• 한국자동차공학회논문집
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• 제25권3호
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• pp.309-316
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• 2017

In shuttle vans designed to transport children, the recognition of a child's approach and departure is very important. Ultrasonic sensors are generally used for a short distance around a vehicle. Although ultrasonic sensors are cheaper than other ADAS sensors, the number of sensors installed in a van should be optimized. In order to recognize the presence of a child around a shuttle van, this paper proposes the placement of ultrasonic sensors in the van. Considering the turning radius of the van and the distance from each sensor to a child, collision risk is classified as 'safe', 'warning', and 'danger'. The sensor placement and the recognition algorithm are verified in a virtual driving environment.

• 한국산업융합학회 논문집
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• 제22권4호
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• pp.427-433
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• 2019

This paper propose a fuzzy inference model for map building and navigation for a mobile robot with an active camera, which is intelligently navigating to the goal location in unknown environments using sensor fusion, based on situational command using an active camera sensor. Active cameras provide a mobile robot with the capability to estimate and track feature images over a hallway field of view. In this paper, instead of using "physical sensor fusion" method which generates the trajectory of a robot based upon the environment model and sensory data. Command fusion method is used to govern the robot navigation. The navigation strategy is based on the combination of fuzzy rules tuned for both goal-approach and obstacle-avoidance. To identify the environments, a command fusion technique is introduced, where the sensory data of active camera sensor for navigation experiments are fused into the identification process. Navigation performance improves on that achieved using fuzzy inference alone and shows significant advantages over command fusion techniques. Experimental evidences are provided, demonstrating that the proposed method can be reliably used over a wide range of relative positions between the active camera and the feature images.

• 한국멀티미디어학회논문지
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• 제24권3호
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• pp.355-372
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• 2021

Recently, high-performance HMDs (Head-Mounted Display) are becoming wireless due to the growth of virtual reality technology. Accordingly, environmental constraints on the hardware usage are reduced, enabling multiple users to experience virtual reality within a single space simultaneously. Existing multi-user virtual reality platforms use the user's location tracking and motion sensing technology based on vision sensors and active markers. However, there is a decrease in immersion due to the problem of overlapping markers or frequent matching errors due to the reflected light. Goal of this study is to develop a multi-user virtual reality moving platform in a single space that can resolve sensing errors and user immersion decrease. In order to achieve this goal hybrid sensing technology was developed, which is the convergence of vision sensor technology for position tracking, IMU (Inertial Measurement Unit) sensor motion capture technology and gesture recognition technology based on smart gloves. In addition, integrated safety operation system was developed which does not decrease the immersion but ensures the safety of the users and supports multimodal feedback. A 6 m×6 m×2.4 m test bed was configured to verify the effectiveness of the multi-user virtual reality moving platform for four users.

• 한국소음진동공학회논문집
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• 제21권12호
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• pp.1120-1131
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• 2011

Researches using time reversal acoustics(TRA) for impact localization have been paid attention to recently. Dispersion characteristics of Lamb waves, which restrict the utility of classical nondestructive evaluation based on time-of-flight information, can be compensated through the application of TRA to Lamb waves on a plate. This study investigates the spatial focusing performance of time reversal Lamb waves on a plate using finite element analysis. In particular, the virtual sensor effect caused by multiple wave reflections at the boundaries of a plate is shown to enable the spatial focusing of Lamb waves though a very small number of surface-bonded piezoelectric(PZT) sensors are available. The time window size of forward response signals, are normalized with respect to the number of virtual active sensors. Then their effects on the spatial focusing performance of Lamb waves are investigated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.418-429
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• 2011

Researches using time reversal acoustics (TRA) for impact localization have been paid attention to recently. Dispersion characteristics of Lamb waves, which restrict the utility of classical nondestructive evaluation based on time-of-flight information, can be compensated through the application of TRA to Lamb waves on a plate. This study investigates the spatial focusing performance of time reversal Lamb waves on a plate using finite element analysis. In particular, the virtual sensor effect caused by multiple wave reflections at the boundaries of the plate is shown to enable the spatial focusing of Lamb waves though a very small number of surface-bonded piezoelectric (PZT) sensors are available. The time window size of forward response signals, are normalized with respect to the number of virtual active sensors. Then their effects on the spatial focusing performance of Lamb waves are investigated.

