• The Journal of Korean Society for Radiation Therapy
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• v.23 no.2
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• pp.83-90
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• 2011

Purpose: This study statistically analyzed the difference of the stability of maintaining a respiratory period shown according to position and use of a device to search the tendency and usefulness of a device. Materials and Methods: The study obtained respiratory signals which maintained a respiratory period for 20 minutes each supine and prone position for 11 subjects. The study obtained respiratory signals in a state of using a belly board for 7 patients in a bad condition of a respiratory period in a prone position to analyze a change in respiration and the stability before and after the use of a device. Results: The supine part showed 54.5%, better than the prone part of 36.4% in a case that the stability for maintaining a respiratory period was in a good condition as a fixed respiratory period was well maintained according to the position. 6 patients (85%) showed a maintenance pattern of a respiratory period significantly different before the use and 4 patients showed a significantly good change in the stability for maintaining a respiratory period as a result that belly boards were used for 7 patients that the maintenance of a respiratory period was not in a good condition on a prone position. Conclusion: It seemed that this study could contribute to the maintenance of respiratory period and of respiratory stability as the optimal position for maintenance of respiration and the use of a device such as a belly board were decided through statistic analysis of respiratory signals and its application even if patient position and use of device were decided by the beam arrangement a treatment part of a patient, location of a target, and an expected plan.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.190-196
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• 2014

In this paper, we get state equations based on wheel's rotation, tilt and steering are independent each other in balancing robot. Accordingly, we propose two LQR controllers which are appropriate for rotation and steering control of a balancing robot. And its superiority and appropriateness are demonstrated by a comparison to a PID method. Simulation results verify the possibility of upright balancing, rectilinear motion and position control. Moreover, experimental results show that it guarantees the performance to apply the two LQR controllers to balance the robot.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.631-632
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• 2013

본 논문에서는 EMG 신호를 기반으로 컬-덤벨 운동의 운동량을 분석하고 각 근육별 최적 운동량을 정의하여 운동을 가이드(guide)하는 방법을 제안한다. 제안하는 방법으로 운동 체육학 분야에서의 EMG 신호 분석 및 활용 범위를 넓힐 수 있으며, 사용자는 컬-덤벨 운동 중 각 근육별 운동량 및 이에 대한 적절성을 안내받아 올바른 자세를 유지함으로써 컬-덤벨의 운동 효과를 극대화할 수 있다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.10
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• pp.875-887
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• 2015

The optimal layout design is used in the development of various areas of industry. In the field of space systems, components must be placed properly in the limited space of spacecraft by considering mechanical, thermal and electrical interfaces. When applying optimal layout design, a proper, even ideal placement of components is possible in the limited space of a satellite platform. Through the optimal placement design, the minimized moment of inertia enhances efficient attitude control, rapid maneuver and mission performance of the satellite. This paper proposes 3D optimal layout design that minimizes the spacecraft's moment of inertia and effect of thermal dissipation between inner components as well as interference between inner components based on a cubic-structure satellite platform. This study proposes the new genetic algorithm for 3D optimal layout design of the satellite platform.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.2
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• pp.162-172
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• 2011

This paper proposes embedded System of two wheeled inverted pendulum robot designed by model based design method, using MATLAB/SIMULINK and LEGO NXT Mindstorms. At first, stability and performance of controller is verified through modeling and simulation. After that direct conversion from simulation model to C code is carried and effectiveness of controller is experimentally verified. Two wheeled inverted pendulum robot has basic function about autonomous balancing control using principle of inverted pedulum and it is also possible to arrive at destination. In this paper, state feedback controller designed by quadratic optimal control method is used. And quadratic optimal control uses state feedback control gain K to minimize performance index function J. Because it is easy to find gain, this control method can be used in the controller of two wheeled inverted pendulum robot. This proposed robot system is experimentally verified with following performances - balancing control, disturbance rejection, remote control, line following and obstacle avoidance.

