• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.161.1-161.1
• /
• 2012

지구 정지궤도는 위성통신, 지구관측 그리고 우주과학을 위해 매우 귀중하고 제한된 자원으로 인식된다. 이에 따라 Inter-Agency Space Debris Coordination Committee (IADC)에서는 정지궤도에서 수명이 종료되는 위성에 대해서 정지궤도에 영향을 미치지 않도록 더 높은 고도로 폐기기동을 수행하도록 권고하고 있다. 그렇지만 여러 가지 사정으로 정상적인 폐기기동을 수행하지 않은 위성들이 많이 있으며 이와 같은 위성들은 정지궤도에서 운영되고 있는 위성에 접근하여 충돌위험을 야기하고 있다. 우리나라의 정지궤도 통신해양기상위성인 천리안은 2010년 6월 26일에 발사되어 동경 128.2도에서 성공적으로 운영되고 있다. 지난 2년 동안 천리안 위성의 궤도구간에 우주물체가 접근하여 충돌위험이 발생한 사례가 3 건이 있었으며 그 중 한 건인 러시아의 라두가 1-7 위성이 접근한 2011년 2월 7일에는 천리안 위성의 회피기동을 수행하였다. 다른 두 가지 사례는 2011년 6월 19일 러시아의 COSMOS 2379의 접근과 2012년 4월 6일 러시아의 SL-12 R/B(2)의 접근이다. 본 논문에서는 정지궤도 위성을 운영하고 있을 때 다른 우주물체가 접근하여 충돌위험이 발생했을 때 어떤 과정을 거쳐서 회피기동을 수행해야 하는가에 대한 문제를 다루고자 한다. 정지궤도 위성과 우주물체와의 거리차이를 최대화할 수 있는 회피기동 시각을 찾아내고 최근접 시각에 있어서 반경방향, 진행방향, 그리고 수직방향에서의 거리차이를 분석한다.

• 대한방사선방어학회:학술대회논문집
• /
• 2011.04a
• /
• pp.156-157
• /
• 2011

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.6
• /
• pp.501-506
• /
• 2017

An infrared seeking missile does not emit any signal by itself as it is guided by passive heat signature from an aircraft. Therefore, it is difficult for the target aircraft to notice the existence of incoming missile, making it a serious threat. The usage of MAW(missile approach warning) that can notify the approaching infrared seeking missile is currently limited due to its high cost. Furthermore, effectiveness of MAW against infrared seeking missile is not available in open literature. Therefore, effect of evasive maneuver by MAW on the survivability of the aircraft is simulated to evaluate the benefit of the MAW in this research. The lethal range is used as a measure of aircraft survivability. An aircraft flying at an altitude of 5km with Mach 0.9 being tracked by air-launched AIM-9 infrared seeking missile is considered in this research. As a variable for the evasive maneuver, the MAW recognition distance of 5~7km and the G-force of 3~7G that limits maximum directional change of the aircraft are considered. Simulation results showed that the recognition of incoming missile by MAW and following evasive maneuver can reduce the lethal range considerably. Maximum reduction in lethal range is found to be 29.4%. Also, the MAW recognition distance have a greater importance than the aircraft maneuverability that is limited by structural limit of the aircraft.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2017.04a
• /
• pp.1214-1216
• /
• 2017

사물인터넷 관련 기술들의 다양한 연구개발은 정치 경제 문화 등 사회 각 분야의 진화를 촉진시키는 기반이 되고 있으며, 이러한 현상은 장애인을 포함한 사회적 약자를 위한 각종 제도 및 기기들의 다양한 개발 및 활용을 촉진시키는 기화로도 작용하고 있다. 그러나 아직까지 장애인을 위한 사물인터넷 기반 장비의 개발은 더디게 이루어지고 있는 것이 사실이다. 특히, 청각장애인의 경우 위험을 회피할 수 있는 소리를 사전에 인지할 수 있을 경우, 다른 장애인 대비 매우 높은 확률로 위험을 회피할 수 있음에도 불구하고 아직까지 이에 대한 연구개발이 매우 부족하다. 때문에 본 논문에서는 청각장애인들이 주변의 소리를 사전에 인지/확인할 수 있도록 하여, 발생할 수 있는 위험을 미연에 방지할 수 있는 디바이스의 개발을 제안한다. 제안하는 디바이스는 특정 크기 이상의 소리를 인지할 수 있는 소리 측정센서를 통해 해당 소리를 청각장애인이 인지할 수 있도록 알림을 제공하는 디바이스이며, 아두이노를 기반으로 하고 있기 때문에 기존의 다양한 청각보조기구 대비 매우 저렴하게 개발이 가능하다. 이를 통해, 청각장애인은 소리의 미인지로 발생할 수 있는 사고의 위험을 회피할 수 있으며, 안전한 보행권 및 이동권을 확보할 수 있을 것으로 기대한다.

