• Journal of Environmental Health Sciences
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• v.45 no.1
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• pp.1-8
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• 2019

Objectives: The purpose of this study was to estimate the ventilation rate of residential homes in Korea through tracer gas methods using indoor and outdoor concentrations of carbon dioxide ($CO_2$) and $CO_2$ generation rates from breathing. Methods: In this study, we calculated the number of occupants in a home by time through data on the average number of people per household from the Korean National Statistical Office and also measured the amount of $CO_2$ generation by breathing to estimate the indoor $CO_2$ generation rate. To estimate the ventilation rate, several factors such as the $CO_2$ generation rate and average volume of residential house provided by the Korean National Statistical Office, indoor $CO_2$ concentrations measured by sensors, and outdoor $CO_2$ concentrations provided by the Korea Meteorological Administration, were applied to a mass balance model for residential indoor environments. Results: The average number of people were 2.53 per household and Koreans spend 61.0% of their day at home. The $CO_2$ generation rate from breathing was $13.9{\pm}5.3L/h$ during sleep and $15.1{\pm}5.7L/h$ in a sedentary state. Indoor and outdoor $CO_2$ concentrations were 849 ppm and 407 ppm, respectively. The ventilation rate in Korean residential houses calculated by the mass balance model were $42.1m^3/h$ and 0.71 air change per hour. Conclusions: The estimated ventilation rate tended to increase with an increase in the number of occupants. Since sensor devices were used to collect data, sustainable data could be collected to estimate the ventilation rate of Korean residential homes, which enables further studies such as on changes in the ventilation rate by season resulting from the activities of occupants. The results of this study could be used as a basis for exposure and risk assessment modeling.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.119-129
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• 2023

Sleep apnea causes various secondary disease such as hypertension, stroke, myocardial infarction, depression and cognitive impairment. Early detection and continuous management of sleep apnea are urgently needed since it causes cardio-cerebrovascular diseases. In this study, wearable device for monitoring respiration during sleep using PVDF film was developed to detect vibration through trachea caused by breathing, which determines normal breathing and sleep apnea. Variables such as respiration rate and apnea were extracted based on the detected breathing sound data, and a noise reduction algorithm was established to minimize the effect even when there is a noise signal. In addition, it was confirmed that irregular breathing patterns can be analyzed by establishing a moving threshold algorithm. The results show that the accuracy of the respiratory rate from the developed device was 98.7% comparing with the polysomnogrphy result. Accuracy of detection for sleep apnea event was 92.6% and that of the sleep apnea duration was 94.0%. The results of this study will be of great help to the management of sleep disorders and confirmation of treatment by commercialization of wearable devices that can monitor sleep information easily and accurately at home during daily life and confirm the progress of treatment.

• Journal of Physiology & Pathology in Korean Medicine
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• v.31 no.2
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• pp.83-93
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• 2017

This study covers pattern differentiation based on Korean medical references, research trend and modern clinical applications about Sleep-Wake disorders of Diagnostic and Statistical Manual of Mental Disorders(DSM-V) published by American Psychiatric Association. Insomnia disorder is mostly caused by yin deficiency of liver-kidney or liver qi depression and main patterns are heart-kidney non-interaction, deficiency-excess complex pattern containing phlegm-heat due to qi stagnation and blood stasis. Hypersomnolence disorder is more due to yang deficiency rather than yin deficiency and it's major pattern is spleen-kidney yang deficiency. Cataplexy is main feature in narcolepsy and corresponds to depressive psychosis or fainting in terms of Korean Medicine and narcolepsy is assumed to be relevant to liver wind. Breathing-related sleep disorders are related with phlegm-fluid retention brought on spleen deficiency with dampness encumbrance. Pattern of circadian rhythm sleep-wake disorders is combined with yin deficiency of liver-kidney or liver qi depression of insomnia disorder and spleen-kidney yang deficiency or dampness-phlegm of hypersomnolence disorder. Yin deficiency with effulgent fire brought on drugs or alcohol is one of main patterns of substance/medication-induced sleep disorder and combined patterns with yin deficiency of liver-kidney and blood stasis or dampness-phlegm-heat are mostly applied clinically. This study drew major and frequently applied patterns of sleep-wake disorders based on Koran medical literature and modern clinical applications. And that can be the groundwork for the task ahead like clinical practice guideline of sleep-wake disorders containing pattern differentiation, diagnosis and prescriptions.

• Journal of Korean Medical classics
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• v.34 no.1
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• pp.47-65
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• 2021

Objectives : An accurate judgment of prognosis when treating diseases is crucial. While the 『Shanghanlun(傷寒論)』 deals with the prognosis of the Three Yin Diseases with great importance, full-scale studies have been lacking. This paper aims to study the Three Yin Diseases with a focus on prognosis analysis. Methods : Among the Three Yin Disease verses, those that could provide clues to prognosis were selected and analysed. Conclusions & Results : When Yang pulse patterns such as long(長脈)·floating(浮脈)·rapid(數脈) pulses and Yang symptoms such as fever, vexing heat, mild perspiration, thirst, warmth in hands and feet are present in Yin disease, it could be taken as signs of Yang Qi restoration. In these situations, Yin Cold pattern such as diarrhea and reversal cold disappear and the prognosis is positive. However, despite Yang pulse patterns and symptoms, there are cases where diarrhea happens as a result of cold dampness being eliminated due to Yang Qi restoration. Also, when Yang Qi starts communicating smoothly after its restoration in the Three Yin Diseases, perspiration can happen. When diarrhea and reversal cold, which are patterns of Yin Cold get worse, with pulse patterns such as unfelt(脈不至)·replete(實脈)·fulminating(脈暴出) pulses, false heat symptoms such as fever and hot flashes happen, accompanied with Yang Qi depleted symptoms such as inability to lie down due to agitation, continuous perspiration, sore throat, dyspnea, and exaggerated breathing happen. When fast pulse, fever, and perspiration are present due to depression and stagnation of ministerial fire, symptoms such as bloody stool with pus, purulent abscess, sore throat, and inability to lie down due to agitation show, which signal negative prognosis. In bad cases of Reverting Yin Disease, there is continuous diarrhea and bloody stool with pus, which can be due to either Kidney Yang deficiency or depression and stagnation of ministerial fire. It could also be caused by excessive heat.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.12 no.1
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• pp.80-92
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• 2008

