• 한국전문물리치료학회지
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• 제23권1호
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• pp.1-10
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• 2016

Background: Patients with chronic low back pain (CLBP) functionally adapt to decreased postural control due to impaired processing of sensory information. Standing postural control has been the focus of recent research in CLBP. Change in postural control may be a risk factor for CLBP, although available studies are not conclusive. Objects: This study aimed to identify the role of partial weight supported treadmill training (PWSTT) in improving balance, dysfunction, and pain in patients with chronic low back pain. Methods: The study included 22 patients with CLBP. Patients in the control group ($n_1=8$) performed three 20 min stabilization exercise sessions per week, for 4 weeks. Patients in the full weight treadmill training group ($n_2=7$) performed treadmill training for 30 min after stabilization exercise. Patients in the PWSTT group ($n_3=7$) performed PWSTT with 20% of their body weight unloaded after stabilization exercises. By using the Biodex balance system, the dynamic balance abilities of the patients in the three groups were assessed in the quiet standing position under combined conditions of visual feedback (eyes open and closed) and platform stability (level 8). The Korean version of the Oswestry Disability Index and visual analogue scale score were used as the main measure. Results: The results of this study showed that dysfunction and pain were significantly improved in all groups. Although dynamic postural stability with eyes closed was significantly improved only in the PWSTT group (p<.05), no significant difference was found in the other groups. Conclusion: The results of this study indicate that PWSTT improved balance, dysfunction and pain in the patients with CLBP. Thus, this intervention is necessary for patients with CLBP with decreased postural control.

• 말소리와 음성과학
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• 제4권4호
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• pp.139-146
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• 2012

This study was designed to examine comfort levels of pitch and loudness with target matching and their effects on electroglottographic (EGG) and acoustic measures. Twelve speakers, six males and six females, were instructed to produce /a/ sustained vowel for three seconds at a comfortable pitch and loudness level without any instruction and with a target matching procedure of either a certain f0 or SPL separately with visual and auditory feedback. The range of pitch for females and males were presented by progressing up and down randomly at intervals of 5Hz from 150 Hz to 310 Hz (total 33 frequency targets) and from 85 Hz to 190 Hz (total 22 frequency targets), respectively. The loudness levels were 65, 75, 85, 95 dB (total of four intensity targets) for both males and females. Subjective estimations of comfortable levels were obtained using a 10-point equal-appearing interval rating scale following each phonation. The results showed that males and females demonstrated similar trends in loudness levels with greatest comfort at 75 dB, whereas pitch comfort ratings showed a greater variability with females having a wider range with target matching. In the comfort levels of individuals, most male and female speakers rated higher comfort at soft, rather than loud phonations. On the other hand, most male speakers perceived highest comfort levels below the comfort pitch levels they phonated under natural conditions. Higher frequency ranges, however, were perceived to be more comfortable than those of natural condition in most female speakers, although the comfortable pitch levels in spontaneous phonations were within the comfort level ranges determined by targeted phonations. When comparing acoustic (%jitter, %shimmer, SNR) and EGG measures (CQ%) between spontaneous comfortable phonations and targeted phonations produced by the same subject at similar f0 and intensity, no significant differences were observed (p>0.05). Thus, target matching procedures may be considered a compatible and alternative method to reduce the variability of comfortable pitch and loudness levels by eliciting consistent comfortable phonations.

• 로봇학회논문지
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• 제1권1호
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• pp.17-24
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• 2006

Though the final goal of mobile robot navigation is to be autonomous, operators' intelligent and skillful decisions are necessary when there are many scattered obstacles. There are several limitations even in the camera-based tele-operation of a mobile robot, which is very popular for the mobile robot navigation. For examples, shadowed and curved areas cannot be viewed using a narrow view-angle camera, especially in bad weather such as on snowy or rainy days. Therefore, it is necessary to have other sensory information for reliable tele-operations. In this paper, sixteen ultrasonic sensors are attached around a mobile robot in a ring pattern to measure the distances to obstacles. A collision vector is introduced in this paper as a new tool for obstacle avoidance, which is defined as a normal vector from an obstacle to the mobile robot. Based on this collision vector, a virtual reflection force is generated to avoid the obstacles and then the reflection force is transferred to an operator who is holding a joystick to control the mobile robot. Relying on the reflection force, the operator can control the mobile robot more smoothly and safely. For this bi-directional tele-operation, a master joystick system using a hall sensor was designed to resolve the existence of nonlinear sections, which are usual for a general joystick with two motors and potentiometers. Finally, the efficiency of a force reflection joystick is verified through the comparison of two vision-based tele-operation experiments, with and without force reflection.

