• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.95-98
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• 2001

Edge detection is an important problem in computer vision and image understanding. Because the threshold is difficult to properly determine, edge images gained by the usually gradient-based segmentation methods are often tend to have many disjoint or overlapping boundaries, which makes the edge images spinous. In this paper, a practical multilevel morphological filter is presented for smoothing spinous edge images. The experimental results show that the method is effective in dealing with the images of a target in the sky.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.298-305
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• 2019

The demand for the revitalization of marine tourism in Busan North Port is increasing due to changes in functions such as an increase in harbor traffic volume and the expansion of marine leisure space in Busan. As a result, Busan City plans to set a phased alleviation target for prohibition of cruise ship operations, and to lift the prohibition of excursion ship operations in North Port following the cancellation of the prohibition of excursion ship operations in South Port in 2017. The purpose of this study is to evaluate the risk of excursion ship operations in Busan North Port by applying the marine traffic assessment index and to examine the possibility of excursion ship operations. For this purpose, port status, marine accidents, and traffic flow of Busan North Port were investigated. In addition, marine traffic assessment indexes, such as traffic congestion, risk based on an ES Model, and IWRAP MkII, a maritime risk assessment tool, were used to assess the risk and possibility of excursion ship operations in Busan North Port. This study can be used as basic data for analyzing the risk factors that may occur when excursion ships are operated in Busan North Port and to define how excursion ships should operate, with related safety measures.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.160-161
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• 2022

Hydrogen is bridge fuel with high energy content and environmentally friendly to satisfy the stringent IMO regulation relating to greenhouse gas (GHG) emissions. There is growing interest in hydrogen in numerous nations and regions illustrated by an extensive range of research and development in technology. Regarding maritime applications, researchers have recognized the utilization of hydrogen as a fuel for fuel cells, a device that converts the chemical energy of the fuel to electrical energy. Solid oxide fuel cell (SOFC), with high working temperature, is easy to combine with the waste heat recovery cycles/devices to increase output power and thermodynamic performances as well. Furthermore, the cold energy from liquid hydrogen supplied to SOFC can also be used to generate more power. In this study, we proposed a SOFC integrated system with the idea of combining the waste heat recovery from the SOFC exhaust stream and cold energy utilization from LH₂. The designation is aimed to target small-scale vessel which uses electric propulsion for short distances voyage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.5
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• pp.754-763
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• 2018

The maritime ICT-convergence equipment are essentially required to a type approval (TA) certification that needs environmental and functional tests, to install in vessel. The environmental test is to experiment the possession for required durabilities of the target device in maritime environment, and the functional test is to check the required functions of target equipment based on international standard. In Korea, the environmental testing facilities amount to 227 sites, but there is no functional testing facility. Because of this, we establish a function test facility for the maritime ICT-equipment. In this paper, we analyze and design the functional testing requirement and required interlocking simulators for digital interfaces and navigation communication equipment. We propose the 2-steps of functional testing procedures, which are single test and integration test, to improve the reliability of testing result. The single test is to examine own functions of the target device, and the integration test is to check harmonized operation with other navigation and communication devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.2
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• pp.164-169
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• 2013

The effect of co-sputtering condition on the structural properties of $Mg_xZn_{1-x}O$ thin films grown by RF magnetron co-sputtering system was investigated for manufacturing UV LED. $Mg_xZn_{1-x}O$ thin films were grown with ZnO and MgO target varying RF power. Structural properties were investigated by X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). The $Mg_xZn_{1-x}O$ thin films have sufficient crystallinity on the high ZnO power. The EDS analyzed showed that the Mg content in the $Mg_xZn_{1-x}O$ films decreased from 3.99 to 24.27 at.% as the RF power of ZnO target increased. The Mg content in the $Mg_xZn_{1-x}O$ films could be controlled by co-sputtering power.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.9
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• pp.740-748
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• 2017

In this paper, we compared performance of conventional inverse synthetic aperture radar(ISAR) imaging methods for maritime target with real data measured by X-band radar. Following conventional approaches were used for performance comparisons: 1) range instantaneous Doppler(RID) method, 2) range Doppler(RD) processing with phase adjustment, and 3) RD processing with prominent point processing(PPP). It is noteworthy that the comparison results have significance of providing basic concept to establish ISAR imaging frame work for maritime targets.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.72-82
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• 2022

The anchorage among harbour facilities should ensure sufficient water surface area for safe anchoring. A general method is to consider the L.O.A of the target ship and the depth and bottom quality of anchorage to calculate the water surface area of anchorage. However, the gross tonnage is used as a unit of the ship capacity standard of anchorage based on the detailed rules for harbour facilities operation in Korea. In this study, the gross tonnage is converted to L.O.A to calculate the actual anchoring radius of the target ship. This actual anchoring radius exceeds at 25 anchorages (among 90 anchorages) compared with the designated water surface area. Therefore, as an improvement plan of the ship capacity standard for anchorage, L.O.A should be used as a unit for anchorage based on the detailed rules for harbour facilities operation and related Korean maritime laws.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.453-458
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• 2018

The analysis of maritime traffic refers to the processes that are used to analyze the environmental characteristics of the target area and, based on this analysis, predict the traffic pattern of the vessels. In recent years, maritime traffic analysis has become significant with increase maritime traffic volume and expansion of VTS coverage area. In addition, maritime traffic analysis is also applicable in the safety assessment of port facilities and the VTS (Vessel Traffic Service). In this paper, we propose a method to analyze the vessels' traffic pattern by using the heat map and the centroid method. This method is efficient for the analysis of the vessel trajectory data where spatial characteristics change with time. In the experiments, the traffic density and centroid by time have were analyzed. Trajectory data collected at Mokpo harbor was adopted. Finally, we reviewed the experimental results to verify the feasibility of the proposed method as a maritime traffic analysis method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.216-217
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• 2008

Zinc-oxide films were deposited by pulsed laser deposition (PLD) technique using doped ZnO target (mixed $In_2O_3$ 0.1, 0.3, 0.6 at. % - atomic percentage) on the p-type Si(111) substrate. A little Indium has added at the n-ZnO films for the electron concentration control and enhanced the electrical properties. Also, post thermal annealed ZnO films are shown an enhanced structural and controled electron concentration by the annealing condition for the hetero junction diode of a better emitting characteristics. The electrical and the diode characteristics of the ZnO films were investigated by using Hall effect measurement and current-voltage measurement.

• Journal of Ocean Engineering and Technology
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• v.26 no.5
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• pp.11-17
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• 2012

In this study, a damage detection method that uses sensitivity-based finite (FE) element model updating with the natural frequency and zero frequency was proposed. The stiffness matrix for a structure was modified using the sensitivity-based FE model updating method. A sensitivity analysis was used to update the FE model, and the natural frequencies and zero frequencies were considered as target parameters to supplement the information on the vibration characteristics. The locations and values of the damages were estimated from the modified stiffness matrix. Several numerical examples were considered to verify the performance of the proposed method.