• Journal of the Korean Society of Systems Engineering
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• v.1 no.2
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• pp.49-55
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• 2005

The Smart UAV Program was motivated by a huge potential market, a various application and future core technologies. The Smart UAV system is defined as the advanced air vehicle with the smart technology such as collision awareness and avoidance, healthy monitering and self-recovering, intelligent active control. Due to the broad interest by government, industry and academia, Smart UAV development center and government steering committee were established. The organization of the Smart UAV program consists of domestic/international companies and academia. In this paper, the process and application of system engineering was introduced for Smart UAV development program.

• Journal of KIISE:Software and Applications
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• v.28 no.4
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• pp.327-337
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• 2001

이 논문에서 제시된 2D Map-Based Navigation (MBN)은 다중 사용자 환경의 가상공간을 이동할 때, 실세계와 유사한 이동방법을 제공하여 사용자로 하여금 가상공간에 대한 현장감 및 현실감의 제고에 초점을 두었다. MBN은 사용자들이 가상공간에서 발생하기 쉬운 spatial loss를 방지하고, 이동 시 부가적인 입력이 없이도 일정한 속도로 이동을 지원하는 Automatic Constant-velocity Navigation, 이동중 장애물 및 다른 사용자(아바타)와의 충돌현상을 감지 및 회피하는 Collision Detection and Avoidance, 그리고 충돌회피 후 기존 방향으로의 계속된 이동을 지원하는 Path Adjustment 등의 기능을 제공한다. MBN은 spatial loss의 방지, 사용자의 부가적인 노력의 감소 및 병행작업의 보장, 현실과 유사한 사용자 중심의 navigation 기법의 제공, 그리고 가상공간과 현실과의 괴리를 줄임으로써 가상현실이 추구하는 현실감 및 현장감을 높일 수 있도록 하였다. 실험을 통하여 본 연구에서 제안한 MBN이 사용자 중심의 매우 자연스럽소, 쉽고 편리한 가상공간 navigation 인터페이사라는 평가를 얻었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.121-123
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• 2017

드론은 군사목적에서 개발되고 사용되어 왔으나 현재에는 촬영, 물류 등의 다양한 분야에서 연구 및 사용되고 있다. 앞으로 수많은 드론이 하늘에서 비행할 것으로 예상됨에 따라 때때로 비슷한 항로를 비행하는 드론간의 충돌 위험 또한 야기될 수 있다. 드론을 안전하게 비행하기 위한 많은 연구들이 진해되어 왔지만 공중 충돌에 의한 피해를 최소화 하려는 연구의 진행은 초기상태에 있다. 본 논문은 민간 항공기에 적용되어 사용되고 있는 1030/1090MHz 대역의 TCAS 시스템을 433MHz LoRa 네트워크를 사용하여 구현하였다. 충돌 위험을 판단하는 근거는 비행준인 드론의 진행 방향 및 비행 고도를 통하여 산출한다.

• International Journal of Control, Automation, and Systems
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• v.6 no.2
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• pp.278-281
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• 2008

Linear motor (LM) based shuttle cars will play an important role in the future transportation systems of marine terminals to cope with increasing container flows. These systems are known as agile port terminals because of their significant advantages. However, routing for multiple shuttle cars is still an open issue. We present a network model of a container yard and propose constrained dynamic programming (DP) for its routing strategy with collision avoidance. The algorithm is a modified version of typical DP which is used to find an optimal path for a single traveler. We evaluate the new algorithm through simulation results for three shuttle cars in a mesh-type container yard.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.291-294
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• 2002

A simple computer vision technology to measure the middle-ranged depth with mono camera and plain mirror is proposed The proposed system is structured wiか the rotating mirror in front of the fixed mono camera In contrast to the previous stereo vision system in which the disparity of the closer object is larger than that of the distant object, the pixel movement caused by the rotating mirror is bigger for the pixels of the distant object in the proposed system Being inspired by such feature in the proposed system the principle of the depth measurement based on the relation of the pixel movement and the distance of object have been investigated. Also, the factors to influence the precision of the measurement are analysed The benefits of the proposed system are low price and less chance of occlusion. The robustness for practical usage is an additional benefit of the proposed vision system.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.191-194
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• 2003

