• 한국항공운항학회지
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• 제20권1호
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• pp.76-85
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• 2012

Air traffic controllers often experience fatigue and stress on the job due to work-related factors. Performance impairment resulting from fatigue and stress is an important concern for aviation safety. The goal of this research was to investigate fatigue and stress factors for air traffic controllers. The research involved an extensive literature review of fatigue and stress in the air traffic control environment and surveyed fatigue and job stress level of Korean air traffic controllers compared to other occupation groups. Results of survey showed that fatigue and stress levels of air traffic controllers were significantly higher than other occupation groups. Specially air traffic controllers reported that night work created high level of fatigue and perceived that physical environment and job demand induced high level of stress. In addition, implications for fatigue and stress management were discussed.

• 한국항해항만학회지
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• 제48권2호
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• pp.88-96
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• 2024

This study examined challenges posed by two ferry routes, namely, Likoni and Mtongwe crossings, in the Mombasa Channel and their impact on navigational safety. Utilizing the Environmental Stress (ES) model, this study analyzed current ship traffic and assessed stress levels imposed by ferry crossing traffic on navigators. ES values revealed significant stress at these ferry crossings attributed to varying transit speeds. Standardizing transit speeds at two ferry passages can reduce high stress levels, presenting a viable solution. Furthermore, the IWRAP Mk2 simulation underscores crossing collisions as a significant concern, particularly at Likoni and Mtongwe crossings, due to increased ferry traffic. This research offers valuable insights for stakeholders, such as the Kenya Ports Authority (KPA), to develop targeted safety measures and enhance the flow of ship traffic in the channel.

• 한국산업융합학회 논문집
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• 제27권4_2호
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• pp.833-840
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• 2024

According to recent data from the Korea Meteorological Administration(KMA), the frequency of typhoons around the Korea Peninsula is almost unchanged, but the intensity is on the rise due to climate change. A typhoon that has become so powerful can cause partial or complete damage to the traffic signal structures, limiting the operation of the vehicle and causing traffic congestion. If the traffic signal structure fails to function properly due to the influence of the typhoon, not only the v ehicle operation will be disrupted, but also direct damage to the traffic signal structure will occur. In addition, if the social overhead cost of traffic congestion is included, the recovery cost caused by the typhoon will increase to an extent that it is difficult to estimate. Therefore, in this study, a wind tunnel experiment was performed by producing a wind tunnel model of an existing fixed traffic signal structure and a traffic signal structure in which signs and traffic lights are hinged. Also, The fixed and hinge structures were modeled as 3D finite elements, and wind-resistant analysis was performed by wind speed, and, wind-resistant safety of traffic signal structures were analyzed and examined through wind-resistant analyses. From the comparative analysis of the results of experiment and FE analysis, it was known that the stress reduction rate of the hinge connection structure was at least 30% compared to that of the fixed connection structure from the results of the wind tunnel experiment and FE analysis. And As a result of finite element analysis for the maximum design wind speed of 50m/s, it was found that the maximum stress generated in the existing structure exceeded all the yield stress, but the maximum stress of the hinge connection structure was within the yield stress. Finally The hinge connection structure showed a relatively large stress reduction rate as the wind speed increased and the length of the lateral beam was shorter at the same wind speed.

• 한국항행학회논문지
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• 제21권1호
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• pp.90-98
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• 2017

본 연구는 교대근무를 수행하는 항공교통 관제사들의 피로와 스트레스와 이에 영향을 미치는 변수와의 연관성을 규명하는 연구이다. 기존 연구결과에 의하면, 관제사의 피로와 스트레스는 근무경과시간, 관할 항공기의 수, 시정 등과 같은 여러 요소에 영향을 받으며, 또한 관제사의 피로와 스트레스는 심장 박동수에 영향을 미치는 것으로 있다고 알려져 있다. 본 논문에서는 항공교통관제사의 피로와 스트레스에 영향을 주는 요소로 근무경과시간, 관할 항공기의 수, 시정을 설정하고, 각 요소와 피로와 스트레스의 정도를 나타내는 심장박동수에 대한 연구 가설을 설정하였다. 실제 수집된 자료를 활용하여 연구가설을 검정한 결과 항공교통관제사의 심장 박동수는 관할 항공기의 수와 근무시간경과에 영향을 받는 것을 확인하였다. 특히, 동일한 대수의 항공기를 관제하는 경우에도, 근무 시간이 경과에 따라서 관제사의 피로와 스트레스 정도가 증가하는 것을 확인할 수 있었다.

• 한국항해항만학회지
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• 제27권6호
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• pp.645-652
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• 2003

A virtual vessel traffic control system is introduced to contribute to prevent a marine accident such as collision and stranding from happening. Existing VTS has its limit. The virtual vessel traffic control system consists of both data acquisition by satellite remote sensing and a simulation of traffic environment stress based on the satellite data, remotely sensed data And it could be used to provide timely and detailed information about the marine safety, including the location, speed and direction of ships, and help us operate vessels safely and efficiently. If environmental stress values are simulated for the ship information derived from satellite data, proper actions can be taken to prevent accidents. Since optical sensor has a high spatial resolution, JERS satellite data are used to track ships and extract their information. We present an algorithm of automatic identification of ship size and velocity. It lastly is shown that based on ship information extracted from JERS data, a qualitative evaluation method of environmental stress is introduced.

