• Journal of Energy Engineering
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• v.22 no.2
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• pp.175-183
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• 2013

For the optimal design of the vehicle electric system, it is important to have a reliable modeling tool to predict the dynamic behavior of the automotive battery. In this work, a one-dimensional modeling was carried-out to predict the dynamic behaviors of a 12-V automotive lead-acid battery. The model accounted for electrochemical kinetics and ionic mass transfer in a battery cell. In order to validate the modeling, modeling results were compared with the experiment data of the dynamic behaviors of the lead-acid batteries of two different capacities that were mounted on the automobiles manufactured by Hyundai Motor Company. The discharge behaviors were measured with various discharge rates of C/3, C/5, C/10, C/20 and combination. And dynamic behaviors of charge and discharge were measured. The voltage curves from the experiment and simulation were in good agreement. Based on the modeling, the distributions of the electrical potentials of the solid and solution phases, and the current density within the electrodes could be predicted as a function of charge and discharge time.

• Journal of Biosystems Engineering
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• v.43 no.1
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• pp.1-13
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• 2018

Purpose: The development of compact tractors that can be used in dry fields, greenhouses, and orchards for pest control, weeding, transportation, and harvesting is necessary. The development and performance evaluation of power transmission units are very important when it comes to tractor development. This study evaluates the performance of a driving power transmission unit of a 50 kW multi-purpose narrow tractor. Methods: The performance of the transmission and forward-reverse clutch, which are the main components of the driving power transmission unit of multi-purpose narrow tractors, was evaluated herein. The transmission performance was evaluated in terms of power transmission efficiency, noise, and axle load, while the forward-reverse clutch performance was evaluated in terms of durability. The transmission's power transmission efficiency accounts for the measurement of transmission losses, which occur in the transmission's gear, bearing, and oil seal. The motor's power was input in the transmission's input shaft. The rotational speed and torque were measured in the final output shaft. The noise was measured at each speed level after installing a microphone on the left, right, and upper sides. The axle load test was performed through a continuous equilibrium load test, in which a constant load was continuously applied. The forward-reverse clutch performance was calculated using the engine torque to axle torque ratio with the assembled engine and transmission. Results: The loss of power in the transmission efficiency test of the driving power unit was 6.0-9.7 kW based on all gear steps. This loss of horsepower was equal to 11-18% of the input power (52 kW). The transmission efficiency of the driving power unit was 81.5-89.0%. The noise of the driving power unit was 50-57 dB at 800 rpm, 70-77 dB at 1600 rpm, and 76-83 dB at 2400 rpm. The axle load test verified that the input torque and axle revolutions were constant. The results of the forward-reverse clutch performance test revealed that hydraulic pressure and torque changes were stably maintained when moving forward or backward, and its operation met the hydraulic design standards. Conclusions: When comprehensively examined, these research results were similar to the main driving power transmission systems from USA and Japan in terms of performance. Based on these results, tractor prototypes are expected to be created and supplied to farmhouses after going through sufficient in-situ adaptability tests.

• Journal of Korean Neurosurgical Society
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• v.29 no.10
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• pp.1296-1302
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• 2000

Objective : Traumatic brain injury including diffuse axonal injury has been shown to result in a decrease in brainfree magnesium concentration, an endogenous inhibitor of calcium entry into neuron, that is associated with the development of neurological motor deficits. The goal of this study is to establish the therapeutic window during which the therapy with $MgSO_4$ and/or hypothermia improve damaged neurons by TUNEL stain. Method : Moderate brain injury was induced in 64 adult Sprague-Dawley rats, weighing 350 to 450gm each, by using a simple weight-drop device(Marmarou model). The animals were randomly assigned to four groups(sixteen rats each, a control group, a group treated with $MgSO_4$, a group treated with hypothermia, and a group treated with $MgSO_4$ and hypothermia) and the rats in each group were sacrificed and studied after 12 hrs, 24 hrs, 1 wk, and 2 wks after insult. In hypothermic group, these rats were subjected to hypothermia after injury, with their rectal temperatures maintained at $32^{\circ}C$ for 1 hour. After 1-hour period of hypothermia, rewarming to normothermic level was accomplished over 30-minute period. In the groups treated $MgSO_4$, hypothermia and $MgSO_4$ were subsequently treated with $MgSO_4$($750{\mu}moles/kg$) infused intra-muscularly at 30 minutes after trauma. Result : In all treated groups, a significant reduction in TUNEL positive cells was found in comparison with the control group each time(p<0.001). Between treatment groups, No differnce was seen 12hrs, 24hrs, and 1wk. However, hypothermic group treated with or without $MgSO_4$ showed more significant reduction in apoptotic cells than group treated with $MgSO_4$ 2 weeks after trauma(p<0.05). However, hypothermic group treated with $MgSO_4$ showed no significant reduction in apoptotic cells compared with hypothermic group(p>0.05). Conclusion : These findings suggest that both hypothermia and $MgSO_4$ significantly improve pathological changes. Otherwise simultaneously $MgSO_4$ and hypothermia treatment groups is failed to provide additional neuroprotection. These results may be relevant to the design of future clinical trials of therapeutic hypothermia and $MgSO_4$ for traumatic brain injury.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2055-2063
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• 2015

