• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.242-245
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• 2013

Monte Carlo method was applied to discriminate the external contamination on radiation workers in nuclear power plants for internal dose assessment generally used with a bed type scanning detector whole body counter. Korean voxel model with internal contamination was used to estimate the detection patterns of whole body scanning. Also, the BOMAB model with various external contamination was assumed to compare with detection of radionuclides inside the human body. From the comparison of detection efficiency between front and back side up, external contamination was easily distinguished.

• School Mathematics
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• v.9 no.2
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• pp.241-257
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• 2007

The study aims to figure out how to improve existing examination tools to distinguish mathematically gifted children and to clarify procedures and criteria for selecting candidates. Toward this end, it examined correlations between grades of gifted children selected through evaluation by pen-and-pencil tests and their creative problem-solving capability and performance assessment, and analyzed learning activities of the gifted children. According to the analysis, results of pen-and-pencil tests turned out to have low correlations with their creative problem-solving capability and performance assessment, but it was found that their creative problem-solving capability has high correlations with results of performance assessment. The analysis also found that there were some students who participated in a program for gifted children with high marks but had difficulties in adapting themselves to it. It found that there were children who joined the program with low marks but emerged as successive performers later on. In this regard, the existing examination tools to tell the gifted students apart need to be used to the fullest extent, and other diversified tools to evaluate mathematical capabilities that include mathematical creativity need to be further studied and developed. Qualitative studies on affective development of the gifted students and their creative problem-solving processes need to be conducted.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.3
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• pp.199-206
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• 2016

Most Koreans walk having their toes in or out, because of their sedentary lifestyles. In addition, using smartphone while walking makes having a desirable walking posture even more difficult. The goal of this study is to make a simple system which easily analyze and inform any person his or her personal walking habit. To discriminate gait patterns, we developed a gait monitoring system using a 3-axis accelerometer and a foot pressure monitoring system. The developed system, with an accelerometer and a few pressure sensors, can acquire subject's foot pressure and how tilted his or her torso is. We analyzed the relationship between type of gate and sensor data using this information. As the result of analysis, we could find out that statistical parameters like standard deviation and root mean square are good for discriminating among torso postures, and k-nearest neighbor algorithm is good at clustering gait patterns. The developed system is expected to be applicable to medical or athletic fields at a low price.

• Journal of the Korea Society of Computer and Information
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• v.28 no.8
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• pp.87-93
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• 2023

In this paper, we propose a system that accurately and efficiently determines forward head posture based on network learning by analyzing the user's skeletal posture. Forward head posture syndrome is a condition in which the forward head posture is changed by keeping the neck in a bent forward position for a long time, causing pain in the back, shoulders, and lower back, and it is known that daily posture habits are more effective than surgery or drug treatment. Existing methods use convolutional neural networks using webcams, and these approaches are affected by the brightness, lighting, skin color, etc. of the image, so there is a problem that they are only performed for a specific person. To alleviate this problem, this paper extracts the skeleton from the image and learns the data corresponding to the side rather than the frontal view to find the forward head posture more efficiently and accurately than the previous method. The results show that the accuracy is improved in various experimental scenes compared to the previous method.

• Journal of the Society of Disaster Information
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• v.20 no.2
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• pp.302-314
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• 2024

Purpose: This study proposes a fall detection model based on a top-down deep learning pose estimation model to automatically determine falls of multiple workers in an underground utility tunnel, and evaluates the performance of the proposed model. Method: A model is presented that combines fall discrimination rules with the results inferred from YOLOv8-pose, one of the top-down pose estimation models, and metrics of the model are evaluated for images of standing and falling two or fewer workers in the tunnel. The same process is also conducted for a bottom-up type of pose estimation model (OpenPose). In addition, due to dependency of the falling interference of the models on worker detection by YOLOv8-pose and OpenPose, metrics of the models for fall was not only investigated, but also for person. Result: For worker detection, both YOLOv8-pose and OpenPose models have F1-score of 0.88 and 0.71, respectively. However, for fall detection, the metrics were deteriorated to 0.71 and 0.23. The results of the OpenPose based model were due to partially detected worker body, and detected workers but fail to part them correctly. Conclusion: Use of top-down type of pose estimation models would be more effective way to detect fall of workers in the underground utility tunnel, with respect to joint recognition and partition between workers.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.683-686
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• 2010

