• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.51-52
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• 2019

In the past, waves, which are the main external forces acting on marine and coastal structures, have been dealt with only in terms of safety. Recently, various studies have been conducted to define the characteristics of waves in a specific area in order to respond to the increasing demand for diversified marine activities such as ocean energy development and marine leisure sports. Although the characteristics of waves are specific to the site, the available spectrum model proposed in previous studies are limited. In this study, we analyzed the shape of the ocean wave spectrum by comparing it with the standard spectrum model.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.211-212
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• 2022

지구온난화에 따른 우리나라 주변 환경의 변화와 최근 중국 불법어선의 연근해 어업자원의 고갈 등으로 인해 우리나라 연근해 어족자원을 보호할 필요성이 증대되고 있으며, 지속 가능한 어업을 위해서는 어획물의 종류와 양을 정확히 파악하고 불법 어업에 대한 철저한 감시 및 관리가 필요하다. 시공간적으로 다양하게 변하는 생태 및 어장 환경 정보와 선박에 대한 정보를 통해 해양관측과 위성 원격탐사를 동시에 이용함으로써 근해와 원양 생물자원 실태를 관측하는 것이 가능하다. 본 연구에서는 야간 불빛 위성 Suomi-NPP (Suomi National Polar-orbiting Partnership) 및 후속위성인 NOAA-20의 VIIRS (Visible Infrared Imaging Radiometer Suite) DNB (Day & Night Band) 영상을 이용하여 야간 불빛을 활용하고자 한다. 이 불빛 위성 자료를 이용하여 야간에 조업하는 어선 선단의 공간 분포를 분석할 수 있다. 또한 이 불빛 위성 자료와 AIS 자료를 상호 비교하여, 불빛 위성 자료를 통해 실제 선박의 위치 정보를 검색하는 것이 가능함을 검증하고자 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.75-77
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• 2020

There was an outbreak of COVID-19 on the Diamond Princess cruise ship. Distinguishing close contacts is the important problem to be addressed. Close contacts mean people who stays with the patients of disease like COVID-19 over a period of time. The passenger position on board can be obtained by indoor positioning technology. The feature of close contacts is similar location with COVID-19 patients. Therefore, this paper proposed the idea of distinguishing close contacts on board based on DBSCAN algorithm.

• Journal of Navigation and Port Research
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• v.29 no.7
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• pp.603-609
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• 2005

This paper presents the method for developing an optimum hull form with minimum wave resistance using SQP( sequential quadratic programming) as an optimization technique. The wave resistance is evaluated by a Rankine source panel method with non-linear free surface conditions and the ITTC 1957 friction line is used to predict the frictional resistance coefficient. The geometry of the hull surface is represented and modified using NURBS(Non-Uniform Rational B-Spline) surface patches. To verify the validity of the developed program the numerical calculations for Wigley hull and Series 60 Cb=0.6 hull are performed and the results obtained after the numerical calculations are compared with the initial hulls.

• Journal of Navigation and Port Research
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• v.37 no.1
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• pp.55-61
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• 2013

In this paper, ship accidents are analyzed briefly and the main objective is to investigate a potential technological approach for risk assessment of vessel stability. Ship nonlinear motion equation and main parameters that induce ship capsizing in beam seas have analyzed, the survival probability of a ferry in random status have estimated and finally find out a risk assessment concept for ship's intact stability estimation by safe basin simulation method. Since a few main parameters are considered in the paper, it is expected to be more accurately for estimating ship survival probability when considering ship rolling initial condition and all other impact parameters in the future research.

• Journal of Ocean Engineering and Technology
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• v.30 no.3
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• pp.214-220
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• 2016

Imaging sonars such as side-scanning sonar or forward-looking sonar are becoming fundamental sensors in the underwater robotics field. However, using sonar images for underwater perception presents many challenges. Sonar images are usually low resolution with inherent speckled noise. To overcome the limited sensor information for underwater perception, we investigated preprocessing methods for sonar images and feature detection methods for a nonlinear scale space. In this paper, we focus on a comparative analysis of (1) preprocessing for sonar images and (2) the feature detection performance in relation to the scale space composition.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.67-68
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• 2015

선상에서의 승객들의 보행속도, 운항 중 피난특성, 피난시 연기농도가 미치는 영향 등 선박에서의 피난상황을 해석하는 데 필요한 몇몇 연구가 수행된 바 있다. 그러나 정전 조건에서 승선자의 피난성능에 관한 연구는 미비하여, 이론적 혹은 실험적 연구가 수행된 사례를 찾아보기 어려운 상황이다. 이에 이 연구에서는 선박에서의 인적안전피난해석 프로그램인 Maritime EXODUS를 활용하여 승선자의 분포특성을 고려한 세 가지 시나리오에 대한 피난시간을 예측 비교하였다. 이 연구에서는 선행된 운항훈련선의 선내 정전조건보행실험에서 취득한 피실험자 보행속도 결과를 반영하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.289-290
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• 2016

본 논문에서는 지속적인 상황인지 작업이 요구되어 업무 피로도가 매우 높은 선박교통관제 업무의 업무 부하 저감을 위해 관제맥락 정보를 활용한 의사결정지원 시스템을 제안하였다. 제안하는 의사결정지원 시스템은 선박교통관제에 활용되는 다양한 정보들을 정량화하여 사실 데이터베이스를 구축하고, 여기에 선박교통관제에 활용되는 비정형의 규칙들을 정형화하여 적용함으로써 의사결정에 필요한 정보를 도출할 수 있도록 하였다. 또한 여러 단계로 추상화된 관제맥락정보를 생성 및 적용할 수 있도록 하여 고수준의 논리 적용이 가능하도록 함으로써 선박교통관제 규칙 생성이 용이하도록 하였다.

• International Journal of Ocean System Engineering
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• v.1 no.2
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• pp.89-94
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• 2011

Underwater localization is a crucial capability for reliable operation of various types of underwater vehicles including submarines and underwater robots. However, sea water is almost impermeable to high-frequency electromagnetic waves, and thus absolute position fixes from Global Positioning System (GPS) are not available in the water. The use of acoustic telemetry systems such as Long Baseline (LBL) is a practical option for underwater localization. However, this telemetry network system needs to be pre-deployed and its availability cannot always be assumed. This study focuses on demonstrating the validity of terrain-based localization techniques in a GPS-denied underwater environment. Since terrain-based localization leads to a nonlinear estimation problem, nonlinear filtering methods are required to be employed. The extended Kalman filter (EKF) which is a widely used nonlinear filtering algorithm often shows limited performance under large initial uncertainty. The feasibility of using a particle filter is investigated, which can improve the performance and reliability of the terrain-based localization.

• International Journal of Ocean System Engineering
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• v.3 no.4
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• pp.218-224
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• 2013

This paper describes the design and control of a hovering AUV test-bed and analyzes the dynamic performance of the vehicle using simulation programs. The main purpose of this vehicle is to carry out fundamental tests of its station keeping, attitude control, and desired position tracking. Its configuration is similar to the general appearance of an ROV for underwater operations, and its dimensions are $0.75m{\times}0.5m{\times}0.5m$. It has four 450-W thrusters for longitudinal/lateral/vertical propulsion and is equipped with a pressure sensor for measuring the water depth and a magnetic compass for measuring its heading angle. The navigation of the vehicle is controlled by an onboard Pentium III-class computer, which runs with the help of the Windows XP operating system. This provides an appropriate environment for developing the various algorithms needed for developing and advancing a hovering AUV.