• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.2
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• pp.156-172
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• 2021

Objectives: To investigate the trends of industrial injuries among long-term health care workers in Korea Methods: T7866 injuries were selected from the total industrial injuries approved by the Industrial Accident Compensation Insurance Act(Occupational Safety and Health Act) among long-term health care workers between 2007 and 2016 in Korea. We analyzied the trends of industrial injuries according to work process, occurrence type, and causes. Results: The industrial injuries among long-term health care workers increased since 2012. The mostly occurred area for industrial injuries were low back areas, which is related that the most serious industrial injuries occurred when the one long-term healthcare worker lift manually the recipient, from bed(ondol, Korean floor heating system) to a wheelchair, bed to bath bed, and wheelchair to bath chair. In addition to this, lack of workforce, increased work intensity due to overwork contributed the increasing of occupational injury. Conclusions: This study suggests that the main causes of industrial injuries were Lack of facilities and equipment for small private long-term care institutions, The physical load that goes into lifting the recipient directly, work intensity such as excessive workload and increased work speed. We suggest that the social publicization of long-term care service for the elderly, avoiding ways to lift recipients directly, introducing lifting machines as well as improving working methods, and reducing the workload of caregivers are required.

• Journal of the Korean Society of Safety
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• v.23 no.2
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• pp.21-29
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• 2008

To evaluate the structural integrity of the NPP containment building more rigorously, the effective prestress, which is one of the most affecting elements, needs to be estimated exactly. This paper presents the results of an experimental study to determine the effective prestress force in prestressed concrete beams. It is possible to improve the effective prestress measuring method by test beam, which is being applied for the investigation of the nuclear power plant in operation. If experimentally evaluated Lift-Off method in this study can be coupled with test beam test currently being used in in-service nuclear power plant, it is possible to measure prestress loss of the tendon and the level of the effective prestress load.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.91-96
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• 2010

우리나라의 승강기 기술은 유럽, 미국, 캐나다의 기술표준을 도입함으로써 선진화를 꾀해오고 있으나, 초기의 틀에서 크게 벗어나지 못하고 있을 뿐만 아니라 품질서비스가 아직도 취약한 실정이다. 그 동안 서비스 품질의 정확한 구성요인을 파악하기 위한 연구가 다양하게 이루어져 왔지만, 대부분 서비스품질의 구성요인들 중 기능적 품질에만 국한된 연구가 주류를 이루어 왔으며, 서비스품질 구성요소를 통합한 승강기 유지보수산업에 대한 실증적인 연구는 거의 이루어지지 않은 실정이다. 이에 본 연구에서는 승강기 유지보수산업의 서비스 품질속성에 대한 고유속성과 척도 도출을 통해 경영성과 요인으로서의 고객만족도와 재무 비재무적 성과에 어떠한 영향을 미치는지에 대하여 실증분석하였다. 본 연구의 결과는 우리나라 중소벤처승강기 유지보수 산업의 서비스 품질 제고를 전략의 수립에 기초적인 자료로 활용될 수 있을 것이다.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.200-205
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• 2010

우리나라의 승강기 기술은 유럽, 미국, 캐나다의 기술표준을 도입함으로써 선진화를 꾀해오고 있으나, 초기의 틀에서 크게 벗어나지 못하고 있을 뿐만 아니라 품질서비스가 아직도 취약한 실정이다. 그 동안 서비스 품질의 정확한 구성요인을 파악하기 위한 연구가 다양하게 이루어져 왔지만, 대부분 서비스품질의 구성요인들 중 기능적 품질에만 국한된 연구가 주류를 이루어 왔으며, 서비스품질 구성요소를 통합한 승강기 유지보수산업에 대한 실증적인 연구는 거의 이루어지지 않은 실정이다. 이에 본 연구에서는 승강기 유지보수산업의 서비스 품질속성에 대한 고유속성과 척도 도출을 통해 경영성과 요인으로서의 고객만족도와 재무 비재무적 성과에 어떠한 영향을 미치는지에 대하여 실증분석하였다. 본 연구의 결과는 우리나라 중소벤처승강기 유지보수 산업의 서비스 품질 제고를 전략의 수립에 기초적인 자료로 활용될 수 있을 것이다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.73-78
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• 2003

Ultrasonic measurement is one of important technologies in the lift-time maintenance of nuclear poler plant. Ultrasonic inspection system is consisted of the operator, equipment and procedure. The reliability of ultrasonic inspection system is affected by its ability. The performance demonstration round robin was conducted to quantify the capability of ultrasonic inspection for in-service. The small number of teams who employed procedures that met or exceeded ASME Sec. XI Code requirements detected the piping of nuclear power plant with various cracks to evaluate the capability of detection and sizing. In this paper, the statistical reliability assessment of ultrasonic nondestructive inspection data using Monte Carlo simulation is presented. The results of the probability of detection (POD) analysis using Monte Carlo simulation are compared to these of logistic probability model. In these results, Monte Carlo simulation was found to be very useful to the reliability assessment f3r the small hit/miss data sets.

