• Journal of International Academy of Physical Therapy Research
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• v.10 no.1
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• pp.1739-1745
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• 2019

Background: There have been many studies on self-myofascial release (SMR) stretching, but there are few comparative studies on the effects of massages using a release ball, which is a type of the SMR method. Objective: To investigate the immediate effects of release ball massage and self-stretching on proprioceptive sensory, hamstring's temperature, range of motion (ROM) muscle strength,. Design: Crossover study. Methods: Thirty women in 20's at S University in Busan voluntarily participated in the study. Participants were random to release ball group (n=15) or self-stretching group (n=15). Both groups performed 3 sets of exercises, stretching for 30 seconds and resting for 15 seconds in each position. The proprioceptive sensory, temperature of the hamstring muscle, ROM, and strength were measured before exercise, 5 minutes after exercise, and 30 minutes after exercise. Results: Release ball group showed significant differences in muscle length and temperature over time (p<.05). The comparison between two group over time showed significant differences in muscle length, temperature, and muscle strength (p<.05). Conclusions: These results demonstrate that release ball massage and self-stretching are beneficial for improving hamstring's temperature, ROM and muscle strength.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.6
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• pp.514-520
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• 2016

Oil and gas production riser systems need to be designed considering a wide band quarter-modal analysis which contains low-, wave-, VIV(Vortex induced vibration) frequencies. The VIV can be separated into cross-flow(CF) and in-line(IL) components. In this study, the various idealized tri- and quarter-modal spectra are suggested to analyze fatigue damage on the production riser system. In order to evaluate the fatigue damage increment caused by the IL's motion, tri- and quarter-modal spectral fatigue damages are calculated in time domain. And the fatigue damage calculated from two different modal spectra are compared quantitatively. Then the suitability of existent wide band fatigue damage models for quarter modal spectrum was evaluated by comparison of frequency domain calculation and time domain calculation. The result show that although spectral density of IL motion is not remarkable in quantity, the effect on the fatigue damage is significant and existent fatigue damage models are not adequately estimating damage by quarter-modal spectra.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.2
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• pp.29-40
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• 2019

PURPOSE: Despite the widespread occurrence in the general population, few studies have directly evaluated the effects of shingles on non-specific neck pain (NSNP). This study investigated whether sensory training or therapeutic stretching exercises are more effective in increasing neck mobility and reducing neck pain in chronic NSNP patients. METHODS: Eighty-one subjects aged between 20 and 32 years with chronic neck pain (> six months), were allocated randomly to three groups: sensorimotor training group (STG), therapeutic stretching group (TSG), and home exercise group (HEG). All participants received a half-hour training session, three times weekly for six weeks. The outcomes were evaluated using the neck disability index for measuring neck pain, and a universal goniometer to measure the cervical passive range of motion before and after the six-week intervention. RESULTS: The post-test neck disability index scores in the STG (t = 4.86) and TSG (t = 3.24) were decreased significantly (p < .05). The passive range of motion changes in all cervical movements in the STG was increased significantly (p < .05) after intervention compared to those in the other two groups. CONCLUSION: Sensorimotor training using chin tuck exercises may improve neck pain and mobility in subjects with chronic NSNP.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.151-156
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• 2021

The speed and direction of the earth's fluid motion is measured by a remote sensing method using electromagnetic waves. Using UHF radar and GPS Sonde, the vertical profile of fluid velocity was calculated by the Euler measurement method and the Lagrange measurement method, respectively. Since the wind direction, which is the direction of motion of the atmosphere, is indicated in the direction of the wind blowing, and a circular value of 0° - 360° is used, it is necessary to pay attention to statistical analysis. Errors caused by calculation conditions are provided, and the corrected accuracy of comparison results is improved by 400%.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.26 no.2
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• pp.19-27
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• 2020

Background: The purpose of this study was to examine the effects of a multi-modal exercise program for patients with chronic low back with respect to pain intensity, trunk muscle strength and Oswestry disability index. Methods: Thirty patients with chronic low back pain were recruited and divided equally into two groups. The multi-modal training program comprised a series of exercises such as warm-up, stabilization exercises, stretching, endurance exercises, and cool down whereas the control group performed only stabilization exercises. The both group spent an equal amount of time performing 60 minutes per day, three times per week, for five weeks. Results: The experimental group demonstrated statistically significant improvements in range of motion, trunk muscle strength, the visual analogue scale, and the Oswestry Disability Index (p<.05). Intergroup comparison showed a statistically significant difference in the range of motion of the lumbar spine and the degree of disability in the experimental group. Muscle strength and pain were statistically significant in both groups. Conclusion: The multi-modal exercise program is effective for patients with chronic low back pain, as it reduces lower back pain, increases trunk muscles strength, and decrease the potential for becoming disabled.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.314-324
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• 2020

Due to the nonlinearity and environmental uncertainties, the design of the ship's steering controller is a long-term challenge. The purpose of this study is to design an intelligent autopilot based on Extended Kalman Filter (EKF) trained Radial Basis Function Neural Network (RBFNN) control algorithm. The newly developed free running model scaled surface vessel was employed to execute the motion control experiments. After describing the design of the EKF trained RBFNN autopilot, the performances of the proposed control system were investigated by conducting experiments using the physical model on lake and simulations using the corresponding mathematical model. The results demonstrate that the developed control system is feasible to be used for the ship's motion control in the presences of environmental disturbances. Moreover, in comparison with the Back-Propagation (BP) neural networks and Proportional-Derivative (PD) based control methods, the EKF RBFNN based control method shows better performance regarding course keeping and trajectory tracking.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2529-2539
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• 2022

