• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.1
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• pp.63-70
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• 2009

The purpose of this paper is to propose a CSMA/CA protocol to reduce the delay time and increase the throughput of the original CSMA/CA protocol. In underwater environments, the efficiency of the protocol is reduced due to the increase of the propagation delay time, which results in increase of the collision possibility causing lowering of the transmission efficiency Considering this propagation delay, this paper propose to insert the STANDBY frame in a CTS packet in order to avoid the TimeOut status of the CSMA/CA protocol. According to the simulated test results, proposed protocol is increased about 20% throughput than original CSMA/CA protocol. And the more value of propagation per transmission delay 'a' is low, the more throughput of protocol is better.

• Journal of the Korean Society of Safety
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• v.23 no.1
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• pp.46-50
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• 2008

The purpose of the present study was to investigate the mariner's information characteristics in ship-ta-ship collision situation using the full mission ship-handling simulator. Risk levels of ship-to-ship collision were manipulated by whether the target ship complies with the naval regulations and by movement patterns of target ship. Dependent variables reflecting mariner's information characteristics in ship-ta-ship collision situation were measured in terms of radar detection reaction time, free recall performance of past navigation situation, and subjective ratings for the task difficulty. The results showed that, in general, the mariners appeared to be deteriorated in their radar detection reaction time and free recall performance as the risk of ship-ta-ship collision increased. Also, the mariners tended to rate required tasks more difficult in the high risk ship-ta-ship collision situation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.259-261
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• 2015

The model for ship maneuvering simulation is to enhance the competence of officer's ship maneuvering skills such as navigation equipment operation, collision avoidances, countermeasure an emergency situation so on. Despite using such ship maneuvering model, critical maritime accidents are occurred periodically in the world. To find adequate simulation model to evaluate competence abilities of deck officer who have maneuvering skills with some competence levels, we search the standard ship maneuvering method representing on the part 3 Person Overboard(POB) to onboard emergences of IAMSAR manual. Moreover we monitor the officer's human factors appearing during education and training and consider the use of human factors as fundamental data.

• Transportation Technology and Policy
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• v.5 no.1
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• pp.161-171
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• 2008

아시아의 도시교통사고는 빠른 인구증가와 경제성장으로 인한 자동차 보급 확대로 인해 OECD 국가에 비해 2${\sim}$3배 높은 수준으로 교통사고절감을 위한 대안 마련이 시급한 실정이다. 이에 본고에서는 ITS기반 도로교통 안전시스템의 정착을 통해서 아시아 도시의 공통된 교통안전문제를 해소하기 위한 공동대응방안을 제시하고 있다. 이를 요약하면, 첫째, 도로사고와 ITS관계를 규명하고 사고요인을 도로상에서 제거할 수 있는 ITS기술을 소개하였다. 교통사고원인의 95%가 운전자관련인자로 나타나 운전자관련 ITS요소기술(HMI 등)의 개발이 시급한 것으로 나타났다. 또한 현재 도로 안전분야에서 적용 가능한 실용기술로는 돌발상황관리시스템, 충돌경고시스템, 비상연락시스템, 단속시스템 등인 것으로 판단된다. 둘째, ITS기반 도로교통 안전시스템의 조기 정착을 위해서는 기존 조직 법 제도의 정비가 필요하다. 아시아 도시에서는 ITS 도입 초기 정부주도형으로 추진하는 것이 바람직한데, 이를 위해서는 정부조직 내 ITS 전담기구 (Headquarter)를 신설하고, 도로안전 ITS관련 법령 및 ITS Master Plan에 근거한 권한과 사업, 예산을 확보해야한다. 또한 인프라 및 ITS 구축 운영과 함께 RSA(Road Safety Audit)와 같은 선진안전제도 시스템을 벤치마킹하여 국내 현실에 맞도록 접목시켜 나가야한다. 셋째, 교통관제 (광역)정보센터, 버스센터, 구간속도단속 등 혁신적인 도로안전사업을 지속적으로 발굴 확충하여 노하우를 축적해야 한다. 넷째, 아시아 도시의 공통된 교통문제를 해소하기 위한 공동대응방안을 마련하기 위하여 각국의 노하우를 전파하고 공유하는 창구로 아시아 태평양지역 ITS포럼을 더욱 육성해야 하겠다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1319-1327
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• 2008

There has been a lot of research on the creation of emergency evacuation simulators for analyzing the evacuation behaviors. However, it is remarkable that there are very few research on the characteristic of the behavior pattern in crowing, especially the evacuation time delay caused by the collisions and falling-downs, etc. In addition, it is necessary to point out the lack of the research on specifying the location where the collisions and the falling-downs take places. This research aims at creating an emergency evacuation simulator which takes the characteristic of the behavior pattern in crowing - collisions, falling downs, etc - into account. We are also hoping that it will be possible to provide more accurate and useful data ffr emergency evacuation system design through using this simulator.

