른 운전자의 운전확신수준 변화가 운전행동에 미치는 영향을 살펴보았다. 운전확신수준을 측정하기 위해 운전확신수준 설문지를 사용하였으며, 조사대상자들의 운전경력, 주행거리, 운전일수, 법규위반(음주, 과속), 교통사고경험(가해, 피해)을 함께 조사하였다. 조사대상자는 만 19세부터 만 80세까지였으며 총 1,055명이 연구에 참여하였다. 운전확신수준의 구조를 알아보고자 요인분석을 실시하였다. 각 연령(29세이하, 30-39세, 40-49세, 50-64세, 65세이상)의 운전확신수준을 비교하고, 운전확신수준과 운전행동과의 관계를 알아보았다. 그 결과, 운전확신수준은 '상황둔감성', '불안전운전', '주의집중소홀', '운전자신감'의 네 요인으로 이루어져 있었으며, 연령의 증가와 함께 운전확신수준은 감소하는 경향을 보였다. 또한, 운전확신수준은 연령과 가해교통사고, 피해교통사고, 운전기간, 음주운전, 과속운전, 운전경력 등과 상관관계를 가지고 있었다. 연구에 참여한 운전자 집단을 음주운전집단, 과속운전집단으로 나누어 운전확신수준과 운전행동의 차이를 알아보았는데, 음주운전이나 과속운전 경험이 없었던 운전자 집단과 음주운전이나 과속운전을 경험한 운전자 집단의 운전확신수준과 운전행동이 유의한 차이를 보이는 것으로 나타났다.

• 한국자동차공학회논문집
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• 제1권1호
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• pp.131-139
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• 1993

Low cycle fatigue characteristics of cast aluminum alloy A356 with a yield strength and ultimate strength of 229 and 283 MPa respectively was evaluated using smooth axial specimen under strain controlled condition. Reversals to failure ranged from 16 to 107. The cast aluminum alloy exhibited cyclically strain-gardening behavior. The results of low cycle fatigue tests indicated that the conventional low cycle fatigue tests indicated that the conventional low cycle fatigue life model was not a satisfactory representation of the data. This occurred because the elastic strain-life curve was not-log-log linear and this phenomena caused a nonconservative and unsafe fatigue life prediction at both extremes of long and short lives. A linear log-log total strain-life model and a bilinear log-log elastic strain-life model were proposed in order to improve the representation of data compared to the conventional low cycle fatigue life model. Both proposed fatigue life models were statistically analyzed using F tests and successfully satisfied. However, the low cycle fatigue life model generated by the bilinear log-log elastic strain-life equation yielded a discontinuous curve with nonconservatism in the region of discontinuity. Among the models examined, the linear log-log total strain-life model provided the best representation of the low cycle fatigue data. Low cycle fatigue life prediction method based on the local strain approach could conveniently incorporated both proposed fatigue life models.

• 여성건강간호학회지
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• 제14권3호
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• pp.205-212
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• 2008

Purpose: The purpose of this study was to survey the health behaviors related to reproductive health, reproductive health history, and sexual behaviors of college students in local areas. Method: With a survey design, 792 college students from C and D areas were recruited to assess health behaviors such as smoking and alcohol drinking, as well as history of reproductive health and sexual behaviors. The data were collected by a self-administered questionnaire from November to December, 2007. Result: Mean age of the students was 20.8(SD=1.96) and gender distribution was 29.2% for male and 70.8% for female. Unhealthy behaviors were alcohol drinking, smoking, excessive weight loss, and irregular exercise; unsafe sex practices were experience of sexual intercourse with multiple sex partners and history of sexually transmitted disease (STD). Male students had more alcohol drinking (p=.04), smoking(p<.001), excessive weight loss(p=.01), experience of sexual intercourse with multiple sex partners(p<.001), history of STD(p=.025) compared to females. On the other hands, female students participated in regular exercise less than males(p<.001). Conclusion: College students seem to perform unhealthy behaviors related to reproductive health and less effective way of safe sex practices. Therefore, a planned education program for reproductive health promotion operated by college level is needed to assess and improve the level of reproductive health in college students.