The purpose of this study is to have a preliminary study in order to identify changes in occupational performance skills and visual perception of patients with mild dementia, who have been provided with a group occupational therapy program, within community day-care center. The subjects of this study were 9 people with mild dementia living in a community. The period of administration was for 60 minutes per session three times a week during four weeks. We assessed their visual perception function(MVPT) and occupational performance(AMPS). One group pre-post test design was implemented as an experimental study to compare the results between before and after applying the group occupational therapy program within sensory, physical, creative activity. While a statistically significant difference between before and after the program of motor skills(occupational performance skill) is not shown, the visual perception function and occupational performance of patients with mild dementia improved significantly after receiving occupational therapy program(p<0.01, p<0.05). Therefore, it is possible to conclude that the group occupational therapy program is helpful to manage the occupational performance skills and visual perception of patients with mild dementia in community day-care center.

• The Journal of Korean Academy of Sensory Integration
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• v.14 no.2
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• pp.46-57
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• 2016

Objective : The purpose of this study is to prove the effects of exercise intervention on postural control of children with cerebral palsy in Korea by systematic review. Methods : Total 18 studies were selected through Korean research database engine such as DBpia, KISS and RISS for the systematic review in this study. Key words used were 'cerebral palsy', 'postural control' and 'balance' and publication time period was limited only after October 2006 in the research selection. All the selected studies were reviewed in terms of quality level of evidence and methodological quality level, and then the results were analyzed with Patient, Intervention, Comparison, Outcome (PICO). Results : For the level of evidence, it is found that 8 studies show Grade I, 5 studies show Grade III, and 2 studies show Grade V. In terms of Methodological quality, majority of the studies showed 'Fare' level. Majority of target population of the studies was children with spastic diplegia. Most research design of the studies were randomized controlled trials. The results in several suited showed that the postural control exercise used in Korea has positive impact on improvement of motor and balance ability. Conclusion : Impact of the exercise intervention used in Korea for postural control of children with cerebral palsy has been evidenced in this study. It is proposed that further research need to be done considering several types of cerebral palsy.

• Journal of IKEEE
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• v.24 no.2
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• pp.654-660
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• 2020

Through the output of brain waves during muscle operation, this paper checks whether it is possible to find characteristic vectors of brain waves that are capable of dividing left and right movements by extracting brain waves in specific areas of muscle signal output that include the motion of the left and right muscles or the will of the user within EEG signals, where uncertainties exist considerably. A typical surface EMG and noninvasive brain wave extraction method does not exist to distinguish whether the signal is a motion through the degree of ionization by internal neurotransmitter and the magnitude of electrical conductivity. In the case of joint and motor control through normal robot control systems or electrical signals, signals that can be controlled by the transmission and feedback control of specific signals can be identified. However, the human body lacks evidence to find the exact protocols between the brain and the muscles. Therefore, in this paper, efficiency is verified by utilizing the results of application of CSP (Common Spatial Pattern) filter to verify that the left-hand and right-hand signals can be extracted through brainwave analysis when the subject's behavior is performed. In addition, we propose ways to obtain data through experimental design for verification, to verify the change in results with or without filter application, and to increase the accuracy of the classification.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.4
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• pp.257-263
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• 2015

The purpose of this study was to survey the elderly patients through Basic information, Problems Wheelchair, Wheelchair Satisfaction, Usage and Requirements. The meaning of purpose is identify the problems and difficulties of wheelchair use in geriatric patients and an alternative for the correct use of wheelchairs elderly patients. The study investigated through questionnaires. That used questionnaires to modified to Gu Hyeon-Mo questionnaire (2005) and Quebec User Evaluation of Satisfaction with assistive Technology 2.0. 120 of 150 questionnaires were collected and one of them is excluded. Analysis results suggest the following. It was often feel joint pain results from physical damage. In addition when you use a wheelchair it was often feel discomfort in lower back and pelvis. And it feels uncomfortable when moving the tilt. Wheelchair satisfaction of the participants responded to the most 'Normal'. Results of the wheelchair operation ability is as follows. In the case of manual wheelchairs was feeling the difficulty to cross the threshold, Wheel lying, Stairs usage. Also In the case of an electric wheelchair was feeling the difficulty to use Tilt and Decline, Separate from the motor, and Replacement battery. In conclusion, To reduce of back pain and hip joints of elderly patients need to modify design and appearance of the wheelchair. In a later study will find to reduce discomfort and to improve satisfaction of the elderly who use wheelchairs. It will have to periodically examine the usage and satisfaction with them.

