• Journal of Institute of Control, Robotics and Systems
• /
• v.8 no.8
• /
• pp.691-697
• /
• 2002

Myocardial ischemia is a disorder of cardiac function caused by insuficient blood flow to the muscle tissue of the heart. We can diagnose myocardial ischemia by observing the change of ST-segment, but this change is temporary. Our primary purpose is to detect the temporary change of the 57-segment automatically In the signal processing, the wavelet transform decomposes the ECG(electrocardiogram) signal into high and low frequency components using wavelet function. Recomposing the high frequency bands including QRS complex, we can detect QRS complex more easily. Amplitude comparison method is adopted to detect QRS complex. Reducing the effect of noise to the minimum, we grouped ECG by 5 data and compared the amplitude of maximum value. To recognize the ECG .signal pattern, we adopted the polynomial approximation partially and statistical method. The polynomial approximation makes possible to compare some ECG signal with different frequency and sampling period. The ECG signal is divided into small parts based on QRS complex, and then, each part is approximated to the polynomials. After removing the distorted ECG by calculating the difference between the orignal ECG and the approximated ECG for polynomial, we compared the approximated ECG pattern with the database, and we detected and classified abnormality of ECG.

• Physical Therapy Korea
• /
• v.19 no.1
• /
• pp.46-55
• /
• 2012

The purpose of this study was to investigate the effect of the two different types of chairs on trapezius muscle activation during dictation tasks. Seventeen university students, each of whom were within ${\pm}1$ standard deviation of the mean Korean standard body size, voluntarily participated in this study. Surface electromyography was used to collect electrical signals from both the upper and lower trapezius muscles. Amplitude Probability Distribution Function (APDF) was performed to analyze the muscle activity. The findings of this study were 1) The backrest-point height of the auditorium chair and the height, length and width of the connected desk were shorter than what was suggested by the KS. Another difference was that the auditorium chair had a bigger angle of the backrest compared to the classroom chair. 2) Regarding within-subject effect the sole statistically significant difference was found between activation of the upper trapezius muscle. The upper trapezius muscle's %RVC in the APDF 10th-50th-90th percentile was statistically higher for participants sitting in the auditorium chair than for participants sitting in the classroom chair (p<.05). 3) There was an interaction effect between the 'two chair-types' and the 'two muscle-sides' in the APDF 10th-50th percentile (p<.05). 4) There was an interaction effect between the 'two chair-types' and the 'three gaze-direction' in the APDF 90th percentile (p<.05). The findings of this study indicated that maintaining a writing posture for a prolonged period of time in an auditorium chair significantly increased the left upper trapezius muscle activation compared to a classroom chair.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.11
• /
• pp.1559-1569
• /
• 2002

In order to investigate the characteristics of electromagnetic flowmeter in two -phase flow, an AC electromagnetic flowmeter was designed and manufactured. In various flow conditions, the signals and noises from the flowmeter were obtained and analyzed by comparison with the observed flow patterns with a high speed CCD camera. The experiment with the void simulators in which rod shaped non-conducting material was used was carried out to investigate the effect of the bubble position and the void fraction on the flowmeter. Based on the results from the void simulator, two -phase flow experiments encompassed from bubbly to slug flow regime were conducted. The simple relation $\Delta$ $U_{TP}$ = $\Delta$ $U_{SP}$ (l-$\alpha$) was verified with measurements of the potential difference and the void fraction. Due to the lack of homogeneity in a rent two -phase flow, the discrepancy between the relation and the present measurement was slightly increased with void fraction and also liquid volumetric flux jf. Whereas there is no difference in the shape of the raw signal between single-phase flow and bubbly flow, the signal amplitude for bubbly flow is higher than that for single -phase flow at the same water flow rate, since the passage area of the water flow is reduced. In the case of slug flow, the phase and the amplitude of the flowmeter output show dramatically the flow characteristics around each slug bubble and the position of a slug bubble itself. Therefore, the electromagnetic flowmeter shows a good possibility of being useful for identifying the flow regimes.ul for identifying the flow regimes.