• 전기학회논문지
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• 제65권2호
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• pp.349-353
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• 2016

The purpose of this study was to investigate possible age differences in the attenuation of acceleration in the upper body (from pelvis through shoulder to head) during fast walking. Thirty young and 29 elderly subjects participated in this study. Wireless acceleration sensors were attached on head, shoulder, and pelvis. Subjects performed two trials of fast walking on a treadmill, where the fast speed was defined as 1.5 times of the comfortable speed. Root-mean-squared (RMS) accelerations of each axis were compared with age group and sensor position as independent factors. In the AP direction, the pelvis acceleration was greater in the young and the shoulder-to-head attenuation was also greater in the young (p<0.001), so that the head acceleration was comparable between age groups (p=0.581). In the ML direction, the pelvis acceleration was greater in the young and also the pelvis-to-shoulder attenuation was greater in the young (p<0.001), so that the head acceleration was greater in the elderly group (p<0.001). Insufficient attenuation ML acceleration in the elderly resulting in the greater acceleration in the head may deteriorate the balance control which utilize feedback signals from the sensory organs in head, e.g., vestibular and visual systems.

• 한국정밀공학회지
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• 제29권7호
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• pp.711-716
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• 2012

The purpose of this study was to investigate how the modulation method affects the effectiveness of eliciting tactile sensations by electrical stimulation. Two methods were employed and the results were compared and analyzed; pulse amplitude modulation (PAM) and pulse width modulation (PWM). Thirty-five healthy subjects participated in the experiments to measure the stimulation intensity that began to elicit a tactile sensation - activation threshold (AT). Constant-current monophasic rectangular pulse trains were employed, and the stimulation intensity was varied from zero until the subject felt any uncomfortable sensation. The step size of the stimulation intensity was 100nC/pulse. After each experiment, the subject described the sensation both quantitatively and qualitatively. The two modulation methods did not make a significant difference as far as the AT values were concerned, but most of the subjects showed 'intra-individual' consistency. Also, it was confirmed that our range of the stimulation parameters enabled us to obtain three major tactile sensations; tickling, pressure and vibration. The results suggested that the stimulation parameters and the modulation type should be selected for each individual and that selective electrical stimulation of the mechanoreceptors needs more diversified researches on the electrode design, multi-channel stimulation protocol, waveforms of the pulse train, etc.

• 대한물리의학회지
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• 제17권1호
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• pp.85-92
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• 2022

PURPOSE: This study aimed to analyze the effects of task exercise on an unstable surface on the involuntary arm and leg movement and balance in stroke patients. METHODS: 20 stroke patients were clinically sampled and randomly assigned to two groups of 10 patients each. Experimental group I received task exercise intervention on an unstable surface and experimental group II received task exercise intervention. The interventions were carried out 3 times a week for 4 weeks (30 minutes per session). The global synkinesis (GS) and Berg Balance Scale (BBS) of the patients were evaluated as pre-tests prior to intervention, and then the post-tests were re-measured in the same manner as the pre-tests after a 4-week intervention period. RESULTS: In the experimental group I, there were statistically significant differences in the changes in the arm and leg GS (p < .01) and in the BBS (p < .05). On the other hand, in the experimental group II, there were statistically significant differences in the changes only in the arm GS (p < .01) and in the BBS (p < .05). Also, in the comparison of the changes between the two groups, there was a statistically significant difference in the changes in the leg GS only (p < .05). CONCLUSION: In the experimental group I, the arm and leg GS were statistically significantly reduced, but the balance ability was statistically significantly improved. The reason was that in the experimental group I, similar movements of the paralyzed arm were promoted due to the double-task exercise on the unstable surface, and sensory feedback and posture strategies were well utilized in the legs, which was found to be effective in reducing the GS and improving the balance ability. Therefore, based on these results, the double-task exercise on an unstable surface should be fully utilized for the rapid rehabilitation of stroke patients.

• 한국전문물리치료학회지
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• 제28권2호
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• pp.101-107
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• 2021

Background: Studies suggest that induced emotional changes can affect the sensory-motor system involved in the practice of muscle activity and movement in physical aspects. Previous studies have shown focused on effects just feedback on muscle activity associated with emotions but rarely have focused induced emotional change on gross motor function such as muscle activity. Objects: The purpose of this study was to compare biceps activity and emotion that before and after viewing a video was induced positive or negative emotion. Methods: The study enrolled 34 healthy male and female who scored at normal points on the Center for Epidermiological Studies-Depression Scale. The study measured over two weeks, showing subjects pleasant and sad videos one by one in a week. We performed to measure the biceps brachii activity which is maximal voluntary isometric contraction (MVIC) and the visual analog mood scale (VAMS) scores before and after one week. The significance level was set to α = 0.05. Results: There was no significant difference in muscle activity of the biceps brachii before and after each video was viewed (p > 0.05). However, the visual analogue mood scale showed an increase in VAMS after viewing each video (p < 0.05). Conclusion: We figured out induced emotional changes are cause actual emotional changes but there are no differences in muscle activity. In this research, watching the video with a short time looks like insufficient to change muscle activity. Nevertheless, there might be different when we check various muscles with sufficient time for viewing the video. Further study is needed to measure a variety of muscles with more time for viewing the video.

