• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.2
• /
• pp.5-7
• /
• 2006

항행하는 선박은 자기선박 주변을 하나의 영역으로 생각하여 그 영역안에 타선박의 허가하지 않는 자기만의 영역을 가지고 있다. 지금까지 우리나라에서는 선박간의 항과거리를 일본의 자료를 이용하여 해상교통 환경평가의 하나인 해상교통혼잡도를 평가하고 있다. 이 일본의 자료는 30년전의 자료이며 선박의 고속화${\cdot}$대형화로 인하여 선박간 항과거리는 선박의 통항형태, 항로의 종류, 선박의 크기에 따라 상이할 것으로 사료된다. 하지만, 상기의 모든 요소를 다 가미하여 일반화한 연구는 찾아보기 힘들며 상당한 자료를 이용하여야 하므로 분석하는데 시간이 많이 걸릴 것으로 판단된다. 이 연구에서는 해상교통량이 대단히 높은 중국 상해항을 입출항하는 선박간의 항행거리를 기초로 선박간의 최소 항과거리를 모델화함으로써 우리나라 실정에 맞는 해상교통혼잡도 평가에 이용하고자 하며, 선박운항자들의 항행에 최소 항과거리를 제공함으로써 안전항행에 도움을 주고자 한다.

• Journal of Navigation and Port Research
• /
• v.35 no.10
• /
• pp.799-804
• /
• 2011

The hydrodynamic interaction effects between the multi-bodies can not be neglected when vessels are close to each other in congested and confined waters, such as in a harbour or narrow channel. Increase in speed and size of modern vessels make it necessary to consider this interaction effects when designing harbours and navigation channels. In this research, the hydrodynamic interaction effects of the spacing between vessels and water depth along with ship's velocity are summarized and discussed. The goal of this research is to propose a guideline of appropriate speed and distance between passing and moored vessels to avoid the influence of hydrodynamic forces and to navigate safely in confined sea areas.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2011.11a
• /
• pp.31-33
• /
• 2011

목포항 진입수로 중 한곳인 불무기도 인근은 남북방향으로 통과 선박 및 목포항 입출항선박이 항행을 하고, 동서방향으로는 여객선 및 쾌속선이 항행을 하고 있다. 또한 이 구간에서 조업 및 항행중인 어선들이 많아 항행특성 파악이 필요하다. 본 연구에서는 목포항 진입수역인 불무기도 부근에서 통항중인 선박들간의 CPA/TCPA를 분석하여 목포구 진입수로 항행특성 파악하여 통항선박의 위험도를 평가 하고자 한다.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.39 no.2
• /
• pp.112-119
• /
• 2003

제한수역에서 바람과 조류와 같은 외력을 받으며 항행하는 선박들 사이에는 대양에서 항행할 때와는 달리 상호간에 여러 가지 작용이 일어나면서 선박의 안전이 위협받는 수가 많다. 본 연구에서는 협수로와 같은 제한수역에서, 해난사고를 피하기 위해 요구되어지는 선박들간의 적절한 안전속도 및 안전거리를 제안하기 위해 선장비, 속도비, 풍향, 풍속, 유향 및 유속 등을 파라메타로 해서 조종운동 시뮬레이션 계산을 행하였다. 시뮬레이션 계산 결과, 두 선박 간의 상호 영향은 대형선박에 비해서 소형선박에 보다 크게 작용하는 것으로 나타났고, 속도비 1.2 의 경우가 속도비 0.6, 1.5의 경우보다 매우 크게 나타났다. 한편, 외력하에서 항행하는 두 선박에 있어서, 고속 선박에 비해서 저속 선박에 미치는 외력의 영향은 상당히 크게 작용하기 때문에 조선할 때, 이 점에 유의하여 항행해야 함을 알 수 있었다.

• Journal of Advanced Navigation Technology
• /
• v.18 no.2
• /
• pp.134-141
• /
• 2014

Mobile robots use various sensors for navigation such as wheel encoder, vision sensor, sonar, and laser sensors. Dead reckoning is used with wheel encoder, resulting in the accumulation of positioning errors. For that reason wheel encoder can not be used alone. Too much information of vision sensors leads to an increase in the number of features and complexity of perception scheme. Also Sonar sensor is not suitable for positioning because of its poor accuracy. On the other hand, laser sensor provides accurate distance information relatively. In this paper we propose to extract the angular information from the distance information of laser range finder and use the Kalman filter that match the heading and distance of the laser range finder and those of wheel encoder. For laser scanner with one feature point error may increase much when the feature point is variant or jumping to a new feature point. To solve the problem, we propose to use two feature points and show that the positioning error can be reduced much.

• Journal of Advanced Navigation Technology
• /
• v.13 no.2
• /
• pp.187-193
• /
• 2009

A lens which is one of cores for the high precision laser range finder is utilized to compute the distance by measuring the phase displacement. In order to measure the phase displacement, we transmit the optical signal from the laser diode to a target and receive the reflected laser light from the target. In this paper, we propose new lens design technique to solve the problem due to the inconsistent curvature of the lens, which consistently collects optical signals and performs the transmission and reception of the optical data, and test the implementation of the laser range finder based on the proposed technique. Since the proposed laser range finder has low error rate comparing to the conventional techniques, it may be apply to the high precision distance measurement.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2007.12a
• /
• pp.77-78
• /
• 2007

The aim if the present research is to develop a guideline if a safe conducting distance according to separated distance and velocity if the two vessels to navigate safely in restricted waterways. The authors studied the hydrodynamic forces between two vessels running closely and calculated safe conducting distances according to separated distances and speeds if the vessels under the condition if wind and strong current.

• Journal of Navigation and Port Research
• /
• v.34 no.10
• /
• pp.735-740
• /
• 2010

This paper focuses on the effects of hydrodynamic forces between overtaking and overtaken vessels moving under the influences of external forces, such as strong wind and current in shallow water, in which condition the ship handling may become very complex. The purpose of this paper is to develop a guideline for safe conducting distance between two ships according to the velocity and the significance of external disturbances.

• Journal of Advanced Navigation Technology
• /
• v.6 no.1
• /
• pp.27-36
• /
• 2002

As the number of autonomous vehicles is increased, drivers are trending toward constant interests in detecting distance between vehicles in close-range and maintaining the distance between forward and backward vehicles for drivers' safety. In this paper, we propose a method of detecting the distance between two vehicles by computing the disparity of the close-rang vehicle using stereo vision. The boundary of the vehicle is obtained by using the modified wavelet transform which has multi-resolution characteristics. Then the disparity between left and right images is computed using coarse-to-fine method and histogram matching. Here we transform the left-right stereo images through 3-steps using the modified wavelet for maintaining the original resolution. An experimental result showed that the proposed method had 4.65% in total error rate.

• Journal of Advanced Navigation Technology
• /
• v.13 no.4
• /
• pp.559-565
• /
• 2009

The implementation possibility and increasement of transmission distance of 1 Tbps WDM transmission systems through the applying optical link configuration with inline dispersion management (DM) and optical phase conjugator (OPC) is investigated. When the considered optical link configuration is applied into $26{\times}40$ Gbps WDM transmission system and the optimal net residual dispersions (NRDs) depending on transmission length are decided, the effective transmission distanceis highly increased than that resulted in same system with fixed 0 ps/nm NRD in all transmission length. And, design rule of inline DM optical link is also shown through inducing the effective range of precompensation and postcompensation depending on transmission distance and launching power of WDM channel.