• Journal of the Korean Society for Precision Engineering
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• v.28 no.5
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• pp.591-598
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• 2011

Tip position control of a flexible cantilever is difficult due to the non-minimum phase dynamics that result from the finite propagating speed of a mechanical wave along the cantilever. In this paper, we propose a method for the tip position control using a light and cheap accelerometer that does not bring any significant change to the dynamics of the cantilever system. The linear system identification model of the flexible cantilever is obtained with measurements by a laser displacement sensor. A Kalman estimator is designed with this model and calculates the estimated tip position with the acceleration data of the accelerometer that is attached on the tip of the cantilever. To verify reliability of the estimator, the estimated tip position is used to the feedback control system that uses a fuzzy logic controller. The control results are compared with those of the fuzzy control system where the real tip position is measured by a laser displacement sensor. Also, the performance of the estimator with the accelerometer is presented and discussed.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.5
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• pp.329-334
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• 2013

A positioning based service uses one's position information with GPS. This application also use the position based characters and change the smart phone to the vibration mode at the registered position. If the user register some places to be vibrated in the smart phone, the smart phone will be automatically changed to the vibration mode as the registered position is same with the position of GPS in the smart phone. If the smart phone is being leaving some distance from the position, the phone will be released from the vibration mode. Therefore, this paper propose aims for intelligent smart phone.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3431-3437
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• 2021

In this study, one-dimensional gamma ray source positions are estimated using a plastic scintillating optical fiber, two photon counters and via data processing with a machine learning algorithm. A nonlinear regression algorithm is used to construct a machine learning model for the position estimation of radioactive sources. The position estimation results of radioactive sources using machine learning are compared with the theoretical position estimation results based on the same measured data. Various tests at the source positions are conducted to determine the improvement in the accuracy of source position estimation. In addition, an evaluation is performed to compare the change in accuracy when varying the number of training datasets. The proposed one-dimensional gamma ray source position estimation system with plastic scintillating fiber using machine learning algorithm can be used as radioactive leakage scanners at disposal sites.

• The Journal of Korean Physical Therapy
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• v.33 no.1
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• pp.40-46
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• 2021

Purpose: This study compared the muscle activity of the lower limb according to the three types of fixed angles of the ankle joint during a lunge exercise. Methods: Twenty healthy subjects performed the lunge motion in a trial including the three types of fixed angle. The lunge motion with a neutral, 20° dorsiflexion, and 20° plantarflexion of the ankle joint were randomized and measured repeatedly. The muscle activity of the rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), and semitendinosus (ST) was measured by surface electromyography. Results: In the change in ankle joint angle, the RF, VL, BF, and ST muscle activity showed significant differences (p<0.05). In the 20° dorsiflexion position, the muscle activity of VL, BF, and ST showed a significant decrease compared to that in the neutral position (p<0.017). The muscle activity of RF and VL in the neutral position was greater than that in the 20° plantarflexion position (p<0.017). Only the muscle activity of the BF in the 20° plantarflexion position was significantly greater than the 20° dorsiflexion position (p<0.017). Conclusion: These results revealed a difference in the muscle activity of lower extremities in the proximal region according to the angle of the ankle joint during the lunge.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2887-2890
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• 2003

This paper describes the possibility of analyzing gait pattern from the variation of the lower leg electrical impedance. This impedance is measured by the four-electrode method. Two current electrodes are applied to the thigh, knee, and foot, and two potential electrodes are applied to the lateral, medial, and posterior position of lower leg. The correlation coefficients of the joint angle and the impedance change from human leg movement was obtained using electrogoniometer and 4ch impedance measurement system developed in this study. We found the optimal electrode position for ankle, knee and hipjoint movements based on high correlation coefficient, least interference, and maximum magnitude of impedance change. The correlation coefficients of the ankle, knee, and the hip movements -0.87, 0.957 and 0.80. respectively. From such features of the lower leg impedance, it has been made clear that different movement patterns exhibit different impedance patterns and impedance level. This system showed possibility that lower leg movement could be easily measured by impedance measurement system with a few skin-electrodes.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.82-84
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• 2003

In case contact between point of contacts is not achieved well, contact resistance is grown, and by current concentration at current conducting contacts can weld. In order to decrease contact resistance between contacts in case of busbar, installing spring between fixed contact and moving contact. and then force on faying surface of contacts increase and contact resistance decrease. But, in case increase force of spring to widen contact area, operating force moving contact can grow, on the contrary force of spring is small, contact resistance becomes low. Therefore, need to optimize force and number of spring. position, and also need to examine force change on contact surface at point of contact moving. In this paper, dynamic kinetics analysis for force on faying surface of contacts is performed at unsteady state. It is showed to not uniform force on surface between contacts, and we can got more uniform force by means of change spring position.

• Journal of Life Science
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• v.8 no.4
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• pp.373-380
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• 1998

A considerable change observed in X-ray diffraction during the muscle contraction was that the movement of myosin head and conformational change of contractile monecules were occurred in the muscle contraction. Time slice requires tension peak after the onset of stimulation and the height of tension peak depends on the number of twitch cycle. The intensity of I$_{11}$, I$_{10}$, 143${\AA}$ reflection is measured with 5ms time resolution and is recorded in isometric tension. The peak height of I$_{11}$ and 143${\AA}$ intensity is changed after the onset of a stimulation I$_{i}$, and the length of twitch is shortened by successive twitches in the case of stimulation TI$_{i}$. On the other hand, the peak height of I$_{11}$ and 215${\AA}$ intensity starts to decrease at the 1st twitch and remains constant at low peak hight without appreciable recovery during the contraction term. In the case of uccessive twitch stimulation, the myosin heads of muscle are once moved from their resting position and never returned to their initial position.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.216-217
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• 2014

Optimum finishing position, thickness and phase change temperature of winter and summer season were selected and suitability of finishing materials was evaluated based on temperature measurement of specimens applying the coating material mixed phase change materials(PCM). As a result, when finishing position was interior and finishing thickness of coating material mixed n-Octadecane(28℃ PCM) was 4mm, thermal performance was effective. n-Octadecane in summer season and n-Hexadecane(18℃ PCM) in winter season are indicated effective on energy savings, respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1434-1437
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• 2003

Sometimes open holes are required for the function and the weight reduction of structure and machinery. However, the serious stress concentration occurs because of the geometric discontinuity caused by the holes and cutting section. In this study, it is attempted to obtain the stress concentration coefficients of the inner surface of the hole boundary by changing the position and the shape of holes on the homogeneous isotropic plate. And the effects on the plate are investigated. The results show that the stress level becomes low and the distribution area widens the position of stress concentration changes as the ratio a/b increases and change to a circle. And as the ratio a/l decreases, the stress concentration reduces. As the plate with three holes. the stress $\sigma$$\_$x/ and $\tau$$\_$xy/ of hole 1,3 becomes high, especially $\sigma$$\_$x/ dominant and high.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.40 no.5
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• pp.250-252
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• 2014

Nasotracheal intubation should be performed in patients with jaw fractures because maxillomandibular fixation is required. However, when there are concomitant fractures of the nose and facial bones, an intubation tube positioned at the nose makes it difficult to perform an intricate surgery. In order to overcome these problems, a variety of ways to change the position of the tube have been introduced. We describe a simple technique of switching the tube from a nasal to oral position, which was easily executed in a patient with concomitant nasal and mandibular fractures, accompanied by a literature review.