• Journal of Navigation and Port Research
• /
• v.28 no.1
• /
• pp.9-16
• /
• 2004

The purpose of this study is to examine the algorithm of ship collision avoidance system and to improve its performance. The study on the algorithm of ship collision avoidance system have been carried out by many researchers. We can divide the study according to the adopted theory into two category such as 'collision risk calculation method' and 'risk area method'. It is not so difficult to find heir merit and demerit in the respective method. This study suggested newly modified model, which can overcome a limit in the two method. The suggested model is based on collision risk calculation method and suggests how to solve the threshold value problem, that is, one of the unsolved issues in collision risk calculation method. To solve that problem this study proposed new system under which the users can select appropriate threshold value according to environments such as traffic situations and weathers conditions. Simulation results of new model is schematized using 'risk area method'to examine the relationships between the two method. In addition, in case of 'collision risk method', when TCPA and DCPA are used to determine collision risk, a problem happens, that is, two ships become too close in their stem area, therefore, partial function of 'risk area method'is adopted to solve the problem in suggested model.

• Journal of Navigation and Port Research
• /
• v.28 no.6
• /
• pp.475-480
• /
• 2004

Author presented some study with regard to “automatic control for ship collision avoidance system” before. Those papers are to deal with unsolved problem,; in the previous study. In this paper, two issues relating to ship collision avoidance were investigated. One is to suggest a new algorithm of avoidance of a group ship. This algorithm is useful when a ship takes avoiding action for a group fish boats and a group of merchant vessels. In the stage of taking avoidance action, newly-developed algorithm was used. the other is to develop a unified model of collision risk. Generally collision risk changes according to various type of encounters. The new model is to take into account of these situations. The above-mentioned algorithm and model were verified through simulation under various encounters between ships.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.12
• /
• pp.469-474
• /
• 2020

This study explains the characteristics of micro-insurance based on the theoretical model of health insurance, such as the low demand of low-income people and the lower demand of higher risk aversion. In particular, these characteristics contradict the existing insurance theory which states that the lower the income, the higher the risk aversion, and the higher the demand for insurance. This study postulates a two-period model focusing on health insurance, contrary to a one-period model assumed in existing studies. As a result, first, we show that the decrease in income leads to a decrease in the preventive effort for illness. Second, we offer a model for micro-insurance in which the individual chooses a partial insurance under an actuarially fair insurance premium, while full insurance is optimal in existing studies. Third, we also show that the insurance demand decreases when the outlook for the future improves. Fourth, we finally show that the lack of trust and default risk of the insurer decrease the insurance demand as risk aversion increases.

• 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.

• KIPS Transactions on Software and Data Engineering
• /
• v.8 no.6
• /
• pp.243-250
• /
• 2019

Because of a moving UAV has a lot of potential/kinetic energy, if the UAV falls to the ground, it may have a lot of impact. Because this can lead to human casualities, in this paper, the population density area on the UAV flight path is defined as a dangerous area. The conventional UAV path flight was a passive form in which a UAV moved in accordance with a path preset by a user before the flight. Some UAVs include safety features such as a obstacle avoidance system during flight. Still, it is difficult to respond to changes in the real-time flight environment. Using public Big Data for UAV path flight can improve response to real-time flight environment changes by enabling detection of dangerous areas and avoidance of the areas. Therefore, in this paper, we propose a method to detect and avoid dangerous areas for UAVs by utilizing the Big Data collected in real-time. If the routh is designated according to the destination by the proposed method, the dangerous area is determined in real-time and the flight is made to the optimal bypass path. In further research, we will study ways to increase the quality satisfaction of the images acquired by flying under the avoidance flight plan.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.21 no.3
• /
• pp.290-295
• /
• 2011

On the basis of DCPA(Distance to Closest Point of Approach) and TCPA(Time to CPA), the conventional algorithms for collision avoidances have a drawback that the '72 CORLEGs(International Regulations for Preventing Collisions at Sea, 1972) has not taken into account to prevent collisions between ships. In this paper, the proposed algorithm decides whether the own ship is a give-way vessel or a stand-on vessel by observing the relative bearing of the encountered ship. To determine the ship position and time for collision avoidance, the proposed algorithm utilizes the ellipse model for ship safety domain. The computer simulation is done to represent the process of adversive behavior. Using the proposed method, the past maritime accident is analyzed. The proposed method can be effectively applied to collision avoidance by CORLEGs even when the target ship's navigational lights is invisible in poor weather and/or in the restricted visibility.