• Sleep Medicine and Psychophysiology
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• v.11 no.1
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• pp.22-28
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• 2004

Objective: The purpose of this study is to investigate the prevalence rate of OSA in subjects whose main sleep complaint is insomnia and to find differential factors of OSA in these insomniac subjects. Method: We reviewed the medical records and polysomnographic findings of patients referred to the Sleep Laboratory at Seoul National University Hospital from January 1996 to December 2002. Four-hundred and seventy subjects complained of insomnia as their main sleep problem (235 males and 235 females, mean age $53.6{\pm}12.4\;years$). First, we investigated the prevalence rate of OSA in these insomniac patients. Second, we compared the clinical and demographic characteristics of the OSA-associated group with those of the non-associated group. Third, we examined whether the degree or presence of differential factors within the OSA group correlate with severity of OSA, as determined by the respiratory disturbance index (RDI). Results: Among 470 insomniac subjects, 125 subjects (26.6%) were diagnosed as OSA by nocturnal polysomnography. OSA-associated subjects were significantly older ($58.4{\pm}12.3\;years$ vs. $51.8{\pm}11.2\;years$, p<0.01), and had significantly higher body mass index (BMI) ($23.4{\pm}3.3\;kg/m^2$ vs. $22.5{\pm}3.1\;kg/m^2$, p=0.44) than non-associated subjects. The OSA-associated group had more subjects with male gender (64.0% vs. 44.9%, p<0.01), hypertension (20.0% vs. 9.3%, p<0.01) or snoring (96.0% vs. 63.5%, p<0.01). Within the OSA-associated group, age had a significant positive correlation with RDI (p=0.01). Conclusion: We found that a considerable portion of patients complaining of insomnia as their main sleep problem were diagnosed as OSA. Snoring, old age, male gender, obesity, and comorbid hypertension were found to be differential factors of OSA in insomniac patients. We suggest that diagnostic efforts including nocturnal polysomnography are needed for insomniac patients with any of the above risk factors of OSA.

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.145-146
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• 2015

폐쇄성수면무호흡증(Obstructive sleep apnea syndrome : OSAS)은 신경근육계, 호흡계, 심혈관계의 복합적인 질환으로서 사회적, 생리학적으로 심각한 문제를 발생시킬 수 있는 질병이다. 수술적치료를 결정하기에 앞서 환자의 증상 및 징후, 신체 상태와 습관 등을 정밀검사하고, 기도폐쇄가 일상생활 및 정신건강에 미치는 영향을 고려하여 수술여부를 결정하여야 한다. 폐쇄성수면무호흡증후군의 진단에 유용한 검사인 수면다원검사와 Videofluoroscopy의 검사결과를 바탕으로 수술소견을 비교분석하고자 하였다.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.64-67
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• 1995

전산화폐활량계를 국산화하기 위하여 호흡기류 계측시스템을 개발하였다. 호흡기류를 측정하는 방법으로 Pneumotachography를 적용하였다. 자체 Pneumotachometer를 설계, 제작하였고, 증폭기와 필터를 통하여 0 - 5 V 범위의 기류신호가 출력되도록 하였다. 온도보정을 위하여 기류의 온도를 K-type 열전쌍으로 연속측정하여 보정신호를 역시 0 - 5 V 범위로 제공하도록 제작하였으며 따라서 온도에 따른 측정오차를 근본적으로 제거하였다. 피검자의 감염 가능성을 최소화하기 위하여 환기기구를 사용하였으며 전력소모가 적고 미세균의 제거가 가능하다. 본 시스템의 특성 측정 결과 충분히 우수한 정특성과 동특성을 얻었으며 현재 호흡기류를 정량분석하는 S/W-시스템을 개발중이다.