본 논문은 최근 이슈가 되고 있는 대형 건축/토목구조물에 대한 동적계측, 시스템판별, 모델향상 등을 통한 건전도 평가기법에 대하여, 현재까지 개발된 혹은 개발되고 있는 기술사항 들을 소개한다. 특히, 가속도계를 사용하여 의도하는 진동기록을 획득하기 위한 합리적인 Hardware Chain 구성, 이로부터 신뢰성 있는 동적 구조성능치를 추출하기 위한 다양한 고급 모달해석기법 및 보다 자세한 구조정보 획득 및 손상감지 등을 위하여 실험치와 유한요소 해석치를 일치시키는 모델향상기법에 대하여 기술하였다. 또한 이러한 기술들을 실제 구조물인 고층건물 및 비닐하우스 아치구조에 적용하였으며, 이러한 경험에 근거하여 현 모니터링 기술의 문제점 및 향후 개선방향 등을 토의하였다.

• Journal of Astronomy and Space Sciences
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• v.20 no.4
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• pp.351-358
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• 2003

The global stability of the attitude motion of a spin-stabilized space vehicle is investigated by performing numerical experiment. In the previous study, a stationary solution and a particular resonant condition for a given model were found by using analytical method but failed to represent the system stability over parameter values near and off the stationary points. Accordingly, as an extension of the previous work, this study performs numerical experiment to investigate the stability of the system across the parameter space and determines stable and unstable regions of the design parameters of the system.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2406-2410
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• 2004

2족 보행로봇은 그 구조적인 특성상 인간 생활환경에 적용이 용이하며 바퀴형 로봇이 이동하기 어려운 환경에서도 이동이 가능하다. 그러나 2족 보행로봇은 높은 자유도와 직렬형 링크 구조로 인해 안정도 해석과 제어가 어려운 점이 있으며 이는 로봇을 제작하는데 있어 난점으로 작용한다. 본 연구에서는 로봇의 발바닥에 압력센서를 설치하여 ZMP(Zero moment point)를 측정하여 안정도를 판별하고 신경망 이론을 이용하여 보행 안정도를 개선하도록 로봇의 자세를 제어하였다.

• Journal of Yeungnam Medical Science
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• v.11 no.1
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• pp.16-29
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• 1994

1. 현재 보편적으로 참고가 되는 간질 환자의 운전 면허 허용의 기준과 관련 법규등을 요약하면 표-5와 같다. 2. 아직 어떤 국가에서는 간질환자의 차량운전을 무경련 기간에 상관없이 금하고 있으나, 대다수의 국가에서는 일정한 기간의 무경련의 존재가 면허 허용의 중요한 기준으로 삼고 있으며, 대략 1년간의 기간을 요구하고 있다. 그러나 간질은 그 특징상 1년 혹은 2년의 무경련후에도 경련이 발생될 수 있어 1년간의 무경련으로 면허 발급을 허가는 제도는 더 연구하여 보완할 필요가 있다. 3. 수면시 간질, 전구증상이 있는 복합 부분 간질, 단순 운동성 간질, 특수한 여건이나 자극에서 생기는 경련환자에게 선택적으로 운전면허 허용은 장시간 운전, 고속 운전, 심리적 육체적 과로상태에서 운전을 하는 경우 기존 경련을 심하게 유발하거나, 평소와 다른 상황에서 경련이 생길 수 있어 이런 환자들에게 일괄적으로 면허를 허용하기 보다는 세밀하게 분석하여 개인별로 판별하여야 하는 것이 바람직하다. 4. 환자의 능동적이고 성실한 경련보고와 아울러 경련발생 가능성이 높아 의사의 운전중단 처방을 수용하고 따르는 협조적인 환자의 자세가 매우 중요한데, 현재까지 환자의 성실한 경련보고와 의사의 조치에 대한 환자의 적극적인 수용자세가 해결되지 않고 있다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.1 s.307
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• pp.13-20
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• 2006

In this paper, we propose a motion control scheme of robot manipulators based on visual feedback under camera-in-hand configuration. The desired joint velocity and acceleration for motion control is made by the feature-based visual data in the outer loop. The control input for tracking feature points on the image plane uses robot kinematics dynamic. The proposed control input consists of the image feature and the joint velocity error to achieve robustness to the parametric uncertainty. The stability of the closed-loop system is proved by Lyapunov approach. Computer simulations and experiments on a two degree of freedom manipulator with 5 links are presented to illustrate the performance of proposed control system.