• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.489-492
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• 2000

본 논문에서는 영상 항법 변수 추출 알고리듬의 실시간 구현에 관해 연구하였다. 영상 항법 변수 추출 알고리듬은 이전 위치를 기준으로 현재 위치를 추정해내는 상대위치 추정 알고리듬과 상대위치 추정에 의해 누적되는 오차를 보정하기 위한 절대위치 보정 알고리듬으로 구성된다. 절대위치 보정 알고리듬은 고해상도 영상과 IRS (Indian Remote Sensing) 위성영상을 기준영상으로 이용하는 방법 및 DEM (Digital Elevation Model) 을 이용하는 방법으로 구성된다. 하이브리드 영상 항법 변수 추출 알고리듬을 실시간으로 구현하기 위해 MVP (Multimedia Video Processor)로 명명된 TMS320C80 DSP (Digital Signal Processor) 칩을 사용하였다. 구현된 시스템은 MVP의 부동 소수점 프로세서인 MP (Master Processor) 를 고정 소수점 프로세서인 PP (Parallel Processor) 를 제어하거나 삼각함수 계산과 같은 부동 소수점 함수를 계산하는데 사용하였고, 대부분의 연산은 PP를 사용하여 수행하였다. 처리시간이 많이 필요한 모듈에 대해서는 고속 알고리듬을 개발하였고, 4개의 PP를 효율적으로 사용하기 위한 영상분할 방법에 대해 제안하였다. 비행체에서 캡코더를 이용해 촬영한 연속 항공 영상과 비행체의 자세정보를 입력으로 실시간 시뮬레이션 하였다. 실험결과는 하이브리드 항법 변수 추출 알고리듬의 실시간 구현이 효과적으로 구현되었음을 나타내고 있다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.6
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• pp.637-643
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• 2010

In this study, we developed a Portable Multi-sensor System, which consists of a video camera, a GPS/MEMS IMU and a UMPC to acquire video images and position/attitude data. We performed image georeferencing based on the bundle adjustment without ground control points using the acquired data and then evaluated the effectiveness of our system through the accuracy verification. The experimental results showed that the RMSE of relative coordinates on the ground point coordinates obtained from our system was several centimeters. Our system can be efficiently utilized to obtain the 3D model of object and their relative coordinates. In future, we plan to improve the accuracy of absolute coordinates through the rigorous calibration of the system and camera.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.1
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• pp.40-48
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• 2015

In this paper, we suggest a measurement modeling of the RF seeker using the ISAR(Inverse Synthetic Aperture Radar) image. Reference scattering points are extracted first from ISAR images which are changed according to target attitude. And then uncertainties included in RF seeker measurement such as noise strength, blink, and boresight error are added to the reference scattering points. The proposed measurement model of the RF seeker can be used to develop various kinds of target tracking algorithms.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.2
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• pp.165-170
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• 2002

For the inaccessible area where the field verification is unable, it is difficult to obtain the ground control points (GCPs) or the acquired GCPs may be inaccurate. In general systematic geometric correction is achieved by utilizing orbit ephemeris and three axis attitude data of the satellite. however, this method results to poor accuracy of the imagery's absolute coordinates. To improve the absolute accuracy as well as the relative accuracy, we added the accessible region into the inaccessible area. We obtained GCPs in the accessible region by the fast static GPS survey and made geometric corrections with these biased GCPs. Because the biased GCPs show a pattern of coordinate errors, we analyzed this tendency to track the estimated errors in the inaccessible area.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.3
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• pp.195-205
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• 2020