• Korean Linguistics
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• v.79
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• pp.91-116
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• 2018

This paper aims at proposing issues of breath and memory in speech based on the quantitative analysis of breath groups and pause units in Korean. As a human being, we have two kinds of limitations on continuing speech; breath and memory. The prosodic structure and temporal structure of spontaneous speech data from six speakers were closely examined. One of the main findings of the present study is that the prosodic structure and temporal structure of Korean appears to reflect the breath and memory problems in speech.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2005.04a
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• pp.64-67
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• 2005

본 연구의 목적은 호흡 운동에 영향을 받는 내부 장기의 움직임을 정량적으로 분석하고, 그 결과를 토대로 움직이는 내부 장기의 선량 분포를 측정하고 평가하는 것이다. 그리고 이전에 보고된 논문에서 개발된 움직임 감소 장치의 사용 유무에 따른 내부 장기의 선량 분포 또한 분석하는 것이다. 이를 위하여 1차원적으로 움직이는 구동 팬톰 시스템을 개발하였고, 6MV X-ray에서 Kodak X-omat V 필름을 사용하여 움직이는 내부 장기의 선량분포를 실험적으로 측정하였다. 이 결과로부터 호흡 운동으로 인한 움직이는 내부 장기 및 종양에 조사되는 선량의 부정확도를 평가할 수 있었고, 움직임 감소 장치를 사용했을 때 선량의 부정확도가 감소함을 확인할 수 있었다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.343-348
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• 2002

생버섯의 환경기체조절저장을 위한 적정 기체조성을 예측하기 위하여 팽이버섯과 느타리 버섯을 대상으로 호흡특성치를 측정 및 모델링한 결과 두 버섯의 호흡속도는 환경기체조성에 영향을 받는 것으로 나타났다. 버섯의 산소소비속도와 이산화탄소발생속도를 반응표면분석한 결과 느타리버섯의 이산화탄소발생속도를 제외하고는 $R^2$=0.9이상의 높은 상관관계를 나타내었다. 반응표면 분석결과를 이용하여 두 버섯의 적정 기체조성은 팽이버섯의 경우 1~2.5% $O_2$와 10.5-11.5% $CO_2$, 느타리 버섯의 경우에는 2.5~4.5% $O_2$와 11.5~13%$CO_2$가 적정 기체조성 것으로 예측되었으며 일반적인 생버섯의 저장기체조건에 포함되는 농도였다. 따라서 예측된 조건에서 생버섯의 환경기체조절 저장이 가능 할 것으로 판단되었다.

• Progress in Medical Physics
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• v.21 no.2
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• pp.127-136
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• 2010

Emerging technologies such as four-dimensional computed tomography (4D CT) is expected to allow clinicians to accurately model interfractional motion and to quantitatively estimate internal target volumes (ITVs) for radiation therapy involving moving targets. A need exists for a 4D radiation therapy quality assurance (QA) device that can incorporate and analyze the patient specific intrafractional motion as it relate to dose delivery and respiratory gating. We built a 4D RT prototype device and analyzed the patient-specific 4D radiation therapy QA for 2D dose distributions successfully. With more improvements, the 4D RT QA prototype device could be an integral part of a 4D RT decision process to confirm the dose delivery.

• Journal of Life Science
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• v.19 no.12
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• pp.1829-1835
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• 2009

Hyperventilation (HV) is routinely induced in order to activate brain waves during an electroencephalogram (EEG). The aim of this study was to examine the effects of HV conditions on EEG and suggested basic data for the standardized procedure. Three degrees of HV were induced for 5 minutes with a ventilation volume of 160 ml/min (control group), 240 ml/min, and 300 ml/min in rats. Powers of delta, theta, alpha, and beta waves were examined by a quantitative EEG. The results showed that there was no significant difference in the powers of all EEG waves between the control and 240 ml/min groups. However, a notable change in EEG powers during HV induced by a ventilation volume of 300 ml/min was observed in the frontal cerebral region as follows: power of the delta was increased by 12.8% (p<0.01), powers of the theta, alpha and beta were decreased by 41.3% (p<0.01), 48.6% (p<0.05), and 41.9% (p<0.05), respectively. Therefore, it is concluded that an increase of about 90% of the normal ventilation volume might be adequate for the hyperventilation, and a useful parameter for evaluation of the qualified hyperventilation might be an alteration of the frontal EEG powers.

