• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.5
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• pp.11-16
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• 2017

The frequency dependent input resistance observed in RF MOSFETs is analyzed in detail by deriving pole and zero frequency equations from a simplified input equivalent circuit. Using this theoretical analysis, we find that the reduction effect of the input resistance in the low frequency region arises from the channel resistance between source and pinch-off region in the saturation region. This channel resistance effect on the low frequency reduction of the input resistance is physically validated by performing small-signal equivalent circuit modeling with varying the channel resistance.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.10
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• pp.817-825
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• 2016

In this paper, we introduce a flexible gripper that we have engineered to precisely pinch in parallel and compliantly grasp objects. As found in most conventional industrial grippers, the parallel pinching property is essential for precise manipulation. On the other hand, the grippers with a flexible structure are more adept at grasping objects with arbitrary shapes and softness. To achieve these disparate properties, we introduce a flexible gripper mechanism composed of multiple flexible beam structures. Utilizing these beam structures, the proposed gripper is able to grasp arbitrarily shaped objects. Additionally, a unique combination of flexible beams enables the gripper to pinch objects using the parallel fingertips for enhanced precision. A detailed description of the proposed mechanism is provided, and an analysis of the strength and stiffness of the fingertip and finger body is presented. The Results section compares the theoretical and experimental analyses and verifies the properties and performance of the proposed gripper.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.3
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• pp.307-322
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• 2021

This study developed an analytical methodology for the mechanical integrity of spent nuclear fuel (SNF) cladding tubes under external pinch loads during transportation, with reference to the failure mode specified in the relevant guidelines. Special consideration was given to the degraded characteristics of SNF during dry storage, including oxide and hydride contents and orientations. The developed framework reflected a composite cladding model of elastic and plastic analysis approaches and correlation equations related to the mechanical parameters. The established models were employed for modeling the finite elements by coding their physical behaviors. A mechanical integrity evaluation of 14 × 14 PWR SNF was performed using this system. To ensure that the damage criteria met the applicable legal requirements, stress-strain analysis results were separated into elastic and plastic regions with the concept of strain energy, considering both normal and hypothetical accident conditions. Probabilistic procedures using Monte Carlo simulations and reliability evaluations were included. The evaluation results showed no probability of damage under the normal conditions, whereas there were small but considerably low probabilities under accident conditions. These results indicate that the proposed approach is a reliable predictor of SNF mechanical integrity.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.3
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• pp.467-476
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• 2010

Purpose : This study was performed to understand the relationship between hand and mouth shapes using functional magnetic resonance imaging(fMRI). Methods : Two healthy volunteers without any previous history of physical or neurological illness were recruited. fMRI was done that volunteers was 6 repeated of natural mouth, close mouth and open mouth while power grip and pinch grip movement. Results : Cerebral cortex activation was not well observed for the natural mouth during the power grip exercise. For the closed mouth, the temporal lobe, Broca's area, the prefrontal area related to thinking and judgment, the supplementary motor area, the auditory area and Wernicke's area were activated. For the open mouth, cortical activation was also observed in the temporal lobe, Wernicke's area, the prefrontal area related to thinking and the orbital frontal area related to visual sense. During the pinch grip exercise, cortical activation was observed for the natural mouth in the primary sensory area, Wernicke's area, the primary and supplementary motor area, and the prefrontal area. For the closed mouth, cortical activation was observed in the temporal lobe, Wernicke's area, the prefrontal area related to thinking, the secondary visual area, the primary sensory area and the supplementary motor area. In the case of the open mouth, cortical activation was observed in a few parts in the temporal lobe as well as Wernicke's area, the prefrontal area related to thinking, and other areas related to visual sense such as the primary visual area, the secondary visual area and the visual association area. Conclusion : Brain was more activation for close mouth and open mouth more than natural mouth movement.

• Journal of Preventive Medicine and Public Health
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• v.30 no.4 s.59
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• pp.779-790
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• 1997

The Association between myofascial pain syndrome and some tests was assessed in a cross-sectional study of 904 female telephone operators using video display terminals(VDTs). 105 cases were diagnosed as Myofascial pain syndrome with symptom questionnaire, laboratory examination and physician's physical examination and 550 controls were defined to show only musculoskeletal symptoms using NIOSH symptom criteria. Data on demographics, musculoskeletal symptom and visual analogue scale(VAS) were obtained by questionnaire. Anthropometric measurements, pressure pain threshold, Grip & Pinch strength and laboratory test were conducted. No significant difference between case and control at comparing of demographics, occupational history and body measurements were observed. But, Grip strength, pressure pain threshold and VAS showed the statistical difference between case and controt. Age, pressure pain threshold of Rt. Upper trapezius and VAS were associated with myofascial pain syndrome in multivariate logistic regression analysis. This results suggest that, to diagnose of myofascial pain syndrome, the consideration of the objective aspects among patients' subjective symptom complaints through the VAS and pressure pain threshold is required.

