• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.799-806
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• 2004

Recently, as the forerunner in establishing the Northeast Asia's logistics base, a lot of marine engineering works such as new ports and container terminals, extension of old ports, new bridges, land reclamation etc. have been progressed. Parallel to it, there is also an increasing demand for improving the safety of construction. In this situation, high resolution seismic reflection profiling can be well used, attempting to classify rocks and sediments under water, if possible, to delineate the distribution of grain sizes in sediments not only for calculating the cost of removing sediments from harbour's channels, but also for estimating the bearing capacities for bridge or port construction. However, the results from the corresponding reflection survey that has been in operation in our country can not be effectively used for engineering purposes mostly due to the insufficient resolution. Thus. in this paper, two innovative strategies are introduced to enhance resolution. The one deals with a newly designed exploration barge that will help reduce several kinds of noises encountered electrically or operationally. The other is associated with an establishment of optimum measuring system comprising e.g. a specially devised hydrophone with a combination of 7 piezoelectric elements. Field experiments performed at Busan harbour are illustrated. The quality of acquired data was thereby fundamentally improved in comparison with that obtained at the same time in a conventional way.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.6
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• pp.872-883
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• 2012

Generally the determination of turning basin for vessels of entering & sailing in the berth has been considered in the design standard of harbor construction rules of the port. In this regard, the turning basin has been determined by the max size of entering vessel of the berth/port. But the size of turning basin may considered the ship's maneuvering ability, operator's skillful power, mooring equipments of the berth, arrangement of the fairway and the environment condition of weather & seas around the designated port area. So this paper suggested the optimum size of turning basin after studying the harbour design rules of the advanced marine countries and using by maneuvering simulator for turning basin size and also evaluated the design standard of harbor construction rules and minimum size of turning basin against ship's length at the Gangjung civil/naval port of Jeju Island.

• Journal of Ocean Engineering and Technology
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• v.20 no.2 s.69
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• pp.36-40
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• 2006

As large waves enter a harbor, during their propagation, the motions a floating body are large and if may even be damaged by waves. This phenomenon may be caused by harbor resonance, resulting from large motion at low wave frequency, which is close to the natural frequency of a vessel. In order to calculate the motion of a floating body in a harbor, it is necessary to use the wave forces containing the body-harbor interference. The simulation program to predict the motions of a floating body by waves in a harbor is developed, and this program is based on the method of velocity potential contiuation method proposed by Ijima and Yoshida The calculated results are shown by the variation of wave frequency, wave angle, and the position of a floating body.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.03a
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• pp.13-19
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• 2002

In inner harbour of Inchon Port, there are two lock gates (50KT, 10KT) which have two gates per lock gate in inner/outer sides except a gate in inner harbour side 7f 10KT. Due to the lack of the fore-mentioned gate, the use of 10KT lock gate Is suspended in every 3 years for regular maintenance. Now an additional gate is under construction in order to improve the efficiency of the 10KT lock gate. This paper will be aimed to evaluate the operational utilization levels of lock gates in present and future. The present operational utilization levels of lock gates are 0.2119 in 10KT lock gate, 0.2051 in 50KT lock gate which were considered the 46.5 closed days every 3 years for 10KT regular maintenance. The levels are estimated to 0.2246(10KT), 0.2539(50KT) in 2006 and 0.2241(10KT), 0.2560(50KT) in 2011. The levels of 50KT lock gate are evaluated to be more rapidly increased up to 24.5% in 2011.

• Proceedings of KOSOMES biannual meeting
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• 2007.05a
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• pp.175-180
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• 2007

Until a recent date Wan-do Port have been made efforts to advance its marine policy toward the base of marine distribution industry. Therefore the administration of Wan-do port have been carried out many projects on improvements of harbour system very actively. The improvement of ship traffic system would be one of them. This research examined the general view of present situations of marine traffic system in Wan-do waters area and suggested improvements in ship route and anchorage.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.172-178
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• 2003

As a typoon gets into harbour, a moored ships shows erratic motions and even mooring line failures is occurred. Such troubles may be caused by harbour resonance phenomena, result in large motion amplitudes at law frequency, which is closed to the natural frequency of the moored ship. The nonlinear motions of a moored ship beside quay are simulated under external forces due to wave, current including mooring forces in time domain. The forces due to waves are obtained from source and dipole distribution method in the frequency domain. The current forces are calculated by using slow motion maneuvering equation in the horizontal plane. The wind forces are calculated from emperical formula of ABS and the mooring forces of ropes and fenders are modeled as linear spring.

