• Journal of the Institute of Convergence Signal Processing
• /
• v.19 no.3
• /
• pp.104-109
• /
• 2018

A non-intrusive ECG and BCG measurement system is introduced. The system is built on a auxiliary backrest of a chair. The developed system is aimed to non-intrusive assessment of cardiovascular dynamic indices such as pulse arrival time(PAT) and pre-ejection period (PEP). In the system, capacitive active electrodes and capacitive grounding were used for the non-intrusive indirect-contact ECG measurement, and EMFi pressure sensor was used for the non-intrusive BCG measurement. The capacitive active electrodes and the EMFi sensor were attached on the backrest. Using the system, ECG and BCG were successfully acquired. The measured BCG showed peaks that following ECG R peaks. It was shown that the time interval between Q wave in ECG and first peak in BCG correlates Pre-ejection period measured by impedance-cardiogram. The results showed that the introduced system can be used for the non-intrusive various cardiovascular information including ECG, PAT, PEP.

• Journal of the Korean Society of Physical Medicine
• /
• v.13 no.2
• /
• pp.1-9
• /
• 2018

PURPOSE: This study investigated the relationship between the daily physical activity level and fall-proof-related fitness in older female adults. METHODS: This study promoted and sampled the subjects who participated in the study for 2 weeks, and developed a basic information questionnaire to select the subjects to be excluded from the research. The amount of energy expenditure through daily physical activity was examined, and the elderly physical fitness, and balance test were analyzed. The subjects were divided into group A (${\geq}1,500kcal/week$), group B (<$1,500-{\geq}1,000kcal/week$), and group C (<1,000 kcal/week) according to their daily physical activity level. RESULTS: A significant difference in the daily physical activity level (energy expenditure), Chair Stand Test (lower body strength), 8-Foot Up-and Go Test (dynamic balance), and CTSIB-M (modified Clinical Test of Sensory Interaction in Balance) was observed among groups A, B, and C (p<.5), but there was no significant difference in the Chair Sit-and-Reach Test (lower body flexibility) (p>.5). CONCLUSION: The increase in physical activity is an essential factor for preventing falls and it provides many health benefits for the elderly. On the other hand, considering that elderly people cannot access exercise programs easily in Korea, it can be predicted that increasing elderly people's physical activity in daily life rather than specific exercises may help prevent falls.

• Journal of the Korean Society of Physical Medicine
• /
• v.10 no.3
• /
• pp.87-93
• /
• 2015

PURPOSE: The purpose of this study was to investigate the effects of the 8.5seconds cut-off of the 8-foot up-and-go test as a predictor of falling and a good discriminator of fallers and non-fallers in women in their 60s to 80s. METHODS: The final subjects of this study were 98 elderly women from six senior centers of B metropolitan city. The 8-foot up-and-go test evaluated agility and dynamic balance. The chair-stand test measured the muscle strength for of the lower body. Ankle dorsiflexion and plantar flexion were measured to assess the ankle mobility of the subjects in this study. RESULTS: The below 8.5seconds group showed significantly low values in age and high values in chair-stand (times/30 s), plantar flexion ($^{\circ}$), and K-MMSE (score) compared to the over 8.5seconds group. This group was significantly faster compared to the over 8.5seconds group. In the below 8.5seconds group, only plantar flexion ($^{\circ}$) of all the items showed significantly higher values among those in their 60s compared to those in their 70s and 80s. CONCLUSION: The 8.5seconds cut-off on the 8-foot up-and-go test as a good discriminator and predictor of falling showed differences among fall risk factors (age, lower extremity strength, cognition, and ankle mobility) in women in their 60s to 80s without having regular exercise and a fall experience over the past ones year.

• Journal of Power Electronics
• /
• v.17 no.4
• /
• pp.1048-1057
• /
• 2017

An indirect matrix converter (IMC) is a modern power generation system that enables a direct ac/ac conversion without the need for any bulky and limited lifetime electrolytic capacitor. This system also allows four-quadrant operation, generation of sinusoidal output voltage waveforms with variable frequency and amplitude, and control of input power factor. This study proposes a pulse-width modulation-based sliding-mode controller to achieve unity input-power factor operation of the IMC independently of the active power exchanged with the grid, as well as a fast dynamic response. The designed equivalent control law determines, at each sampling period, the appropriate q-axis component of the modulated input current to be injected into the grid through the LC input filter. An integral term of the error is included in the expression of the sliding surface to increase the accuracy of the control method. A double space vector modulation method is used to synthesize the direction of the space vector of the input currents as required by the sliding-mode controller and the space vectors of the target output voltages. Simulation and experimental results are provided to show the effectiveness and evaluate the performance of the proposed control method.

