• Journal of the Korean Society of Earth Science Education
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• v.9 no.2
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• pp.186-198
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• 2016

The purpose of this study is to identify the composition elements and processes of the rock cycle that pre-service teachers in earth science field understand. Second-year students majoring in earth science were selected as research objects, all of whom attended teacher's university located in the southern region. The methods of arranging the composition elements of the rock cycle in a structured way and displaying the cycle direction through the arrow and describing the cycle processes in detail were applied. Pre-service teachers recognized 5 composition elements: magma, igneous rocks, sediments, sedimentary rocks, metamorphic rocks of the rock cycle and cycle processes was represented into 20 branches. The cycle type was analyzed by four criteria: linear, triangular, circular, complex, some pre-teachers did not complete the loop of the cycle or some showed incomplete understanding of the cycle structure simply displayed in one direction. The rock cycle is an important theme of the earth system education characterized by dynamism and complexity.

• Journal of Chest Surgery
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• v.37 no.12
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• pp.1003-1009
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• 2004

Mechanical circulatory support (MCS) has been used for myocardium failure, but moreover, it may be essential for the life support in cardiac arrest or cardiogenic shock. Many commercial devices can be used effectively for the long-term support. However, there are some limitations in the aspects of the cost and technical support by production company. Short-term support with centrifugal type has been reported numerously with the purpose of bridging to heart transplantation or recovery. We successfully treated 5 patitents who were in the status of cardiogenic shock (n=3) or arrest (n=2) with the technique of extracorporeal life support system (ECLS) or left ventricular assist device (LVAD) using the centrifugal type pump. The MCS were performed emergently (n=2) under cardiac arrest caused by ischemic heart disease, and urgently (n=3) under cardiogenic shock with ischemic heart disease (n=1) or acute fulminant viral myocarditis (n=2). All patients were weaned from MCS. Complications related to the use of MCS were bleeding and acute renal failure, but there were no major complications related to femoral cannulations. Mechanical circulatory support may be essential for the life support and rescue in cardiac arrest or cardiogenic shock.

• Journal of Animal Science and Technology
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• v.49 no.2
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• pp.279-286
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• 2007

A submerged biofilm sequencing batch reactor (SBSBR) process, which liquor was internally circulated through sandfilter, was designed, and performances in swine wastewater treatment was evaluated under a condition of no external carbon source addition. Denitrification of NOx-N with loading rate in vertical and slope type of sandfilter was 19% and 3.8%, respectively, showing approximately 5 times difference, and so vertical type sandfilter was chosen for the combination with SBSBR. When the process was operated under 15 days HRT, 105L/hr.m3 of internal circulation rate and 54g/m3.d of NH4-N loading rate, treatment efficiencies of STOC, NH4-N and TN (as NH4-N plus NOx-N) was 75%, 97% and 85%, respectively. By conducting internal circulation through sandfilter, removal performances of TN were enhanced by 14%, and the elevation of nitrogen removal was mainly attributed to occurrence of denitrification in sandfilter. Also, approximately 57% of phosphorus was removed with the conduction of internal circulation through sandfilter, meanwhile phosphorus concentration in final effluent rather increased when the internal circulation was not performed. Therefore, It was quite sure that the continuous internal circulation of liquor through sandfilter could contribute to enhancement of biological nutrient removal. Under 60g/m3.d of NH4-N loading rate, the NH4-N level in final effluent was relatively low and constant(below 20mg/L) and over 80% of nitrogen removal was maintained in spite of loading rate increase up to 100g/m3.d. However, the treatment efficiency of nitrogen was deteriorated with further increase of loading rate. Based on this result, an optimum loading rate of nitrogen for the process would be 100g/m3.d.

• Journal of Chest Surgery
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• v.39 no.1 s.258
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• pp.12-17
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• 2006

Background: Circulatory arrest under deep hypothermia is an important auxiliary means for surgical correction of total anomalous pulmonary venous connection (TAPVC), However, cardiac operations under deep hypothermic circulatory arrest are associated with the risk of post-arrest neurologic abnormalities. The purpose of this study is to evaluate the results of the surgical correction of total anomalous pulmonary venous connection without the total circulatory arrest. Materiai and Method: Between April 2000 and October 2004, hospital records of 10 patients were reviewed retrospectively. Result: The locations for abnormal anatomical connections were supracardiac in 7 cases, cardiac in 1 case, and infracardiac in 2 cases. The mean cardiopulmonary bypass time and aorta cross clamp time were 116.8$\pm$40.7 and 69.5$\pm$24.1 minutes. There was no surgical mortality. Postoperative complications were post-repair pulmonary venous stenosis in 1 case, pneumonia in 1, pneumothorax in 1, wound infection in 1,and diaphragmatic paralysis in 1. All patients without pulmonary venous stenosis were in NYHA class I at mean follow-up of 16.6 months (3$\∼$49 months) Conclusion: We could obtain excellent results by repair without the total circulatory arrest for total anomalous pulmonary venous connection.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.341-341
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• 2009

