• Journal of Biomedical Engineering Research
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• v.22 no.5
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• pp.439-448
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• 2001

This paper considers the acoustical characteristics of the closing click sounds of the mechanical valves employed in an implantable biventricular assist device (BYAD) and their re1evance to the Physical states of the valved. Bj rk Shiley Convexo Concave tilting disk valve was chosen for the study and acoustic measurement was made for the BYAD operated in a mock circulatory system as well as implanted in an animal (sheep). In the BYAD operated in the mock circulatory system. three different states of the valve were examined, ie. normal. mechanically damaged. pseudo-thrombus attached. Microphone measurement for the BVAD implanted in the animal was carried out for five days at a regular time interval from one day after implantation. Characteristic spectrum of the sound from the valve was estimated using Multiple Signal Classification (MUSIC) in which the optimal order was determined according to Bayesian Information Criterion (BIC) . It was observed that the mechanical damage of the valve resulted in changes of the structure of the acoustic spectrum. In contrast. the thrombus formed on the valve did not change much the basic structure of the spectrum but brought about altering the spectral Peak frequencies and energies. Maximum spectral Peak (MSP) with the greatest energy was seen at 2 kHz for the normal valve and it was shifted to 3 kHz for the calve attaching the Pseudo-thrombus. Unlike the normal valve, strong spectral Peak appeared around 7 kHz in the sound from the valve mechanically damaged. In the case of the BYAD implanted in the animal. as the thrombus grew, acoustic energy was reduced relatively more in the low frequency components (〈 2 kHz) and the frequencies of the 1st, 2nd and 3rd MSP were increased little. The thrombus formation would result in reduction in both the variability of the 1st, 2nd and 3rd MSP and the value of the BIC optimal order.

• Journal of Korean Medicine for Obesity Research
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• v.9 no.2
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• pp.33-45
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• 2009

Objectives This study was performed to evaluate the relation between hair tissue mineral elements(HTME) and Heart rate variability(HRV) of the metabolic syndrome(MS). Methods 89 persons(41-69 ages) who visited Oriental hospital for medical examination were divided MS group(n=22) and control group(n=67). HTME and HRV were compared, and were analyzed correlation with five contents of the MS. Results (1) In total subjects, waist circumference had a positive correlation with Pb. Blood pressure had a negative correlation with Mg. High density lipoprotein cholesterol(HDL-chol) had a negative correlation with Pb, Sb and K, while positive correlation with Ca/K. Triglyceride(TG) had a negative correlation with Mg and Na/K, while positive correlation with K and Ca/Mg. (2) In total subjects, TG and fasting blood sugar(FBS) had negative correlation with high frequency(HF), while positive correlation with low frequency/high frequency ratio(LF/HF). (3) In MS group, most of the level of toxic minerals were higher, and the level of major nutritional minerals were lower, but there were no statistical signficance. In two groups, there is no contrast between the correlations of the MS contents and HTME. (4) In MS group, HF was significantly lower and LF/HF was higher than normal group. LF/HF had a negative correlation with waist circumference in MS group, while positive correlation in normal group. (5) In total subjects, TP had a positive correlation with Mg. In two groups, there is no contrast between the correlations of the MS contents and HRV. However LF/HF had a positive correlation with Na in MS group, TP and LF had negative correlation with Ca, while RMSSD and HF had negative correlation with Cu in normal group. Conclusion These results may suggest that HTME and HRV are useful in diagnosing and preventing the metabolic syndrome.

• The Korean Journal of Nuclear Medicine
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• v.37 no.3
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• pp.162-170
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• 2003

The probabilistic anatomical maps are used to localize the functional neuro-images and morphological variability. The quantitative indicator is very important to inquire the anatomical position of an activated legion because functional image data has the low-resolution nature and no inherent anatomical information. Although previously developed MNI probabilistic anatomical map was enough to localize the data, it was not suitable for the Korean brains because of the morphological difference between Occidental and Oriental. In this study, we develop a probabilistic anatomical map for Korean normal brain. Normal 75 blains of T1-weighted spoiled gradient echo magnetic resonance images were acquired on a 1.5-T GESIGNA scanner. Then, a standard brain is selected in the group through a clinician searches a brain of the average property in the Talairach coordinate system. With the standard brain, an anatomist delineates 89 regions of interest (ROI) parcellating cortical and subcortical areas. The parcellated ROIs of the standard are warped and overlapped into each brain by maximizing intensity similarity. And every brain is automatically labeledwith the registered ROIs. Each of the same-labeled region is linearly normalize to the standard brain, and the occurrence of each legion is counted. Finally, 89 probabilistic ROI volumes are generated. This paper presents a probabilistic anatomical map for localizing the functional and structural analysis of Korean normal brain. In the future, we'll develop the group specific probabilistic anatomical maps of OCD and schizophrenia disease.

