• Proceedings of the Korean Information Science Society Conference
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• 2012.06c
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• pp.335-337
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• 2012

전투공간 시뮬레이션 결과를 가시화할 뿐 아니라 시나리오 가시화 중에 사용자가 선택한 엔티티의 상세한 관찰을 제공하기 위해 스테레오 3D 모델 뷰어를 개발하여 가시화 시스템의 프로토타입을 구성하였다. 전투공간 가시화를 위해서는 가시화 스프트웨어인 SIMDIS를 사용하였다. 사용자는 시뮬레이션 가시화 스크린 상에서 엔티티를 선택할 수 있으며, 이 엔티티의 자세한 관찰은 스테레오 3D 모델 뷰어에 가시화 된다. 모델 뷰어는 사용자에게 엔티티 관찰 시 몰입감과 인지도를 향상시키기 위하여 헤드 트래킹 기술을 적용하였다. 사용자의 위치를 추적하기 위해서는 깊이 카메라를 이용하였으며, 획득한 깊이 영상을 통해 실시간 사용자 헤드 트래킹을 적용하였다. 구현된 시스템은 SIMDIS를 이용한 전투공간 시뮬레이션 가시화와 스테레오 3D 뷰어를 각각 가시화하기 위하여 2D 디스플레이와 3D TV를 사용하였다.

• Annual Conference of KIPS
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• 2021.05a
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• pp.533-535
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• 2021

본 연구에서는 서비스 역할을 수행하는 6축 모듈형 매니퓰레이터 개발을 목표로 하며, 최종 기술 사양에 따른 설계를 진행하는 과정에서 기구의 섬세한 동작을 효율적으로 제어하기 위해 로봇 제어 소프트웨어의 오픈소스 환경인 ROS를 사용한다. 매니퓰레이터의 동작 설계를 ROS 기반에서 제어하기 위해 중요한 기본 환경을 구축하였으며, 특히 로봇 모델링을 위한 시각화를 위해 URDF파일에 해당 매니퓰레이터의 필수 파라미터값들을 지정하여 적용하였고, 전체 동작 시나리오에 맞춰 매니퓰레이터가 특정 자세를 취할 경우의 역기구학적인 해석과 그에 따른 경로를 생성하도록 매니퓰레이터의 라이브러리인 MoveIt을 활용하여 시각적으로 표현하고 시뮬레이션을 수행하였다. 또한, 설계한 ROS 환경 설계 방법을 바탕으로 MCU와의 통신을 통해 모터의 실시간 각도 값을 제어하고, 3D 깊이 카메라의 거리정보와 이미지 정보의 융합을 통해 로봇의 서비스 내용의 개선을 기대할 수 있다.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.883-890
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• 2017

Among the augmented reality services, the most frequently used services are marker based augmented reality services. However, there is a problem that the augmented reality service can not be provided in an environment in which the marker image can not be recognized. In this paper, we propose a method to provide more stable service by estimating the user's posture even if the marker image can not be correctly recognized due to occlusion, obstacle or marker damage in the marker based augmented reality. In the proposed method, when a failure occurs in the provision of a marker based augmented reality, the attitude of the user is estimated using the 3-dimensional coordinates measured through communication between the three beacons and the user, and it allows the user to receive the augmented reality service continuously. We describe the scenario of augmented reality technique using proposed marker recognition and beacon communication, and present the results of experiments based on the degree of occlusion and damage.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.1
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• pp.106-112
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• 2013

In this paper, human exposure of wireless devices was analyzed for various positions of the transmitter. The scenario for the position of the transmitting antenna was decided after discussion with ADD(Agency for Defense Development), and Korean male phantom model developed by ETRI were used to conduct simulations. The SAR values were analyzed by changing the position of the transmitter, and compared with Korean EMF regulations and ICNIRP guidelines. Additionally, human exposure was also investigated for two typical postures which can be posed by war-fighter.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.106-106
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• 2014

