• The Korean Journal of Physiology
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• v.15 no.1
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• pp.37-43
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• 1981

In the present study, an effort was directed to elucidate the effect of the physical training on the pulmonary function. Twenty-four male athletics major students who have undergone regular physical training for more than five years were randomly chosen as the athletic subjects, and 12 regular male students who have not been engaged in any form of regular physical exercise or training were chosen as the non-athletic subjects, and a comparison was made between the two groups. The following were mainly observed by spirometry for the study; respiratory rate, tidal volume, vital capacity, maximum voluntary ventilation(MVV), forced expiratory volume for 1 second$(FEV_1)$, percent $FEV_1$ to forced vital capacity$(FEV_1%)$, forced expiratory flow for initial 1 liter$(FEF_{0.2-1.2}L)$, and forced mid-expiratory flow$(FEF_{\;25-75}%)$. The results obtained are summarized as follow. 1) The respiratory rate, tidal volume, and vital capacity showed no significant difference between athletes and non-athletes. The MVV in athletes was significantly (p<0.01) increased to $148.1{\pm}3.1\;L/min$ comparing with $118.3{\pm}9.1\;L/min$ in non-athletes. 2) $FEV_1$ was $3.310{\pm}0.070\;L$ in athletes and $2.779{\pm}0.104$ in non-athletes; $FEV_1%\;83.63{\pm}1.29%$ in athletes and $75.33{\pm}1.75%$ in non-athletes, both showing significant(p<0.01) increase in athletes. 3) $FEF_{0.2-1.2}L$ was $297.1{\pm}13.5\;L/min in athletes and $222.7{\pm}15.0\;L/min$ in non-athletes; $FEF_{\;25-75}%$ was $3.543{\pm}0.109\;L/sec$ in non-athletes, both showing significant(p<0.01) increase in athletes. 4) Some discussions were made on these results. The lung volumes showed no significant difference between the two groups. But MVV, $FEV_1$, $FEV_1%$, $FEF_{0.2-1.2}L$ and $FEF_{25-75}%$ in athletes were significantly(p<0.01) higher than in non-athletes. It is therefore concluded that the athletes have more powerful respiratory muscles, or higher compliance of the lung and thorax than the non-athletes.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.305-312
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• 2016

Purpose: The purpose of this study is to provide a sensitivity analysis of system reliability for recognizing effectiveness of changing of BD mode failures using reliability growth projection model based on NHPP. Methods: Crow extended reliability projection model (CERPM) is used to analyze the changing of two factors 1) the number of BD mode failures, 2) fix effectiveness factor (FEF) values. Results: The system reliability has increased in accordance with the number of BD mode failures and FEF values have increased. Conclusion: It is necessary to design failure modes and FEF values to supervise the reliability.

• Journal of Preventive Medicine and Public Health
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• v.28 no.3 s.51
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• pp.690-705
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• 1995

Pulmonary function tests were conducted on 815 healthy primary school children (390 males and 425 female) in rural area using Collins Survey Spirometer (Warren E. Collins, Inc., U.S.A.) with X-Y Recorder. Respiratory symptoms(cough, sputum, sore throat, chest pain, chest tightness, dyspnea, coryza) were surveyed by the interviews. Multiple regression analysis and regression diagnostics were done for prediction equations of FVC, $FEV_1,\;PEFR\;and\;FEF_{25-75%}$. FVC, $FEV_1,\;PEFR\;and\;FEF_{25-75%}$ values in 3 groups of children classified by the number of symptom were compared each other through standard variable value. FVC, $FEV_1,\;PEFR\;and\;FEF_{25-75%}$ showed highly significant correlation with age, height and weight. Prediction equations for FVC, $FEV_1,\;PEER,\;FEF_{25-75%}$ are functions of height only in both male and female children aged between 6 and 12 years old. PEFR showed a significant difference related with the number of symptom in female. These results suggest that the PEFR is sensitive PFT parameter in this study.