• The Journal of Korean Physical Therapy
• /
• v.21 no.1
• /
• pp.73-80
• /
• 2009

Purpose: In order to examine difference in the activity of potential of spinal neurons and cortical neurons according to muscle contraction type in post stroke hemiplegic subjects and healthy subjects, the present study conducted an experiment as follows. Methods: The subjects in the experimental group were 17 left-side hemiplegic subjects (9 female, 8 male; mean age, 63.41$\pm$9.86 years) with the right hand as the dominant hand selected among post stroke hemiplegic subjects, and 17 age matched healthy control subjects (10 female, 7 male; mean age, 64.12$\pm$12.07 years). Movement-related cortical potentials (MRCPs) were measured using surface electromyography and electroencephalography while concentric and eccentric movements were made alternately. Results: As to the pattern of the activity of MRCP, which indicates the activity of motor cortical neurons, we found that the amplitude is high (p<0.01), the length of excitement is short (p<0.01) and the ascending gradient of amplitude to the peak increases (p<0.05) in post stroke hemiplegic subjects' lesion sites different from healthy subjects. Conclusion: The activity of cortical neurons was no difference in activity according to contraction type was observed in post stroke hemiplegic subjects' lesion sites. This suggests that there is no distinction in the activity of cortical neurons between concentric contraction and eccentric contraction. Accordingly, if post stroke hemiplegic subjects' activity of motor cortex is analyzed by measuring MRCPs, it is considered useful in research on neural plasticity or as a ground of clinical effects in the area of physical therapy for the central nervous system.

• Journal of Korean Neurosurgical Society
• /
• v.47 no.4
• /
• pp.247-251
• /
• 2010

Objective : Selective neurotomy is generally a safe, effective, and long-lasting treatment for patients with spastic equinovarus foot deformity. We retrospectively analyzed the results of microsurgical selective tibial neurotomy (STN) for spastic feet in adults and children. Methods : A neurosurgeon selected 32 patients with 45 spastic feet (adults : 13, children : 32) to undergo microsurgical STN between October 1998 and September 2007. A physician of rehabilitation assessed spasticity pre- and postoperatively, that was based on the Ashworth scale, ankle clonus, and the amplitude of ankle dorsiflexion. The mean postoperative follow-up period was 36.7 months in adults and 42.5 months in children. Results : Spastic components of the feet were corrected immediately after surgery in both the adult and child groups. The mean Ashworth's grade changed from $3.6{\pm}0.40$ to $1.6{\pm}0.70$ in adults and from $3.7{\pm}0.69$ to $1.4{\pm}0.49$ in children. Mean ankle clonus decreased markedly, from $1.6{\pm}0.79$ to $0.3{\pm}0.42$ in adults and from $1.7{\pm}0.65$ to $0.3{\pm}0.56$ in children. The mean amplitude of ankle dorsiflexion was improved, but eight (adults: 4, children: 4) contracted feet needed complementary orthopedic correction for acceptable results. Conclusion : STN can be effective in the long-term for improving lower limb function and reduction of equinovarus deformity. Our results demonstrate that STN might be an effective procedure for treating localized harmful spastic feet in adults and children.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.54 no.11
• /
• pp.680-688
• /
• 2005

The electrical current generated by heart creates not only electric potential but also a magnetic field. We have observed electrophysiological phenomena of the heart by measuring components of magnetocardiogram(MCG) using 61 channel superconducting quantum interference device(SQUD) system. We have analyzed the possibility and characteristics of MCG parameters for diagnosis of ischemic heart disease. A technique for automatic analysis of MCG signals in time domain was developed. The methods for detecting the position, the interval, the amplitude ratio, and the direction of single current dipole were examined in the MCG wave. The position and interval parameters were obtained by calculating the gradients of a envelope curve which could be formed by the difference between the maximum and minimum envelope of multi-channel MCG signals. We show some differences of the frequency contour map between the normal MCG and the abnormal (ischemic heart disease) MCG. The direction of single current dipole can be defined by rotating the magnetic field according to Biot-Savart's law at each point of MCG signals. In this study, we have examined the direction of single current dipole from searching for the centroids of positive and negative magnetic fields. The amplitude ratio parameters for measuring 57 deviation consisted of A$_{T}$/A$_{R}$ and other ratios. and We developed a new analysis method, which is based on the frequency contour map of electromagnetic field. Using theses parameters, we founded significant differences between normal subjects and ischemic patients in some parameters.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.19 no.5
• /
• pp.457-466
• /
• 2007