SIGMA (Scientific cubesat with Instrument for Global Magnetic field and rAdiation)는 근 지구공간에서 우주방사선량 측정과 자기장 변화 검출의 과학적 목적과 교육적 목적을 가지고 개발하고 있는 초소형 큐브위성이다. $100mm{\times}100mm{\times}340.5mm$의 크기로 약 3.6 kg의 무게를 가지며, 탑재체는 방사선에 대하여 인체와 동일한 산란 흡수 특성을 가진 Tissue Equivalent Proportional Counter (TEPC)와 자기장 측정을 위한 Magnetometer (Mag)이다. 위성체는 구조계, 자세제어계, 전력계, 명령 및 데이터처리계, 통신계로 구성되어있다. 구조계는 위성의 뼈대인 Chassis와 Mag deployer로 이루어져있고, 위성의 안정적인 자세유지를 목적으로 Attitude Control System (ACS) Board와 Torque Coil이 자세제어계로 구성된다. 전력의 생산과 공급 및 충전은 태양전지판과 Electrical Power System (EPS), 리튬 배터리로 구성된 전력계에서 이뤄지며, 명령 및 데이터처리계는 On Board Computer (OBC)와 Instrument Interface board (IIB)를 중심으로 서브시스템의 명령체계와 데이터처리를 다룬다. 통신계는 Uplink인 VHF 안테나와 Downlink인 UHF, S-band 안테나로 구성되며 지상과 명령을 송수신한다. SIGMA는 타임인터럽트 기능을 활용한 Flight Software (FSW)로 운용되며 임무에 따른 6가지 모드의 시나리오로 위성을 운용한다. 이에 SIGMA의 개발과 테스트 결과를 소개한다. 본 큐브위성 개발기술을 바탕으로 향후 천문관측용 위성에도 활용할 예정이다.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.2
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• pp.84-91
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• 2009

This paper presents an online partial 3D modeling methodology that uses a mobile augmented reality system and aerial photographs, and a tracking methodology that compares the 3D model with a video image. Instead of relying on models which are created in advance, the system generates a 3D model for a real building on the fly by combining frontal and aerial views. A user's initial pose is estimated using an aerial photograph, which is retrieved from a database according to the user's GPS coordinates, and an inertial sensor which measures pitch. We detect edges of the rooftop based on Graph cut, and find edges and a corner of the bottom by minimizing the proposed cost function. To track the user's position and orientation in real-time, feature-based tracking is carried out based on salient points on the edges and the sides of a building the user is keeping in view. We implemented camera pose estimators using both a least squares estimator and an unscented Kalman filter (UKF). We evaluated the speed and accuracy of both approaches, and we demonstrated the usefulness of our computations as important building blocks for an Anywhere Augmentation scenario.

• Journal of Astronomy and Space Sciences
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• v.15 no.1
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• pp.251-260
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• 1998

We consider the motion of the subsystems as separate bodies as well as the entire satellite for the attitude and orbit control of a communication satellite by multi-body modeling technique. Thus, the system, can be applied to a general communication satellite as well as a specific communication satellite, i. e. Koreasat I,II. The simulation results can be viewed by two-dimensional graphics and three-dimensional animation. The graphical user interface(GUI) makes its usage much simpler. We have simulated a couple of scenarios for Koreasat I,II which are being operated as geostationary communication satellites to verify the system performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.8
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• pp.590-598
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• 2019

Today, satellites are widely used in many fields like communication and image recoding. The image acquired by satellites contains variety information of wide region. Therefore, they are used for agriculture, resource exploitation and management, and military purpose. The satellite is required to acquire images effectively in a given time period. Because the period that satellites can acquire images is very restrictive. In this study, the modeling of processing time and attitude maneuvering for satellite image acquisition is performed. From this modeling, mission planning algorithm using heuristic evaluation function is suggested and performance of the proposed algorithm is verified by numerical simulation.

• Journal of the Korea Computer Graphics Society
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• v.22 no.3
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• pp.11-20
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• 2016

This paper introduces an effective method for generating 3D stereoscopic images that gives immersive 3D experiences to viewers using mobile-based binocular HMDs. Most of previous AR systems with monocular cameras have a common limitation that the same real-world images are provided to the viewer's eyes without parallax. In this paper, based on the assumption that viewers focus on the marker in the scenario of marker based AR, we recovery the binocular disparity about a camera image and a virtual object using the pose information of the marker. The basic idea is to generate the binocular disparity for real-world images and a virtual object, where the images are placed on the 2D plane in 3D defined by the pose information of the marker. For non-marker areas in the images, we apply blur effects to reduce the visual discomfort by decreasing their sharpness. Our user studies show that the proposed method for 3D stereoscopic image provides high depth feeling to viewers compared to the previous binocular AR systems. The results show that our system provides high depth feelings, high sense of reality, and visual comfort, compared to the previous binocular AR systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.5
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• pp.576-584
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• 2014

In this paper, a study on the optimization of fuzzy classifier using radar cross section(RCS) values is presented to classify shell-shaped targets. Method of moments(MOM) is exploited to construct RCS database of generic shell-shaped targets in uniform angular intervals. Relative orientations are estimated from various flight scenarios of shell-shaped targets, and associated RCS values are interpolated from the generated RCS database with uniform angular intervals. Initial membership functions are determined using the interpolated RCS values, and particle swarm optimization(PSO) is utilized to optimize the membership functions of the fuzzy classifier in terms of probability of correct classification.