• 한국해양공학회지
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• 제23권6호
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• pp.44-52
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• 2009

In this study, the behavior of a breasting dolphin with various dolphin heights and formations in the coastal area of Incheon was investigated. The dynamic deflection, shear stress, and moment of the pile were analyzed using the coefficient of the horizontal subgrade reaction that resulted from loading tests of different DWT (Dead Weight Tonnage). In the case of a vertical pile type dolphin, the deflection, shear stress, and moment increased as the dolphin height increased. In the case of the battered pile type dolphin, small values of shear stress and moment were shown at a low dolphin height, and the characteristics of the dynamic behavior of the dolphin showed that the deflection, shear stress, and moment increased as the pile slope of the dolphin decreased or the DWT increased.

• 수산해양교육연구
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• 제20권1호
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• pp.121-126
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• 2008

This study presents the results of basic sighting surveys conducted for dolphin watching from 2004 to 2006 in the northeastern waters of Jeju. The sighting probability of dolphins (bottlenose dolphin, Tursiops truncatus) was 71.9% (82 sightings out of 114 surveys). The dolphin's attractive behaviors observed included leaping, tail or peduncle slapping and surfing. The findings of this study provide useful baseline data for dolphin watching in the northeastern waters of Jeju.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.143-150
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• 2005

In this study, to evaluate the collision behaviors of the navigating vessel and the dolphin protective system protecting the substructures of bridges, the numerical simulation was performed. The analysis model of vessel bow that the plastic deformations are concentrated was composed by shell elements, and the main body of vessel was modeled by beam elements to represent the mass distribution and the change of potential energy. The material model reflecting the confining condition was used for the modeling of the filling soil of dolphin system. The surrounding soil of the dolphin system was modeled as nonlinear springs. As results, it is verified that the dolphin system can adequately dissipate the kinematic energy of the collision vessel. The surrounding soil of the dolphin system is able to resist the collision force of the vessel. And the major energy dissipation mechanism of collision energy is the plastic deformation of the vessel bow and the dolphin system.

• 한국해양공학회지
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• 제13권3호통권33호
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• pp.3-11
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• 1999

Optimum design of mooring dolphin is numerically investigated. Design optimization problem of moring dolphin is first formulated. Geometry and cross sections of piles are used as design variables. Design objective is the total weight of steel piles of mooring dolphin, and the constraints of stress, penetration depth, lower and upper bounds on design variables are imposed. Based on the design variable linking and fixing, several class of design variations are sought. For the numerical optimization, both PLBA(Pshenichny - Lim - Belegundu - Arora) program and DNCONF subroutine code in IMSL library are used. For a dolphin structure with 20 steel piles, vertical and inclined, optimum designs for different cases are successfully obtained, which can be applied for the mooring of a very large floating structure.

• 한국수산과학회지
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• 제51권6호
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• pp.704-713
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• 2018

Globally, the survival of many marine mammals is threatened by entanglement in fishing gear and there is also a high bycatch in Korea. This study analyzed the bycatch data of most cetacean species for Korean waters from 2011 to 2017, including the narrow-ridged finless porpoise Neophocaena asiaeorientalis, common dolphin Delphinus delphis, common minke whale Balaenoptera acutorostrata, and Pacific white-sided dolphin Lagenorhynchus obliquidens. A total of 12,262 cetaceans were captured as bycatch. In the Yellow and South Seas, the main species affected was the narrow-ridged finless porpoise, with 82.9% caught in stow nets and 11.5% captured in trawls. In the East Sea, the common minke whale, common dolphin, and Pacific white-sided dolphin were reported. The main common minke whale bycatch (43.5%) was in set nets, while common dolphins (49.0%) and Pacific white-sided dolphins (91.4%) were mainly caught in gill nets. The narrow-ridged finless porpoise, common dolphin, and common minke whale were most commonly reported in March, April, and May, while the Pacific white-sided dolphin was most frequently captured as bycatch in January and December. Each of these factors (season and gear responsible for bycatch) depended on the characteristics of the cetacean species. To conserve cetaceans, it is necessary to reduce the bycatch.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.237-244
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• 1998

Optimum design of mooring dolphin is numerically investigated. Design optimization problem of mooring dolphin is first formulated. Geometry and cross sections of piles are used as design variables. Design objective is the total weight of steel piles of mooring dolphin and the constraints of stress, penetration depth, lower and upper bounds on design variables are imposed. Based on the design variable linking and fixing, several class of design variations are sought. For the numerical optimization, both PLBA( Pshenichny-Lim-Belegundu-Arora) program and DNCONF subroutine code in IMSL library are used. For a dolphin with 20 steel piles, vertical and inclined, optimum designs for different cases are successfully obtained, which can be applied for the mooring of a large floating structure.