• Structural Engineering and Mechanics
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• 제54권5호
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• pp.855-875
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• 2015

Many novel materials exhibit a property of different elastic moduli in tension and compression. One such material is graphene, a wonder material, which has the highest strength yet measured. Investigations on buckling problems for structures with different moduli are scarce. To address this new problem, firstly, the nondimensional expression of the relation between offset of neutral axis and deflection curve is derived based on the phased integration method, and then using the energy method, load-deflection relation of the rod is determined; Secondly, based on the improved constitutive model for different moduli, large deformation finite element formulations are developed and combined with the arc-length method, finite element iterative program for rods with different moduli is established to obtain buckling critical loads; Thirdly, material mechanical properties tests of graphite, which is the raw material of graphene, are performed to measure the tensile and compressive elastic moduli, moreover, buckling tests are also conducted to investigate the buckling behavior of this kind of graphite rod. By comparing the calculation results of the energy method and finite element method with those of laboratory tests, the analytical model and finite element numerical model are demonstrated to be accurate and reliable. The results show that it may lead to unsafe results if the classic theory was still adopted to determine the buckling loads of those rods composed of a material having different moduli. The proposed models could provide a novel approach for further investigation of non-linear mechanical behavior for other structures with different moduli.

• 한국건설관리학회논문집
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• 제20권6호
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• pp.66-73
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• 2019

정부와 안전보건공단의 재해 절감을 위한 다양한 노력덕분에 산업과 건설업 전반에 걸쳐 재해 사고는 감소추세를 보이고 있다. 하지만 건설업에서의 추락재해는 감소하지 않고 오히려 증가하고 있다. 특히, 달비계에 의한 추락재해는 매년 발생빈도는 낮지만 발생 시 작업자의 사망과 직결한다는 측면에서 재해강도가 매우 크다고 할 수 있다. 국내 건설업에서의 달비계 작업환경은 매우 열악하다. 특히 소규모 건설현장에서의 달비계 작업자들은 안전에 대한 감독과 관리를 받을 수 있는 주체가 없다. 달비계 작업자들은 자신들이 직접 제작한 성능이 확인되지 않은 달비계를 가지고 불안전한 작업환경에 내몰리고 있다. 따라서 본 연구는 15년간 달비계에서 기인한 242건의 사고사례들을 분석하여 추락재해 발생 주요 원인 및 개선방안을 제시하였으며, 주요내용은 불안전한 행동에 의한 재해발생률이 높아서 작업대 안착 시, 안전난간을 넘어가는 과정, 몸의 불균형 등에서 사고가 많으며 설비개선 및 작업방법개선으로 해결이 요구된다. 또한, KOSHA Guide에서 제시하는 작업순서 상의 문제점으로 발생되는 재해는 없었으며, 다만 작업 순서를 따르지 않아 안전대를 안전대 걸이용 로프에 미설치 및 미부착에 의한 사망으로 이르는 재해가 다수 발생된 것으로 파악되어 작업방법의 개선에서 가장 중요한 사항은 수직구명줄 및 안전대의 설치 및 착용이 가장 중요한 사항으로 도출되었다.

• 전산구조공학
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• 제10권3호
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• pp.167-174
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• 1997

계가 혼돈거동을 나타낼 경우에는 변수들의 미소변화에 의해서도 계가 전혀 다른 거동을 나타낼 수 있기 때문에 비선형계의 설계 및 해석시에는 이를 고려해야 한다. 따라서 본 연구에서는 구형 쉘의 중앙에 충격하중이 수직방향으로 작용하는 경우, 쉘의 기하학적 비선형성과 재료적 비선형성으로부터 기인되는 혼돈거동을 해석하였다. 쉘의 탄소성거동을 유한요소법을 이용하여 구한 후 계의 거동을 변위-시간이력, 프앙카레 맵, phase diagram등의 표준적인 방법들을 이용하여 쉘의 혼돈거동을 규명하였다. 해석결과, 계는 혼돈거동을 나타내었으나 탄소성보의 경우와는 달리 초기조건의 미소변화에 대한 극도의 민감도는 나타나지 않았으며 시간에 대한 쉘의 거동특성도 크게 변하지 않았다. 프앙카레 맵은 한정된 영역에 결쳐서 점들이 분포되었기 때문에 계의 거동이 혼돈거동임을 보여 주고 있지만 혼돈계의 프앙카레 맵에서 나타나는 기하학적 구조는 나타나지 않았다. 에너지선도를 이용하여 쉘이 하중의 작용방향 또는 반대방향으로 불규칙적으로 snap-through되는 원인을 규명하였다.