• Physical Therapy Korea
• /
• v.24 no.1
• /
• pp.97-104
• /
• 2017

Background: South Korea is one of fastest aging countries in the world. Poor balance and falls of the elderly are main health issues. Objects: The goal of this study was to understand the association between the socioeconomical factors and the standing balance of elderly living in the rural and urban area. Methods: One hundred sixty-six elderly participants who were older than 65 and were able to walk without an assistive device were recruited in the city of Gwangju and in the rural area of Jeonnam, South Korea. All participants performed the static and dynamic standing balance tests. Static standing balance was measured with chronometer in seconds while standing on one leg. Dynamic balance was tested with the timed up and go test (TUG), measured in seconds while getting up from a chair and walking 3 meters and back to sit. The static and dynamic standing balance was analyzed using analysis of variance and the Fisher's Least Significant Difference post hoc test. Results: Male participants from both areas had no difference in one leg standing and TUG. The female elderly living in rural area took shorter in TUG than females living in urban area. Age decreased the one leg standing time in both areas while did not affect the TUG significantly. As the monthly income increased, both of one leg standing and TUG increased in urban area, while the medium monthly income showed best performance (it was not statistically significant) in both of one leg standing and TUG in rural area. Conclusion: Socioeconomical factors affects differently the standing balance of the elderly living in rural and urban South Korea. Female living alone in urban area with low monthly income demonstrated worst standing balance in this study.

• Physical Therapy Rehabilitation Science
• /
• v.3 no.1
• /
• pp.69-75
• /
• 2014

Objective: We developed a Motor-Assisted Rowing Machine (MARM) for Spinal Cord Injury (SCI), by modification of the Concept II rowing machine, so that the seats could be operated automatically in a backward and forward direction by a motor. Design: Case report. Methods: Motor rowing consisted of a chair with inclination control, a motor system, control button, monitor, program, leg supporter, safety belt, and seat. The patients were 2 men rowing athletes with SCI, classified as American Spinal Injury Association class B, participated in the study. Level of thoracic injury ranged from T8 to T10. The subjects rowed at a self-selected stroke rate with 50 watts. Two different rowing methods (static rowing without movement of the seat, dynamic rowing using MARM) were assigned to each participant during 10 minutes; 34 reflective markers were attached to their full bodies. Kinematic data were collected using the Vicon motion analysis system. Based on the full body model provided as a default by the equipment. In the rowing exercise, the rowing motions were divided into Drive Phase and Recovery Phase. Results: The two rowing methods differ in handle range, seat range, handle and seat ratio, handle velocity, and seat velocity during static and dynamic rowing. The rowing exercise using a rowing machine developed MARM increased tendency to the range of motion in the dynamic method compared to the static method. Conclusions: The newly developed MARM could be a useful whole body exercise for people with SCI.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.2
• /
• pp.601-609
• /
• 2016

This study evaluated the dynamic balance and pain after 12 weeks aquatic exercise in old osteoarthritis patients. The dynamic balances were assessed using 2 different experimental conditions (Open Eye Condition; OEC, Closed Eye Condition; CEC). Twenty-two subjects were assigned one of the two experimental groups: arthritis group (ART, age=$65.25{\pm}5.9$, n=11), control group(CON, age=$64.50{\pm}7$, n=11). All subjects participated in the aquatic exercise program three times a week for 12 weeks. The dynamic balances (OEC (p<.001), CEC (p<.05)) capability were improved significantly in the ART group after 12 week aquatic exercise. Visual Analogue Scale (VAS) was decreased significantly [Factor 10(Soft chair, p<0.01), 11 (Lying down, p<0.05), 12(Handicap, p<0.05), 13 (Work interference, p<0.01)] in the ART group. In conclusion, aquatic exercise was effective in improving the overall health status and the capacity of dynamic balances and reducing the degree of pain in osteoarthritis patients.