In IEEE 802.11b, Medium Access Control Sublayer consists of DCF (Distributed Coordination Function) and PCF (Point Coordination Function). DCF provides contention based services and PCF provides contention free services for QoS satisfaction. DCF uses CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) as an access protocol. And PCF uses Polling Scheme. In this paper, a modified New-PCF, which gives weights to channels with heavier traffic load, was suggested. NS-2 simulations were conducted to compare the service performances with original DCF, PCF and the modified New-PCF respectively. Simulation results has shown the increased overall throughput with the proposed New-PCF compared with other cases.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.05a
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• pp.179-182
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• 2000

A Classifier System processes a discrete coded information from the environment. When the system codes the information to discontinuous data, it loses excessively the information of the environment. The Fuzzy Classifier System(FCS) makes the classifier system be able to carry out the mapping from continuous inputs to outputs. It is the FCS that applies this ability of the machine learning to the concept of fuzzy controller. It is that the antecedent and consequent of classifier is same as a fuzzy rule of the rule base. In this paper, the FCS is the Michigan style and fuzzifies the input values to create the messages. The system stores those messages in the message list and uses the implicit Bucket Brigade Algorithms. Also the FCS employs the Genetic Algorithms(GAs) to make new rules and modify rules when performance of the system needs to be improved. We will verify the effectiveness of the proposed FCS by applying it to AMR avoiding the obstacle.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.03a
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• pp.161-176
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• 2002

Collision avoidance is the most important part of a small vessel. Small and mediurn sized ships are surprisingly poor targets for radar reflection and are frequently in danger of being overrun by large vessels, even under good condition of visibility. One of the best way to prevent collisions at sea is to use as large and well designed a radar reflector. Thus, RCS(Radar Cross Section) increase is key element in the design of radar reflector. Radar Reflectors are normally classified into active-type and passive-type. In this paper, the RCS increase methods for passive-type reflector through shaping are explained, and analyzed with RCS performance test by computer simulation. As results from analysis, It is shown that the effective diameter of radar reflector is over 10 λ to provide a return above the threshold RCS of 25m$^2$, lower limit of detectability using X-band radar in a moderate sea.

• Journal of Navigation and Port Research
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• v.33 no.9
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• pp.603-608
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• 2009

In this paper, a 3m-class free running model ship will be introduced with its manoeuvring performance experiments. The results of turning circle test and zig-zag test will be explained. The developed system are equipped with GPS, main control computer, wireless LAN, IMU (Inertial Measurement Unit), self-propulsion propeller and driving rudder. Its motion can be controlled by RC (Radio Control) and wireless LAN from land based center. Automatic navigation is also available by pre-programmed algorithm. The trajectory of navigation can be acquired by GPS and it provides us with important data for ship's motion control experiments. The results of manoeuvring performance experiment have shown that the developed free running model ship can be used to verify the test of turning circle and zig-zag. For next step, other experimental researches such as ship collision avoidance system and automatic berthing can be considered in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.708-709
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• 2013

본 논문에서는 차량 충돌 예방 레이더 시스템-온-칩용 24GHz 믹서(Mixer)를 제안한다. 이러한 회로는 24GHz의 동작주파수를 가지며, Gilbert 셀 구조로 구성된다. 이러한 회로는 TSMC $0.13{\mu}m$ 혼성신호/고주파 CMOS 공정 ($f_T/f_{MAX}=120/140GHz$)으로 설계되어 있다. 제안한 회로는 10.96dB의 변환이득으로 최근 발표된 연구결과 중 가장 우수한 수치를 보였다. 또한 7.62dBm의 우수한 IIP3의 특성과 -43.64dB의 입력/출력 반사손실 (S11/S22) 및 -49.3dB의 LO-RF간 격리 특성 (S12)으로 기존 연구결과 중 가장 우수한 결과를 각각 보였다.