• Journal of Korea Game Society
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• v.21 no.3
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• pp.147-156
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• 2021

In this paper, we planned to see the positive effects of the immersive virtual environment. In particular, the positive effect of presence on physical performance was explored. A total of 25 participants were recruited for this experiment and his/her physical performance was measured by Electromyography (EMG) while they were exercising (rowing), and presence was measured by a self-reported measure. The participants were randomly assigned to experience either a) Virtual Reality (VR) or b) non-VR (2D screen) condition when they played the exergame. The result showed that 1) there was a positive relationship between representation mode and presence and 2) the higher level of presence reinforced the user's physical performance. The limitation of the study and future study were also discussed.

• The Journal of Korean Physical Therapy
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• v.26 no.5
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• pp.331-343
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• 2014

Purpose: The purpose of this study is to assess the effectiveness of short-wave therapy (SWT) for treatment of knee osteoarthritis (OA) as compared to placebo and control, and to assess the question of whether the effects are related to the mode, dosage, and application method. Methods: We searched randomized, placebo-controlled trials using electronic databases. We also manually reviewed sources in order to identify additional relevant studies. Results: Eight studies (597 participants) with OA were included in the meta-analysis. Pulse SWT had a significant effect on pain relief compared with control treatment, while did not favour compared with the placebo group. Pulse SWT had a significant effect on functional improvement compared with control and placebo treatment. Continuous SWT had no effect on pain relief and functional improvement. Capacitive SWT a significant effect on pain relief, functional improvement, and muscle strength. Continuous and capacitive SWT had increased muscle strength significantly. We found no clinical significance of all outcomes except pain and functional improvement in pulsed SWT with low dose. There was no difference in adverse events. None of the participants experienced any serious adverse events. Conclusion: Low dose pulsed SWT provided a short-term clinical benefit for pain relief and functional improvement. Pulsed SWD with low and high dose had effects on pain and function. There seems to be a placebo effect. We found significant effects on pain and function in capacitive SWT. Despite some positive findings, this analysis lacked data on how effectiveness is affected by mode, dosage, and application method of SWT. Further well-designed clinical studies are required in order to confirm the effectiveness of SWT.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.3
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• pp.197-207
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• 2005

Design analysis for underground spaces requires evaluating stability related to heading collapses. A failure mode is one of the critical factors in the conventional methods of stability evaluation. Identification of failure modes is, therefore, essential in securing safe construction. In this study failure modes at the tunnel heading in cohesionless soils are investigated using physical model tests for various tunnel depths and ground surface inclinations. Test results showed that the effect of depth and the inclination of ground surface on a failure mode are of significance. It is identified that, with an increase in depth, failure modes become localized in a region close to tunnel face. It is also known that an increase in the inclination of ground surface results in inclined an d wide failure modes. Numerical simulation of laboratory tests was performed, and shown that the numerical analysis is useful in identifying the heading failure modes, particularly for large underground spaces.

• The Korean Nurse
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• v.33 no.3
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• pp.79-91
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• 1994

The purpose of this study was to identify the meaningful nursing diagnosis in maternity unit and to suggest formally the basal data to the nursing service with scientific approach. The subject for this paper were 64 patients who admitted to Chung Ang University Hospital, Located in Seoul, from Mar. 10, to July 21, 1993. The results were as follows: 1. The number of nursing diagnosis from 64 patients were 892 and average number of nursing diagnosis per patient was 13.9. 2. Applying the division of nursing diagnosis to Roy's Adaptation Model, determined nursing diagnosis from the 64 patients were 621 (69.6%) in physiological adaptation mode and (Comfort, altered r/t), (Injury, potential for r/t), (Infection, potential for r/t), (Bowel elimination, altered patterns r/t), (Breathing pattern, ineffective r/t), (Nutrition, altered r/t less than body requirement) in order, and 139 (15.6%) in role function mode, (Self care deficit r/t), (Knowledge deficit r/t), (Mobility, impaired physical r/t) in order, 122 (13.7%) in interdependence adaptation mode, (Anxiety r/t), (Family Process, altered r/t) in order, 10(1.1%) in self concept adaptation mode, (Powerlessness r/t), (Grieving, dysfunctional r/t) in order. 3. Nursing diagnosis in maternity unit by the medical diagnosis, the average hospital dates were 3.8 days in normal delivery and majority of used nursing diagnosis, (Comfort, altered r/t) 64.6%, (Self care deficit r/t) 13.6% in order, and the average hospital dates were 9.6 days in cesarean section delivery and majority of used nursing diagnosis, (Comfort, altered r/t) 51.6%, (Self care deficit r/t) 15.2%, (Infection, potential for r/t) 9.9%, (Injury, potential "for r/t) 8.1%, (Anxiety r/t) 5.0%, (Mobility, impaired physical r/t) 3.3% in order, and the average hospital dates were 15.8days in preterm labor and majority of used nursing diagnosis, (Comfort, altered r/ t), (Anxiety r/t), (Injury, potential for r/t) in order, and the average short-term hospital dates were 2.5days, long-term hospital dates were 11.5days in gynecologic diseases and majority of used nursing diagnosis, (Comfort, altered r/t). (Self care deficit r/t), (Injury, potential for r/t), (Infection, potential for r/t) in order.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3349-3352
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• 2014