• Journal of Korea Multimedia Society
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• v.15 no.3
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• pp.372-379
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• 2012

This paper presents a group based propagation method for multi-hop transmission, in order to deliver an emergency message to the reasonable size of vehicle troop. A group head is selected in considering of the position information of vehicles and radio transmission range. With benefits of the group based transmission, it is possible to minimize the unnecessary transmissions and the possibility of message collisions. We evaluate the performance of the proposed scheme compared with conventional schemes. Simulation results show that the message propagation performance is so stable regardless of vehicle's congestion degree.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.977-985
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• 2011

Airborne separation assurance is a key requirement for Free Flight Airspace operations, This paper study the feasibility of airborne separation assurance for free flight Airspaces operations by evaluating the efficiency measurement models. Three qualitatively different methods are utilized; one based Ground and Air conflict probability model, other based Dynamic Density model. the other based Direct operating cost model. The evaluation is Direct Operating Cost model and Two metrics are utilized for the efficiency measurements; airborne separation assurance performed quite well in the Free Flight evaluation; (1) 2 scenario of the conflict situations are resolved; (2) The MD-80 flight peformed separation assurance and efficiency, Not only appling for geometric method algorithm is more efficiently than potential method, but also the most efficiently geometric combined method.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.851-855
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• 2009

Constructing CDS in wireless ad-hoc network, it is necessary to make more efficient algorithm that is fast, simple and has low power consumption. It is worried about losing data which brought a bottleneck state from confliction and delay when the nodes are concentrated or CDS is reconstructed. So, after constructing most efficient CDS, It is better not to reconstruct CDS in moveless wireless ad-hoc network. In this paper, we compared and estimated the performance in each situation of a CDS construction algorithm based on Node degree and Energy level.

• Current Industrial and Technological Trends in Aerospace
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• v.6 no.2
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• pp.143-153
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• 2008

This paper describes the current research trend and future development direction of autonomous flight of the aircraft. The autonomous flight means that aircraft control system recognize and cope with the emergency situation confronted during the flight by itself. Current research for autonomous flight technology is mainly performed for the application to unmanned air vehicle. Considering advent of future air traffic management system and increasing demand of the unmanned air vehicle application, however, autonomous flight technology required to be combined with future air traffic management system. In this paper, the current air traffic management system and anticipating change in future air traffic management system was investigated and research activities of autonomous flight technology was described as well as future prospect.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.329-332
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• 2015

야간에 자동차를 운행할 때 검정색 차량 같은 어두운 색상의 자동차는 운전자가 인지를 못하는 경우가 많고 안개가 짙게 낀 상황도 운전자의 시야가 좁아져 교통사고율이 급격하게 증가한다. 도로교통공단의 자료에 의하면 최근 5년(2009~2013) 동안 가해자의 안전거리 미확보로 인한 교통사고는 매년 감소하는 것으로 나타나지만, 안전운전 의무 불이행 다음으로 두 번째로 높은 사고 건수를 기록하고 있다. 이는 아직도 운전자의 시인성 저하에 대한 방안이 부족하기 때문이다. 시인성 저하를 위한 대책으로 BMW, AUDI, Benz 회사에서 적외선 카메라를 이용한 나이트 비젼이 있으나 거리감지기능이 없어 디스플레이를 계속 주시하면서 운행하여야 하므로 시야가 좁아져 다른 위험이 발생할 수 있다. 현재 시중에 제공되고 있는 적외선 나이트 비젼 카메라를 이용하였을 때 일반 시야보다 약 4배 정도의 거리를 인식할 수 있었고, 이러한 나이트 비젼의 장점을 활용하여 전면 차량과의 안전거리를 확보하는 시스템을 제안한다. 본 논문에서는 제시하는 시스템은 시인성이 떨어지는 환경을 가정하여 설계하였고 나이트 비젼 카메라를 이용해 디스플레이로 출력하여 육안으로 구분할 수 없는 물체도 인지할 수 있어 헤드라이트를 켜고 운행할 때보다 안전한 운행을 할 수 있을 것으로 보인다. 하지만 디스플레이를 지속적으로 주시하며 운행할 경우 거리 감각이 떨어져 근접해 오는 물체와의 충돌 사고를 막기 힘들 것으로 보인다. 따라서 이러한 단점을 보안하기 위해 영상 데이터를 활용하여 앞 차량의 유무를 파악하고 차량이 있을 때 안전거리를 디스플레이에 표시함으로 앞 차량과의 거리를 유지하여 사고를 예방하여 안전 운행이 가능하도록 설계하였다.