• Analytical Science and Technology
• /
• v.7 no.2
• /
• pp.213-224
• /
• 1994

Several isotopomers of cyclooctanone were prepared by selective deuterium substitution. Intrinsic isotope effects on $^{13}C$ NMR chemical shifts of these isotopomers were investigated systematically at low temperature. These istope effects were discussed in relation to the preferred boat-chair conformation of cyclooctanone. Deuterium isotope effects on NMR chemical shifts have been known for a long time. Especially in a conformationally mobile molecule, isotope perturbation could affect NMR signals through a combination of isotope effects on equilibria and intrinsic effects. The distinction between intrinsic and nonintrinsic effects is quite difficult at ambient temperature due to involvement of both equilibrium and intrinsic isotope effects. However if equilibria between possible conformers of cyclooctanone are slowed down enough on the NMR time scale by lowering temperature, it should be possible to measure intrinsic isotope shifts from the separated signals at low temperature. $^{13}C$ NMR has been successfully utilized in the study on molecular conformation in solution when one deals with stable conformers or molecules were rapid interconversion occurs at ambient temperature. The study of dynamic processes in general requires analysis of spectra at several temperature. Anet et al. did $^1H$ NMR study of cyclooctanone at low temperature to freeze out a stable conformation, but were not able initially to deduce which conformation was stable because of the complexity of alkyl region in the $^1H$ NMR spectrum. They also reported the $^1H$ and $^{13}C$ NMR spectra of the $C_9-C_{16}$ cycloalkanones with changing temperature from $-80^{\circ}C$ to $-170^{\circ}C$, but they did not report a variable temperature $^{13}C$ NMR study of cyclooctanone. For the analysis of the intrinsic isotope effect with relation to cylooctanone conformation, $^{13}C$ NMR spectra are obtained in the present work at low temperatures (up to $-150^{\circ}C$) in order to find the chemical shifts at the temperature at which the dynamic process can be "frozen-out" on the NMR time scale and cyclooctanone can be observed as a stable conformation. Both the ring inversion and pseudorotational processes must be "frozen-out" in order to see separate resonances for all eight carbons in cyclooctanone. In contrast to $^1H$ spectra, slowing down just the ring inversion process has no apparent effects on the $^{13}C$ spectra because exchange of environments within the pairs of methylene carbons can still occur by the pseudorotational process. Several isotopomers of cyclooctanone were prepared by selective deuterium substitution (fig. 1) : complete deuterium labeling at C-2 and C-8 positions gave cyclooctanone-2, 2, 8, $8-D_4$ : complete labeling at C-2 and C-7 positions afforded the 2, 2, 7, $7-D_4$ isotopomer : di-deuteration at C-3 gave the 3, $3-D_2$ isotopomer : mono-deuteration provided cyclooctanone-2-D, 4-D and 5-D isotopomers : and partial deuteration on the C-2 and C-8 position, with a chiral and difunctional case catalyst, gave the trans-2, $8-D_2$ isotopomer. These isotopomer were investigated systematically in relation with cyclooctanone conformation and intrinsic isotope effects on $^{13}C$ NMR chemical shifts at low temperature. The determination of the intrinsic effects could help in the analysis of the more complex effects at higher temperature. For quantitative analysis of intrinsic isotope effects, the $^{13}C$ NMR spectrum has been obtained for a mixture of the labeled and unlabeled compounds because the signal separations are very small.

• Proceedings of the KIEE Conference
• /
• 2004.11c
• /
• pp.307-309
• /
• 2004

In this study, we have evaluated and classified arthritic pathology using the auscultation of knee joint sound. Six normal persons and 11 patients with knee problem were enrolled. Six patients of Group 1 needed an orthopeadic surgery because of the ruptured wounds of meniscus or ACL(Anterior Cruciate Ligament) and 5 patients of Group 2 diagnosed as osteoarthritis. Subjects were taken knee flexion and extension being seated in a chair for 20 seconds which repeated 3 times. Also subjects stood up and sit down repeatedly in the same way. After the movement of knee was divided into 18 degrees, the pitch perturbation according to partial degrees was analyzed and the DTW(Dynamic Time Warping) method was applied for normalizing a time-axis and unpaired t-test was used for statistic results among groups. As a result, the amplitude and frequency perturbations of group 2 was higher than group 1(p<0.05) and showed a characteristic 'w-shape' in angle-amplitude graph. These results suggest that the analysis of knee joint sound might assist in early diagnosis of knee joint disease.

• Journal of the Korean Society of Physical Medicine
• /
• v.2 no.1
• /
• pp.73-84
• /
• 2007

Purpose : The purpose of this study was to determine risk factors and methods in balance assessment associated with fall in older adults. Methods : This article describes many of the tools that can be used to evaluate the physical parameters associated with fall risk in older adults. Results : Composite ratings of performance(Tinetti balance assessment, Guralnik test battery, Berg balance scale, modified-physical performance test) measures the score compounding the balance measure to determine fall risk. Static balance instruments are composed of FICSIT-4 that measures the ability of maintaining foot positions and CTSIB that measures postural stability. Dynamic balance instrument is composed of functional reach test. To measure walking velocity and mobility, 8-foot up-and-go test and walking around two cones are used. We can use 1-RM and to measure muscular strength, isokinetic dynamometery, and 30-second chair stand to measure lower extremity muscle strength. Conclusion : The described instruments are easy to use and widespread. To select and use these tool kits carefully is considered to be helpful in identifying those who are most likely to fall. The final part of the article includes a brief discussion of the potential role of exercise training interventions to improve these physical parameters and prevent falls.