• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.6
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• pp.524-530
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• 2002

A control of the body posture and movement is maintained by the vestibular system, vision, and proprioceptors. Afferent signals from those receptors are transmitted to the vestibular nuclear complex, and the efferent signals from the vestibular nuclear complex control the eye movement and skeletal muscle contract. The postural disturbance caused by loss of the vestibular function results in nausea, vomiting, vertigo and loss of craving for life. The purpose of this study is to develop a off-vertical rotatory system for evaluating the function of semicircular canals and otolith organs, selectively, and visual stimulation system for- stimulation with horizontal, vortical and 3D patterns. The Off-vortical axis rotator is composed of a comportable chair, a DC servo-motor with reducer and a tilting table controlled by PMSM. And a double feedback loop system containing a velocity feedback loop and a position feedback loop is applied to the servo controlled rotatory chair system. Horizontal, vertical, and 3D patterns of the visual stimulation for applying head mounted display are developed. And wireless portable systems for optokinetic stimulation and recording system of the eye movement is also constructed. The gain, phase, and symmetry is obtained from analysis of the eye movement induced by vestibular and visual stimulation. Detailed data were described.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.6
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• pp.546-553
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• 2002

A control of the body posture and movement is maintained by the vestibular system, vision, and proprioceptors. Especially, vestibular system has a very important function that controls the eye movement through vestibuloocular reflex and contraction of skeletal muscles through vestibulospinal reflex. However, postural disturbance caused by loss of vestibular function results in nausea, vomiting, vertigo and loss of craving for life. Lose of vestibular function leads to abnormal reflex of eye movements named nystagmus. Analysis of the nystagmus is needed to diagnose the vertigo, which is performed by means of electrooculography(EOG). The purpose of this study is to develop a computerized system for data processing and an algorithm for the automatic evaluation of the slow component velocity(SCV) of nystagmus induced by optokinetic(OKN) stimulation system. A new algorithm using recursive least square method(RLSM) to detect SCV of nystagmus is suggested in this paper. This method allows a fast and precise evaluation of the nystagmus, through artifact rejection techniques. The results are depicted in this paper.

• The Journal of Korean Physical Therapy
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• v.29 no.1
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• pp.33-38
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• 2017

Purpose: This study was conducted to investigate the effects of variations in arm swing during gait on movement of the trunk and pelvis. During the gait task, the angle of the trunk and pelvic rotation were analyzed according to arm swing conditions. Methods: Seventeen healthy males participated in this study. All subjects were analyzed for gait on a treadmill three times each under three different types of arm swing conditions - natural arm swing, restricted arm swing using a phone, restricted swing in both arms. 3-D motion analysis systems were used to collect and analyze the kinematic data of trunk and pelvic movements, and repeated one-way ANOVA was used to compare the trunk and pelvic kinematic data and symmetry index. The level of significance was ${\alpha}=0.05$. Results: The results showed kinematic differences in trunk and pelvic during gait based on the arm swing conditions. Specifically, there were significant differences in trunk rotation, left and right trunk rotation and symmetry index of trunk rotation during gait among the three arm swing conditions. ROM was used to calculate a symmetry index (SI) based on the average left and right trunk rotation in which a value closer to zero indicated better balance. The SI obtained for arm swing restricted with the phone was closer to -1 than the other conditions. Conclusion: Restricted arm swing due to use of a phone had the possibility to induce instability of postural control while walking, which could be seen to suggest a risk of falling during gait.