• The Journal of Internal Korean Medicine
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• v.38 no.6
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• pp.955-970
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• 2017

Objectives: The aim of this observational study was to identify and analyze the patterns to compare the characteristics of asthma patients. Methods: The subjects were 40 asthma patients who had satisfied the inclusion and exclusion criteria. They were divided into deficiency syndrome and excess syndrome groups, and cold syndrome and heat syndrome groups. Their quality of life was measured by the quality of life questionnaire for adult Korean asthmatics (QLQAKA) and VAS. Heart rate variability (HRV) was measured, and the degree of obesity was evaluated by body mass index (BMI). Hematological, biochemical, and immunoglobulin (Ig) E laboratory tests were included. Results: Based on pattern identification, the 40 asthma patients could be divided into two categories of groups: 1) the deficiency syndrome (N=18) and the excess syndrome (N=22) groups: 2) the cold syndrome (N=35) and the heat syndrome (N=5) groups. The mean value of HF differed significantly between the deficiency and excess syndrome groups. The mean value of IgE in blood tests of asthmatics was greater than four times the reference value. For BMI, the subjects were classified into three groups: normal weight (N=12), overweight (N=12), and obese (N=16). Conclusions: Development of a more accurate asthma-specific pattern identification tool could play a crucial role in asthma control. In addition, good control of asthma can improve the quality of life. Obesity is one of the factors associated with asthma exacerbation.

• The Journal of the Acoustical Society of Korea
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• v.16 no.5
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• pp.112-121
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• 1997

In this paper, we study a model parameter compensation method for noise-robust speech recognition. We study model parameter compensation on a sentence by sentence and no other informations are used. Parallel model combination(PMC), well known as a model parameter compensation algorithm, is implemented and used for a reference of performance comparision. We also propose a modified PMC method which tunes model parameter with an association factor that controls average variability of gaussian mixtures and variability of single gaussian mixture per state for more robust modeling. We obtain a re-estimation solution of environmental variables based on the expectation-maximization(EM) algorithm in the cepstral domain. To evaluate the performance of the model compensation methods, we perform experiments on speaker-independent isolated word recognition. Noise sources used are white gaussian and driving car noise. To get corrupted speech we added noise to clean speech at various signal-to-noise ratio(SNR). We use noise mean and variance modeled by 3 frame noise data. Experimental result of the VTS approach is superior to other methods. The scheme of the zero order VTS approach is similar to the modified PMC method in adapting mean vector only. But, the recognition rate of the Zero order VTS approach is higher than PMC and modified PMC method based on log-normal approximation.

• Korean Security Journal
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• no.31
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• pp.7-24
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• 2012

In this study a practical guarding work is carried out for 180 minutes as the same as the actual guarding work that is done by nine students of the department of security services in K University in order to investigate changes in circadian rhythms during long hour guarding in bodyguards at practical sites. In the results of the tests of the heart rate variation and autonomic nervous system with the interval of 30 minutes using HRV (Heart rate variability), there are no significant differences in HRV and SDNN and that leads to maintain it stably during the guarding work for 180 minutes. In the case of TP which reflects the overall activity level in the autonomic nervous system, it shows a high significant difference (p<.05) at 90 and 120 minutes compared to that of normal states. Also, it shows a significant decrease in the level after a lapse of 120 minutes and that shows a decrease in the activity of the autonomic nervous system for the guarding work more than 120 minutes. Although differences in VLF, LF, and HF are not significant levels, these are influenced on the change in TP. The LH/HF ratio that represents the balance between the sympathetic nerve and the parasympathetic nerve shows a significant high level (p<.05) after a lapse of 30 minutes. Thus, it is considered that the concentration of the guarding work after a lapse of 120 minutes is decreased and there are some tensions and excitations after a lapse of 30 minutes since the beginning of the guarding work.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.4
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• pp.305-310
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• 1983

Spatial variability of infiltration rates of 96 samples from Hwadong SiCL was studied by using geostatistical concepts. The measurement was made at the nodes of the regular grid consisting of 12 rows and 8 columns. Sample spacing within rows and columns was 3 and 2 meters, respectively. This study illustrated the use of variogram as a tool to identify the degree of dependency of the infiltration rate on the distance between pairs of measurements and how to take advantage of this dependency. Fractile diagram showed that the distribution of observation was approximately normal. The range of the variogram was about 7.4 meters. The minimum number of samples necessary to reproduce the results similar to the 96 measured values was 8 to 10. Coefficients of theoretical variogram function for computing kriged values and kriged varionces of nuogget effect, slope, and range were 0.444 cm/day, 0.003 cm/day, and 7.4 m, respectively.