• Radiation Oncology Journal
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• v.23 no.4
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• pp.217-222
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• 2005

Purpose: To develop the respiration simulating phantom with thermocouple for evaluating 4D radiotherapy such as gated radiotherapy breathing control radiotherapy and dynamic tumor tracking radiotherapy. Materials and Methods: The respiration monitoring mask(ReMM) with thermocouple was developed to monitor the patient's irregular respiration. The signal from ReMM controls the simulating phantom as organ motion of patients in real-time. The organ and the phantom motion were compared with its respiratory curves to evaluate the simulating phantom. ReMM was used to measure patients' respiration, and the movement of simulating phantom was measured by using $RPM^{(R)}$. The fluoroscope was used to monitor the patient's diaphragm motion. relative to the organ motion, respectively. The standard deviation of discrepancy between the respiratory curve and the organ motion was 8.52% of motion range. Conclusion: Patients felt comfortable with ReMM. The relationship between the signal from ReMM and the organ motion shows strong correlation. The phantom simulates the organ motion in real-time according to the respiratory signal from the ReMM. It is expected that the simulating phantom with ReMM could be used to verify the 4D radiotherapy.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.1
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• pp.25-32
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• 2010

Purpose: In radiotherapy that takes into account respiration using a RPM (Real time Position Management, Varian, USA) system, which can treat in consideration of the movement of tumor, infrared reflective markers supplied by manufacturers cannot obtain respiratory signal if the couch rotates at a certain angle or larger. In order to solve this problem, the author developed the 3D infrared reflective marker named 'Kw-marker' that can obtain respiratory signal at any angle, and evaluate its usefulness. Materials and Methods: In order to measure the stability of respiratory signal, we put the infrared reflective marker on the 3D moving phantom that can reproduce respiratory movement and acquired respiratory signal for 3 minutes under each of 3 conditions (A: $couch\;0^{\circ}$, a manufacturer's infrared reflective marker B: $couch\;0^{\circ}$, Kw-marker C: $couch\;90^{\circ}$, Kw-marker). By analyzing the respiratory signal using a breath analysis program (Labview Ver. 7.0), we obtained the peak value, valley value, standard deviation, variation value, and amplitude value. In order to examine the rotation error and moving range of the target, we placed a B.B phantom on the 3D moving phantom, and obtained images at a couch angle of $0^{\circ}$ and $90^{\circ}$ using OBI, and then acquired the X, Y and Z values (mm) of the ball bearing at the center of the B.B phantom. Results: According to the results of analyzing the respiratory signal, the standard deviation at the peak value was A: 0.002, B: 0.002 and C: 0.003, and the stability of respiration for amplitude was A: 0.15%, B: 0.14% and C:0.13%, showing that we could get respiratory signal stably by using the Kw-marker. When the couch rotated $couch\;90^{\circ}$, the mean rotation error of the ball bearing, namely, the target was X: -1.25 mm, Y: -0.45 mm and Z: +0.1 mm, which were within 1.3 mm on the average in all directions, and the difference in the moving range of the target was within 0.3 mm. Conclusion: When we obtained respiratory signal using the Kw-marker in non-coplanar treatment where the couch rotated, we could acquire respiratory signal stably and the Kw-marker was effective enough to substitute for the manufacturer's infrared reflective marker. When the rotation error and moving range of the target were measured, there was little difference, indicating that the displacement of the reflector movement in couch rotation is the cause of change in the scale and amplitude of respiratory signal. If the converted value of amplitude height according to couch angle is studied further and applied, it may be possible to perform non-coplanar phase-based gating treatment.