• The Journal of Korean Society for School & Community Health Education
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• v.21 no.2
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• pp.59-71
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• 2020

Objectives : The purpose of this study was to investigate the change of posture balance and muscular strength before and after exercise by conducting a health gymnastics program for the elderly with chronic diseases of musculoskeletal system. Methods : The subjects of this study were 32 elderly people who had no experience participating in the musculoskeletal system linkage gymnastics program over 65 years old in a rural area in H city, Gyeonggi-do. The data were analyzed by computerized processing with SPSS 23.0. Results : The results of the study were as follows: First, the average of muscular strength before and after gymnastics according to general characteristics was significant in average according to age, presence of spouse, education level, and cohabitation type. Second, the subjects exercised for 2 days a week, and 25.59(±0.51) minutes on average. Third, the change of balance of the face (t=2.993, p=.011), shoulder (t=3.811, p=.002) and pelvic left and right (t=3.584, p=.004) was statistically significant in the posture balance. Fourth, muscular strength was statistically significant in motor function of AMS, SMS, and FMS (p<0.001). Conclusion : Therefore, after applying the health gymnastics program, the improvement of posture balance and muscular strength of the elderly became apparent, so it is necessary to disseminate this gymnastics program. The health gymnastics program is expected to positively improve the quality of life for the elderly.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.2
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• pp.129-136
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• 2020

PURPOSE: This study aimed to determine the most effective feedback condition for static balance in elderly subjects. METHODS: Thirty-eight elderly subjects (12 men and 26 women with a mean age of 77.21 years) participated in this study. They each completed a questionnaire on their general characteristics, excluding personal identification codes. The static balance ability of the participants was evaluated using a Wii Balance Board and the Balancia program (version 2.0). The following three feedback conditions were considered: condition 1 (tactile feedback), condition 2 (visual feedback), and condition 3 (no feedback). One-way repeated-measures analysis of variance was used for the comparisons according to sway length and sway velocity. The statistical significance level was set to α = .05 for all variables. RESULTS: Significant differences in the sway length and sway velocity were observed between the three conditions (p < .05). Significant differences in the sway length were noted in the order of conditions 1, 2, and 3 (p < .05), and significant differences in the sway velocity in the order of conditions 3, 2, and 1 (p < .05). CONCLUSION: Significant differences in static balance ability were observed between the three conditions. In this study, tactile feedback was found to be the most effective feedback for balance training. Owing to aging and impairment of the senses, such as that observed in the tactile receptors, visual receptors, and proprioceptors, it is recommended that elderly subjects participate in balance training.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.2
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• pp.39-48
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• 2020

PURPOSE: This study examined the effects of integrating transcutaneous electrical nerve stimulation into treadmill gait training by applying functional electrical stimulation on the spasticity, balance, and gait ability of chronic stroke patients METHODS: Twenty participants were assigned randomly to two groups: the treadmill gait training group with applied functional electrical stimulation (FES) with integrated transcutaneous electricalstimulation (TENS) (experimental group, EG, n = 10) and the treadmill gait training group with FES (control group, CG, n = 10). Both groups received treadmill gait training with FES for 30 minutes a time, four times a week, during five weeks. The experimental group received additional TENS on their L3, L5, and S2 dermatome for 30 minutes before the interventions. The spasticity, balance, and gait ability were evaluated before and after the training to compare the intergroup and intragroup changes. RESULTS: Both groups showed significant improvements in the static, dynamic balance, and gait ability (p < .05), but did not show any significant changes in the muscle tone. The EG showed significant improvements in the static balance ability and gait cycle compared to the CG (p < .05). CONCLUSION: Treadmill gait training combined with FES with integrated TENS is an effective method for improving the static balance and gait cycle. On the other hand, the effects of treadmill gait training with FES on spasticity need to be studied further.

• Journal of the Ergonomics Society of Korea
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• v.29 no.3
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• pp.383-391
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• 2010

The present study evaluated a preliminary control room (CR) design of radioactive waste facility using the $JACK^{(R)}$ human simulation system. Four digital humanoids ($5^{th}$, $50^{th}$, $95^{th}$, and $99^{th}$ percentiles) were used in the ergonomic evaluation. The first three were selected to represent 90% of the target population (Korean males aged 20 to 50 years) and the last to reflect the secular trend of stature for next 20 years in South Korea. The preliminary CR design was assessed by checking its compliance to ergonomic guidelines specified in NUREG-0700 and conducting an in-depth ergonomic analysis with a digital prototype of the CR design and the digital humanoids in terms of postural comfort, reachability, visibility, and clearance. For identified design problems, proper design changes and their validities were examined using JACK. A revised CR design suggested in the present study would contribute to effective and safe operations of the CR as well as operators' health in the workplace.