The effect of depth correction in the coastal sea has been investigated through a series of tide simulations in the area of $115{\sim}150^{\circ}E,\;20{\sim}52^{\circ}N$ of northwestern Pacific with $1/12^{\circ}$ resolution. Comparison of the solutions varying the minimum depth from 10m to 35 m with the 5m interval shows that the amplitude accuracies of $M_2,\;S_2,\;K_1$ tide using the minimum depth of 25 m have been improved up to 42%, 32%, 26%, respectively, comparing to those using the minimum depth of 10m. The discrepancy between model results using different minimum depth is found to be up to 20 cm for $M_2$ tidal amplitude around Cheju Islands and the positions of amphidromes are dramatically changed in the Bohai Sea. The calculated ARE(Averaged Relative Error) values have been minimized when the bottom frictional coefficient and the minimum depth is 0.0015 and 25 m, respectively.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.36 no.6
• /
• pp.451-459
• /
• 2016

Crack detection on panels during manufacturing process is an important step for ensuring the product quality. The accuracy and efficiency of traditional crack detection methods, which are performed by eye inspection, are dependent on human inspectors. Therefore, implementation of an on-line and precise crack detection is required during the panel pressing process. In this paper, a regular CCTV camera system is utilized to obtain images of panel products and an image process based crack detection technique is developed. This technique uses a comparison between the base image and a test image using an amplitude mapping of the local image. Experiments are performed in the laboratory and in the actual manufacturing lines to evaluate the performance of the developed technique. Experimental results indicate that the proposed technique could be used to effectively detect a crack on panels with high speed.

• Archives of Plastic Surgery
• /
• v.35 no.1
• /
• pp.56-61
• /
• 2008

Purpose: There was no controlled study on botox injection and neurectomy for treatments of muscle hypertrophy. Although many studies have shown the clinical effects of each treatment, it was not able to evaluate and compare the effects of each treatment because there was no comparison of the two treatments under the same experimental condition. Hence, the aim of this study is to com Methods: The study was carried out on 21 rabbits. 9 rabbits received botox injection(botox injection group), and neurectomy was performed to another 9 rabbits (neurectomy group). 3 rabbits did not receive any treatment(control group). To compare and analyze the effects of muscular atrophy, muscle was stained with NADH-TR, and the changes in size of the muscle fiber were examined. And the electromyography was examined. In each group, muscle fiber was stained and electromyography was performed 2, 3, and 6 months after injection or operation. Results: In histological test and electromyography, in the neurectomy group, the size of muscular fiber and amplitude of electromyography decreased until 2 months after neurectomy. And decreased results were maintained with the passage of time. It showed irreversible aspect. On the other hand, in the botox injection group, the decrease in the size of muscular fiber and amplitude of electromyography was observed until 2 months after injection. In 3 months after the injection, it was slowly getting back to original size and had almost recovered by 6 months after the injection. It showed reversible aspect. Conclusion: This study shows researches about clinical effect of botox injection and neurectomy coincide with the results of experiment under the same experimental condition.

• Anxiety and mood
• /
• v.16 no.1
• /
• pp.41-48
• /
• 2020

Objective : There have been limited scientific studies differentiating those who attempt suicide from those who think about suicide but do not attempt suicide. Altered event-related potential (ERP) performance, such as GoNogo ERP has been regarded as the neurocognitive processes associated with behavioral inhibition and poor impulse control. The purpose of this study was to investigate the association between Nogo ERP and suicide attempt. Methods : A total of 63 participants (33 participants with suicide ideation and 30 with suicide attempt) were recruited, and performed GoNogo tasks during the electroencephalogram measurement. Depression, anxiety, emotional regulation and impulsivity were evaluated by self-rating scales. The clinical measures and Nogo P3 component were compared between the groups. The correlational analyse was conducted to evaluate the relationship between the clinical characteristics and the Nogo P3 component. Results : Participants with suicide attempt significantly decreased the Nogo P3 amplitudes at the frontal-central electrode than participants with suicide ideation (p=0.004, FDR adjusted p=0.032). In the correlation analysis, the Nogo P3 amplitude at frontal-central electrode was correlated with the total score of the Barrett impulsivity scale (r=-0.383, p=0.002), attentional impulsivity (r=-0.365, p=0.003) and motor impulsivity (r=-0.389, p=0.002) subscales of the Barrett impulsivity scale. Conclusion : These findings suggest that the decreased Nogo P3 amplitude may be one of the candidates of biological marker for poor impulse control in those who attempt suicide.