• Journal of Navigation and Port Research
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• v.31 no.8
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• pp.645-652
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• 2007

As a method to improve the present operational and safe function in navigation this paper developed an efficient and economical integrated system of ship's information. This system is, systematically and comprehensively, to monitor, save, analyse, and display information on navigation and environment around own ship in real time by connecting one user to another through an on-board LAN or data communication via satellite so that many users on board can obtain simultaneously and easily the information in real time not only in the wheelhouse and engine room but also in many robins and ship's offices. And it consists of four(5) components; data distribution program, database of navigational and engine-related information, multi-functional monitoring program, ship management program and other application program.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2839-2846
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• 2014

New VHF band for use in VDE is determined by WRC-12 due to the overload of AIS VDL, and the system characteristics of the VDE is recommended as ITU-R M. 1842-1. CS-TDMA, a multiple access method of AIS class B, is recommended as that of the VDE. It is inefficient for CS-TDMA just applying the report interval used in AIS class B to transmit high speed data with higher payload in the aspect of efficiency. In this paper, a simulation is executed in order to determine adequate report interval according to the number of active ships that affects directly network traffic. To this end, the performance of CS-TDMA, which includes the number of received packets, reception success rate, channel utilization, and collision rate, is investigated via a simulation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.300-301
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• 2012

불특정 다수의 사람들이 다양한 목적으로 이용할 수 있는 플로팅 다중이용건축물 활용에 대한 요구가 점차 증가하고 있으며 관련된 다양한 계획이 시도되고 있다. 하지만 관련 사례의 부족과 법제도의 미비로 인하여 예상되는 재해에 대한 방재측면의 고려는 미비한 실정이다. 따라서 본 논문에서는 플로팅 다중이용시설에서 향후 발생할 수 있는 재해의 유형을 플로팅 다중이용건축물 특성 분석, 선박 및 건축물 재해사례 조사등을 통해 파악하였으며 특히 시설물의 안전 및 이용자의 안전에 가장 큰 영향을 미치는 화재에 대하여 계획단계에서 고려되어야 하는 방재계획 특성에 대하여 고찰하였으며 이를 통해 방재계획 기본방침을 제안하였다.

• The Journal of the Acoustical Society of Korea
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• v.38 no.1
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• pp.73-81
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• 2019

This paper proposes an acoustical inversion method using cepstrum analysis of underwater ship noise. Through the cepstrum analysis, multipath structure can be extracted from the recorded ship noise. The multipath structure comes from interferences between a direct arrival and multiple reflections from the sea surface and the bottom. The acoustic inversion is the optimization process to find the best parameters which show good correlation between cepstrums of the measured signal and the replica. The inversion method was applied to the underwater ship radiated noise data measured at Straits of Korea in order to estimate the acoustic center of the ship and the hydrophone position. The inversion results showed good agreement with the measured information.

• Journal of Navigation and Port Research
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• v.43 no.1
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• pp.23-32
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• 2019

In this paper, we proposed a multi-chain Time of Arrival (ToA) positioning method to estimate positions using all received Loran-C signals from multiple chains without constraining to a single chain. Conventionally, we have to choose only one chain among several available chains for position estimation using Loran-C. Therefore, the number of signals to be used for positioning is limited to three to five. In general, if more signals are used for positioning estimation, its performance tends to be improved in terms of accuracy and availability. To validate the proposed method for multi-chain Loran-C, we firstly carried out a static positioning test in land. By analyzing the test results, we confirmed that the proposed method works well under a multi-chain Loran-C scenario. Subsequently, another mobile positioning test was conducted on board a vessel under a practical application scenario. From this second test, we successfully demonstrated that the multi-chain ToA positioning method even in situations where the conventional single-chain Loran-C approach fails for positioning.

• Proceedings of the Korea Contents Association Conference
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• 2016.05a
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• pp.351-352
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• 2016

조선소의 생산계획 담당자가 기존 실적 정보를 이용하여 관심 대상인 미래의 생산계획 상황을 보다 쉽게 예측하여 생산계획의 적중률을 높일 수 있도록 할 예정이다. 2006년에서 2016년의 S조선사의 2차 데이터를 이용하여 요인 분석을 하고 다중회귀분석 모형을 설계하여 활용하는 프로세스를 설계한다. 사례 연구를 통해 연구 모형이 적절한지를 검증할 계획이다.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.2
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• pp.103-112
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• 2012

We demonstrate the preliminary results of ship detection application using synthetic aperture radar (SAR) and automatic identification system (AIS) together. Multi-frequency and multi-temporal SAR images such as TerraSAR-X and Cosmo-SkyMed (X-band), and Radarsat-2 (C-band) are acquired over the West Sea in South Korea. In order to compare with SAR data, we also collected an AIS data. The SAR data are pre-processed considering by the characteristics of scattering mechanism as for sea surface. We proposed the "Adaptive Threshold Algorithm" for classification ship efficiently. The analyses using the combination of the SAR and AIS data with time series will be very useful to ship detection or tracing of the ship.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.195-196
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• 2019

Studied for multiple obstacle avoidance algorithm based on COLREG for autonomous navigation vessel's safety navigation. By used VECTOR value of external obstacle provided by RADAR, CPA and TCPA of each obstacle are analyzed, and the obstacle is classified based on the value, the risk level is calculated considering multiple obstacle avoidance situations, and the avoidance action is applied to secure minimum safety situation.

• Journal of Navigation and Port Research
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• v.31 no.5 s.121
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• pp.325-332
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• 2007

This study develops a control algorithm on berthing/unberthing system using a joystick for ships with thrusters and a rudder. A nonlinear mathematical model for low speed maneuvering of typical container ships is used to develop a MIMO(multi-input multi-output) nonlinear control algorithm for velocity feedback joystick control. Also a virtual HILS(hardware in the loop simulation) software program for berthing/unberthing is developed to test the performance of the nonlinear and a PID control algorithm. The program is developed using LabWindow/CVI, and a user can see current position and desired trajectory of ship in a monitor, then he can control forward and yaw velocities of a ship using a joystick. The simulation results show that the nonlinear mfd the PID controller have superior performance over a simple open loop joystick control algorithm.

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.145-150
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• 2020

The ship motion of large LNG ships affects ships' safety. The purpose of this study was to estimate the transfer function of roll motion among the hull motion of 153,000 m3 class LNG vessels. The ship motion transfer function was modeled using a Linear Time-Invarient system with single input, single output, and transfer function. The transfer function of the ship motion was estimated by the system identification method using single ocean wave as input of the model, and using the roll motion of the LNG ship obtained through ANSYS as the output of the model. The usefulness of the experimental results was evaluated using the precision and estimation rate of the model for cases wherein the different transfer function dimensions. Results of the experiment showed a precision at 99% and 98%, with estimation rate at 78% and 50%. From these results, we found the proposed method of estimating the transfer function of ship motion in this study reasonable. In the future, data of ship motion in actual sea conditions will be acquired and it will be applied to make the construction of models with multiple inputs and multiple outputs for practical use.