• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.2
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• pp.47-53
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• 1987

Many studies are conducted to evaluate the risk of maneuvering ships in the congested harbours and narrow channels. These studies are very important for the prevention of sea traffic accidents in those sea areas. In this paper, the author carried out a series of observations on sea traffic condition of the vessels entering and leaving the harbour of CHUNG MU, in order to evaluate the risk of grounding, the margin and burden of route keeping maneuver of vessels proceeding along the fairway of this harbour. The results obtained are as follows: 1. The grounding risk indices for the east bound and west bound vessels at the middle part and western part of the fairway were higher than those of them at the eastern part. 2. The margin of route keeping maneuver in the fairway appeared to be the highest at the western part of the fairway for the east bound vessels, and the highest at the middle part for the west bound vessels, but the lowest at the western entrance for both of them. 3. The burden of route keeping maneuver in the fairway appeared to be the highest at the western part of the fairway for both of the east bound and west bound vessels, but the lowest at the eastern part for both of them. 4. The influence of maneuvering indices T' on the grounding risk indices appeared to be larger than that of maneuvering indices K' on them.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.2
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• pp.1-1
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• 1987

Many studies are conducted to evaluate the risk of maneuvering ships in the congested harbours and narrow channels. These studies are very important for the prevention of sea traffic accidents in those sea areas. In this paper, the author carried out a series of observations on sea traffic condition of the vessels entering and leaving the harbour of CHUNG MU, in order to evaluate the risk of grounding, the margin and burden of route keeping maneuver of vessels proceeding along the fairway of this harbour. The results obtained are as follows: 1. The grounding risk indices for the east bound and west bound vessels at the middle part and western part of the fairway were higher than those of them at the eastern part. 2. The margin of route keeping maneuver in the fairway appeared to be the highest at the western part of the fairway for the east bound vessels, and the highest at the middle part for the west bound vessels, but the lowest at the western entrance for both of them. 3. The burden of route keeping maneuver in the fairway appeared to be the highest at the western part of the fairway for both of the east bound and west bound vessels, but the lowest at the eastern part for both of them. 4. The influence of maneuvering indices T' on the grounding risk indices appeared to be larger than that of maneuvering indices K' on them.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.1
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• pp.136-144
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• 2010

The bar-shaped electrode is very popular for earth construction in Korea. Copper ground rod, Deep-buried ground rod and conductive concrete ground rod are major types of the bar-shaped electrode and generally applied on the distribution system. But in most case, to obtain the targeted ground resistance is difficult, because ground resistance is very different by soil condition. Therefore, a chemicals for reducing ground resistance is applied. In this paper, the initial and the variation of ground resistance according to the applied methods and types of chemicals over one year are compared with copper ground rod applied with water and the experimental results show that the new methods with chemicals reduced not only the initial ground resistance but also the variation of ground resistance over year.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1474-1479
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• 2004

In electrification of the Honam line, the grounding method of the copper wire shield of 66kV feeder cable was disputed. This paper describes that the review of the proper earthing method(one-side earthing or both-side earthing) under consideration of the site condition and the acceptability of the induction voltage of the shield on the end of the cable.

• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.324-331
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• 2007

The purpose of this study is to analysis effects of defect factors of combine header for cutting speed of combine header, feeding depth of straw, and cylinder speed of thresher. Measurement system for defect factors was consists of sensors to monitor the combine operation and I/O interface to convert the signals. Cutting speed of combine header, feeding depth of straw, cylinder speed of thresher were measured and analyzed. The data were collected from three paddy field during rice harvesting. The tests were conducted at different grounding speeds, lug troubles, and cutter condition. The one way ANOVA and the multiple comparison tests were performed. The results showed that the measured data were useful to monitor the defect factors of combine during harvesting. The faults conditions of grounding speeds, lug troubles, and cutter conditions affected cutting speeds, feeding depths and cylinder speeds of the combine. The data seem to be useful to analysis the faults conditions of combine header.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.5
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• pp.195-201
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• 2006

Tower footing resistance and fault current division factor are important design factors for evaluation of the lightning performance of the transmission line and/or design of the grounding electrode system. The periodic measurement of those factors are also important to verify that the grounding performance of the towers has been maintained good. However, the direct measurement of those factors in operating or energized condition is very difficult because of many practical reasons, such as the difficulty of disconnecting overhead groundwires from the tower under test. With supports by GECOL (General Electricitiy Company of Libya), we had a special chance to conduct Fall-Of-Potential (FOP) test on the energized 220 kV transmission towers before and after disconnecting the overhead groundwires from the towers under test. In this paper, the FOP test results on the towers and the fault current division factors estimated from the comparision of the FOP tests with and without overhead groundwires were presented. The computer models for the FOP test simulations were also constructed to find that the simulated results agreed very well with the measured ones.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.4
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• pp.398-408
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• 2009

Crude oil carriers or product oil carriers are confronted with sea pollution due to hull damage from various accidents. To reduce the oil spillage of tankers, IMO(International Maritime Organization) and OPA 90(Oil Pollution Act 1990) adopted the hull structures of double skin type. In this study, oil spillage test of the double skin tanker with 1/100 scaled model was carried out under damaged condition due to collision and grounding accidents. A new structural type of oil tanker was also tested with pipe and valve system arranged in double side and single bottom hulls. Their results were compared with that of conventional type double hull on the view point of ship safety and oil spillage.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.3
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• pp.339-347
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• 2021

Recently, the incidence of lightning in Korea has been increasing more and more. The damage caused by lightning is also getting worse. Lightning protection system is a prerequisite, not a sufficient condition. Considering the characteristics of lightning, there is a high frequency of lightning strikes in highlands. So, high grades of LPS should be applied to ground facilities of anti-aircraft weapons systems. 4-Level LPS was applied on groung facilities of anti-aircraft weapons system based on lightning incidence rate in past. There are some possibilities of damage from lightning in anti-aircraft weapons system. So, we have to readjust the LPS level with grounding, lightning rods and surge protect device based on lightning incidence rate in now days. Propose 2-level LPS and design with lightning rods, surge protector, separated grounding in this paper.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2000.11a
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• pp.155-159
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• 2000

This paper describes the self healing characteristics of metalized polypropylene film(MPPF) under ac condition. PDs were generally observed at relatively low voltage, and the PDIVs were differently varied depending on the number of pre-self healing due to void defects. Several pre-self healing events took place at lower voltage than the critical breakdown voltage of PPF. Self healing mainly occurred at pin tips, wrinkle sides, and cross points of wrinkles. The applied voltage at self healing was increased with PPF thickness. The burn out area at self healing was also increased with the applied voltage and PPF thickness. The peak currents in a grounding conductor at self healing was also increased with the applied voltage.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.244-246
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• 2002

In this paper, We studied about effects of human safety due to leakage current on the point of cable connection for outdoor electrical facility in the submerged condition and conducted its evaluation in the testing field. In this case, the reason of leakage on the point of cable connection is caused by formation of electrical pass between the grounded outdoor electrical facility and the enclosure of electrical facility which is connected to grounding system.