• Journal of Broadcast Engineering
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• v.20 no.2
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• pp.310-339
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• 2015

In this paper, the possibility of a terrestrial fixed 4K UHD (Ultra High Definition) and mobile HD (High Definition) convergence broadcasting service through a single channel employing the FEF (Future Extension Frame) multiplexing technique in DVB (Digital Video Broadcasting)-T2 (Second Generation Terrestrial) systems is examined. The performance of such a service is also investigated. FEF multiplexing technology can be used to adjust the FFT (fast Fourier transform) and CP (cyclic prefix) size for each layer, whereas M-PLP (Multiple-Physical Layer Pipe) multiplexing technology in DVB-T2 systems cannot. The convergence broadcasting service scenario, which can provide fixed 4K UHD and mobile HD broadcasting through a single terrestrial channel, is described, and transmission requirements of the SHVC (Scalable High Efficiency Video Coding) technique are predicted. A convergence broadcasting transmission system structure is described by employing FEF and transmission technologies in DVB-T2 systems. Optimized transmission parameters are drawn to transmit 4K UHD and HD convergence broadcasting by employing a convergence broadcasting transmission structure, and the reception performance of the optimized transmission parameters under AWGN (additive white Gaussian noise), static Brazil-D, and time-varying TU (Typical Urban)-6 channels is examined using computer simulations to find the TOV (threshold of visibility). From the results, for the 6 and 8 MHz bandwidths, reliable reception of both fixed 4K UHD and mobile HD layer data can be achieved under a static fixed and very fast fading multipath channel.

• Tuberculosis and Respiratory Diseases
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• v.59 no.4
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• pp.368-373
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• 2005

Background : Bronchial anthracofibrosis usually manifest as a form of obstructive airway disease, and can be accompanied by parenchymal diseases such as pneumonia, and pulmonary tuberculosis. This study investigated the ventilatory dynamics according to the severity of bronchial stenosis in patients with bronchial anthracofibrosis. Method : One hundred and thirteen patients with bronchial anthracofibrosis that was confirmed by bronchoscopy and who had undergone a pulmonary function test were enrolled in this study group. The correlation coefficients between the pulmonary functional parameters and the number of lobes with bronchial stenosis were investigated. Results : The incidence of ventilatory dysfunction was 56(49.6%) for obstructive, 8(7.1%) for restrictive, 2(1.8%) for mixed, and 47(41.6%) for a normal pattern. The $FEV_1/FVC$, $FEF_{25{\sim}75%}$, $FEF_{25%}$, $FEF_{50%}$, $FEF_{75%}$, and PEF showed a significant negative correlation (p<0.05) and the Raw had a significant positive correlation with the number of lobes with bronchial stenosis(p<0.001). Conclusion : These findings suggest that the most common abnormality of the ventilatory function in bronchial anthracofibrosis is an obstructive pattern with a small airway dysfunction according to the severity of bronchial stenosis.

• Journal of Korean Physical Therapy Science
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• v.6 no.2
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• pp.997-1005
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• 1999

To evaluate the effect of winter intensive training on pulmonary function in high school baseball players, comparisons of various ventilatory parameters were made before and 3-3.5 months of winter intensive tranining. The subjects were 18 members of a high school baseball players with mean age and career of 6.3 and 7.3 years, respectively. The following were mainly observed by spirometry for the study ; respiratory rate, vital capacity(VC), maximum voluntary ventilation(MVV), forced vital capacity (FEV1%) and forced mid-expiratory flow (FEF25-75%). The result obtained are summarized as follow. 1) Resipratory rate, tidal volume, forced vital capacity, 1FEV%, FEF50% and FEF75% showed no significant difference between before and after. 2) MVV in after was significantly(p<0.001) increased to 166 L/min comparing with 136L/min in before. 3) 1FEV in after was significantly(p<0.05) increased to 4.46L comparing with 3.76L in before. 4) PEF in after was significantly(p<0.05) increased to 10.40 L/sec comparing with 9.18 L/sec in before.