• Current Optics and Photonics
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• 제7권1호
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• pp.38-46
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• 2023

Optical Fourier-domain reflectometry (OFDR) sensors have been widely used to measure distances with high resolution and speed in a noncontact state. In the electroplating process of a printed circuit board, it is critically important to monitor the copper-plating thickness, as small deviations can lead to defects, such as an open or short circuit. In this paper we employ a phase-based OFDR sensor for in situ relative distance sensing of a sample with nanometer-scale resolution, during electroplating. We also develop an optical-path difference (OPD)-regulated sensing probe that can maintain a preset distance from the sample. This function can markedly facilitate practical measurements in two aspects: Optimal distance setting for high signal-to-noise ratio OFDR sensing, and protection of a fragile probe tip via vertical evasion movement. In a sample with a centimeter-scale structure, a conventional OFDR sensor will probably either bump into the sample or practically out of the detection range of the sensing probe. To address this limitation, a novel OPD-regulated OFDR system is designed by combining the OFDR sensing probe and linear piezo motors with feedback-loop control. By using multiple OFDR sensors, it is possible to effectively monitor copper-plating thickness in situ and uniformize it at various positions.

• Physical Therapy Rehabilitation Science
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• 제5권3호
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• pp.138-142
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• 2016

Objective: The purpose of this study was to investigate how light touch with a finger affects balance ability when a posture is maintained in the condition of visual information blockage and to provide a fundamental material for developing balance ability in the process of rehabilitation treatment. Design: Cross-sectional study. Methods: The study subjects were 17 healthy men and women in their twenties and thirties who were studying at S University in Seoul. The system was comprised of an equilateral triangular force platform. Subjects were asked to step on the foot position of the force platform (Good Balance, Finland) barefooted for 30 seconds, with eyes closed, hands hanging down loosely, and feet comfortably apart. It was connected to a laptop by using Bluetooth technology. An experiment was conducted in the following three circumstances: 1) no-touch trial, 2) light touch to the back (T7 area), and 3) light touch to the middle finger of the left hand. Each subject was given a 10-minute break between consecutive measurements. The experimental circumstances were performed randomly. Anteroposterior sway (APSV), mediolateral sway velocity (MLSV), and velocity moment (VM) were measured. Results: The APSVs (mm/s) were $9.32{\pm}3.37$ and $5.45{\pm}2.98$; the MLSVs (mm/s), $6.39{\pm}3.35$ and $3.31{\pm}2.48$; and VM ($mm^2/s$), $17.13{\pm}11.75$ and $6.76{\pm}8.31$ in the first and second experimental circumstances, respectively. APSV, MLSV, and VM values were significantly improved with the 1) no-touch trial and 2) light touch to the back trail conditions compared with the 3) light touch to the middle finger of the left hand condition (p<0.05). Conclusions: This study revealed that the balance ability for maintaining a body posture was influenced more by light touch to the back (T7) than by light touch with the sensitive fingertip and body sway diminished after visual information was blocked.

• 대한지역사회작업치료학회지
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• 제7권1호
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• pp.59-70
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• 2017

목적 : 본 연구의 목적은 뇌졸중 환자를 대상으로 가상 현실 기반의 원격재활 효과를 체계적으로 고찰하여 그 효과와 국내 적용방법을 알아보고자 하였다. 연구방법 : 자료의 검색을 위해 EMBASE, CINAHL의 데이터베이스를 이용하였다. 주요 용어는 "Virtual Reality", "Telerehabilitation", "Stroke"으로 관련 연구를 검색하였다. 선정기준에 적합한 총 7편의 연구를 대상으로 질적 수준, 일반적 특성, PICO를 사용하여 연구 주제에 따른 자료를 분석하였다. 결과 : 선정된 7편의 연구는 가상현실 기반으로 한 원격재활 시스템으로 중재를 실시하였으며, 가상현실은 게임 프로그램과 수동적인 팔 보조 그리고 Balance Trainer등을 활용하여 원격재활 중재를 실시하였다. 주된 결과 측정도구는 상지기능, 균형 및 보행, 일상생활 등을 평가하기 위한 도구가 사용되었다. 가상현실 기반의 원격재활 중재방법은 모든 연구에서 상지기능, 균형감각능력에서 효과를 보였으며, 일상생활 활동에서의 부분적인 효과를 확인하였다. 환경적 특이성을 보완하기 위한 원격재활 서비스는 클라이언트의 만족감을 향상시키고 기능의 유지를 위한 중재법으로 그 효과를 확인할 수 있었다. 결론 : 가상현실 기반의 원격재활 시스템은 대부분 상지기능과 균형감각, 일상생활 활동을 위한 중재가 적용되었으며, 가정환경에서도 치료사의 중재, 감독, 교육 등을 통해 기능향상에 도움이 되는 것으로 나타났다. 본 연구는 가상현실 기반의 원격재활의 임상적 적용에 대한 근거와 가능성을 제시하고자 한다. 향후 연구에서 다양한 가상현실의 중재방법과 원격재활을 활용한 재활 프로그램 개발과 같은 추가적인 연구가 필요할 것이다.