• Journal of Advanced Navigation Technology
• /
• v.12 no.5
• /
• pp.412-419
• /
• 2008

Genetic algorithms are efficient techniques for searching optimum solution but have the premature convergence problem getting stuck in the local optimum according to the evolutionary operator. In this paper we analyzed the reason for converging to the local optimum and proposed the method which able transit to the global optimum from the local optimum. In these methods we used the variable evolutionary operator with the average hamming distance, to maintain the genetic diversity of the population for getting out of the local optimum. The theoretical results are proved by the simulation experiments.

• Journal of Advanced Navigation Technology
• /
• v.8 no.1
• /
• pp.38-47
• /
• 2004

To achieve functions of doppler measurement, MTI(Moving Target Indicator), high-resolution, and others in radar system, all circuits of transmitter and receiver are to be performed in coherent system. In this paper, we use TWTA(Traveling Wave Tube Amplifier), STALO(Stable Local Oscillator) and COHO(Coherent Oscillator) to design of coherent radar transceiver, and calculates noise figure of designed receiver. Using radar equation calculated noise figure, maximum detecting range of each transmitting mode can be calculated.

• Journal of Advanced Navigation Technology
• /
• v.16 no.4
• /
• pp.627-634
• /
• 2012

This paper considers the performance of the non-participating GPS software receivers under the presence of GPS pseudolite(PL). For the continuous PL signal and pulsed PL signal, the impact of PL signals on the GPS software receivers is investigated according to the signal strength of the PL and the distance between the PL and the GPS receiver.

• Journal of Advanced Navigation Technology
• /
• v.15 no.2
• /
• pp.256-263
• /
• 2011

The nerve impulse is induced by the stimulation of neuron or axon, and this stimulated voltage decays along the propagation distance and time if it is subtreshold potential. This behavior can be estimated using the electrical equivalent circuit because it is very similar to propagation phenomenon of electrical circuit to which Ohm's law is applied. Therefore, I calculated various biometric parameters of body, and then analyzed the propagation behavior of stimulated potential voltage using the distributed parameters of electrical circuit in this paper.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2011.06a
• /
• pp.362-364
• /
• 2011

자동조타장치에 의한 조선을 행할 시, 선박의 정침성은 Autopilot의 P와 D값 설정에 따라 많은 영향을 받게 된다. 이 값들은 선종별로 외력에 따라 조정되어야 한다. 이 연구에서는 바람에 의해 가장 많이 영향을 받는 자동차운반선(Pure Car Carrier, PCC)을 대상으로 하여, 풍압력하에서 자동조타시 P와 D치의 적정 설정값을 알아 보았다. 이를 위하여 대상 선박을 저속항행하는 시뮬레이션을 실시하였고, 각 P-D 설정값에 따른 최대 횡이동거리, 횡이동시간 그리고 주어진 침로로 복귀하는데 걸린 시간을 비교하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2023.05a
• /
• pp.241-242
• /
• 2023

등부표는 선박의 안전한 항행을 지원하는 시설인 항로표지의 한 종류로 항행하는 선박에게 암초나 수심이 얕은 곳의 소재를 알리거나 항로의 경계를 알리기 위해 침추를 해저에 정치하여 해상의 고정위치에 띄워 놓은 등화가 설치된 것을 말한다. 등부표의 표체는 해저에 정치된 침추와 체인으로 연결하며 체인의 길이는 수심의 1.5 ~2.5배로 하여 표체를 계류한다. 등부표는 조류, 바람 등 외력에 의해 이출거리가 발생하여 일정한 패턴으로 선회반경이 형성되나 외력으로 인하여 정상범위에서 벗어나 유실, 위치이동 등이 발생할 수 있고 이는 선박추돌 등 항해안전 사고로도 이어질 수 있다. 이러한 등부표 사고는 물적 피해비용과 이용자의 안전운항에 대한 심리적 부담감 또는 위험감수 등의 추가적인 행정소요 비용이 발생할 수 있다. 따라서 선박의 안전한 도선을 위해서는 등부표의 이출범위와 위치가 변할 수 있음을 염두해 둘 필요가 있다. 이와같은 등부표로 인한 사고 예방과 안전한 도선을 위해 등부표 이출범위와 안전도선에 관한 연구를 하였다.

• Journal of Navigation and Port Research
• /
• v.46 no.6
• /
• pp.554-561
• /
• 2022

Technology development related to maritime autonomous surface ships (MASS) is actively progressing around the world. However, since there are still many technically unresolved problems such as communication, cybersecurity, and emergency response capabilities, it is expected that it will take a lot of time for MASS to be commercialized. In this study, we proposed a ship group navigation system in which one leader ship and several follower ship are grouped into one group. In this system, when the leader ship begins to navigate, the follower ship autonomously follows the path of the leader ship. For path following, PD (proportional-derivative) control is applied. In addition, each ship navigates in a straight line shape while maintaining a safe distance to prevent collisions. Speed control was implemented to maintain a safe distance between ships. Simulations were performed to verify the ship group navigation system. The ship used in the simulation is the L-7 model of KVLCC2, which has related data disclosed. And the MMG (Maneuvering Modeling Group) standard method proposed by the Japan Society of Naval Architects and Ocean Engineering (JASNAOE) was used as a model of ship maneuvering motion. As a result of the simulation, the leader ship navigated along a predetermined route, and the follower ship navigated along the leader ship's path. During the simulation, it was found that the three ships maintained a straight line shape and a safe distance between them. The ship group navigation system is expected to be used as a navigation system to solve the problems of MASS.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2005.10a
• /
• pp.5-10
• /
• 2005

T.S. HANBADA will navigate to maintain the adequate distance between own ship and other ships safely for about 17 hours on the about 2 kts. On the above situation, M broadcasting station requires to maintain the distance from 100m to 500m between ships. This paper aims to calculate the minimum safe distance between ships, the distance is assessed by using ES Model which is a quantitative model for evaluating the difficulty of shiphandling. After marine traffic flow simulation, minimum safe distance for HANBADA on the 2kts is about 260m based ES value. On this paper, the result was compared about its distance to the actual navigating distance.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2011.11a
• /
• pp.29-30
• /
• 2011

본 연구에서는 부산항 신항 선박급유 및 유류중계기지 건립에 따른 JETTY 평면재배치 검토로 인하여 발생되어지는 부산항 신항에 입항하는 대형 컨테이너 선박이 계류중인 선박에 작용하는 간섭력을 수치적으로 계산하고, 계류중인 선박의 안전 및 유류중계기지 건립 안전에 유의해야 할 점 등에 관하여 검토한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.11a
• /
• pp.7-8
• /
• 2022

국내 해상풍력발전단지가 증가함에 따라 소형선박의 단지 내 위험통항이 증가하고 있으며, 제한된 시계 또는 야간항해 시 해양풍려발전단지 부근을 항해하는 선박들의 안전항행 우도 및 해양풍력단지 시설물 보호의 필요성이 높아지는 등 해상풍력발전단지 내 항로표지가 중요한 의미를 갖게 되었다. 이 연구에서는 국제항로표지협회의 권고안과 주요국가의 국내규정 그리고 국내관련 규정을 비교·분석하여 항로표지의 기능 및 규격에 관한 기준의 개정방안을 제시하였다.