• Clinical and Experimental Pediatrics
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• v.51 no.3
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• pp.323-328
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• 2008

Purpose : Asthma is defined as chronic inflammation of the lower small airways, and bronchial hyperreactivity (BHR) is a pathophysiologic feature of asthma. It has been proposed that although there is no direct variable capable of assessing the small airways, a forced expiratory flow of between 25 and 75 percent ($FEF_{25-75}$) might be considered a more sensitive early marker of small airway obstruction than the forced expiratory volume in 1 second ($FEV_1$). Thus, we proposed that the presence and degree of positive responses to bronchial methacholine testing were related to the difference (DFF) and ratio (RFF) between $FEV_1$ and $FEF_{25-75}$ in asthmatic children. Methods : The subjects were 583 symptomatic children, including 324 children with BHR and 259 controls. Pulmonary function tests, methacholine challenge tests, and skin prick tests were performed, and the total eosinophil count, total serum IgE, and serum eosinophil cationic protein level were measured in all subjects. From a concentration-response curve, the methacholine concentration required to produce a decrease of 20% from post-saline $FEV_1$ was calculated ($PC_{20}$). Results : The median DFF and RFF values decreased in controls compared to subjects with bronchial hyperresponsiveness, and this trend was found in groups ranked by its severity. $PC_{20}$ had a negative correlation with DFF and RFF. Cutoff values of 0.5 for DFF and 1.042 for RFF were identified, and sensitivity and specificity were calculated. Conclusion : This study revealed that DFF and RFF might be predictive of bronchial hyperresponsiveness in the context of normal $FEV_1$ in children.

• The Journal of Korean Physical Therapy
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• v.13 no.2
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• pp.347-357
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• 2001

It is well known that there is an adverse effect of long-term cigarette smoking on pulmonary function. Therefor we attempted to consider the vital capacity for position changes in a smokers and non-smokers. The pulmonary functions on sitting and supine positions were measured in 28 young healthy students fer the change of vital capacity. Forced expiratory flow-volume curve were performed sitting position and supine position and smoking. The results were summarized as follows; 1) The spirometric values(VC, FVC, FEV$_{1}$) were progressively decreased from sitting position to 30minutes after supine position in a non-smoking group(p<.05). 2) The VC, FVC. FEV$_{1}$, FEF25 ${\sim}$ 75% were decreased from sitting position to 30minutes after supine position in a smoking group(p< .01). The PEF and FEF25% were decreased from supine position to after smoking(p< .05). 3) non-smoking group and smoking group not showed significant change(p> .05). But the spirometric values were more decreased nonsmokers than smokers.

• Journal of Korean Society for Atmospheric Environment
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• v.1 no.1
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• pp.17-23
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• 1985

In order to study the effect of air pollution on the ventilatory function of lung, pulmonary function studies were carried out in middle school students (male) living isn Sasang industrial area more than 10 years, and were compared with those of control group. The following results were obtained; 1. Lung capacities were normal in observed & control group, and were not significantly different between two groups. 2. The respective parameters of ventilatory function test of observed group were smaller than that of control group, but FVC, $FEV_1$, $FEV_1/FVC$, FEF 25-75%, Vmax 50, MVV of two groups were normal. 3. PEFR, Vmax 25, Vmax 75 of observed group were significantly decreased, and there were statistically significant differences between two groups in FEF 25-75% (p < 0.01), Vmax 25 (p < 0.05), Vmax 50 (p < 0.01), Vmax 75 (p < 0.05), PEFR (p < 0.05) and MVV (p < 0.02).

• Elastomers and Composites
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• v.27 no.4
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• pp.281-288
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• 1992

The purpose for this study is to examine the vulcanization characteristics, especially the damping, elastic modulus and viscous modulus properties of filler 50phr filled NR compounds and to find out the compounds which can be used as damping materials in industry. For this study, compounds were prepared with filler filled compounding formula. Their vulcanization characteristics, elastic modulus, viscous modulus and damping properties were examined by mean of the rheometrics dynamic spectrometer. The results of this study can be summarized as follows. 1. The elastic modulus values of the maxium under the condition of 1Hz frequency, showed the order as follows, $HAF>Silica>FEF>GPF>SRF>Clay>CaCO_3\;coated>CaCO_3$. 2. The damping values of the maxium under the condition of 1Hz frequency, showed the order as follows $Silica>HAF>FEF>GPF>SRF>Clay>CaCO_3\;coated>CaCO_3$.