• Journal of Ocean Engineering and Technology
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• v.29 no.4
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• pp.322-330
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• 2015

As a new technical approach, a hydraulic and magnetic clamp device was developed to realize a magnetic clamp crane system by simultaneously actuating eight individual hydraulic cylinders. In this approach, an Sr-type of ferritic permanent magnet (SrO· 6Fe₂O₃), rather than the previous electromagnet, was utilized for the purpose of lifting and transporting the large curved steel plates used for manufacturing ships. This study had the goal of developing and manufacturing a hydraulic, magnetic clamp prototype composed of three main parts, including the base frame, cylinder joint, and magnet joint, in order to safely transport curved steel plates. Furthermore, this research included a performance evaluation of the manufactured prototype and acquired the purposed quantity value in the performance test. The most significant item, the magnetic adhesive force (G), was evaluated in a performance test, which utilized a ferritic permanent magnet (Sr type) with 3700~4000 G of residual induction (Br) and 2640/2770 Oe of coercive force (Hc). In particular, relevant items such as the hoist tension (kN), transportation time (s), and applied load (Kgf) on the hydraulic cylinders were also evaluated in order to determine the optimum values.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.11a
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• pp.155-159
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• 2002

Wire ropes are used in a myriad of various industrial applications such as elevator, mine hoist, construction machinery, lift, and suspension bridge. Especially, wire rope of crane is important component to container transfer. If it happens wire rope failures in operating, it may lead to safety accident, economic power loss by productivity decline, competitive power decline of container terminal and so on. To solve this problem, we developed wire rope fault detecting system as a portable instrument, and this system is consisted of 3 parts that fault detecting part using hall sensor, permanent magnets and analog unit, and digital signal processing part using data acquisition card, monitoring part using wavelet transform, denoising method. In this paper, a wire rope is scanned by this system after makes several broken parts on the surface of wire rope artificially. All detected signal has external noise or disturbance according to circumstances. So, we applied to discrete wavelet transform to extract a signal from noisy data that was used filter. In practical applications of denoising, it is shown that wavelet pursue it with little information loss and smooth signal display. It is verified that the detecting system by denoising has good efficiency for inspecting faults of wire ropes in service. As a result, by developing this system, container terminal could reduce expense because of extension of wire ropes exchange period and could competitive power. Also, this system is possible to apply in several fields like that elevator, lift and so on.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.116-122
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• 2016

With the changes of industrial structure, contents and types in hazardous and dangerous works have been changed considerably. However, the hazardous and dangerous works by defined "Regulation for the hazardous and dangerous work employment restriction" and "Special education for safety and health"have not been amended over twenty years. This study aimed to identify the recent trends of the works by analyzing the death accidents cases from 2004 to 2013 and to present the management methods about future hazardous and dangerous works. The results showed that amount of 1,972 cases among 11,513 death accidents were equivalent to the works presented by "Regulation for the hazardous and dangerous work employment restriction". The amount of death accidents in 'Work of using construction equipment following construction machinery management act' was biggest among the death accidents cases and that of 'Work of handling pressure vessels following high-pressure gas safety control act' didn't show up. For the works in "Special education for safety and health"amount of 1,650 death accidents cases were equivalent. The amount of death accidents in 'Work involving a crane with a capacity of 1 ton or more or work which is carried out with a crane or hoist with a capacity of less than 1 ton in a workplace having at least 5 such machines' presented by "Special education for safety and health"was biggest. Also, death accidents case didn't occurred in three works presented by "Special education for safety and health". It was analyzed that works with low death accidents cases should be needed to study thoroughly the whole disaster research involving nonfatal accidents. Through this study, it was expected that regulation can be operated practically in the industrial field. Also, it is considered to increase

• Journal of the Korean Institute of Navigation
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• v.23 no.4
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• pp.43-61
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• 1999

To ensure ship's safety and preserve the marine environment from ship, IMO(International Maritime Organization) has been making much efforts. Nevertheless there are still many possibilities threatening ship's safety and the marine environment. Many vessels navigate at sea in lack of standard required by the International Convention relevant to ship's safety and the protection of marine environment. Even though the administration is responsible for perfect and continuous control for safety of ship, it cannot has jurisdiction over ships hoist its flag reasonably at all times. So the Port State has strengthened the Port State Control(PSC) activity as one step of eliminating sub-standard vessels. In the light of the fact that mentioned above, this study deals with PSC activity in Korea and port of Pusan. Total 582 ships, inspected in port of Pusan from 1st January 1998 to 30th September 1999, were analyzed in various aspect and extracted results as follows : \circled1 The inspection rate in Korea was much lower than the other states taking part in Tokyo MOU, \circled2 For flag state, the ships belong to flag of convenience(FOC) had much more deficiencies than non-convenience flag ships, \circled3 For ship type, 39 number of general dry cargo ship were detained at Pusan with serious deficiencies, \circled4 For deficiency item, the items such as life saving appliances, safety in general, navigation, load lines and fire-fighting appliances were occupied over 71.7% of total number of deficiencies, \circled5 In Asia-Pacific region, Korea was one of flags with detention percentages exceeding 3-year(1996~1998) rolling average detention percentage. Average detention rate of Korean vessels was 6.73% which was over 0.24% of average detention rate(6.49%) in Asia-Pacific region. These results may reflect to improve the performance of PSC inspection for foreign vessels and are useful for preparing PSC inspection for ocean-going ships registered in Korea.

• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.34-39
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• 2010

The purpose of this study is to suggest objective evaluation model as a plan to utilize as opportunity in establishing judgment standard of mutual inspection criteria and to upgrade inspection ability by reviewing and analyzing level of danger and importance in advance based on inspection results of inspection institutions regarding tower cranes used in construction fields. Tower crane is a mechanical device transporting construction supplies and heavy materials to places over 20~150M high from the ground for the period ranging from a short time of 2~3 months to two years after being installed in construction sites in vicinity of buildings or structures and is an important facility indispensable for construction sites. However, since use period after installation is short and professional technical ability of technicians working on-site about of tower crane is poor, systematic and quantitative safety management is not carried out As a part of researches on procedure of RBI(Risk Based Inspection) possible to apply to Knowledge Based System based on knowledge and experiences of experts as well as to tower cranes for solving these problems, quantitative RPN(Risk Priority Number) was applied to RPN utilizing technique of FMEA(Failure Mode and Effect Analyses). When general RBI 80/20 Rule was applied parts with high level of risks were found out as wire rope, hoist up/down safety device, reduction gear, and etc. However, since there are still many insufficient parts as risk analyses of tower crane were not established, it is necessary for experts with sufficient experiences and knowledge to supplement active RBI techniques and continuous researches on tower cranes by sharing and setting up data base of important information with this study as a starting point.

• Journal of Navigation and Port Research
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• v.27 no.1
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• pp.97-102
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• 2003

Wire ropes are used in a myriad of various industrial applications such as elevator, mine hoist, construction machinery, lift, and suspension bridge. Especially, the wire rope of crane is important component to container transfer. If it happens wire rope failures during the operation, it may lead to safety accident, economic loss by productivity decline and so on. To solve this problem, we developed remote wire rope fault detecting system, and this system is consisted of 3 parts that portable fault detecting part, signal processing part and remote monitoring part. All detected signal has external noise or disturbance according to circumstances. So, we applied to discrete wavelet transform to extract a signal from noisy data. It is verified that the detecting system by de-noising has good efficiency for inspecting faults of wire ropes in service. As a result, by developing this system, container terminal could reduce expense because of extension fo wire ropes exchange period and could competitive power. Also, this system is possible to apply in several field such as elevator, lift and so on.