• Atmosphere
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• v.19 no.2
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• pp.183-198
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• 2009

The purpose of this study is to summarize the tropical cyclone (TC) activity of 2008 over the western North Pacific including the verification of the official track and intensity forecast errors of these TCs. The TC activity - frequency, Normalized Typhoon Activity (NTA), and life span - was lower than 58-year (1951-2008) average. 22 tropical cyclones of tropical storm (TS) intensity or higher formed in the western North Pacific and the South China Sea in 2008. The total number is less than 58-year average frequency of 26.4. Out of 22 tropical cyclones, 11 TCs reached typhoon (TY) intensity, while the rest 11 TCs only reached severe tropical storm (STS) and tropical storm (TS) intensity - six STS and five TS storms. One typhoon KALMAEGI (0807) among them affected the Korea peninsula. However, no significant impact - casualty or property damage - was reported. On average of 22 TCs in 2008, the Korea Meteorological Administration (KMA) official track forecast error for 48 hours was 229 km. There was a big challenge for individual cyclones such as 0806 FENGSHEN and 0817 HIGOS presenting significant forecast error, with both intricate tracks and irregular moving speed. The tropical cyclone season in 2008 began in April with the formation of NEOGURI (0801). In May, four TCs formed in the western North Pacific in response to enhanced convective activity. On the other hand, the TC activity was very weak from June to August. It is found that the unusual anti-cyclonic circulation in the lower level and weak convection near the Philippines are dominant during summertime. The convection and atmospheric circulation in the western North Pacific contributed unfavorable condition for TC activity in the 2008 summertime. The 2008 TC activity has continued the below normal state since mid 1990s which is apparent the decadal variability in TC activity.

• The Journal of Internal Korean Medicine
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• v.27 no.4
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• pp.798-810
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• 2006

Objectives : This study was designed to investigate heart rate variability(HRV) in patients with abnormality on EKG by power spectrum analysis of HRV. Methods : The patient group consisted of 147 patients diagnosed as abnormal on EKG at the Oriental Medical Hospital of Dong-eui University from November 2003 to September 2005. We divided the patient group into 9 subgroups (bradycardia, arrhythmia, PVC, AF, AV block, RBBB, LVH, cardiac ischemia, LAD ). The control group consisted of 117 patients who were diagnosed as normal on EKG at the same hospital during the same period. We checked HRV of the two groups over 5 minutes and compared the HRV index between groups. Results and Conclusions : In the time domain analysis, SDNN was significantly higher in the PVC and AF groups than control group and RMSSD was significantly higher in the all patient group and the bradycardia, PVC and AF groups than in the control group. In the frequency domain analysis, Ln(LF) was significantly higher in the all patient group and the PVC and AF groups than the control group but lower in the LAD group. Ln(HF) was significantly higher in The all patient group and bradycardia, PVE and AF groups than control group. LF/HF ratio was significantly lower in the all patient group and bradycardia, arrhythmia, AF, AV block and LAD groups than control group. The autonomic nerve system and parasympathetic nerve system were higher in the patient group with abnormal EKG compared with the control group.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.343-349
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• 2004

Electroglottograph(EGG) is a signal recorded from the vocal cord vibration by measuring electrical impedance across the vocal folds through the neck skin. The purpose of this study was to develop EGG system and to evaluate possibility for the application on speech analysis and laryngeal disease diagnosis. EGG system was composed of two pairs of ring electrodes, tuned amplifier, phase sensitive detector, low pass filter, and auto-gain controller. It was designed to extract electric impedance after detecting by amplitude modulation method with 2.7MHz carrier signal. Extracted signals were transmitted through line-in of PC sound card, sampled and quantized. Closed Quotient(CQ), Speed Quotient(SQ), Speed Index(SI), fundamental frequency of vocal cord vibration(F0), pitch variability of vocal fold vibration (Jitter), and peak-to-peak amplitude variability of vocal fold vibration(Shimmer) were analyzed as EGG parameters. Experimental results were as follows: the faster vocal fold vibration, the higher values in CQ parameter and the lower values in SQ and SI parameters. EGG and speech signals had the same fundamental frequency. CQ, SQ, and SI were significantly different between normal subjects and patients with laryngeal cancer. These results suggest that it is possible to implement portable EGG system to monitor the function of vocal cord and to test functional changes of the glottis.