• 한국해양공학회지
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• 제37권6호
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• pp.247-255
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• 2023

Interference and collisions often occur in the loading process at shipyards. Existing simulation methods focus primarily on resource processes and schedules, and there is a lack of real-time reflection in the complex and highly variable loading process. This study aims to develop a spatial environment incorporating real-time product data, such as hulls, and confirms its effectiveness by simulating various construction scenarios. As a method, a near real-time spatial environment based on broadband laser scanning was established, with the situation of loading heavy cargo assumed when converting an existing ship into an LNG dual-fuel propulsion ship. A case study simulation of near-real-time cargo loading processes was then conducted using Unity 3D to confirm the interference and collision risks within the spatial environment. The results indicated that interference occurred in structures previously not identified in the design data, and a collision occurred during the loading object erection phase. The simulation confirmed that the identification of interference and collision risks during the erection phase highlights the need for a relocation or removal process of potential hazards before erection takes place. An improved erection simulation that integrates near real-time data could effectively prevent interference and collision risks.

• 대한원격탐사학회지
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• 제26권2호
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• pp.157-165
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• 2010

정지궤도에서는 세계 최초로 개발된 정지궤도 해색위성(GOCI)이 2010년 6월에 발사될 예정이다. GOCI는 발사 이후 7년간 매일 주간(晝間) 8회 한반도 주변 해양의 클로로필 농도, 용존유기물 농도, 부유물질의 양 등 해양환경분석자료를 생산함으로써 한반도 주변 해양환경의 실시간 감시 임무를 수행할 계획이다. 정지궤도 해색위성의 관측 자료는 어장정보 제공 서비스 및 적조 등 해양재해 예측에 활용될 예정이며, 정지궤도 해색위성에서 산출된 해양의 일차생산력 자료는 해양 탄소순환 연구에 활용되어 해양의 기후변화를 연구하는 데 유용하게 활용될 수 있다. 본 연구에서는 정지궤도 해색위성의 개발 배경 및 사용자 요구사양, 하드웨어 구조, 센서 운용 개념에 대해 설명한다.

• 한국발생생물학회지:발생과생식
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• 제17권3호
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• pp.257-268
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• 2013

Morphometric changes in the Ussurian bullhead, Leiocassis ussuriensis, and the Korean bullhead, Pseudobagrus fulvidraco, were observed during the early period of growth. Yolk length, yolk height, and yolk volume in the two species decreased within 9 days post-hatching (DPH) (p<0.05). The body lengths and body heights of both species increased gradually to 150 and 130 DPH, respectively (p<0.05). The horizontal distance between the anteriormost extension of the head and the anterior insertion of the pectoral fin, the anteriormost extension of the head ${\times}$ the verticality position of the anterior insertion of the primary dorsal fin rays, and the anterior insertion of the primary dorsal fin ${\times}$ the anterior insertion of the pectoral fin were greater in the Korean bullhead than in the Ussurian bullhead (p<0.05). However, the relative sizes of the head region, pectoral fin, ventral fin, and anal fin were greater in the Ussurian bullhead than in the Korean bullhead (p<0.05), and relative body depth and the size of the outer-mandible barbel were greater in the Korean bullhead than in the Ussurian bullhead (p<0.05). The growth curves of the morphometric characteristics of both species were divided into three types.

• 대한조선학회논문집
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• 제45권5호
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• pp.530-537
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• 2008

Austenitic stainless steels(SUS 304, SUS 316), which are used for safety control valve of LNG carrier, are occasionally exposed in the cryogenic environment. In this regards, it is required to evaluate the mechanical characteristics under the low temperature environment. In this study, a series of uniaxial tensile test was carried out varying temperature for austenitic stainless steel. The phenomena of the strain-induced plasticity have been observed on the all temperature ranges. The critical value for threshold of 2nd hardening due to the phase transformation induced plasticity as well as the increase of hardening have been reported. The summarized experimental results would be used for the validation of numerical techniques applicable for the nonlinear hardening behavior of austenitic stainless steel under the cryogenic temperature environment.

• Ocean and Polar Research
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• 제27권4호
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• pp.397-417
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• 2005

