• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.250-253
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• 2010

Underwater sensor network has attracted more and more attention from the networking research community recently. Most of traditional studies focus on the topology with a single gateway. Underwater sensor network consists of a variable number of sensors and multi-gateway to ensure the reliability of the network. In this paper, we propose a new MAC protocol that can reduce collisions among sensor nodes and improve QoS(Quality of Service) for underwater sensor network with multi-gateway. We evaluate the performance of the proposed scheme through simulation. Simulation results show that the proposed scheme outperforms the existing MAC protocol.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2119-2124
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• 2008

An information-oriented basis in today's society has been changing fast, and the desire for connectivity has caused an exponential growth in wireless communication and sensor network. Sensor networks using RFID, in particular, have led this trend due to the increasing exchange of data in Ubiquitous such as the home RF, access control system, U-Healthcare, and Logistics information Systems. Also, the RFID when it applies a technique, is able to raise the stability of shipping as controling the mobile course and an entrance and exit of the crews an well as previously preventing an accident from shipping. In this paper, we designed and implemented personnel control system using UHF-RFID in vessels which shows through host PC reading and writing tag.

• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.136-145
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• 2009

There are two purposes for the marine structures used for fossil fuel: transporting huge amounts of crude oil and petroleum products and producing petroleum resources on the ocean in an isolated operational environment. Both types of structures are exposed to dangerous situations by sea conditions. Such marine structures are greatly affected by ocean climate conditions and its changes. Because of such ocean climate changes, it has been necessary to monitor marine structures. This research discusses the difficulties with adopting a new methodology based on a ubiquitous sensor network and develops an optimized sensor network management system design for a marine structure.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06b
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• pp.87-89
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• 2011

전 세계적으로 수중 또는 해양의 정보는 매우 중요하며 다양한 활용가치를 지닌다. 수중 또는 해양을 개발하고 활용하기 위해서는 실시간으로 지속적으로 모니터링하면서 데이터를 수집하고 필요에 따라 수중 장치나 장비를 제어하는 기술이 기본적으로 요구된다. 본 논문에서는 수중 센서네트워크에 특징에 대해서 알아보고 클러스터링을 적용한 수중 네트워크내의 전송 효율 향상에 대해 연구하고, 통신을 위하여 MAC 계층으로 협업 통신을 적용하는 가능성 그리고 몇 가지 주의점에 대하여 알아보았다. 본 연구를 통하여 수중 네트워크로의 협업 통신 적용은 큰 가능성을 지니고 있으며, 지상에서와의 다른 환경 때문에 프로토콜의 적절한 설계가 매우 필요하다는 것을 알았다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.3
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• pp.202-214
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• 2014

We introduce status and prospect of increasingly utilizing, unmanned, global ocean observing systems, and the global network to integrate, coordinate, and manage the systems. Platforms of the ocean observing system are diversified in order to resolve/monitor the variability occurring at multiple scales in both three-dimensional space and time. Here purpose, development history, and current status of the systems in two kinds - mobile (surface drifter, subsurface float, underwater glider) and fixed platforms (surface and subsurface moorings, bottom mounts), are examined and the increased future uses to produce synergies are envisioned. Simultaneous use of various mobile and fixed platforms is suggested to more effectively design the observing system, with an example of the NSF-funded OOI (Ocean Observations Initiative) program. Efforts are suggested 1) to fill the data gap existing in the deep sea and the Southern Ocean, and toward 2) new global network for oceanic boundary currents, 3) new technologies for existing and new sensors including biogeochemical, acoustic, and optical sensors, 3) data standardization, and 4) sensor calibration and data quality control.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.269-277
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• 2007

Wireless sensor network system is expected to get high attention in research for now and future owing to the advanced hardware development technology and its various applicabilities. Among variety of sensor network systems, the seashore and marine sensor network, which are extended to get sampling of marine resources, environmental monitoring to prevent disaster and to be applied to the area of sea route guidance. For these marine applications to be available, however, the provision of precise location information of every sensor nodes is essential. In this paper, the sequential localization algorithm for obtaining the location information of marine sensor nodes. The sequential localization is done with the utilization of a small number of beacon nodes along the seashore and gets the location of nodes by controling the sequences of localization and also minimizes the error accumulation. The key idea of this algorithm for localization is that the localization priority of each sensor nodes is determined by the number of reference nodes' information. This sequential algorithm shows the improved error performance and also provide the increased coverage of marine sensor network by enabling the maximum localization of sensor nodes as possible.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.168-169
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• 2022

다양한 종류의 센싱 데이터를 수집·분석하여 하천의 가뭄·홍수·오염 등의 감시·예측을 하기 위한 환경정보 분석·예측 기술, 환경 오염, 홍수 등 재난 상황 발생 시 실시간 대처를 위한 액츄에이터 제어/관리, 센서정보 웹 서비스 등의 환경정보 기반 지식 서비스를 제공하고, 다수의 이종 센서네트워크를 효율적 통합관리를 위한 지능형 환경관리 서비스 기술, 광역 환경관리 센서네트워크 요소 기술의 현장 검증에 필요한 테스트베드 구축을 위한 핵심기술 적용 실증시스템 구축을 위한 네트워크 구성 방안을 제시한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1128-1134
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• 2007

Recently, sensor network technology is a highly concerned area due to the expectation of many applications in various fields. The application of sensor network technology to the marine and ocean surveillance and investigation makes the marine environmental research easier since intelligent sensor nodes substitute the human labor work. In ocean sensor network, the localization scheme for the sensor nodes is most essential because all the information without from sensor nodes might be useless unless the positional information of each sensor nodes is provided. In this paper, the localization scheme with mobile beacons in ocean sensor networks is suggested and showed it could be effective for applying to marine circumstances. Even though the previous localization scheme(Ssu's) has advantages that additional hardware is not required for obtaining the information of distance and angle and shows the high accuracy of location and energy efficiency and easy expandability as well, it has also demerits the location error increases as the minimum distance between the absolute positional information become closer. In our works, the improved localization scheme with the presumed area of sensor node using geometric constraints is suggested.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.613-619
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• 2020

Hybrid media access control (MAC) is used in internet of things (IoT) network, because of communication feature concern with data capacity and communication interval between gateway and sensor nodes and the cost efficiency. Hybrid MAC consists of TDMA and CSMA generally. The distance between gateway and sensor node is openly changed in marine IoT network. Therefore, it is needed to control the period of timeslot of hybrid MAC used in marine IoT network. In this paper, the design rule of TDMA timeslot with the variable period depending on communication distance was proposed. It was confirmed from the analysis that 72 times communication between gateway and sensor nodes is possible in LoRa network by using the proposed TDMA variable timeslot scheme.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.268-273
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• 2015

Recently many countries are researching actively underwater sensor networks for securing ocean resources and changes of ocean environment in all over the world. Current the commercial modem are not suitable because it has characteristics of long distance, higher price, larger power consumption with the special object mainly. In this paper, a low power and compact underwater communication modem which is suitable for underwater sensor networks is implemented. It is comprised by using a simple analog circuit for non-coherent BFSK modulation method, ultra low power MCU and orthogonal codes with a less operation and a simple implementation. It was experimented an underwater communication using our modem in a water tank and open sea farms. It communicates fewer than $10^{-4}$ bit error rate.