• Journal of The Korean Astronomical Society
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• v.56 no.1
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• pp.91-96
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• 2023

In this paper, we describe the first multi-frequency synthesis observations of blazar 0059+581 made with the Radioastron space-ground interferometer in conjunction with the Korean VLBI Network (KVN), Medicina and Torun ground telescopes. We conducted these observations to assess the spaceground interferometer multi-frequency mode capability for the first time.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1260-1264
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• 2009

Precipitation time series is a mixture of complicate fluctuation and changes. The monthly precipitation data of 61 stations during 36 years (1973-2008) in Korea are comprehensively analyzed using the EOFs technique and CSEOFs technique respectively. The main motivation for employing this technique in the present study is to investigate the physical processes associated with the evolution of the precipitation from observation data. The twenty-five leading EOF modes account for 98.05% of the total monthly variance, and the first two modes account for 83.68% of total variation. The first mode exhibits traditional spatial pattern with annual cycle of corresponding PC time series and second mode shows strong North South gradient. In CSEOF analysis, the twenty-five leading CSEOF modes account for 98.58% of the total monthly variance, and the first two modes account for 78.69% of total variation, these first two patterns' spatial distribution show monthly spatial variation. The corresponding mode's PC time series reveals the annual cycle on a monthly time scale and long-term fluctuation and first mode's PC time series shows increasing linear trend which represents that spatial and temporal variability of first mode pattern has strengthened. Compared with the EOFs analysis, the CSEOFs analysis preferably exhibits the spatial distribution and temporal evolution characteristics and variability of Korean historical precipitation.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.6
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• pp.75-81
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• 2010

The purpose of this study was to investigate the short-term effects of electrical massager on stress-related parameters including heart rate variability (HRV), heart rate (HR) using the photoplethysmogram (PPG) signal with motion artifact correction. Twenty healthy subjects were randomly allocated to receive a 15-min section of three types ((1) resting mode (control group), (2) light massage mode, (3) strong massage mode). Results indicated that self-report, VAS (Visual Analog Scale) significantly decreased for two massage modes after massage except control group. In strong massage mode, it was associated with significant increases in HF, but significant decreases in LF and LH/HF ratio compared with the light massage mode. For all outcomes, similar changes were not observed in the control group. Also, the result founded that mean HR of all groups decrease. We conclude that electrical massager reduces perceived stress and improves adaptive autonomic response to stress in healthy adults.

• Journal of Power Electronics
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• v.18 no.6
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• pp.1708-1719
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• 2018

A complete current loop decoupling control strategy based on a sliding mode observer (SMO) is proposed to eliminate the influence of current dynamic coupling and back electromotive force (EMF) in the vector control of permanent magnet synchronous motors. With this strategy, current dynamic decoupling and back EMF compensation can be simultaneously achieved. Unlike conventional methods, the proposed strategy can avoid the disturbances caused by the parametric variations of motor systems and maintain the advantages of proportional integral (PI) controllers, which are robust and easy to operate. An improved SMO, which uses a special PI regulator other than a linear saturation function as the equivalent control law in the boundary layer of a sliding surface, is proposed to eliminate the estimated errors caused by the quasi-sliding mode and obtain a satisfactory decoupling performance. The stability and parameter robustness of the proposed strategy are also analyzed. Physical experimental results are presented to verify the validity of the method.

• Wind and Structures
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• v.37 no.3
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• pp.191-209
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• 2023

This work investigates the subcritical free-shear prism wake at Re=22,000 by the Koopman analysis using the Dynamic Mode Decomposition (DMD) algorithm. The Koopman model linearized nonlinearities in the stochastic, homogeneous anisotropic turbulent wake, generating temporally orthogonal eigen tuples that carry meaningful, coherent structures. Phenomenological analysis of dominant modes revealed their physical interpretations: Mode 1 renders the mean-field dynamics, Modes 2 describes the roll-up of the Strouhal vortex, Mode 3 describes the Bloor-Gerrard vortex resulting from the Kelvin-Helmholtz instability inside shear layers, its superposition onto the Strouhal vortex, and the concurrent flow entrainment, Modes 6 and 10 describe the low-frequency shedding of turbulent separation bubbles (TSBs) and turbulence production, respectively, which contribute to the beating phenomenon in the lift time history and the flapping motion of shear layers, Modes 4, 5, 7, 8, and 9 are the relatively trivial harmonic excitations. This work demonstrates the Koopman analysis' ability to provide insights into free-shear flows. Its success in subcritical turbulence also serves as an excellent reference for applications in other nonlinear, stochastic systems.