• Journal of Fisheries and Marine Sciences Education
• /
• v.15 no.1
• /
• pp.47-56
• /
• 2003

Recently with the conclusion of fisheries agreements between Korea and Japan, and between Korea and China, trawlers in korea must operate in smaller fishing ground than before. As a result of this, the possibilities of collisionin increases gradually between trawlers under operation in this area. Authors performed a series of experiments on board to give the information of collision avoiding action to navigators of trawlers. The obtained results are summerized as follows : 1. The greater the rudder angle, the smaller the value of T, but there is no big diffierence in K due to rudder angle. 2. The greatest distance is to be kept by the give way vessel to avoid collision when the crossing course angle is $70^{\circ}{\sim}90^{\circ}$. In this case the safety minimum approaching distance must be more than 5 times of her own length. 3. Risk of collision in crossing is more greater in obtuse situation than in acute one. 4. The navigator of the give way vessel must take an action to avoid collisions outside of the minimum safety approaching distance.

• Journal of Korea Game Society
• /
• v.19 no.1
• /
• pp.5-14
• /
• 2019

This paper presents a practical method to compute the closest approach distance of two ellipsoids in their inter-center direction. This is the key technique for collision handling in the dynamic simulation of rigid and deformable bodies approximated with ellipsoids. We formulate a set of equations with the inter-center distance and the contact point and normal for the two ellipsoids contacting each other externally. The equations are solved using fixed-point iteration and Aitken's delta-squared process. In addition, we introduce a novel stopping criterion expressed in terms of the error in distance. We demonstrate the efficiency and practicality of our method in various experiments.

• Journal of the Korea Computer Graphics Society
• /
• v.17 no.1
• /
• pp.17-24
• /
• 2011

In Computer Graphics, interaction between a particle-based fluid and a rigid body is important. In General, this interaction has been simulated in a discrete environment. As a result, there have been lots of errors. The larger the time step is used, the bigger the error is. This paper describes how to minimize the error in a discrete environment. To be specific, the collision handling method is that estimates particle collision using a signed distance function increases continuously according to space. At the time a fluid particle and a rigid body model collide, the exact collision time and the position is estimated. Through this, we propose the method how to be simulated the interaction between a fluid and a rigid body model as a continuous environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.50 no.11
• /
• pp.763-770
• /
• 2022

In an environment where multiple drones are operated, collisions can occur when path points overlap, and collision avoidance in preparation for this is essential. When multiple drones perform multiple tasks, it is not appropriate to use a method to generate a collision-avoiding path in the path planning phase because the path of the drone is complex and there are too many collision prediction points. In this paper, we generate a path through a commonly used path generation algorithm and propose a collision avoidance method using speed profile optimization from that path segment. The safe distance between drones was considered at the expected point of collision between paths of drones, and it was designed to assign a speed profile to the path segment. The optimization problem was defined by setting the distance between drones as variables in the flight time equation. We constructed the constraints through linearize and convexification, and compared the computation time of SQP and convex optimization method in multiple drone operating environments. Finally, we confirmed whether the results of performing convex optimization in the 20 drone operating environments were suitable for the multiple drone operating system proposed in this study.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.15 no.1
• /
• pp.98-106
• /
• 1991

Future generation of robots will be considerably more autonomous than present robotic systems. The main objective of research on theoretical problems in robotics is to endow robotics system with basic capabilities they will need to operate in an intelligent and autonomous manner. This paper discusses the problem of collision free movement of robot manipulator. It is formulated in path planning with obstacle avoidance expressed in the term of the distance between convex shapes in the three dimensional space. The examples are given to illustrate the main feature of the method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2007.12a
• /
• pp.112-113
• /
• 2007

실습생 및 초급항해사에게 항해 중 가장 기본적으로 요구되는 충돌회피를 위한 선박조종 실습은 법적 책임 및 타 선박과의 불규칙한 조우로 인하여 직접적인 충돌회피 조종 실습이 곤란할 뿐만 아니라 타 선박과의 조우 상황 자체가 극히 제한되어 있는 실정이다. 이에 이 연구는 한국해양대학교 실습선 한나라호의 2007년 원양항해 중 타 선박과의 조우형태를 조사하여 해양계열 대학 실습생 및 초급 항해사에게 실제 해역에서 발생할 수 있는 조우상황별 위험도를 분석하여 이를 기초로 하여 충돌회피를 위한 효율적인 판단 능력 향상을 위한 기초 실습교육 자료를 개발하고자 한다. 그리고 추후에는 이러한 자료를 선박조종시뮬레이터에 적용하여 임의의 조우 상황하에서 안전한 선박조종이 가능하도록 교육 훈련함으로써 보다 효율적인 실습교육에 이바지 할 것으로 판단된다.