초전도 케이블의 대용량 전력수송능력을 실계통에 적용하기 위해서는 정상상태 뿐 아니라 계통운용상 발생하는 비정상 상태에 대해서도 안정된 성능을 나타내야 한다. 계통운영시 가장 일반적으로 발생하는 비정상 상태의 하나인 계통불평형부하 상태에서의 초전도 케이블의 특성을 실증적으로 확인하기 위해 한전 고창전력시험센터에서 신뢰성시험을 실시하였다. 삼상 송전계통에서 각 상 도체전류는 각 상의 부하량에 의해 결정이 되므로 과도상태라 해도 상당한 시간동안 도체전류가 불평형일 경우 자기적으로 결합된 차폐층전류의 불평형상태가 발생한다. 차폐층전류는 삼상 순환회로의 중성도체가 존재하지 않는 경우 도체전류와의 차이가 발생하게 되어 자기차폐 실패의 원인이 됨으로서 AC손실 증가요인으로서 영향이 커진다. 본 논문에서는 도체전류의 불평형 상태를 실증적으로 모의 발생시켜 연관된 차폐층 순환전류의 형태 및 특성을 검토함으로서 삼상 초전도 케이블의 불평형 부하특성에 대한 연구 진행경과를 요약한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.11a
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• pp.137-139
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• 2019

본 논문은 다양한 음성 특징과 텍스트를 이용한 멀티 모드 순환신경망 네트워크를 사용하여 음성을 통한 범주형(categorical) 분류 방법과 Arousal-Valence(AV) 도메인에서의 분류방법을 통해 감정인식 결과를 제시한다. 본 연구에서는 음성 특징으로는 MFCC, Energy, Velocity, Acceleration, Prosody 및 Mel Spectrogram 등의 다양한 특징들의 조합을 이용하였고 이에 해당하는 텍스트 정보를 순환신경망 기반 네트워크를 통해 융합하여 범주형 분류 방법과 과 AV 도메인에서의 분류 방법을 이용해 감정을 이산적으로 분류하였다. 실험 결과, 음성 특징의 조합으로 MFCC Energy, Velocity, Acceleration 각 13 차원과 35 차원의 Prosody 의 조합을 사용하였을 때 범주형 분류 방법에서는 75%로 다른 특징 조합들 보다 높은 결과를 보였고 AV 도메인 에서도 같은 음성 특징의 조합이 Arousal 55.3%, Valence 53.1%로 각각 가장 높은 결과를 보였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1345-1348
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• 2005

We designed the compound CVT (Continuously Variable Transmissions) by combining power circulation mode CVT and power split mode CVT, which have been proposed for connecting 2K-H I differential gear to the V- belt type CVU (Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.170-178
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• 2004

Continuously variable transmission (CVT) mechanisms considered here are input coupled types that combine the functions of a 2K-H II type differential gear and a V-belt type continuously variable unit (CVU). For the 8 different mechanisms, 4 of them are power-circulation modes while the other 4 are power-split modes, various performance analysis (speed ratios, power flows, divisions of power transmission in a differential gear and a CVU, and theoretical efficiencies) are performed to vary design parameters. Experimental studies are executed to validate fundamental relations (speed ratios, power flows, efficiencies, occurrence of geared neutral). Some useful characteristics associated with performance also are discussed in the mechanisms.

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.603-609
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• 2014

차세대 제트 추진기관으로 주목받고 있는 스크램제트 엔진의 핵심은 연소기 내부에서의 성공적인 초음속 연소를 필요로 한다. 초음속 연소는 공기-연료 혼합(fuel-air mixing)의 정도에 따라 연소효율이 영향을 받게 된다. 공동형 화염 보염기(cavity flameholder)는 재순환 영역(recirculation zone)을 생성하여 연료 혼합의 효율을 높여 지속적인 초음속 연소가 진행될 수 있는 시간을 제공한다. 본 연구에서는 EDISON 전산유체역학 소프트웨어를 이용하여 공동형 화염 보염기를 지나는 초음속 유동의 재순환 영역과 전압력 변화에 대한 전산 해석을 수행하였다. 초기 형상을 생성하여 유동 해석을 수행한 후, 3개의 형상 변수에 대한 매개 변수 연구를 통하여 공동의 형상과 위치에 따른 재순환영역의 제어가 가능함을 확인하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.670-673
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• 2005

We designed the compound CVT (Continuously Variable Transmissions) by combining power circulation mode CVT and power split mode CVT, which have been proposed for connecting 2K-H II differential gear to the V- belt type CVU (Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.