Phytoplankton community structure and distribution pattern in the surface water around the Ieodo Ocean Research Station were investigated during seven cruises carried out from July, 2003 to October, 2004. Samples were analyzed using various tools including a microscope, flow cytometer, and HPLC. Satellite images were used to analyze spatio-temporal phytoplankton biomass distribution. SeaWiFS chlorophyll a (chl a) images showed that spring blooms occurred in April-May near the Ieodo Station, and these waters were under the influence of Changjiang Dilute Water during July-October. Also, during the July-October period, HPLC pigments data showed increasing zeaxanthin concentrations, a marker pigment of cyanobacteria whereas increasing concentrations of various other pigments such as fucoxanthin, peridinin, prasinoxanthia alloxanthin, 19'-hexanoyloxyfucoxanthin and chlorophyll b were noted during spring blooms. Such pigment marker data were consistent with picoplankton data analyzed by flow cytometer and nano-microplankton analyzed by microscope. The pigment-CHEMTAX method was used to drive the phytoplankton group apportioned chi a. Diatoms, chlorophytes, dinoflagellates, and cryptophytes comprised 25.8, 20.7, 15.9, and 14.1%, respectively, of the total chl a in May. Average cyanobacteria concentrations in July-October contributed 25.4% of the total concentration. This was the highest percent contribution and was followed by chlorophytes, diatoms, and prymnesiophytes. This study discusses results from various methods, similarities and differences in the results among those methods, and the application range of the results from different analytical methods. Also, the study reveals a detailed phytolpankton community structure in the waters around the Ieodo Station, and suggests future monitoring considerations in relation to cell morphology, ecology and diversity factors according to taxonomic groups.

• 한국해양학회지:바다
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• 제12권3호
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• pp.142-146
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• 2007

2001년 5월에 황해 연안의 수심 약 20 m의 해역에서 10시부터 13시까지 3시간 동안 수중소음을 관측하였다. 측정기간 내내 생물음으로 추정되는 강한 수중음이 지속적으로 관찰되었다. $1{\sim}20kHz$의 주파수 대역에서 측정된 수중음의 레벨은 수중 배경소음 레벨과 비교하여 매우 높게 측정 되었다. 이러한 수중음은 연안 수중소음 레벨에 지속적으로 영향을 줄 수 있으므로 수중음의 발생 원인을 규명하고자 하였다. 본 연구에서는 기존에 발표된 논문들을 근거로 하여 수중음의 가장 유력한 음원으로 해저바닥에 서식하는 딱총새우의 음을 제시하였으며, 동일해역에서 채집한 살아있는 딱총새우로부터 방출되는 음향신호를 실험실에서 측정함으로서 이 수중음이 딱총새우에 의하여 발생된 것임을 재확인할 수 있었다.

• 한국콘텐츠학회논문지
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• 제6권9호
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• pp.164-173
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• 2006

컴퓨터 그래픽스 기술의 발달로 영화, 게임 등의 엔터테인먼트 산업에서 장면의 사실성이 증대됨에 따라, 다양한 소재의 콘텐츠 개발을 위한 디지털 콘텐츠 기술의 요구가 증가되고 있다. 지상에서의 생태 및 환경 변화에 대한 연구 및 시뮬레이션 기술 개발에 비해, 해양 생태 및 환경 변화 등을 콘텐츠화하기 위한 기술 개발은 아직 미비한 상태이다. 본 논문에서는 가상 해저 환경의 변화에 따른 해양 객체의 성장과정을 효과적으로 시뮬레이션할 수 있는 모델링 방법과 객체의 움직임에 따른 효율적인 변형 방법을 제안하고자 한다. 제안 방법은 비등방성 메타큐브를 이용하여 해양 생물들을 모델링함으로써 가상 해저 환경에서 물고기의 성장과 모양 변화가 가능하게 해준다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.304-306
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• 2003

Oceanic pycnocline depth is usually obtained from in situ measurements. As ocean internal waves occur on and propagate along oceanic pycnocline, it is possible to estimate the depth remotely. This paper presents a method for retrieving pycnocline depth from synthetic aperture radar (SAR) imagery where internal waves are visible. This model is constructed by combining a two-layer ocean model and a nonlinear internal wave model. It is also assumed that the observed groups of internal wave packets on SAR imagery are generated by local semidiurnal tides. Case study in East China Sea shows a good agreement with in situ CTD data.

• 해양환경안전학회지
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• 제25권3호
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• pp.354-365
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• 2019

Megabenthos samples were collected using 10-min trawls towed at 17 stations from 2015 to 2016. The dominant species (>1% of the total density) were Stegophiura sterea (10.4%) and two subtropical species, Mactrinula dolabrata (9.0%) and Acila divaricate (8.3%), respectively. The community structure of the megabenthos fell into four groups: the southeast, the southernmost region off Jeju Island, the frontal zone of the South Sea with C3, and a diagonal area from the south coast to the western side of Jeju Island. The total numbers of species, diversity, density and biomass were higher in the C3 region of the South Sea. Environmental factor analysis showed that differences in the megabenthos community were related to depth, gravel contents, and sorting value (${\sigma}$). These results indicate that changes in the marine environmental conditions in the South Sea of Korea affect the megabenthos species' composition and diversity.

• Ocean Systems Engineering
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• 제5권1호
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• pp.21-30
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• 2015

This study is devoted to the optimal design of compressed bars under axial tensile or compressive forces and exposed to a corrosive environment. Dolinskii's linear stress corrosion model is adopted for analysis. Analytical and numerical results are derived for optimal variation of the cross-sectional area of the bar along its axis.