• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.11 no.3
• /
• pp.119-126
• /
• 2017

In the clinical setting, the pressure bio-feedback device is used for the spinal rehabilitation of patients with back pain, but it has several disadvantages. The purpose of this study was to develop a digitalized pressure biofeedback system that provides precise exercise method and posture in real time during the spinal rehabilitation exercise by sensing and monitoring body movements and balance of users and providing biofeedback to users. After that, the usability testing for a digitalized pressure biofeedback system will be conducted to identify problems such as safety, performance, operability, and satisfaction, and suggest improvement directions. A total of 33 subjects were participated in the usability testing. The experts group and the users group evaluated the developed digitalized pressure biofeedback system on a scale of 5 points after using the equipment. In the user group, safety was 3.59, operability was 4.38, satisfaction was 4.49. In the expert group, safety was 2.86, operability was 3.91, and performance was 4.28. Based on the usability evaluation, if the problems of stability of the cradle for tablet PC, air injection, screen display, etc. are solved, it becomes a exercise device capable of accurately exercising and evaluating the function of the spine by checking its own motion state while the spinal stabilization exercise.

• Science of Emotion and Sensibility
• /
• v.5 no.2
• /
• pp.29-34
• /
• 2002

Our previous studies investigated that narrow field of view (FOV : 50˚) and slow navigation speed decreased the frequency of occurrence and severity of cybersickness during immersion in the virtual reality (VR). It would cause a significant reduction of cybersickness if it were provided cybersickness alleviating virtual environment (CAVE) using biofeedback method whenever subject underwent physiological agitation. For verifying the hypothesis, we constructed a real-time cybersickness detection and feedback system with artificial neural network whose inputs are electrophysiological parameters of blood pulse volume, skin conductance, eye blink, skin temperature, heart period, and EEG. The system temporary provided narrow FOV and decreased speed of navigation as feedback outputs whenever physiological measures signal the occurrence of cybersickness. We examined the frequency and severity of cybersickness from simulator sickness questionnaires and self-report in 36 subjects. All subjects experienced VR two times in CAVE and non-CAVE condition at one-month intervals. The frequency and severity of cybersickness were significantly reduced in CAVE than non-CAVE condition. Virtual environment of narrow FOV and slow navigation provided by electrophysiological features based artificial neural network caused a significant reduction of cybersickness symptoms. These results showed that efficiency of a cybersickness detection system we developed was relatively high and subjects expressed more comfortable in the virtual navigation environment.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.12
• /
• pp.2079-2084
• /
• 2003

In biological cell manipulation, manual thrust or penetration of an injection pipette into an embryo cell is currently performed by a skilled operator, relying on visual feedback information only. Accurately measuring cellular forces is a requirement for minimally invasive cell injections. Moreover, the cellular force sensing is essential in investigating the biophysical properties for cell injury and membrane modeling studies. This paper presents cellular force measurements for the force feedback-based biomanipulation. Cellular force measurement system using piezoelectric polymer sensor is implemented to measure the penetration force of a zebrafish egg cell. First, measurement system setup and calibration are described. Second, the force feedback-based biomanipulation is experimentally carried out. Experimental results show that it successfully supplies real-time cellular force feedback to the operator at tens of uN and thus plays a main role in improving the reliability of biological cell injection tasks.

• Journal of Korean Academy of Nursing
• /
• v.34 no.2
• /
• pp.213-224
• /
• 2004

Purpose: This study was aimed to evaluate the effect of progressive muscle relaxation training using biofeedback on perceived stress, stress response, immune response and climacteric symptoms, Method: This was a crossover, pre-post test design, The study subjects are 36 middle-aged women who were selected at 2 public health centers, The independent variable was Biofeedback training for 4 weeks, twice a week and home training for 4 weeks, Dependent variables were perceived stress, stress response, immune response, and climacteric symptoms measured with Hildtch's scale (1996), Result: Progressive muscle relaxation training using biofeedback was not effective in reducing perceived stress, but it was shown to be effective in reducing physiological stress responses such as pulse rate and EMG, Though blood pressure and skin conductance were repeatedly down, and skin temperature slowly increased, there were no statistically significant differences. Progressive muscle relaxation training using biofeedback was not effective in reducing serum cortisol, enhancing immune responses, or decreasing climacteric symptoms. Conclusion: The findings point to a pressing need for further, well-controlled and designed research with consideration in selection of subjects and instruments, frequency of measurements, the sampling method, and intervention modalities.

• Perspectives in Nursing Science
• /
• v.15 no.2
• /
• pp.107-114
• /
• 2018

Purpose: The purpose of this study was to observe the effects of biofeedback training on the perceived stress, stress response, and academic resilience of nursing students. Methods: The research used a randomly assigned control group pretest-posttest design. The study participants were 34 senior students from the College of Nursing of S University. The study was conducted from March to April 2012. The biofeedback training conducted in this study consisted of eight sessions, each divided into two stages: 15 minutes each for breathing biofeedback training and electromyography (EMG) biofeedback training. The collected data were analyzed using SPSS version 19.0. Results: We found statistically significant decreases in perceived stress and EMG levels and an increase in academic resilience in the experimental group. Conclusion: The results showed that the biofeedback training for the nursing students was extremely effective in reducing their levels of perceived stress and EMG while increasing academic resilience. To clarify the effects of biofeedback training on the biological stress response, participants with a higher level of stress response should be recruited in future studies.