• Physical Therapy Korea
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• v.27 no.4
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• pp.272-277
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• 2020

Background: Forward head posture (FHP) is common postural malalignment. FHP is described relatively extension to upper cervical and lower cervical is relatively flexion. Although several researchers mentioned the lower cervical flexion posture in FHP, most of the studies related to FHP is focused on the deep cervical flexor function. Objects: The purposes of present study is to compare the cervical strength (upper cervical extension [UCE], lower cervical extension [LCE], upper cervical flexion [UCF], lower cervical flexion [LCF]) between individuals with and without FHP. Methods: Fifty-one participants are recruited. Participants who have the craniovertebral angle (CVA) less than 48 degree were classified to the FHP group (n = 24) and the others were included in without FHP group (n = 27). The cervical strength (UCE, LCE, UCF, LCF) were measured using Smart KEMA strength sensor and the strength data was normalized by body weight. All strength measurement conducted at head and neck neutral position in sitting. Independent t-test was used to compare the cervical strength between individuals with and without FHP. Results: The mean value of CVA was greater in without FHP group than with FHP group (p < 0.000). The strength value of UCF (p < 0.002) and LCE (p < 0.001) was significant less in FHP group than without FHP group. But no significant differences were seen in the LCF and UCE strength between two groups. Conclusion: UCF and LCE weakness in FHP group should be considered to evaluate and manage the individuals with FHP.

• Physical Therapy Korea
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• v.21 no.3
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• pp.11-19
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• 2014

The purpose of this study was to investigate the activity of the transverse abdominal muscle resulting from changed posture by measuring the thickness of the transverse abdominal muscle in a supine posture, a slouched sitting posture, and an erect sitting posture. The subjects of the study were 28 patients with cerebral palsy. All their transverse abdominal muscles at the end of inhalation were measured at supine, slouched sitting (S sitting) and erect sitting (E sitting) postures by using ultrasonography, and then their dynamic sitting balance was measured at S sitting and E sitting postures by using BioRescue. For the statistical analysis, the Kruskal-Wallis test and the Wilcoxon signed-rank test were used to compare the differences among each the postures. The results were as follows. The thickness of the transverse abdominal muscle when comparing the supine posture and the S sitting posture showed no statistically significant difference. But the E sitting posture showed a statistically significant difference as compared with the others. In addition, the dynamic sitting balance in comparing the S sitting and E sitting postures showed a significant difference. In conclusion, the E sitting posture has a more positive effect on postural control and balance than generally taking the S sitting posture, for the sitting posture of a patient with cerebral palsy. It is suggested that patients with cerebral palsy mainly experiencing a sedentary life or being in a wheelchair should be seated in the E sitting posture during their daily life, and it may be necessary to continue to monitor and manage the proper E sitting posture.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.661-664
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• 2002

A control of the body posture and movement is maintained by the vestibular system, vision, and proprioceptors. Afferent signals from those receptors are transmitted to the vestibular nuclear complex, and the efferent signals from the vestibular nuclear complex control the eye movement. The postural disturbance caused by loss of the vestibular function results in nausea, vomiting, vertigo and loss of craving for life. The purpose of this study is to develop a off-vertical rotatory system for evaluating the function of semicircular canals and otolith organs, selectively, and visual stimulation system for stimulation with horizontal, vertical and 3D patterns. The Off-vertical axis rotator which stimulates semicircular canals and otolith organs selectively is composed of a comportable chair, a DC servo-motor with reducer and a tilting table controlled by PMSM. And a double feedback loop system containing a velocity feedback loop and a position feedback loop is applied to the servo controlled rotatory chair system. Horizontal, vertical, and 3D patterns of the visual stimulation for applying head mounted display are developed. And wireless portable systems for optokinetic stimulation and recording system of the eye movement is also constructed. The Gain, phase, and symmetry is obtained from analysis of the eye movement induced by vestibular and visual stimulation. Detailed data were described.