• Geophysics and Geophysical Exploration
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• v.22 no.2
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• pp.72-79
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• 2019

Underwater object detection method adopting electrical resistivity technique was proposed recently, and the need of advanced data processing algorithm development counteracting various marine environmental conditions was required. In this paper, we present an improved water tank experiment system and its operation results, which can provide efficient test and verification. The main features of the system are as follows: 1) All the processes enabling real time process for not only simultaneous gathering of object images but also the electrical field measurement and visualization are carried out at 5 Hz refresh rates. 2) Data acquisition and processing for two detection lines are performed in real time to distinguish the moving direction of a target object. 3) Playback and retest functions for the saved data are equipped. 4) Through the monitoring screen, the movement of the target object and the measurement status of two detection lines can be intuitively identified. We confirmed that the enhanced physical modeling system works properly and facilitates efficient experiments.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.3
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• pp.405-412
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• 2023

With the development of drone and ICT convergence technology, the use of underwater drones such as leisure underwater drones such as underwater exploration for fishing and industrial drones such as bridge piers is increasing. Existing motor controllers are suitable for aerial drones and these can increase the completeness of underwater drones and their reliability in motor control by developing BLDC motor controllers dedicated to underwater drones. By developing a battery management system (BMS) exclusively for underwater drones, battery stability was ensured by checking the state of charge, checking the state of discharge, adjusting cell balancing, and implementing high/voltage protection functions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.171-171
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• 2003

• Korean Journal of Heritage: History & Science
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• v.14
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• pp.156-196
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• 1981

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.1250-1253
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• 2017

본 논문은 드론 산업이 발전함에 따라 하천, 호수, 바다 상공에서 활용하는 드론이 수중에 빠졌을 때, 물에 빠진 드론을 모선(Mothership)과 집게팔이 달린 ROV(Remotely Operated Vehicle)를 이용하여 인양하는 시스템을 제안한다. 제안한 시스템의 구성 요소는 세 가지로 첫 번째는 실시간으로 GCS(Ground Control Station)에 영상을 전송하며 ROV와 전력선 모뎀을 이용하여 통신을 하는 모선, 두 번째는 수중에 들어가 수중 카메라를 이용하여 육안으로 드론을 탐색하고 장착된 집게팔로 드론을 몸체에 고정시키는 ROV, 세 번째는 모선, ROV와 실시간으로 영상 데이터와 명령 신호를 주고 받는 GCS 이다.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.509-515
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• 2010

Such as disaster rescue in deep water, undersea exploration and monitering for environmental pollution, many applications require the acoustic communication for high data rate over underwater acoustic channel. As underwater channel is very complex and is time-varying, conventional single carrier communication has good performance. In this paper, An adaptive OFDM system is analyzed for high data rate and reliability and rubust service over UWA channels. Through the adaptive system, we show threshold switching for an adaptive algorithm.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.414-416
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• 2008

본 연구의 목적은 수중의 다양한 공간정보를 무인으로 획득할 수 있는 다목적용 플랫폼을 개발하는데 있다. 다목적용 플랫폼은 GPS, 음향측심기, 사이드스캔소나, 지층탐사기 등을 탑재하고 자동제어에 의한 방법으로 내수면 및 연안의 수중공간정보를 획득하는 기능을 수행한다. 무인 원격 수중 공간정보 획득장비를 개발함으로써, 기존의 측량선을 이용하기가 어려운 저수지, 댐 등의 지역 및 오염으로 인해 사람이 접근하기 불가능한 지역의 각종 수중정보 취득이 가능할 것으로 기대된다. 또한 하나의 플랫폼에 다중 에코사운더, 영상센서, 수질측정 센서 등 사용목적에 맞는 센서의 장착하여 다목적으로 사용할 수 있으므로 내수면과 관련된 정보의 획득을 필요로 하는 거의 모든 산업분야에서의 경제적인 활용이 가능할 것으로 판단된다.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.3
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• pp.333-341
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• 2014

Since distribution and preservation of cultural artifacts in the submarine sediments are directly affected by not only ocean currents and tides, but also their composition, it is very important to investigate geological characteristics of sediments and ocean-sediment interactions for maritime archaeological survey. Physical properties of submarine sediments, which are collected by grab sampler and vibro-corer, are analyzed in order to investigate effects of submarine environment on development of maritime archaeological survey techniques. Result of physical property analysis showed that bulk density, shear strength, and magnetic susceptibility increase with depth, while water contents and porosity decrease with depth. Since the magnetic susceptibility of bedrock is about 40 times that of submarine sediments, it might impact greatly on the response of magnetic survey. Physical properties of sediments with depth and sediment classification by Folk's ternary diagram indicate that submarine sediment mainly consists of silt, and cultural artifacts can not penetrate no deeper than 1.5 m in sediments.

• 한국지구물리탐사학회:학술대회논문집
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• 2004.08a
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• pp.84-103
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• 2004

Cruiser Dmitri Donskoi was constructed in 1895. During the Russo-Japanese War (1904-1905), she was damaged in an attack by Japanese destroyers at the battle of Tsushima, and scuttled in the east sea of Ulleungdo, Korea Peninsula on the 29th May 1905. In 2003, Dmitri Donskoi was found at the distance of 2 km off the east coast of Ulleung Island and at the depth of 400 m. Archival research was performed as the preliminary study for investigating the sunken ship.

• Geophysics and Geophysical Exploration
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• v.16 no.4
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• pp.234-239
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• 2013

The $M_W$ 9.0 thrust-fault earthquake has occurred in the Pacific coast of Tohoku, Japan, on March 11, 2011. We present the detection of the great earthquake and analyze T-waves associated with the main event and two other big aftershocks ($M_W$ > 7) recorded in a hydroacoustic array (H11N) in the Pacific Ocean by performing array and spectral analysis to examine characteristics of T-waves generated from the big events. The complex rupture process of the main event directly influences on the shape of the T-waves, and the peak locates on where T-waves excited from fast rupturing process arrive. We compare the two aftershocks with different fault type and show that the fault type and the source depth change shape and spectral contents of T-waves.