• Journal of Korean Port Research
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• v.12 no.2
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• pp.233-242
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• 1998

The Inchon port has been heavily congested due to the tidal restriction in passing the lock and the shortage of berths or warehouses. The current congestion is predicted to become worse by the induced traffics near the lock entrance after completion of North harbour expansion and of Kyung-In canal construction. It is also expected that the newly developed configuration of the Inchon port will result in increasing the rate of marine accidents around the lock entrance because of the over-utilization of the limited capacity of the junction from the North harbour and the Kyung-In canal. This study adopts a systematic approach in analysing the physical distribution system of the inner-lock area in order to figure out alternative routes which are designed to improve the port efficiency. Ship maneuvering simulation is also attempted to propose a new approaching route to the canal as an alternative path in order to avoid the traffic accidents caused by the extreme congestion. The result of the ship maneuvering simulation demonstrates that the alternative routes by way of Buk-Sudo, Janbong-Sudo, north of Si-Do and Sin-Do is recommended routes which can satisfy the safety requirements of approaching to the canal entrance.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.2
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• pp.82-88
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• 2004

To evaluate the tidal flow around the transmission type harbour structures, the numerical models considering hydraulic resistance are used. The traditional governing equations of depth-integratef hydrodynamics are modified by using of the drag force term. As a numerical model to evaluate the rate of tidal exchange, the Random-walk method is used. The models are applied in a design of the pile-supported pier structures in Busan harbour site, Korea, where the flow speed and the tidal exchange are more promotive than the case of non-transmission structure. The developed model will be applied usefully to design the transmission type structure in the ocean space.

• Structural Monitoring and Maintenance
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• v.2 no.3
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• pp.181-197
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• 2015

Assessing the condition of paint on civil structures is an important but challenging and costly task, in particular when it comes to large and complex structures. Current practices of visual inspection are labour-intensive and time-consuming to perform. In addition, this task usually relies on the experience and subjective judgment of individual inspectors. In this study, hyperspectral imaging and classification techniques are proposed as a method to objectively assess the state of the paint on a civil or other structure. The ultimate objective of the work is to develop a technology that can provide precise and automatic grading of paint condition and assessment of degradation due to age or environmental factors. Towards this goal, we acquired hyperspectral images of steel surfaces located at long (mid-range) and short distances on the Sydney Harbour Bridge with an Acousto-Optics Tunable filter (AOTF) hyperspectral camera (consisting of 21 bands in the visible spectrum). We trained a multi-class Support Vector Machines (SVM) classifier to automatically assess the grading of the paint from hyperspectral signatures. Our results demonstrate that the classifier generates highly accurate assessment of the paint condition in comparison to the judgement of human experts.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.354-366
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• 2020

This work mainly focuses on determination of the fully plastic J-integral solutions for welded center cracked plates subjected to remote tension loading. Detailed three-dimensional elasticeplastic Finite Element Analyses (FEA) were implemented to compute the fully plastic J-integral along the crack front for a wide range of crack geometries, material properties and weld strength mismatch ratios for 900 cases. According to the database generated from FEA, Back-propagation Neural Network (BPNN) model was proposed to predict the values and distributions of fully plastic J-integral along crack front based on the variables used in FEA. The determination coefficient R2 is greater than 0.99, indicating the robustness and goodness of fit of the developed BPNN model. The network model can accurately and efficiently predict the elastic-plastic J-integral for weld centerline crack, which can be used to perform fracture analyses and safety assessment for welded center cracked plates with varying strength mismatch conditions under uniaxial loading.