• 한국환경보건학회지
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• 제49권6호
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• pp.353-361
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• 2023

Background: Noise has been linked to an increased risk of various health issues, including stress, anxiety, insomnia, and cardiovascular disorders. However, research on the relationship between residential traffic noise and mental health in South Korea is limited. Objectives: This study aims to examine the correlation between regional traffic noise levels and mental health using an ecological study design. Methods: In this ecological study, all data were collected from the Korean Statistical Information Service. Traffic noise data in residential areas and the prevalence of mental health indices in 44 cities with noise monitoring stations were obtained. Pearson correlation coefficients were calculated to assess the relationship between regional traffic noise levels and mental health indices. Results: Daytime traffic noise levels were found to have a positive correlation with stress perception (r=0.428, p=0.004) and showed a borderline positive correlation with depressive symptom prevalence (r=0.273, p=0.073). In cities with airports, significant correlations was observed between 24-hour average noise levels and depressive symptoms (r=0.604, p=0.010), whereas this relationship was not observed in cities without airports (r=0.048, p=0.813). Multiple regression analysis, which adjusted for factors such as age, gender ratio, smoking, obesity, unemployment, urban size, and the presence of an airport, confirmed the relationship between 24-hour average noise levels and stress perception (beta=0.287, p=0.024). Conclusions: This study identified correlations between regional traffic noise levels and depressive symptoms or stress perception in adults, with a more pronounced effect in areas with airports. These findings suggest a potential impact of residential traffic noise on mental health, highlighting the importance of preventive measures like noise management in urban planning to promote mental well-being.

• Steel and Composite Structures
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• 제38권3호
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• pp.271-280
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• 2021

In this study, the fatigue property of U rib-to-crossbeam connections in orthotropic steel bridge (OSB) crossbeams under heavy traffic vehicle load was investigated considering the effects of in-plane shear stress. The applicability of an improved structural stress (ISS) method was validated for the fatigue behavior analysis of nonwelded arc-shaped cutout regions in multiaxial stress states. Various types of fatigue testing specimens were compared for investigating the equivalent structural stress, fatigue crack initiation positions, and failure modes with the unified standards. Furthermore, the implications of OSB crossbeams and specified loading cases are discussed with respect to the improved method. The ISS method is proven to be applicable for analyzing the fatigue property of nonwelded arc-shaped cutout regions in OSB crossbeams. The used method is essential for gaining a reliable prediction of the most likely failure modes under a specific heavy traffic vehicle load. The evaluated results using the used method are proven to be accurate with a slighter standard deviation. We obtained the trend of equivalent structural stress in arc-shaped cutout regions and validated the crack initiation positions and propagation directions by comparing them with the fatigue testing results. The implications of crossbeam spans on fatigue property are less significant than the effects of crossbeams.

• 한국도로학회논문집
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• 제14권5호
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• pp.31-45
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• 2012

PURPOSES: In Korea, rapid maintenance of distressed concrete pavement is required to prevent traffic jam of the highway. Asphalt concrete overlay has been used as a general maintenance method of construction for aged concrete pavement. AC overlay on existing concrete pavements experience various early distresses such as reflection crack, pothole and rutting, due to different physical characteristics between asphalt overlay and existing concrete pavement. Bonded concrete overlay(BCO) is a good alternative since it has advantages that can reduce various distresses during the service life since overlay material has similar properties with existing concrete pavements. Recently, BCO which uses the ultra rapid harding cement has been applied for maintenance of highway. BCO has advantage of structural performance since it does monolithic behave with existing pavement. Therefore, it is important to have a suitable bond strength criteria for securing performance of BCO. Bond strength criteria should be larger than normal tensile stress and horizontal shear stress occurred by traffic and environmental loading at bond interface. Normal tensile stress and horizontal shear stress need to estimated for the establishment of practical bond strength criteria. METHODS: This study aimed to estimate the bond stresses at the interface of BCO using the three dimensional finite element analysis. RESULTS: As a result of this study, major failure mode and maximum bond stress are evaluated through the analysis of normal tensile stress and horizontal shear stress for various traffic and environmental load conditions. CONCLUSIONS: It was known that normal tensile stresses are dominated by environmental loading, and, horizontal shear stresses are dominated by traffic loading. In addition, bond failure occurred by both of normal tensile stresses and horizontal shear stresses; however, normal tensile stresses are predominated over horizontal shear stresses.

• Structural Engineering and Mechanics
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• 제19권3호
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• pp.261-279
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• 2005

The hot spot stress approach is usually adopted in the fatigue design and analysis of tubular welded joints. To apply the hot spot stress approach for fatigue evaluation of long span suspension bridges, the FEM is used to determine the hot spot stress of critical fatigue location. Using the local finite element models of the Tsing Ma Bridge, typical joints are developed and the stress concentration factors are determined. As a case for study, the calculated stress concentration factor is combined with the nominal representative stress block cycle to obtain the representative hot spot stress range cycle block under traffic loading from online health monitoring system. A comparison is made between the nominal stress approach and the hot spot stress approach for fatigue life evaluation of the Tsing Ma Bridge. The comparison result shows that the nominal stress approach cannot consider the most critical stress of the fatigue damage location and the hot spot stress approach is more appropriate for fatigue evaluation.

• 한국항해학회지
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• 제25권3호
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• pp.257-268
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• 2001

이 연구는 자연조건, 지형조건, 시설조건 및 다른 선박과의 상대적 위치 관계 등의 특정한 운항환경에서 조선자가 갖는 심리적 부담을 계량화하고, 이를 통해 해상교통의 안전성을 평가하는 환경스트레스 모델을 적용하여 부산항 접근수역의 현행 통항분리방식과 선행 연구에서 제안한 원형분리대방식에 의한 해상교통의 안전성을 상호 비교하여 그 타당성을 검증하고자 한다.