• 제어로봇시스템학회논문지
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• 제15권4호
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• pp.439-444
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• 2009

Recently, a wide range of next-generation's game consoles has been developed by many game makers. Particularly, active interaction between users and games is required more than ever before for giving gamers the fullest pleasure. In this work, an infrared image sensor based position recognition system which can be used for virtual game interface is proposed. Furthermore, two kinds of compensation algorithms and Extended Kalman Filter are utilized to enhance the performance of the proposed system. The proposed system can effectively generate the position of the gamer in the face of the coordinate distortion and noise. To verity the feasibilities of the proposed system, various experiments are carried out.

• 한국전산구조공학회논문집
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• 제24권5호
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• pp.553-567
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• 2011

최근 3년간 판 구조물 건전성 감시분야에서 시간반전램파(Time reversal Lamb waves)의 가능성이 주목받고 있다. 이 연구에서는 직사각형 평판에서 시간반전램파의 공간모임을 적은 연산비용으로 효과적으로 모사할 수 있는 수치기법을 제안한다. 제안된 기법에서는 파 반사에 의해 발생하는 실제 탐지자의 거울상 효과와 등가를 이루는 활성 가상탐지자를 이용하여 시간반전과정을 주파수 영역에서 정식화한다. 시간반전램파의 공간모임 모사에서 필요한 순방향 및 역방향 파 전달은 스칼라 형태의 함수로 표현한다. 제안된 방법을 웨이퍼 형태의 압전소자가 병치된 직사각형 평판에서 시간반전램파의 공간 모임 문제에 적용하고 유한요소해석 결과와 비교하여 타당성을 검증한다.

• 한국자동차공학회논문집
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• 제21권2호
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• pp.26-36
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• 2013

Purpose of this study is to develop virtual components and environment for developing a controller of an Active Air Suspension System in laboratory that slough off existing development environment using real vehicle test. This paper presents an air spring modeling and analysis of air suspension system for a commercial vehicle. Preferentially, It was performed vehicle test for pneumatic system and an air spring for characteristic analysis of system. Each component of an air spring suspension system was developed through emulations and modeling of system for pressure and height sensors in the basis on test results in SILS environment. Non-linear characteristics of air spring are accounted for using the measured data. Also, pressure and volume relations for vehicle hight control is considered. After performance verification of virtual model was performed, we developed virtual environment based on HILS for an Active Air Suspension System. We studied estimation and verification technology for control algorithm that developed.

• 한국군사과학기술학회지
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• 제18권5호
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• pp.538-547
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• 2015

The goal of this study is to develop an algorithm to propose optimal deployment of detection sensor nodes in the target area, based on a performance surface, which represents detection performance of active and passive acoustic sonar systems. The performance surface of the active detection system is calculated from the azimuthal average of maximum detection ranges, which is estimated with a transmission loss and a reverberation level predicted using ray-based theories. The performance surface of the passive system is calculated using the transmission loss model based on a parabolic equation. The optimization of deployment configurations is then performed by a hybrid method of a virtual force algorithm and a particle swarm optimization. Finally, the effectiveness of deployment configurations is analyzed and discussed with the simulation results obtained using the algorithm proposed in this paper.

• 디지털콘텐츠학회 논문지
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• 제15권4호
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• pp.473-480
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• 2014

오늘날 컴퓨터의 사용이 대중화 되면서 키보드나 마우스와 같은 기존의 사용자 인터페이스에 비해 보다 편리하고 자연스러운 인터페이스에 대한 연구가 활발히 진행되면서, 최근 마이크로소프트의 동작 인식 모듈인 키넥트에 대한 관심이 높아지고 있다. 키넥트는 내장된 센서를 통해 신체의 주요 관절의 움직임 및 깊이 정보를 인식할 수 있으며 내장 마이크를 통해 간단한 음성인식도 가능하다. 본 논문에서는 OpenCV 라이브러리를 키넥트에 접목하여, 키넥트의 깊이 데이터, skeleton tracking, labeling 알고리즘으로 손 영역 추출 및 움직임의 정보를 인식하여 가상 마우스와 가상 키보드를 구현하고, 음성인식을 통해 기존 입력 장치의 기능을 구현하는 것을 목표로 한다.