Stochastic and an empirical Green's function (EGF) methods are preliminarily applied to simulate strong ground motions (SGMs) at seismic stations within nuclear power plant (NPP) sites in South Korea by an assumed large earthquake with M_W6.5 (scenario earthquake) on the causative fault of the 2016 Gyeongju earthquake with M_W5.5 (mainshock). In the stochastic method, a ratio of spectral amplitudes of observed and simulated waveforms for the mainshock is assumed to be an adjustment factor. In the EGF method, SGMs by the mainshock are simulated assuming SGMs by the 2016 Gyeongju earthquake with M_W5.0 (foreshock) as the EGF. To simulate SGMs by the scenario earthquake, a ratio of fault length to width is assumed to be 2:1 in the stochastic method, and SGMs by the mainshock are assumed to be EGF in the EGF method. The results are similar based on a bias of the simulated response spectra by the two methods, and the simulated response spectra by the two methods exceeded commonly standard design response spectra anchored at 0.3 g of NPP sites slightly at a frequency band above 4 Hz, but considerable attention to interpretation is required since it is an indirect comparison.

• Earthquakes and Structures
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• v.20 no.4
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• pp.457-471
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• 2021

This study aims at providing a simple and effective methodology to define a meaningful characteristic period for special class of earthquake records named "pulse-like ground motions". In the proposed method, continuous wavelet transform is employed to extract the large pulse of ground motions. Then, Fourier amplitude spectra obtained from the original ground motion and the residual motion is simply compared. This comparison permits to define a threshold pulse-period (Tp∗) as the threshold period above which the pulse component has negligible contributions to the Fourier amplitude spectrum. The effect of pulse on frequency content of motions was discussed on the light of this definition. The advantage and superior features of the new definition were related to the inelastic displacement ratio (IDR) for single-degree-of-freedom systems with period equal to one half of the threshold period. Analyses performed for the proposed period at three ductility levels u=2,4,6 were compared with the results obtained at half of pulse period derived from wavelet analysis, peak-point method and the peak of product of the velocity and the displacement response spectra (Sv x Sd). According to the results, pulse effects on inelastic displacement ratio seem to be more important when $\frac{T_p^*}{T}=2$ (T is the fundamental vibration period of system). The results showed that utilizing of the proposed definition could facilitate an enhanced understanding of pulse-like records features.

• Physical Therapy Rehabilitation Science
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• v.12 no.1
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• pp.48-55
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• 2023

Objective: The purpose of this study is to compare the effects of extracorporeal shock wave therapy (ESWT) and injection therapy through qualitative and quantitative analysis by synthesizing randomized controlled trials (RCTs) conducted on patients with various shoulder diseases. Design: A systematic review and meta-analysis of randomized controlled trials Methods: This review conducted a literature search through international electronic databases in January 2023 to compare the effects of ESWT and injection therapy. Qualitative analysis was performed as a risk of bias tool, and quantitative analysis was synthesized with a random effect model to show the effect size as a standardized mean difference (SMD). Results: Five RCTs involving 298 individuals with shoulder disorders were included in this systematic review and meta-analysis. ESWT showed a moderate effect on pain (SMD=-0.44; 95% CI, -0.95 to 0.06) and a large effect on shoulder function (SMD =-0.81; 95% CI, -1.70 to 0.07) than injection therapy. A significant difference was found in the shoulder range of motion, showing a large effect size (SMD=1.50; 95% CI, 0.58 to 2.43). Conclusions: When considering treatment options for the management of patients complaining of shoulder disorders, it is appropriate to recommend ESWT first rather than injection therapy to increase the range of motion of the joint. In addition, ESWT is safe for pain control and shoulder function improvement, and a positive prognosis could be expected.

• The Korean Journal of Pain
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• v.36 no.2
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• pp.242-252
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• 2023

Background: Neck pain is a common problem in the general population and second only to low back pain in musculoskeletal problems. The aim of this study is to compare three different types of exercise training in patients with chronic neck pain. Methods: This study was conducted on 45 patients with neck pain. Patients were divided into 3 groups: Group 1 (conventional treatment), Group 2 (conventional treatment plus deep cervical flexor training), and Group 3 (conventional treatment plus stabilization of the neck and core region). The exercise programs were applied for four weeks, three days a week. The demographic data, pain intensity (verbal numeric pain scale), posture (Reedco's posture scale), cervical range of motion ([ROM] goniometer), and disability (Neck Disability Index [NDI]) were evaluated. Results: In all groups, a significant improvement was found in terms of pain, posture, ROM, and NDI values in all groups (P < 0.001). Between the groups, analyses showed that the pain and posture improved more in Group 3, while the ROM and NDI improved more in Group 2. Conclusions: In addition to conventional treatment, applying core stabilization exercises or deep cervical flexor muscle training to patients with neck pain may be more effective in reducing pain and disability and increasing ROM than conventional treatment alone.