• Korean Journal of Soil Science and Fertilizer
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• v.24 no.2
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• pp.124-129
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• 1991

A mass balance method which measures directly both the sorbed pesticide and equilibrium solution concentration was compared with the batch method in a hypothetical experiment to determine the precision of sorption measurement. The mass balance method was shown to improve precision of sorption measurement. The two methods were also tested experimentally on the Wahiawa soil, 0-20, 40-60 and 100-120 cm, and Salinas soil, 0-15 and 115-130 cm. The mass balance method greatly improved precision of sorption measurement on the deep Wahiawa subsoil having the lowest sorption. The coefficient of variation (CV) for $K_d$ measurement was 20.3% for the batch method and 8.4% for the mass balance method. For other soil samples tested, precision of the batch method was relatively high but was still improved by the mass balance method.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.29 no.3
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• pp.43-53
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• 2023

Background: Patients with neck pain develop instability due to muscle imbalance, decreased proprioception, and balance disorders. Studies have examined various exercise methods as treatment methods, but few studies have compared the effects of cervical stabilization exercise and dynamic balance exercise. The purpose of this study was to investigate the effects of dynamic balance exercise on pain, functional level, and psychosocial level in patients with non-specific chronic neck pain. Methods: Thirty-four non-specific chronic neck pain patients were randomly assigned to the experimental group (EG, n=17) and control group (CG, n=17); the cervical stabilization exercise and dynamic balance exercise program were applied to the EG; and only the cervical stabilization exercise program was applied to the CG. The intervention was conducted twice a week, for six weeks. Assessment items evaluated pain, dysfunction (Korean version neck disability index), range of motion, craniocervical flexion test, cervical deep flexor endurance test, and psychosocial level. Data analysis was performed using intention-to-treat analysis as assigned. To analyze differences in the items assessed in the two groups, we used a repeated measures analysis of variance with an interaction between group (EG, CG) and time point (baseline, 6 weeks, 12 weeks). Results: The endurance of the cervical flexor muscles between the group and the measurement point after intervention (p<.05). Both groups showed significantly improved endurance between time points after the intervention (p<.05), with the EG showing a greater change than the CG. None of the other measurement items differed in the pattern of change between measurement points. Conclusion: In conclusion, the EG applying a cervical stabilization exercise and a dynamic balance exercise experienced a significant difference in muscle endurance improvement compared to the CG. We propose an exercise intervention program that includes stabilization exercises and dynamic balance exercises for patients with chronic cervical pain who lack muscle endurance.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.1
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• pp.1-8
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• 2019

Purpose : The purpose of this study was to examine the correlation between static and dynamic balance according to the virtual reality-based squat and conventional squat exercise. Methods : Twenty four participants were randomly assigned to the virtual reality-based squat (VRS) group (n=12) or conventional squat (CS) group (n=12). The static balance (C90 area, C90 angle, trace length, sway average velocity) and dynamic balance (forward, rearward, leftward, rightward) were measured using a force plate by BT4. The VRS group used the virtual reality system during 4 weeks, while the CS group underwent classical squat training. Independent t-test was used to test the homogeneity of the general characteristics of the subjects. The collected data was analyzed using the paired t-test for static and dynamic balance comparisons before and after exercise in both groups and Pearson's test for the correlation between static and dynamic balance according to the measured time. The significance level was set to 0.05. Results : There was no significant correlation between group and static and dynamic balance related variables (p>.05). There was a significant correlation between measurement time and static and dynamic balance related variables (p<.05). According to the measurement time, the static balance parameter C90 area in the VRS group after exercise was significantly decreased (p<.05). The values of forward, leftward and rightward in the VRS group were significantly increased after exercise (p<.05). Conclusion : It is suggested that 20 normal healthy adult men and women who have normal balance ability can improve their ability to control their posture by improving the balance ability when applying virtual reality-based squat exercise.

• The Journal of Korean Physical Therapy
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• v.30 no.4
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• pp.146-150
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• 2018

Purpose: This study aimed to investigate the effect of active vibration exercise on trunk muscle activity, balance, and activities of daily living in patients with chronic stroke. Methods: Twenty-four patients with chronic stroke were randomly assigned to an experimental (n=12) or a control (n=12) group. The experimental group performed an active vibration exercise workout for 20 minutes a day five times a week for 4 weeks using a flexi-bar. Trunk muscle activity was measured using surface electromyography. Balance was measured using the Berg balance scale. Activities of daily living were measured using the functional independence measure. Results: The intragroup comparison showed significant differences in the rectus abdominis, internal oblique, and external oblique muscle activity values, Berg balance scale score, and functional independence measurement values in the experimental group. The intergroup comparison showed that differences in the rectus abdominis and internal oblique external oblique muscle values, Berg balance scale score, and functional independence measurement value for the experimental group were significantly related to those in the control group. Conclusion: Based on these results, this study proved that the active vibration exercise effectively improved trunk muscle activity, balance, and activities of daily living in patients with chronic stroke.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.4
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• pp.139-146
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• 2017

