• 재활복지공학회논문지
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• 제11권3호
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• pp.231-238
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• 2017

본 연구에서는 개인 피트니스를 수행하는 과정에서 건강관리와 운동효과를 증대시킬 수 있도록 운동동작을 분석하는 방법을 제안하였다. 본 연구에서는 사용자가 밴드 형태의 가속도, 각속도, 지자계 모듈이 장착된 운동 센서를 착용하고 피트니스 운동 중에 발생하는 신호를 획득하고 운동동작을 분석하였다. 본 논문에서 제시한 기법을 활용하여 세 가지 저항성 운동의 동작을 분석하였으며 이는 기존의 연구결과와 일치함을 확인하였다. 저항성 운동 상황에서 생성된 데이터로부터 개인화된 운동정보를 가공할 수 있는 기술을 확보하였다.

• 제어로봇시스템학회논문지
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• 제14권6호
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• pp.548-553
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• 2008

In this paper, we propose a new swing-up control strategy for rotary inverted pendulums with restricted rotation range. The control law is derived from a Lyapunov function. The Lyapunov function is defined as the square of the sum of the absolute value of the total mechanical energy and weighted squares of the arm's angular displacement and velocity. By adjusting the weighting parameters in the Lyapunov function, we can affect the swing-up strategy such that the restriction on rotation range can be satisfied. Finally, we verify the performance of the proposed control law through simulation and experiments.

• 천문학회지
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• 제23권1호
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• pp.63-70
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• 1990

The original axisymmetric, stationary electrodynamic model of the central engine in an active galactic nucleus proposed by Macdonald and Thorne consists of a supermassive black hole with magnetic field lines that pass through the region just outside the event horizon of the black hole. Each magnetic field line rotates with a constant angular velocity which will exceed the speed of light at large radii. Even though the field lines are purely mathematical entities this condition sets a stringent physical constraint on the motion of the magnetic field lines and the particles on them. In this paper we will show that we can remove this auxiliary constraint in our model by allowing nonstationary processes. As a result the magnetic field lines can be twisted and wound up in a region lying outside of the quasi-stationary magnetosphere of the black hole. We conclude that astrophysical jets are formed in that region due to the twisted and wound magnetic field lines powered by the Blandford-Znajek process and the other driving forces.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제14권3호
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• pp.200-208
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• 2014

This paper presents the control of an inverted pendulum system using intelligent algorithms, such as fuzzy logic and neural networks, for advanced control education. The swing up balancing control of the inverted pendulum system was performed using fuzzy logic. Because the switching time from swing to standing motion is important for successful balancing, the fuzzy control method was employed to regulate the energy associated with the angular velocity required for the pendulum to be in an upright position. When the inverted pendulum arrived within a range of angles found experimentally, the control was switched from fuzzy to proportional-integral-derivative control to balance the inverted pendulum. When the pendulum was balancing, a joystick was used to command the desired position for the pendulum to follow. Experimental results demonstrated the performance of the two intelligent control methods.

• 한국항해항만학회지
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• 제28권8호
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• pp.653-657
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• 2004

이 논문은 자유자이로의 방향보존성을 이용하여 위치를 결정하는 방법을 이론적으로 유도한 것이다. 즉, 임의 위치에서 두 대의 자유자이로 회전축의 경사각과 기준 위치로부터 측정한 경과 시간을 기본 요소로 하여 위치를 결정하는 시스템을 제시하고 이 시스템을 구축할 때 나타나는 문제점을 열거하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제31권4호
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• pp.417-424
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• 2007

This paper presents a solution that an analytical model for an induction motor and the formula of regenerative power and instantaneous torque are derived. based on the spiral vector. The torque is controlled linearly through variations of the slip angular velocity, based on the field acceleration method (FAM). And also PWM inverter fed induction motor drives is schemed to be easily a regenerative drive. The voltage source inverter fed induction motor drives that regenerative power occurs with back current type is presented, to easily controlled the feedback power and to proper the adaption of energy shaving drives. The experimental tests verify the performance of the FAM, proving that food behavior of the drive is achieved in the transient and steady state operating condition, and are discussed to save the power that regenerative power is measured at the operating acceleration or deceleration of servo system.

• Journal of Advanced Marine Engineering and Technology
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• 제32권4호
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• pp.578-584
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• 2008

In this study, a extrusion process with torsion of the bottom die is investigated to improve the forming performance of conventional extrusion process. In the experiment, plasticine is used as a model material. The results of experiments are compared with the two numerical methods, the Experiment and the Finite Element Method(FEM). An attempt is made to link programs incorporating with the process variables obtained by commercial FEM software, DEFORM-3D a useful package. Numerical result is compared with experimental one. These results show that the torsional extrusion process is very useful process because this process can obtain the homogenous deformations.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1772-1777
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• 2004

The performances of the newly constructed Stereoscopic PTV and Stereoscopic PIV which had been completed based on a 3D-PTV principle are tested using the Standard Images. Virtual images were produced for the benchmark tests of the constructed two Stereoscopic techniques. The arrangement of the two cameras was based on angular position. The calibration of cameras and the pair-matching of the three-dimensional velocity vectors were based on Genetic Algorithm based 3D-PTV technique. The Standard data of LES are on the impinged jet proposed by VSJ. It is shown that the results obtained by Stereoscopic PTV have better reliability than those by Stereoscopic PTV.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1540-1545
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• 2004

This paper presents a semi-empirical model to predict the frost growth formed on the cold cylinder surface. The model is composed of the correlations for frost properties including the various frosting parameters and local heat transfer coefficient. The effects of varying the correlations for local heat transfer coefficient on the frost growth are examined to establish the model. The numerical results are compared with experimental data obtained by the previous researchers. The results agree well with the experimental data within a maximum error of 13%. As the results, the frost thickness decreases with changing angular position from front stagnation to separation point. Also the effects of air velocity on the frost growth are negligible, as compared to the other frosting parameters.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3693-3696
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• 2010

We experimentally measure the kinetic energy and angular distributions of photoelectrons of $N_2$ as a function of 410 nm femtosecond laser intensity by using velocity map imaging technique. The strong-field multiphoton ionization of molecules shares many of the characteristics with those of atoms. Electron kinetic energies are nearly independent of laser intensities. The independence suggests that the electron peaks in the photoelectron spectrum actually result from a two-step process, indicative of the occurrence of real population in the intermediate states. The relative amplitudes of electron peaks indicate that in the two-step process, nonresonant population transfer dominates for low intensities, while resonant population transfer dominates for higher intensities.