• Journal of the Korean Society for Railway
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• v.8 no.3
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• pp.260-266
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• 2005

The deterioration of a shunting locomotive was characterized for the lifetime assessment. The locomotive has been used for shunting works in steel making processes, and in this investigation, various types of technical evaluation methods for the locomotive parts were employed to assess the current deterioration status and to provide important clue for lifetime prediction. Unlike other rolling stocks in railway applications, the diesel shunting locomotive is composed of major components such as diesel engine, transmission, gear box, brake system, electronic devices, etc., which cover more than 70 percent of the total price of the locomotive. Therefore, in this paper, each part of major components in the diesel locomotive was analyzed in terms of the degree of deterioration. The lift-cycle-cost (LCC) analysis was performed based on the maintenance and repair history as compared with economical cost to provide the cost-effective prediction, i.e., to assess either repair for reuse or putting the locomotive out of service based on cost-effective calculation.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1450-1459
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• 2007

Line type rigid bearings for Open-Steel-Plate-Girder railway bridges have several problem in service, and they are unstable structurally. Thus, spherical bearings having advanced maintenance capability and device to resistance up-lift are developed and replace the existing ones. A experiment of maintenance for a new placed spherical bearings under real Open-Steel-Plate-Girder bridge is conducted and their good maintenance performance is proved. The dynamic behavior of the bridge is measured and analyzed for the two cases of the existing and replacing bearings. Therefore, the effect of the new spherical bearings on the railway bridge is assessed.

• Journal of the Korean Society for Railway
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• v.7 no.1
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• pp.14-19
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• 2004

The effect of surface damage on fatigue properties of catenary wires were investigated to estimate their service lift. As surface defects of the wires caused by surface corrosion increase, surface roughness gets worse, and as roughness increases, it is easy for moisture coming from rain and dew to be condensed around uneven parts of the surface. The condensed moisture causes a locally severe corrosion which leads to damage of the wires. Corrosion of catenaty wires can make their actual lifetime shorter than that originally designed. The amount of decrease was more prominent as environmental conditions became more corrosive. They are also vibrated with some amplitude everytime pantographs touch contact line. The frequent cyclic load on the wire may result in a fatigue fracture. Surface damage by corrosion can make formation of crack initiation at fatigue. In the present study, the fatigue life of the used wire was measured 35 to 50% compared with that of new one in average.

• International Journal of Korean Welding Society
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• v.3 no.2
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• pp.29-39
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• 2003

The durability and reliability of thermal barrier coatings (TBCs) play an important role in the service reliability, availability and maintainability (RAM) of hot­section components in advanced turbine engines for aero and utility applications. Photostimulated luminescence spectroscopy (PSLS) and electrochemical impedance spectroscopy (EIS) are being concurrently developed as complimentary non­destructive evaluation (NDE) techniques for quality control and life­remain assessment of TBCs. This paper overviews the governing principles and applications of the luminescence and the impedance examined in the light of residual stress, phase constituents and resistance (or capacitance) in TBC constituents including the thermally grown oxide (TGO) scale. Results from NDE by PSLS and EIS are discussed and related to the microstructural development during high temperature thermal cycling, examined by using a variety of microscopic techniques including focused ion beam (FIB) in­situ lift­out (INLO), transmission and scanning transmission electron microscopy (TEM and STEM).

• Journal of the Korean Geotechnical Society
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• v.38 no.4
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• pp.21-32
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• 2022

Steel pile foundations are widely used for offshore constructions due to their high bearing capacity and efficiency. Typically, offshore structures that have reached the end of their design life are required to be demolished. However, pile foundations are often left on site due to technical and economic limitations. The pile left on the site not only pollutes the environment, but can also cause obstacles for the construction of new structures. Therefore, research is required to completely eliminate these foundations at the site. In this study, a new type of double-wall pile foundation that can drastically reduce the pull-out load was conceptually proposed, and a series of model tests were performed to validate the performance of the double-wall pile foundation. The installation and extraction of the double-wall pile were simulated in dry sand in the model test, and the measured up-lift load was compared to that of the conventional pile. According to the result, the maximum up-lift load induced by the decommissioning of the double-wall pile was reduced by 45% when compared to the traditional pile in dense sand. This study verified the mechanism for reducing the up-lift load of the double-wall foundation and confirmed the possibility of completely decommissioning a pile that has reached the end of its nominal service life.