• Phonetics and Speech Sciences
• /
• v.15 no.2
• /
• pp.31-40
• /
• 2023

Tube phonation in water has been widely used for voice training among semi-occluded vocal tract (SOVT) exercises in which the patient bubbles with phonation keeping the tube submerged in water. This study aims to investigate the effect of tube diameter and water depth on bubble height and maximum phonation time (MPT) for patients with hyperfunctional voice disorders. Seventeen patients with hyperfunctional voice disorders were asked to bubble with sustained /u/ at the different inner diameters of tube (5, 7, and 10 mm), water depth (4, 7, and 10 cm). A water resistance phonation biofeedback system using a water height sensor was used for recording bubble height and MPT. The bubble height was significantly changed by the tube diameter while MPT was significantly changed with the tube diameter and water depth. Although the wider tube presented significantly lower bubble height for a given depth, relatively consistent bubble height was maintained. Depending on the water depth, the bubble height did not significantly differ for a given tube diameter. In addtion, MPT significantly decreased with water depth and a wider tube led significantly shorter MPT. A water level-driven water resistance biofeedback system provided useful information on bubble characteristics and vocal fold vibration depending on tube diameter and water depth. It can be useful to monitor the breath support during water resistance phonation for patients with hyperfunctional voice disorders.

• Sleep Medicine and Psychophysiology
• /
• v.16 no.2
• /
• pp.79-84
• /
• 2009

Objectives: Chronic pain is one of the most common experiences of humans and a typical psychophysiological disorder. The aim of this study was to measure the psychophysiological responses in chronic pain patients using a biofeedback system, and to compare them with the results from normal healthy subjects. Methods: Forty two patients with chronic pain (17 males and 25 females, average age $44.67{\pm}11.10$ years) and 42 normal healthy controls (17 males and 25 females, average age $45.17{\pm}10.46$ years) participated in this study. Electromyography (EMG), skin conductance (SC), and skin temperature (ST) were recorded using biofeedback system during the 3 phases (baseline, stress, and recovery) of stress reactivity test, and average values of them were calculated. Difference of values between two groups in each corresponding phase was analyzed with independent t-test, and change of values across phases of stress reactivity test was analyzed with paired t-test (all two-tailed, p<0.05). Results: Compared to normal controls, chronic pain patients had higher value of EMG (baseline: $8.10{\pm}5.97{\mu}V$ vs $4.72{\pm}1.52{\mu}V$, t=-3.56, p<0.01; stress: $11.25{\pm}6.89{\mu}V$ vs $8.49{\pm}4.78{\mu}V$, t=-2.13, p<0.05; recovery: $7.12{\pm}3.77{\mu}V$ vs $4.78{\pm}1.59{\mu}V$, t=-3.70, p<0.01) and SC (baseline: $1.06{\pm}1.0{\mu}S$ vs $0.42{\pm}0.29{\mu}S$, t=-4.0. p<0.01; stress: $1.87{\pm}2.05{\mu}S$ vs $1.03{\pm}0.86{\mu}S$, t=-2.47, p<0.05; recovery: $1.74{\pm}1.77{\mu}S$ vs $0.64{\pm}0.59{\mu}S$, t=-3.8, p<0.01) in all the 3 phases. But, skin temperature comparison did not reveal significant differences in all the 3 phases between two groups. Conclusion: Psychophysiological responses of chronic pain patients in stress reactivity test were different from those of normal healthy controls. These results suggest that sympathetic nervous system is more activated in chronic pain patients.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.1
• /
• pp.245-255
• /
• 2017

This study was conducted to investigate the effects of neurofeedback (NFB) on attention in college students with ADHD. Participants were 27 university students, 10 in an NFB training group (experiment group), eight in a CBT group (comparison group) and nine in a no-treatment group. The score of CAARS-K decreased significantly in both the NFB group and the CBT group relative to the no-treatment group. Additionally, the score of the digit span test increased significantly in the NFB group, CBT, and no-treatment group, and the scores of these three groups differed significantly. Moreover, significant changes in EEG were found in the NFB Group, while the CBT group showed no significant changes in EEG. The significant change in EEG implies that NFB training improved the stability of brain function on the cerebral neurological level. The effects of improved attention remained after 5 weeks in both the NFB and CBT group. Finally, implications, limitations, and suggestions for future studies were discussed.

• Journal of IKEEE
• /
• v.25 no.3
• /
• pp.420-424
• /
• 2021

The massive MIMO system, which is a core technology of 5G communication systems, has a problem that it is difficult to implement in a frequency division duplex system based on limited channel feedback because a large amount of channel information is required at the transmitting end. In order to solve this problem, the Joint Spatial Division and Multiplexing (JSDM) technique that dramatically reduces the channel information requirement by removing interference between the user groups using channel correlation information that does not change for a long time has been proposed. Recently, a regularized JSDM technique has been proposed to further improve performance by allowing residual interference between the user groups. However, such JSDM-related studies were mainly designed to focus on inter-group interference cancellation, and thus performance analysis was not performed in a more realistic environment assuming limited feedback in the intra-group interference cancellation phase. In this paper, we analyze the performance of the JSDM and regularized JSDM techniques according to the number of groups and users in a limited feedback environment, and through the simulation results, demonstrate that the regularized JSDM technique shows a more remarkable advantage compared to the existing JSDM in a limited feedback environments.

• Electronics and Telecommunications Trends
• /
• v.24 no.5
• /
• pp.38-51
• /
• 2009

정보통신망을 이용하여 언제 어디서나 모든 사람이 의료서비스를 제공받을 수 있고, 나아가서는 생활관리서비스를 제공하는 유비쿼터스 건강관리 사회를 구현하기 위하여 생체정보 센서, 생체정보 모니터링, 데이터 분석, 피드백 등의 4가지 핵심기술에 대한 개발이 진행되고 있다. 본 고에서는 현장진단이 가능한 바이오센서 기술에 대한 개요와 국내외 기술개발 동향 및 특허 동향을 분석하고 향후 현장진단용 바이오센서 시장에 대하여 전망하고자 한다.