• 한국전산유체공학회지
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• 제13권3호
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• pp.51-61
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• 2008

The SMAC (Simplified Marker And Cell) algorithm is extended for an application to thermal non-equilibrium two-phase flows in light water nuclear reactors (LWRs). A two-fluid three-field model is adopted and a multi-dimensional unstructured grid is used for complicated geometries. The phase change and the time derivative terms appearing in the continuity equations are implemented implicitly in a pressure correction equation. The energy equations are decoupled from the momentum equations for faster convergence. The verification of the present numerical method was carried out against a set of test problems which includes the single and the two-phase flows. The results are also compared to those of the semi-implicit ICE method, where the energy equations are coupled with the momentum equation for pressure correction.

• Journal of Chest Surgery
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• 제20권4호
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• pp.780-785
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• 1987

Pulmonary atresia with VSD is uncommon congenital anomaly with high mortality in neonatal period. Recently we experienced surgical correction of 2 cases of pulmonary atresia with VSD. The first case was 7-year old female patient and diagnosed as pulmonary atresia with VSD combined PDA. So, total correction was undertaken which consisted of PDA ligation, patch repair of VSD, transannular enlargement of RVOT with woven Dacron vascular graft, and closure of PFO. Postoperative systemic Rt. ventricular and radial artery pressure ratio was 0.44 and her postoperative course was uneventful. The second case was 6-year old male patient diagnosed as pulmonary atresia with VSD and large systemic-pulmonary collateral arteries. There were two large systemic-pulmonary collaterals, one was simply controlled by ligation, but the other was considered to supply Rt. upper lung. So end to side anastomosis was performed to the RVOT patch. Postoperative systolic Rt. ventricular and radial artery pressure ratio was 0.54. During the follow up period he showed clinical picture of Rt. heart failure, which is relatively well controlled with anticongestive therapy.

• Journal of Chest Surgery
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• 제10권1호
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• pp.90-97
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• 1977

This is a report of a. case in which a long narrow segment coarctation of the aorta was successfully corrected with Teflon graft. The patient was 30 year old man with hypertensive symptoms that occurred 7 years prior to operation. Blood pressure measured 230/110 mmHg in the arms and 110/80 mmHg in the legs. Pulses were strongly tensive in radial artery, but very weak in femoral artery and even absent in dorsal pedis artery. Final preoperative diagnosis was made by aortography which showed a long narrow segment between aortic arch and descending thoracic aorta and highly developed collateral circulations. A long hypoplastic narrow segment was located proximal to the ligament arteriosus, and diaphragmatic stenosis of the aorta was located just distal to the ligamentum arteriosus. After prosthetic correction of the coarctation of the aorta, blood pressure were measured 130/ 80 mmHg in the arms and 150/100 mmHg in the legs. Peripheral pulses were palpated normally, and the postoperative course was uneventful.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2019년도 제59차 동계학술대회논문집 27권1호
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• pp.291-292
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• 2019

본 논문에서는 자세 교정에 도움을 줄 수 있는 압력센서 기반의 스마트 방석 개발 사례를 소개한다. 스마트 방석은 스마트폰과 블루투스로 연결되며 스마트폰 앱은 사용자의 자세 정보를 분석한 후 자세가 불안정한 징후가 판단되면 알림을 통해 바람직한 자세를 취할 수 있도록 안내한다. 본 시제품 개발에서는 압력센서의 값을 분석한 후 단순한 형태의 자세 추정 방식을 채택하였지만 향후 다양한 실험 및 딥러닝 응용을 통해 정확한 자세 추정을 위한 알고리즘을 개발할 계획이며 알림에 의한 수동적 자세 교정이 아닌 기구 설계, 모터 제어 등을 통해 능동적인 자세 교정을 지원하는 스마트 방석을 개발할 계획이다.