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.195-201
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• 2020

This paper implemented quadcopter-type drone system and proposed the heuristic method for obtaining the optimum gain coefficients in order to minimize the settling time. Control system for quadcopter posture stabilization reads the posture data from accelerator and gyro sensor, revises the original posture data using Mahony filter, and drives 4 DC motors using PID controller. The first step of the proposed method is to obtain the gain coefficients using the Ziegler-Nichols method, and then determine the optimum gain coefficients using the heuristic method at the next 3 steps. The experimental result shows that the maximum overshoot decreases from 44.3 to 29.8 degrees and the settling time decreases from 2.6 to 1.7 seconds compared to the Ziegler-Nichols method. Therefore, we proved that the proposed method works well in quadcopter flight system with high motor noise while reducing trial and error to obtain the optimal PID gain coefficients.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.7
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• pp.137-143
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• 2002

This paper concerns the spin-stabilization for the second stage of KSR-III(Korea Sounding Rocket-III). The error sources in the second stage are defined, and then the effect on attitude error of KSR-III is analyzed quantitatively and qualitatively. Based on the analysis, some conditions for optimal spinning frequency and optimal steady-spinning duration are suggested. Among several solutions, an optimal value can be determined in the point of minimum impact-point error. An approach to a sub-optimal solution is also suggested. Application to the KSR-III shows that a proper spinning frequency and a steady-spin duration to give the smallest impact-point error can be effectively determined.

• Radiation Oncology Journal
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• v.10 no.1
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• pp.95-100
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• 1992

Since LINAC-based stereotactic radiosurgery uses multiple noncoplanar arcs, three-dimensional dose evaluation and many beam parameters, a lengthy computation time is required to optimize even the simplest case by a trial and error. The basic approach presented in this paper is to show promising methods using an experimental optimization and an analytic optimization The purpose of this paper is not to describe the detailed methods, but introduce briefly, proceeding research done currently or in near future. A more detailed description will be shown in ongoing published papers. Experimental optimization is based on two approaches. One is shaping the target volumes through the use of multiple isocenters determined from dose experience and testing. The other method is conformal therapy using a beam's eye view technique and field shaping. The analytic approach is to adapt computer-aided design optimization in finding optimum irradiation parameters automatically.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.378-380
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• 2013

본 논문에서 구현한 경량단말을 활용한 이종 박물관 관람 환경별 최적의 적응적 관광 서비스 제공 모듈은 서로 다른 박물관을 관람하는 상황에 맞춰 그 관람객에게 가장 적합한 서비스를 제공을 해주는 모듈이다. 종래의 박물관 관람 형태는 사용자가 박물관에서 나누어준 하드카피 형태의 팜플렛 또는 가이드 안내에만 의존한 관람 형태이고, 주제별 아이템에 관한 상세 정보도 현장에 배치된 안내물을 보던가, 박물관에서 대여형태로 제공하는 오디오 장비만을 활용 하는 수준이며, 특히나 제한된 시간내에 대형 박물관을 관람해야 하는 경우 자신이 관심있는 것만 볼 수 없는 환경이다. 본 논문에서 소개될 이 모듈은 가상화 기술과 경량 단말을 활용하여 대형 박물관 또는 미술관등을 방문한 관람객에게 본인에게 맞는 최적의 관람 서비스를 제공한다. 좀더 자세하게는 대형 박물관에서 이 모듈이 사용되는 경우 넓은 공간에 무수히 많은 작품들이 전시되어 있는 상황에서 가용한 관광시간에 본인이 보고자 하는 것들만 추천받아볼 수 있도록 도와줄 수 있고, 최소한의 원가를 들여서 제작된 경량 스마트 단말을 통하여 해당 작품에 대해 상세한 부가 정보를 제공받아 박물관의 관람효과를 극대화 할 수 있도록 도와준다.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.2
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• pp.223-228
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• 2016

People try to maintain optimal sleep activity to a changing attitude 20-30 times while sleeping 7-8 hours a day. In order to provide optimal sleep, we need to develop sensing device for apply effective various sleep data acquired through display device that can provide program and information which process and analyze information printed out from sensor and sensing system. In this paper, we analyze sleep pattern to detect the toss and turn while a person's sleeping and we develop a wellness pillow that can be active on sleep health management based on the analyzed data for sleep patterns.