Background: The consequences of disordered breathing patterns are not only distressing to the patient but also expensive to our health care systems if they are not diagnosed and treated. So we performed this study to investigate clinical significants trough gigong, yoga and hyperventilation in oriental medicine and westen medicine Objective: To review the relationship of electrogastrography with autonomic nervous system and to study its clinical application. Method: We investigate the research results through internet search engine, Pubmed. Conclusion: Electrogastrography is a reliable, non-invasive method for recording gastric myoelectrical activity and is used for objectification of diagnosis related to gastric peristalsis. Gastric myoelectrical activity seem to involve autonomic nervous system, especially parasympathetic nervous system. The study should be continuing about relationship between electrogastrography and autonomic nervous system.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.6
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• pp.85-93
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• 2001

Minimized canister flow restriction and maximized flow uniformity are desired to maximize a purge capability. With the impending ORVR(On Board Refueling Vapor Recovery) systems, the reduction of restriction and increase of flow uniformity in a carbon canister becomes even more critical to meet the stringent regulation. In this study, three-dimensional numerical simulations have been performed to investigate the three-dimensional internal flow patterns in a carbon canister during purge. The effects of the declined angle of the purge pipe and the number of partitions on the pressure drop and purge efficiency in a carbon packed bed are examined. Results show that the purge efficiency and space velocity distribution are affected in the upstream region of 40% of total canister bed by porosity of carbon granule and angle of purge pipe. It is also found that the purge efficiency decreases with increasing the number of partitions.

• The Journal of the Acoustical Society of Korea
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• v.19 no.3E
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• pp.25-32
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• 2000

The main question addressed in this research was whether an adaptation of a standard exercise Physiology Procedure would be sensitive enough to record excess oxygen uptake associated with speech activity. Oxygen consumption was recorded for a single subject during 7-minute rest periods and an automatic speech task, also 7-minutes long and performed at three different vocal efforts. The data show measurable and systematic speech-induced modifications of breathing and oxygen uptake patterns. The subject was found to use less power for normal than for soft and loud speech. This result is similar to findings reported by experimental biologists on the energetics of locomotion. However, more comprehensive feasibility studies need to be undertaken on a larger population before solid and detailed conclusions about speech energy costs are possible. However, it appears clear that, for experimental tasks like the present one, i.e., variations in vocal effort, standard exercise physiology methods may indeed offer a viable approach to recording excess oxygen uptake associated with speech movements.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.09a
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• pp.40-44
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• 2005

Catalytic performance of Co catalysts supported on MgO for the formation of multiwall carbon nanotubes (MWCNTs) Having 40-60 nm in diameter has been investigated through acetylene decomposition at $600^{\circ}C$. Scanning electron microscopy measurements show that the nanotubes are chain and coiled structures whereas x-ray diffraction patterns indicate the formation of MWCNTs with Co nanoparticles. In addition Raman spectra confirms the format ion of MWCNTs due to presence of characteristic radial breathing mode along with D and G bands.

• Sleep Medicine and Psychophysiology
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• v.27 no.2
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• pp.33-40
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• 2020

An infant's sleep varies considerably from that of adults in terms of structure, amount, and breathing pattern. After birth, sleep becomes evenly distributed throughout the day and night. Nighttime sleep gradually increases with the maturation of circadian rhythm, and sleep is gradually consolidated. Electroencephalography characteristics change with age, from early and dominant active (REM) sleep in newborns to increasing NREM sleep. Similar to other elements of growth, the upper respiratory tract and ribcage gradually increase in size with age, and respiratory control also improves. With these changes, sleep patterns also change. At this time that various sleep disorders may appear. Improved understanding of age-dependent changes in infant sleep can help determine the etiology and facilitate diagnosis of infant sleep diseases.

• Journal of the Korean Society of Visualization
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• v.18 no.3
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• pp.96-102
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• 2020

Oral cancer surgery changes the morphologic characteristics of the human upper airway. These changes can affect the flow patterns. In this study, computational fluid dynamics (CFD) simulations with transient solver were performed to numerically investigate the air flows in the human upper airways depending oral cancer surgery. 3D reconstructed models were obtained from 2D CT images of one patient. For the boundary condition, the realistic breathing cycle of human was applied. The hydraulic diameters of cross-sections for post-surgical model are changed greatly along streamwise direction, so these variations can cause higher wall shear stress and flow disturbance compared to pre-surgical model. The recirculation flows observed in the protruding region result in the relatively large pressure drop. These results can be helpful to understand the flow variations after resection surgery of oral cancer.