• Annual Conference of KIPS
• /
• 2015.10a
• /
• pp.400-401
• /
• 2015

해상 교통 관제를 함에 있어서 선박간의 충돌 사고를 미연에 방지하기 위해 관제사의 의사 결정을 도울 수 있는 기술들이 많이 개발되고 있다. 관제 시 선박간의 충돌 위험을 판단하고 사고를 미연에 방지하기 위해, 관제사들이 가장 빈번하게 사용되는 기능이 CPA와 거리/방위각 측정기능이다. 하지만, 기존 해상관제 시스템들은 이러한 기능들이 독립적으로 구성되어 있어, 관제사들의 신속한 업무 처리를 방해할 뿐만 아니라, 관제사의 업무 피로도를 종종 증가시킨다. 본 논문에서 제안한 방법은 관제사 설문조사를 통해 수렴된 내용을 토대로 기존의 CPA, 거리/방위각 측정 기능을 보완하여 CPA 계산 시 선박 조우 정보를 제공하고, 관제사로 하여금 충돌예상 선박들에 대해 신속한 초동 조치 지시를 가능하게 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2020.11a
• /
• pp.138-138
• /
• 2020

전세계적으로 자율운항선박 기술개발이 활발하게 이루어지고 있으며, IMO(국제해사기구)에서는 자율운항선박 도입을 위한 제도적 측면에서 검토 중이다. 우리나라도 해수부-산업부 공동으로 자율운항선박 기술개발사업을 진행 중이며, 2025년까지 자율화등급 3수준의 기술개발을 목표로 한다. 본 연구는 자율운항선박 항해에 기초가 될 충돌회피 시점을 도출하고자 한다. 이를 위해 우리나라 연안의 해상교통조사 자료를 이용하여 선박운항자의 피항시점(CPA, TCPA, 위험도, 이격거리, 선수방향차이 등)을 파악하고자 한다. 피항시점은 자율운항시스템의 기초학습자료로 이용할 수 있을 것으로 예상된다.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.8 no.3
• /
• pp.433-438
• /
• 2013

Interference reduction method of vehicle collision avoidance sensor which is used for the low speed electric vehicle has been investigated. Various methods were attempted for the vehicle collision avoidance distance sensor, which received a transmitted signal from a front driving vehicle to measure the distance between two vehicles, to avoid interference by the own transmitter signal toward the rear following vehicle. In this study, -12dB of interference cancellation ratio was realized by using the phase cancellation method to the transmitted signal from the own vehicle. Proposed phase cancellation method is regarded to have the advantage of continuous monitoring in comparison to the conventional time sharing transmitting and receiving method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1996.04a
• /
• pp.246-252
• /
• 1996

본 연구는 아음속 충돌분류의 소음특성에 관한 연구로서 분류가 매끄러운 판(smooth plate)에 충돌 할 때 발생하는 충돌소음의 음압레벨, 지향성 그리고 음향파워 등을 구하기 위한 것이다. 연구방법은 Fig.1에서와 같이 노즐지름 d와 노즐과 평판과의 거리를 h라 할 때 노즐상류측에 있는 서지 탱크(surge tank)의 압력이 1.0atg에 도달한 상태에서 단계적으로 강하시키면서 h/d에 따른 충돌소음의 레벨을 측정하였다. 또한 탱크압력을 일정하게 유지시킨 상태에서 충돌소음의 지향성을 측정하고 음향파워를 계산하였다. 자유분류인 경우에도 같은 방법으로 측정하여 충돌음의 경우와 비교 고찰하였다.