• The Journal of Korean Academy of Sensory Integration
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• v.13 no.2
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• pp.53-61
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• 2015

Objective : The purpose of this study was to investigate the effects on sensory integration interventions for korean children which focused on vestibular - proprioceptive system. Methods : Authors systematically searched published studies in DBpia, KISS and RISS databases from August to September 2015. Key words in the search were 'sensory integration intervention', 'sensory integration therapy' and 'vestibular-proprioceptive'. By using the inclusion and exclusion criteria, we selected seven studies for further analyses examining level of evidence and methodological qualities. Information for the analyses were on study designs, participants, interventions, outcome measures and results. Results : Grade IV rated evidence was found from five studies, and Grade III and Grade V rated evidence was found from one for each study. The methodological levels of the quantitative studies were 'fair' (2) and 'poor' (5). Subjects for the studies were developmental delay (5), Asperger Syndrome (1), and not specific diagnosis (2). Single-subject design was most frequently used and motor area were most frequently evaluated. The interventions used the studies showed positive effects on outcome measures. Conclusion : This study presented the summary of sensory integration intervention based on vestibular-proprioceptive system for Korean children. More studies with high level of evidence and various study designs need to be followed.

• Women's Health Nursing
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• v.7 no.4
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• pp.642-656
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• 2001

The purpose of this study is to find the difference of the climacteric symptoms and quality of life according to hormone replacement therapy (HRT) in climacteric women. The research design was a descriptive survey with questionaries. A convenience sample of 181 climacteric women aged 45-65 who had climacteric symptoms were selected in Kwangju city, Korea. Sixty-six climacteric women among those subjects were receiving HRT at K university hospital in Kwangju city. Data were collected by the interview with questionaries from Feb 3. 1999 to March 25, 1999. Climacteric symptoms were measured using scores developed by Neugarten(1965) and modified by Park(1989), and the quality of life scale related to climacteric symptoms developed by Hildtich(1996) and modified Kim(1998). Data were analyzed by $x^2$-test, t-test, ANOVA and Pearson's correlation procedures, using SAS/win PC+. The results were as follows ; 1. No statistically significant differences were found between the receiving HRT group and not receiving HRT group in demographic, obstetrical and health related characteristics. 2. There were no significant difference on the climacteric symptoms between the group of women receiving HRT (score 2.4) and the group of women who were not (score 2.6) except psychological area (t= 2.407, p= 0.017). 3. The quality of life of the group of women receiving HRT was significantly higher than that the group of women who were not (t=2.151, p=.032). 4. The quality of life of the group of women receiving HRT were high scores There were significantly high of the quality of life in the vaso-motor change area (t=2.634, p= 0.009), psycho-social change area (t=3.239, p=0.001), and physical change area (t=2.031, p=0,043) in the group of receiving HRT compared to not receiving HRT group. 5. The variables showed significantly differences on the degree of climacteric symptoms of the group of women not receiving HRT were the subjective health state (t=15.81, p=0.000), age (t=7.50, p=0.007), feeling of menopause (t=30.88, p=0,000) and climacteric periods (t=8.66, p=0.003), and receiving HRT were number of para (t=3.95, p=0.050) and feeling of menopause (t=3.94, p=0.050). 6. The variables showed significantly difference on the quality of life of the group of women not receiving HRT were the subjective health state (t=4.14, p=0.044) and feeling of menopause (t=10.86, p=0.001). 7. There were significantly positive correlations between the climacteric symptoms and the quality of life in climacteric women (r=0.512, p=0.000).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.11
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• pp.979-986
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• 2016

The tripod shafts of constant-velocity joint are used in both the trains KTX and KTX-sanchon. It is an important component that connects the motor reduction unit and the axle reduction unit in a power bogie. The tripod shaft not only transmits drive and brake torque in the rotational direction, but also slides in the axial direction. If the drive system is loaded with an excessive torque, the fuse part of the shaft will be fractured firstly to protect the other important components. In this study, a rig was developed for conducting torsion tests on the tripod shaft, which is a type of mechanical fuse. The tripod shafts were subjected to torsional fracture test and torsional fatigue test on the rig. The weak zone of the tripod shaft was identified, and its fatigue life was predicted using finite element analysis (FEA). After analyzing the FEA results, design solutions were proposed to improve the strength and fatigue life of the tripod shaft. Furthermore, the deterioration trend and time for failure of the tripod shaft were verified using the hysteresis loops which had been changed with the advancement of the torsional fatigue test.