• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.143-144
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• 2009

• The Journal of Korea Robotics Society
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• v.11 no.3
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• pp.127-132
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• 2016

For a practical mobile robot team such as carrying out a search and rescue mission in a disaster area, the localization have to be guaranteed even in an environment where the network infrastructure is destroyed or a global positioning system (GPS) is unavailable. The proposed architecture supports localizing robots seamlessly by finding their relative locations while moving from a global outdoor environment to a local indoor position. The proposed schemes use a cooperative positioning system (CPS) based on the two-way ranging (TWR) technique. In the proposed TWR-based CPS, each non-localized mobile robot act as tag, and finds its position using bilateral range measurements of all localized mobile robots. The localized mobile robots act as anchors, and support the localization of mobile robots in the GPS-shadow region such as an indoor environment. As a tag localizes its position with anchors, the position error of the anchor propagates to the tag, and the position error of the tag accumulates the position errors of the anchor. To minimize the effect of error propagation, this paper suggests the new scheme of full-mesh based CPS for improving the position accuracy. The proposed schemes assuring localization were validated through experiment results.

• Journal of Navigation and Port Research
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• v.30 no.5 s.111
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• pp.357-362
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• 2006

This paper describes two kinds of personal hand-held electronic devices to enhance marine leisure safety. The one is Radar response-type safety device triggering by the pulse signal from a commercial 9GHz-band Radar to provide quick search and rescue with combined civilian-government-military fleets. The other one is M-RFID (Marine Radio Frequency IDentification) based safety electronic device using 900MHz Tx/Rx with spread spectrum frequency hopping and GPS. Through the field tests at sea using Korea Coast Guard's warship the operating performances are verified. Further plan for practical use of each device was also discussed.

• Journal of Navigation and Port Research
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• v.34 no.5
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• pp.349-354
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• 2010

Cheonan, Republic of Korea Navy patrol ship sank had happened by an unknown incident in the vicinity of Baekryeongdo southwest 1.6km(1 mile) sea at 21:45 on March 26, 2010. In terms of coastal researcher's point of view, it is meaningful to provide the sea condition of basic data necessary for search and rescue, more detailed predictions and inference data through the numerical simulations. Thus, in this study, we investigated the weather, wave, tide, tidal current, bottom soil conditions, and suspended sediment are investigated at the coast of Baekryeong-Daechung islands. And based on these data, the characteristics of sea conditions were analyzed. The tidal period at the time of incident corresponds between neap tide to mean tide. Until April 3-4 after March 26, the date of incident, the strongest velocity was progressed towards the spring tide. Thus, it was considered to be difficult to search and rescue operations. Also, because the ebb tide was in progress during 21:00 to 22:00, mass transport seems to be prevailed to the southeast. In particular, as the sudden turbulence due to the irregular topography existed was anticipated, we had carried out particle tracking experiment. From this experiment, depending on the situation of flow, the initial movement of the particles were directed to the southeast but it turned out moving towards the offshore based on the long term prediction. Through this result, it is considered that the scope of the search operation should be expanded towards the open sea.

• The Journal of Korea Robotics Society
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• v.3 no.3
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• pp.186-193
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• 2008

We propose a novel real-time obstacle avoidance method for rescue robots. This method, named the ELA(Emergency Level Around), permits the detection of unknown obstacles and avoids collisions while simultaneously steering the mobile robot toward safe position. In the ELA, we consider two sensor modules, PSD(Position Sensitive Detector) infrared sensors taking charge of obstacle detection in short distance and LMS(Laser Measurement System) in long distance respectively. Hence if a robot recognizes an obstacle ahead by PSD infrared sensors first, and judges impossibility to overcome the obstacle based on driving mode decision process, the order of priority is transferred to LMS which collects data of radial distance centered on the robot to avoid the confronted obstacle. After gathering radial information, the ELA algorithm estimates emergency level around a robot and generates a polar histogram based on the emergency level to judge where the optimal free space is. Finally, steering angle is determined to guarantee rotation to randomly direction as well as robot width for safe avoidance. Simulation results from wandering in closed local area which includes various obstacles and different conditions demonstrate the power of the ELA.

• Journal of Satellite, Information and Communications
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• v.11 no.4
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• pp.68-73
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• 2016

This paper describes the prototyping of CDMA bi - directional group search system using USRP and LTE. This paper describes the results of RF signal generation and transmission by implementing a spread spectrum signaling system, which is a new standard of COSPAS SARSAT, using a bi-directional search structure system using commercial LTE network and USRP.

• 한국항공운항학회:학술대회논문집
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• 2015.11a
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• pp.88-91
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• 2015

MISSING Malaysia Airlines flight MH370 has not been discovered and unknown whether it crashed on the ground or under the sea. There are a couple of emergency equipment in the airplane not only outside of airplane but inside airplane such as ELT(Emergency Locator Transmitter). Since the ELT developed, it is required to be installed in the airplane for regulation requirement. However, despite of its important function, it is not working properly or shows wide search range for rescue during the crash or ditching on the water. I would like to propose how to over come the up-to-dated position data just before the event. Connecting with ADIRS or GPS which is installed internal airplane system will help to reduce the rescue time for survival passenger.

• Proceedings of KOSOMES biannual meeting
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• 2004.05b
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• pp.1-6
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• 2004

This paper suggests an evaluation of risk level for damage of marine accidents in SRRs. Qualitative analyses in words is sometimes priorior to quantative analyses in numeric symbols. This paper intoduces a concept of fuzzy theory with the plenty of related literature review and AHP in the Korean SRRs of RCC and RSC. The methodology of this paper is max . min composition of fuzzy extensive principle, defuzzifiation is centroid of gravity methods. At the result, the evaluation of risk level is especially over Serious for smarine accident of Taean, Gunsan, Mokpo, Yosu, Tongyoung, Busan SRR. This paper recommends that many Rescue Vessels and Equipments need to the reduction of risk level about those.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.909-915
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• 2004

This paper suggests an evaluation of risk level for damage of marine accidents in SRRs. Qualitative analyses in words is sometimes priorior to quantative analyses in numeric symbols. This paper introduces a concept of fuzzy theory with the plenty of related literature riview and AHP in the Korean SRRs of RCC and RSC. The methodology of this paper is $max{\cdot}min$ composition of fuzzy extensive principle, defuzzifiation is centroid of gravity methods. At the result, the evaluation of risk level is especially over Serious for marine accident of Busan SRRs. This paper recommends that many Rescue Vessels and Equipments need to the reduction of risk level about those.

• Proceedings of KOSOMES biannual meeting
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• 2004.11a
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• pp.83-88
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• 2004

This paper suggests on evaluation of risk level for damage of marine accidents in SRRs. This paper intoduces a concept of fuzzy logic with the plenty of related literature riview, fuzzy measure t-seminormed fuzzy integral and in the Korean. SRRs of RCC and RSC. The methodology of this paper is max$\cdot$min composition of fuzzy extensive principle, defuzzifiation is centroid of gravity methods. And final evaluation value using t-seminormed fuzzy integral. At the result, the evaluation of risk level is especially over Serious for marine accident of Mokpo, Tongyoung, Busan SRRs. This paper recommends tint many Rescue Vessels and Equipments need to the reduction of risk level about those.