• Smart Structures and Systems
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• 제21권3호
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• pp.321-333
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• 2018

Simplified Dolphin Echolocation (SDE) algorithm is a recently developed meta-heuristic algorithm. This algorithm is an improved and simplified version of the Dolphin Echolocation Optimization (DEO) method, based on the baiting behavior of the dolphins. The main advantage of the SDE algorithm is that it needs no empirical parameter. In this paper, the SDE algorithm is applied for optimization of three well-studied frame structures. The designs are then compared with those of other meta-heuristic methods from the literature. Numerical results show the efficiency of the SDE algorithm and its competitive ability with other well-established meta-heuristics methods.

• 대한토목학회논문집
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• 제29권3B호
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• pp.281-287
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• 2009

본 연구에서는 우리나라 인천 남구 시화호 연안의 퇴적토를 가토제(containment dyke)내에 펌핑 매립한 인천 LNG 인수기지 조성부지 내의 준설지반과 인근 시화호 조성공사 지역의 해성퇴적토에 대해 토질시험을 실시하여 토질정수를 산정하고, 돌핀 기초말뚝의 배열 조건을 달리하여 태풍 내습 시 돌핀에 작용하는 최대 파고에 의한 돌핀 기초말뚝의 변위, 전단력과 모멘트에 대한 거동 특성을 해석하였다. 수치해석 결과, 최대 심해설계파와 만내발생파의 파력에 의한 돌핀구조물의 거동은 일반적으로 준설토와 퇴적토의 지반반력계수 보다는 말뚝 직경의 크기에 더 큰 영향을 받는 것으로 나타나고 있다. 또한 돌핀구조물 기초말뚝을 직항으로 모델링한 경우와 경사말뚝을 조항으로 모델링한 경우, 조항이 직항보다 돌핀에 작용하는 외력에 대해 수십 배 이상의 저항효과가 있는 것으로 나타나고 있다.

• 한국산학기술학회논문지
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• 제21권5호
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• pp.103-110
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• 2020

수중 로봇의 가장 기본 성능이라 할 수 있는 동적 성능인 유영속도와 동적 효율 향상을 위해 수중생물을 모사한 로봇들이 주로 연구되고 있다. 그중에서 생체모사 소프트 로봇은 유연한 꼬리지느러미를 적용함으로써 높은 자유도를 구현할 수 있다. 다만, 유연한 구동부의 효율을 높이기 위해서는 구동 주파수에 맞추어 꼬리지느러미의 강성이 바뀌어야 한다. 따라서, 연구를 통해 새로운 형태의 가변강성 메커니즘을 구현하고, 이를 연구 과정에서 검증하였다. 본 연구에서는 실제 돌고래의 해부도에서 영감을 얻어, 가변강성 메커니즘을 적용한 돌고래 로봇을 새로이 설계하고 제작하는 과정을 기술하였다. 실제 돌고래의 척추 모양을 모사하여, 절삭과 적층형 공정으로 가변강성 구동부를 제작하였다. 로봇 돌고래를 구동하기 위한 텐던도 실제 돌고래의 텐던 위치를 고려하여 배치하였으며, 추가로 강성 변화를 위한 텐던을 설치하였다. 돌고래의 유선형 외형을 모사하여 로봇 돌고래를 제작하였고, 강성 변화에 따른 로봇 돌고래의 유영속도를 측정하였다. 동일한 구동 주파수에 꼬리지느러미 구동부의 강성을 변화시켰을 때, 로봇 돌고래의 유영속도의 차이가 약 1.24배, 추력으로는 약 1.5배 변화하였다.

• 한국수산과학회지
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• 제48권6호
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• pp.940-946
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• 2015

The Indo-Pacific bottlenose dolphin Tursiops aduncus commonly inhabits the coastal waters of Jeju Island, Korea. An investigation was conducted using data from vessel sightings and point sightings from land. During 40 days of vessel sighting surveys between 2007 and 2010, a total of 18 dolphin groups were encountered. The overall sighting rate was 0.01 group/n.m. Most Indo-Pacific bottlenose dolphins were sighted within 500 m of the northern coast of Jeju Island during surveys. Also, dolphin groups were observed 47 times during 109 days of shore-based surveys conducted between 2011 and 2015. The results of a dolphin distribution survey conducted in 2011 were generally similar to the results of previous surveys. However, there were no dolphin sightings from 2012 in Hanllim-eup, in the north-western part of the island, where dolphins were sighted frequently until 2011, whereas dolphin observations increased in the southern part of the island. The mean group size was 35.4 (SD=18.08) individuals. The most frequently sighted group size was 36-40 individuals. To conserve resident dolphins off Jeju Island, long term sighting surveys and environmental assessment are required to monitor their distribution patterns.