This study addresses analysis on reactions which are induced in restraint system for airframe full-scale static structural test. This system restraints 6 degrees of freedom of a test article. It is valuable to study evaluating test error through analysis on the reactions which include all errors in a test. It is required to calculate fistly right reactions for the evaluation. This study focuses on calculation of the right reactions. The reaction is represented by sum of nominal reaction(Rn) and testing error reactions(Rce, Rerr) and is analyzed by two steps (inital vs relative reaction) in this study. It would evaluate intrinsic error at 0%DLL and error induced from applying test load, separately. Based on analysis using test data of a full-scale static test(canard type aircraft), resultant force of Rces and Rce_rs are distributed within 82.8N while resultant force of Rerr_rs shows to increase upto max. 808N as load level increment. Such well distribution of the Rce within the small range is caused from TMF values characteristics which are well distributed within -30N~40N. Additionally, it is shown through qualitative analysis on three components(X0, Y0, Z0) of the relative reaction(Rerr_r) that the reactions must be calculated with considering deformation of test article to calculate correctly reactions. This study shows also that equations characterizing deformation of components of test article are required to calculate the correct reactions, the equations must include information which will be used to calculate movement of all loading points.

• Clinical and Experimental Pediatrics
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• v.49 no.6
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• pp.602-609
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• 2006

Purpose : As the prone position is thought to be an important factor in sudden infant death syndrome(SIDS), this study was conducted to contribute to reducing SIDS by analyzing sleeping positions of infants. Methods : A face-to-face questionnaire was carried out with a total of 170 parents with a baby aged less than 6 months. Results : A total of 170 infants included 95 males(55.9 percent) and 75 females(44.1 percent); their average age was 2.8 months. 45.3 percent slept in a supine position; 34.7 percent in a side or supine position; 7.1 percent in a side position; 4.7 percent in a prone position; 4.1 percent in a non-specific position. Among those in a side position, 59.7 percent were in a supine position in the morning; 19.5 percent were in the side position; 13.4 percent were in a non-specific position; and 4.1 percent were in a prone position. To the question why they slept in a specific position, 34.9 percent answered their baby slept comfortably, and particularly, 42.9 percent in the prone position group answered so. In the supine position group, 21.6 percent answered they had no reason. Both in the prone position and side position groups, 21 percent each answered they were worried about the shape of their baby's head. In the side position group, 22 percent answered that they had a fear of choking due to vomiting. In all sleeping position groups, 8.2 percent and 7.4 percent answered it was because they had a fear of suffocation and they wanted to avoid SIDS, respectively. Conclusion : Many of the parents preferred unstable positions, e.g. the side position and the prone position, which could cause SIDS. Their decision on their baby's sleeping position was not based on exact medical knowledge, but on convenience in taking care of their baby. As it was found that only 6 percent of the subjects were advised from their pediatrist about their baby's sleeping position, moreover, it is necessary to carry out more studies and activities for preventing SIDS caused by improper sleeping positions and educating patents about recommended sleeping positions for their baby.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.12
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• pp.865-873
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• 2019

To improve the survivability of a missile, it needs to be lowered that the detection possibility by radars on the ground. The radar exposure of the target is given as a function of relative distance from the radar to the target and RCS (Radar Cross Section). The RCS of the missile is determined by the incidence angle of the target to electromagnetic radiation emitted from the radar. Under the assumption that the missile equips appropriate attitude control system, the attitude of the missile to minimize radar exposure at a high altitude is investigated in this paper. Two different types of performance cost are considered: the total sum of RCS and the total sum of SNR during the flight. Optimal solutions against multiple ground radars are found by using a SQP (Sequential Quadratic Programming)-based optimization technique.

• Proceedings of the Safety Management and Science Conference
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• 2002.05a
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• pp.199-205
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• 2002