PURPOSE: The purpose of this study was to systematically analyze the reliability and validity of the Korean-version of the balance assessment tools. METHODS: Two reviewers of this study independently evaluated the titles of articles and abstracts of studies published until December 2016 through electronic databases (RISS, NDSL, KISS, DBpia) using the keywords "Balance or posture or postural control or postural stability", "Test or assessment or measurement or outcome measure or assessment tool or measurement tool", "Korean version", "Reliability" and "Validity". Regarding the questions considered suitable for the purpose of this study, consensus was reached after reading the full text. Selecting journals suitable for the purpose of the study, they were analyzed as data. RESULTS: The reviewers selected nine papers suitable for the purpose of this study, and Korean-version of the balance assessment tools, included the Berg Balance Scale (BBS), Activities-specific Balance Confidence (ABC) scale, Postural Assessment Scale for Stroke (PASS), Motor Assessment Scale (MAS), Trunk Impairment Scale (TIS), Falls Efficacy Scale (FES), Tinetti-Balance scale, Fullerton Advanced Balance (FAB) scale, and Function In Sitting Test (FIST). Our study showed that the reliability and validity of the Korean-version of the balance assessment tools were high. CONCLUSION: The Korean-version of the balance assessment tools with high reliability and validity would enable physical therapists to make a more accurate evaluation of balance.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.2
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• pp.221-230
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• 2023

Purpose : This study was performed to evaluate the effects of virtual reality combined robot assist gait training (VRG) on improvement of balance and respiratory function in chronic stroke patients. Methods : A single-blind, randomized controlled trial (RCT) was conducted with 35 chronic stroke patients. They were randomly allocated 2 groups; VRG group (n=18) and conservative treatment group (CG; n=17). The VRG group received 30 minutes robot assisted gait training combined virtual reality training, robot assisted gait training was conducted in parallel using a virtual reality device (2 sessions of 15 minutes in a 3D-recorded walking environment and 15 minutes in a downtown walking environment). In the conservative treatment group, neurodevelopmental therapy and exercise therapy were performed according to the function of stroke patients. Each group performed 30 minutes a day 3 times a week for 8 weeks. The primary outcome balance and respiratory function were measured by a balance measurement system (BioRescue, Marseille, France), Berg balance scale, functional reach test for balance, Spirometry (Cosmed Micro Quark, Cosmed, Italy) for respiratory function Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), and maximum expiratory volume (PEF) were measured according to the protocol. The measurement were performed before and after the 8 weeks intervention period. Results : Both groups demonstrated significant improvement of outcome in balance and respiratory function during intervention period. VRG revealed significant differences in balance and respiratory function as compared to the CG groups (p<.05). Our results showed that VRG was more effective on balance and respiratory function in patients with chronic stroke. Conclusion : Our findings indicate that VRG can improve balance and respiratory function, highlight the benefits of VRG. This study will be able to be used as an intervention data for recovering balance and respiratory function in chronic stroke patients.

• Physical Therapy Korea
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• v.3 no.3
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• pp.82-91
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• 1996

Normal balance is defined as state in which the body is equlilibrium. It is complex motor control task, requring integration of sensory information, neural processing, and biomechanical factors. There are major two factors contribute to balance control, the neurological and the musculoskeletal. The neurological factor provides the sensory processing and motor output mechanisms that are the neurophysiological basis for response. The musculoskeletal factor provides the mechanical structure for response. When all components of two factors are operating effectively, the postural response should be appropriate and effective for good balance control. Therfore, balance can be influenced by above all factors. In addition, balance can be also influenced by muscle tone, hearing, physiological factors, and environmental factors. Physical therapists must understand factors of balance control so that we can accurately assess balance. Therefore, physical therapists have to develop useful balance measurement tools to evaluate balance.

• Wind and Structures
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• v.18 no.4
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• pp.375-389
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• 2014

The high-frequency force-balance (HFFB) technique and its subsequent improvements are reviewed in this paper, including a discussion about nonlinear mode shape corrections, multi-force balance measurements, and using HFFB model to identify aeroelastic parameters. To apply the HFFB technique in engineering practice, various validation studies have been conducted. This paper presents the results from an analytical validation study for a simple building with nonlinear mode shapes, three experimental validation studies for more complicated buildings, and a field measurement comparison for a super-tall building in Hong Kong. The results of these validations confirm that the improved HFFB technique is generally adequate for engineering applications. Some technical limitations of HFFB are also discussed in this paper, especially for higher-order mode response that could be considerable for super tall buildings.

• The Journal of Korean Physical Therapy
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• v.20 no.1
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• pp.33-40
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• 2008

Purpose: This study was designed to investigate the correlations between muscle strength of the ankle and balance, walking in the elderly. Methods: Thirty-nine subjects were selected from a population of female volunteers. Measurement of balance ability included evaluation of timed "up and go", functional reach, and a one leg standing test. Measurement of walking analysis included evaluation of cadence, stride length, step length, and walking speed. Maximal voluntary isometric contraction (MVIC) of the ankle muscle strength was measured by use of a dynamometer. Results: For balance, there were significant negative correlations between timed "up and go" and the MVIC of the ankle dorsiflexor. There were significant positive correlations between one leg standing with the eyes closed and the MVIC of the ankle dorsiflexor. For walking, there were significant positive correlations between cadence, walking speed and the MVIC of the ankle dorsiflexor. Conclusion: This study showed that there were close relationships between muscle strength of the ankle dorsiflexor and walking and balance in the elderly.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.310-319
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• 2017

This paper introduces the method how to measure the thrust in impulse facility. In a Facility having such a short duration time of steady flow, there's no time to reach a steady state of the forces acting on model so that the test model vibrates until the end of the flow. The forces exerted on an engine exist with vibration so that the usual force balance can not be used. SWFB(Stress Wave Force Balance) technique is utilized in a shock tunnel to get the thrust. As an example, a model force balance has been calculated its strain against impulse force by using FEM(Finite Element Method). A transfer function between the impulse force and strain has been obtained by the way of de-convolution.