• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.401-407
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• 2012

This paper analyzes performance of major obstacle avoidance methods. For the analysis, numerical performance indexes are proposed: motion distance to goal point, motion time, distance to obstacles, and smoothness of the motion. Especially, the index of smoothness measures efficiency of the motion using the angular acceleration and jerk of the robot heading. Four major obstacle avoidance methods are compared in terms of the performance indexes. The four methods are artificial potential field(APF) method, elastic force(EF) method, APF with virtual distance, and EF with virtual distance. Through simulation, the four methods are compared and features of the methods are explored.

• The Journal of the Korea Contents Association
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• v.13 no.2
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• pp.62-70
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• 2013

This study proposes smart-phone game applications success model based on mobile internet success model and investigates the effects of cultural propensities especially, uncertainty avoidance and power distance at the individual level. To achieve our research purposes, the study conducted survey in Korea and a total of 221 people participated in the survey. We classified user types by cultural difference as a moderating variable. User's cultural propensity classified two groups: high uncertainty avoidance and high power distance, low uncertainty avoidance and low power distance. This study results reveal that the impact of quality factors on user satisfaction have difference according to cultural propensities.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.21-22
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• 2011

In this study, an analytical algorithm for collision avoidance is proposed, which is applicable to designing collision avoidance maneuvers for two encountering ships. The minimum separation distance is defined and an appropriate maneuver sequence is computed for safe and effective collision avoidance. Two approaches: 1) collision avoidance through speed change and 2) collision avoidance through heading change, are considered, and the initiation point of the avoidance maneuver is computed analytically using the geometric configuration of the two encountering ships. To verify the feasibility of the proposed algorithm, numerical simulations are carried out using a set of ship-to-ship encountering scenarios.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.916-918
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• 2004

본 논문에서는 3D 게임에서 다중 캐릭터의 충돌 회피에 대한 방법을 제안한다. 캐릭터는 충돌 감지 서클을 이동 상태 정보와 결합하여 다른 캐릭터와의 충돌을 예측하여, 충돌이 예측될 경우 충돌을 발생시킨 캐릭터들에 대해 초기화시에 설정된 레벨을 참고하여 충돌을 발생시키지 않는 정점을 목표지점과의 거리자를 이용하여 탐색하고 캐릭터를 이동한다. 이동한 지점은 캐릭터의 목표지정과 충돌을 발생시키지 않으며 최단 거리를 보장할 수 있는 위치이고, 이동된 지정에서 목표지정까지는 A* search를 이용하여 Pathfinding을 수행한다. 본 논문에서 제안한 방범을 적용함으로써 3D 게임에서 캐릭터와의 충돌을 회피하면서 목표지정까지 최단거리를 보장받을 수 있다.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.186.2-186.2
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• 2005

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.6
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• pp.501-506
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• 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 KIEE Conference
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• 2015.07a
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• pp.1389-1390
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• 2015

본 논문에서는 선도-추종자 로봇의 대형을 유동적으로 변형하며 장애물을 효과적으로 회피하는 방법을 제안한다. 로봇이 장애물을 회피함에 있어서 고정된 대형으로 이동하는데 어려운 문제가 발생한다. 본 논문에서는 이러한 문제점을 해결하기위해 장애물 회피시 선도로봇의 방향각과 위치, 선도로봇과 추종자 로봇의 거리를 이용하여 대형을 유동적으로 변형하여 장애물과의 충돌을 회피하는 방법을 사용하고 로봇의 경로계획을 위하여 포텐셜 필드 알고리즘을 사용하였다. 본 논문에서는 Matlab을 이용한 모의실험을 통하여 제안된 방법의 성능을 확인하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10b
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• pp.521-525
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• 2006

본 논문에서는 초음파 및 적외선 센서와 무선 카메라를 장착한 소형 이동 로봇의 장애물 회피 및 물체 추적 방법을 제시한다. 장애물 회피를 위해서 제어부의 초음파 발생 신호의 귀환시간과 거리와의 관계 및 적외선 센서에서 측정한 아날로그신호와 거리와의 관계를 추출하여 이동 로봇과 물체와의 거리를 판단하여 로봇의 움직임을 제어하는데 사용한다. 물체 추적 모드에서는 첫째, 물체와 배경 및 유사잡음들과의 강인한 분리를 위하여 고유색상정보와 움직임 정보 등의 사전정보를 활용하였으며 둘째, 형태의 변화가 수반되는 경우에도 유연한 대처능력을 갖도록 하기 위해 영상의 영역분할 방법을 통해 모든 후보영역내의 물체의 존재를 확인하고 물체영역만을 추출하였다. 셋째, 물체 형태정보함수를 정의하고 해당함수를 형태의 보전 에너지로 활용하여 동일 물체의 대응문제를 효과적으로 해결하였다.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.3
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• pp.67-75
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• 1998

This paper presents a new robot motion planning method for moving obstacle avoidance. To consider the mobility of a moving obstacle, we define virtual distance function(VDF) between the robot and the obstacle. At each sampling time, we use the VDF to construct an artificial potential, considering the motion of obstacles. The robot moves according to the repulsive and attractive force vector induced by the artificial potential function. The proposed algorithm can be driven the robot to avoid moving obstacles in real time. Some simulation studies show the effectiveness of the proposed method.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.10
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• pp.996-1002
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• 2008

This paper presents the development of a real-time algorithm for collision detection, collision avoidance and guidance to way-point. Three-dimensional point-mass aircraft models are used. For collision detection, time of closest point of approach(CPA) and distance at CPA are compared to threshold values. For collision avoidance, optimal acceleration input which maximizes the terminal relative distance is calculated based on optimal control theory. For guidance to way-point, proportional navigation guidance, the well-known method, is used. Two scenarios of encounter situation are illustrated to validate performance of proposed algorithm.