최근 산업안전/보건분야에서 누적외상성질환(Cumulative Trauma Disorders： CTDs)과 직업성요통(Low Back Injury)과 같은 근골격계질환은 산업현장에서 어렵지 않게 발견할 수 있는 신종 산업재해의 일종이다. 특히 미국의 경우, 발생건수와 그로 인한 인적/물적 손실이 급격하게 증가되고 있는 것으로 나타나고 있다. 그러나 미국과 같이 근골격계질환의 폐해를 일찌감치 인식하고 그 해결방안을 연구해온 나라들에서는 현재 환자관리 및 인간공학적인 기준 등을 포함하는 예방지침들이 잘 정착되어 있는 실정이다. 우리나라의 경우에는 작업환경 등의 조건과 상황이 미국과 같은 구미 선전국과 비숫하고, 특히 제조업의 생산체계가 그런 나라들과 매우 유사하여 근골격계질환의 발생과 그로 인한 인적/물적 손실이 적지 않을 것이라고 예상할 수 있지만 아직까지 CTDs에 대한 전반적인 이해가 부족하고, 정확한 실태가 파악되지 못하였으며, 따라서 체계적인 관리 대책 또한 마련되어있지 않은 실정이다. 본 조사에서는 서울 근교의 수송기계관련 사업장의 작업들에 대한 작업자세에 중심을 둔 인간공학평가를 통하여 조사 작업의 근골격계질환에 대한 상대적인 위험도, 위험요인 등을 파악하고, 그에 따른 개선 대책의 방향을 제시하고자 하였다. 특히, 각 부위별 위험점수와 부위별 증상호소율의 상환분석결과, 작업자 개인적 수준에서는 통계적으로 유의한 차는 없는 것으로 분석되었으나, 부서별로 분석한 결과, 작업시 주로 사용하는 오른쪽 상지의 경우, 오른쪽 어깨, 팔꿈치, 손목 순으로 통계적으로 유의하게 관련이 있는 것으로 나타났다. 즉 증상호소율과 해당 신체부위의 위험도 점수는 서로 정적(positive)한 관계에 있는 것으로 나타났고, 상지 중 주로 사용하는 오른쪽 부담의 위험도 자세 점수와 증상호소는 비교적 높은 상관관계에 있는 것으로 나타났다. 따라서 이와 같은 인간공학적 분석결과는 향후 인간공학적인 개선대책의 개발 뿐만 아니라 의학쪽에서 근골격계질환을 접근하는 초기단계에서 매우 유용한 역할을 할 수 있으리라 생각된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.298-300
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• 2021

The Ministry of National Defense decided to build a realistic combat simulation training system based on virtual reality and augmented reality in accordance with the expansion of the scientific training system of "Defense Reform 2.0". The realistic combat simulation training system should be able to maximize the tension and training effect as in actual combat through engagement between trainers. In addition, it should be possible to increase the effectiveness of survival training at the same time as shooting training similar to actual combat through cover training. Previous studies are suitable techniques to improve the shooting precision of the trainee, but it is difficult to practice bilateral engagement like in actual combat, and it is particularly insufficient for combat shooting training using cover. Therefore, in this paper, we propose a S/W algorithm for generating a virtual avatar by recognizing the shooting posture of the opponent on the screen of the virtual shooting trainer. This S/W algorithm can recognize the trainer and the cover based on the depth information acquired through the depth sensor and estimate the trainer's posture.

• Journal of IKEEE
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• v.18 no.4
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• pp.636-644
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• 2014

This paper is to technically implement the sensing platform for Home-Wellness Robot. First, self-localization technique is based on a smart home and object in a home environment, and IOT(Internet of Thing) between Home Wellness Robots. RF tag is set in a smart home and the absolute coordinate information is acquired by a object included RF reader. Then bluetooth communication between object and home wellness robot provides the absolute coordinate information to home wellness robot. After that, the relative coordinate of home wellness robot is found and self-localization through a stereo camera in a home wellness robot. Second, this paper proposed fuzzy control methode based on a vision sensor for approach object of home wellness robot. Based on a stereo camera equipped with face of home wellness robot, depth information to the object is extracted. Then figure out the angle difference between the object and home wellness robot by calculating a warped angle based on the center of the image. The obtained information is written Look-Up table and makes the attitude control for approaching object. Through the experimental with home wellness robot and the smart home environment, confirm performance about the proposed self-localization and posture control method respectively.