• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1107-1114
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• 2010

In this paper, a development of a new 5 d.o.f. underwater manipulator which is actuated by electric motors capable of carrying over 20kg payload and of various operation under the water has been studied. The manipulator for applying to midium-sized AUV or ROV has been designed small and light but to handle a heavy 25kg payload. The joint actuator for the manipulator is designed and builted as a new modular typed double oil jacket for waterproofness. Also, superior joint torque performance of the developed joint actuator has been varified through tests in the air. And, a 5 d.o.f. highly perfomable underwater manipulator has been builted applying the developed underwater joint actuators.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.267-274
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• 2005

Preparation of cellulose type underwater non-segregation admixture was attempted and the hardening characteristics of underwater concrete according to the addition of this admixture was investigated in order to make underwater concrete with the compressive strength ratio of 0.8 to that of concrete manufactured in common atmosphere. The proposed underwater non-segregation admixture consisted of methyl cellulose of 0.4% by weight, silicon type antifoaming agent of 20% by weight, and sodium aluminate of 0.1% by weight to the amount of cement as setting accelerant, respectively. As the proposed non-segregation admixture was increased, the amount of suspended solid decreased, air content in concrete was increased but the flow loses by elapsed time did not change. The proper amount added of the proposed non-segregation adimixture was 0.8 wt% to the amount of cement. The compressive strength of the test sample underwater concrete manufactured by the addition of the proposed admixture was $325Kg/cm^3$, and the ratio of compressive strength of this sample concrete to that of a concrete manufactured in air was 0.94.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.488-496
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• 1991

Dynamic chanracterisitcs and control of a submerged working robot manipulator have been investigated for articulated type robot manipulator with three revoluted joints. A dynamic equation of the manipulator has been derived. The dynamic equation includes not only mass matrix, centrifugal and Coriolis terms and gravity terms but also added mass, buoyant force and drag force terms, which are important terms for underwater motion description. A series of simulations using computed torque method have been performed for the cases of straight and circular trajectory motion controls. The results of this study show that the dynamic characteristics of the submerged working robot manipulator are very different from that of the manipulator which works in air. The influences of added mass, buoyant force and drag force terms to the total required torques have been discussed as distribution ratios to the total required torques.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.29-31
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• 2013

유조선이 화물유 탱크 내 유류를 적재한 채 국내 연안 해저면에 침몰하는 경우 화물유 탱크 내 적재유가 유출되어 대형 오염사고로 연결될 가능성이 있으므로 화물유 탱크 내 적재유는 신속하고 안전하게 제거 되어야만 한다. 심해 수중작업 특성상 이러한 잔존유 회수작업 완료 후 화물유 탱크 내 잔존유 제거상태의 직접적 확인은 매우 곤란하므로 회수작업 종료 기준 및 절차는 매우 중요하다. 이에 따라, 국내에서 실제 이루어 진 제1유일호 및 제3오성호, 경신호 잔존유 작업사례에 적용된 회수방법에 따른 종료절차를 비교분석하여, 향후 국내 연안에 침몰되는 유조선 잔존유 회수작업에 적용 가능한 합리적 표준 작업종료 절차를 제시하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.307-307
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• 2002

• Bulletin of the Society of Naval Architects of Korea
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• v.57 no.3
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• pp.7-11
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• 2020

• Tunnel and Underground Space
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• v.10 no.4
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• pp.544-552
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• 2000

Norway has the geological of condition of hard bedrocks, high mountains, deep valleys and fjords. In this background many tunnels and rock caverns are developed. In this process of constructing tunnels and rock caverns Norway seems to have strong competitiveness in the construction of tunnels. In spite of high salaries to the tunnel workers, Norwegian contractors are probably producing the cheapest tunnels and rock caverns in the world. Besides benefit of hard-rock geology, Norwegian cost-saying is owing to the Norwegian excavation technique in hard rocks such as unlined pressure tunnels, air cushion chambers, underwater piercing, and reasonable contract system and organization of workers developed from the accumulated experience. Brief analytical description of them are given in this paper in order to stimulate the utilization of the underground spaces.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.959-966
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• 2020

With the growing importance of the fishery industry and the rapid growth of the aquaculture industry, research on smart farms through ICT convergence in the aquaculture field is in progress. To enable monitoring of the growing environment at the farm site, an underwater drone drive unit, an image collection device, an integrated controller for posture stabilization, and a remote control device capable of controlling and controlling drones through real-time underwater images were proposed, and design, development, and tests were conducted. By utilizing underwater drones, it is possible to replace the supply and demand of manpower and high-cost work in the aquaculture industry, and to manage fish farms in a stable manner by reducing the probability of farming deaths.

• Explosives and Blasting
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• v.33 no.2
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• pp.25-39
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• 2015

The common underwater rock removal methods involve underwater blasting and crane's chisel dropping impact method. From an environmental point of view, these methods cause ground vibrations and underwater noise. At the site for this study, a method of dropping heavyweight chisel is selected to remove the underwater bedrock near the ferry rack in the course of improving the cargo handling ability of the loading dock. A prediction formula for the vibration was obtained based on the measurement and evaluation of the vibrations caused by the chisel dropping impacts during the test droppings. The prediction formula was successfully applied to the main construction for securing the stability of the structure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.163-166
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• 2002

The underwater acoustic communication has been widely applied to various objects such as ocean exploration-development and military affairs. And recently for embodiment of the communication system that is installed in a submarine and underwater work system, many studies have been progressing. This scope of the main studies in the meantime. It made it possible for a diver and a scuba diver who arc difficult to notice the situation of the outside because of staying in the water to hear a sound through a small speaker by using a ultra sound transducer that a central frequency is 32KHz after modulation of a voice to give the information of the outside. Also in case of happening an emergency to a diver in the water, it made him/her ask for help to a person in the outside by pressing a key and send a letter data to a person in the outside by using a keyboard. Through this system, it is possible to send a voice or data between the underwater and the outside and it is available to a diver or skin scuba diver.