• Journal of the Korean Home Economics Association
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• v.29 no.2
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• pp.17-34
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• 1991

The purpose of this study was to find out problems which occured between clothes and motor ability traits of the hemiplegic aged. The samples were 32 hemiplegic aged men and were compared with 43 healthy aged men. Motor ability of the samples were measured by ROM test, muscle power test and finger function test(grip strength, hand's coordination, lateral pinch, 3pt. pinch). Design of the clothes consisted of 25 variables and the analysis of dressing and undressing motion consist of 10 motions of dressing and undressing dress shirts and 8 motions of trousers. The results were as follows: 1. There were significant relationship between ROM and muscle power and finger function of the hemiplegic aged(P<.001). 2. There were significant differences between the nomal side's finger function of the hemiplegic aged and that of the healthy group(P<.001). 3. The designs of clothes such as tutle neck line, long sleeve, button cuffs, fastening lace, open zipper and belt of trousers gave much difficulty to the hemiplegic when dressing and undressing. 4. The most difficult motion of dressing and undressing was fastening when dressing both dress shirts and trousers. 5. There were partly significant relationship between design of clothes and ROM, muscle power, finger function of hemiplegic aged man. 6. There were partly significant relationship between the degree of difficulty in dressing and undressing motions and ROM, muscle power, finger function of hemiplegic aged man.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1259-1264
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• 1990

During the past two decades, a lot of researches have been done on the synthesis of grassroot heat exchanger networks(HEN). However, few have been dedicated to retrofit of existing heat exchanger networks, which usually use more amount of utilities (i.e. steam and/or cooling water) than the minimum requirements. This excess gives motivation of trades-off between energy saving and rearranging investment. In this paper, an algorithmic-evolutionary synthesis procedure for retrofitting heat exchanger networks is proposed. It consists of two stages. First, after the amount of maximum energy recovery(MER) is computed, a grass-root network featuring minimum number of units(MNU) is synthesized. In this stage, a systematic procedure of synthesizing MNU networks is presented. It is based upon the concept of pinch, from which networks are synthesized in a logical way by the heuristics verified by the pinch technology. In the second stage, since an initial feasible network is synthesized based on the pre-analysis result of MER and must-matches, an assignment problem between new and existing units is solved to minimize total required additional areas. After the existing units are assigned, the network can be improved by switching some units. For this purpose, an improvement problem is formulated and solved to utilize the areas of existing units as much as possible. An example is used to demonstrate the effectiveness of the proposed method.

• PNF and Movement
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• v.20 no.1
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• pp.125-134
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• 2022

Purpose: The aim of this study was to establish an association between grip strength and gait variability in the elderly. Methods: The participants in this experiment (n = 20) were aged 65 or older. Power grip and lateral pinch forces were obtained in grip strength tests, and spatiotemporal gait parameters were collected from IMU sensors during 6 min actual walking to test the gait of participants. The collected gait parameters were converted to coefficient of variation (CV) values. To confirm the association between grip strength and gait variability, a partial correlation analysis was conducted in which height, weight, and gait speed were input as controlling variables. Results: Grip power showed a significant negative correlation with the stride length CV (r = -0.52), and the lateral pinch force showed a significant negative correlation with the stance CV (r = -0.65) and swing CV (r = -0.63). Conclusion: This study reveals that gait variability decreases as grip strength increases, although height, weight, and gait speed were controlled. Thus, grip strength testing, a simple aging evaluation method, can help identify unstable gait in older adults at risk of falling, and grip strength can be utilized as a non-invasive measurement method for frailty management and prevention.

• Journal of the Korea Convergence Society
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• v.3 no.4
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• pp.29-34
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• 2012

Power window motor assembly including ECU system is important to doors of automobile. This study is done for own development instead of importing of power window motor assembly. This paper is written under five specific subjects. The first, making of prototype sample and analysis of mass-production problem using CAE, the second, design of mass-production mold(2D and 3D), the third, manufacturing of sample mold, the fourth, tryout and measuring of 3 dimensions, the fifth, data analysis and mold modify. In the among them, product sample and analysis of mass-production using CAE, design and manufacture of mass-production mold, and production of sample mold are successfully done. In the results, it is made clear that two cavity and one gate are proper to make a mold of power window motor assembly housing. Besides, it is acquired own technology for mass-production of power window motor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1305-1306
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• 2012