• 한국항공우주학회지
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• 제30권8호
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• pp.30-36
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• 2002

풍동시험 모형은 모형 지지부 삽입 등으로 실제 비행체와 다른 형상을 갖게 된다. 이러한 형상의 차이는 비행시험과 다른 힘과 모멘트를 발생시키게 되므로 이에 대한 보정은 필수적이다. 이러한 보정에는 cavity 압력 보정, 모형 지지부 간섭 보정 등이 있다. 본 시험에 사용된 모형은 내장밸런스와 함께 벨리 스팅 지지부를 사용하였으며 보정을 위하여 모형지지부 두께변화 방법과 더미 스팅 방법, wire support 방법의 시험결과를 비교하였다. 모형 지지부 두께 변화 방법은 간섭이 거의 없는 것으로 알려진 wire support 방법과 시험결과가 잘 일치하였다.

• 디지털산업정보학회논문지
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• 제13권4호
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• pp.81-90
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• 2017

This paper presents a smart seat for correction of driver posture while driving. We introduce good postures with seat height, seat angle, head height, back of knees, distances of foot pedals, tilt of seat, etc. There have been some studies on correction of good posture while driving, effects of driving environment on driver's posture, sitting strategies based on seating pressure distribution, estimation of driver's standard postures, and others. However, there are a few studies on guide of good postures while driving for problem of driver's posture using machine leaning. Therefore, we suggest a smart seat for correction of driver's posture based on machine leaning, 1) developed the system to get postures by 10 piezoelectric effect element, 2) collect piezoelectric values from 37 drivers and 28 types of cars, 3) suggest 4 types of good postures while driving, 4) analyze test postures by kNN. As the results, we can guide good postures for bad or problems of postures while driving.

• 한국항공우주학회지
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• 제36권7호
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• pp.621-627
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• 2008

풍동에서 측정된 공력자료에는 풍동벽면의 영향으로 인하여 불가항력적인 오차가 포함되어 있다. 벽면영향이 없는 공력자료를 얻기 위해서는 이러한 원하지 않는 벽면효과를 제거 하여야 한다. 유선곡률 효과는 풍동벽면의 영향으로 유선의 곡률이 자유 흐름의 것과 다르기 때문에 발생한다. 고정익 항공기에 사용되고 있는 전통적인 유선곡률 효과를 보정방법인 Glauert의 보정방법은 회전익 항공기에 적용이 적절하지 않다. 본 논문에서는 로터에 적절한 후류모델을 사용하는 Heyson의 보정방법을 사용하여 로터축 기울어짐 각과 동압을 보정하였다. Heyson 보정방법의 결과를 Glauert 보정방법의 결과와 비교하였다.

• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.178-186
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• 2007

This study is attempted to correct an error of electronic blood pressure meter with an optical sensor. In general, for a hospitalized patient, ECG, blood pressure, oxygen saturation, and respiration are basically measured to monitor the patient's condition. Opening of a blood vessel after it is occluded by pressurizing the cuff influences the blood flow of peripheral blood vessels as well as oscillation changes in the cuff. Blood vessels are occluded and peripheral blood flow disappears at cuff pressure above the examinee's blood pressure, while blood vessels are opened and peripheral blood flow appears again at cuff pressure under the examinee's blood pressure. Then Disappear-Appear Point Length(DAPL) of peripheral blood flow can be judged with the signal of peripheral blood flow, thus is available as a factor of error correction for electronic blood pressure meter. Also, systolic or diastolic blood pressure can be corrected with Appear-Point-Pressure(APP) of cuff pressure at a point where blood flow occurs and Appear-Maximum Pressure(AMP) of cuff pressure at the maximum amplitude point of peripheral blood flow after peripheral blood flow appears again. For verification, 27 examinees were selected, and their blood value was obtained through experimental procedure of 4 stages including induction of blood pressure change. The examinees were divided into two groups of experimental group and control group, regression analysis was conducted for experimental group, and correction of a blood pressure error was verified with optical signal by applying the regression equation calculated in experimental group to control group. As an experimental result, mean of the whole measurement errors was 5mmHg or more, which did not meet the standard fur blood pressure meter. As a result of correcting blood pressure measurements with data of DAPL, APP, and AMP as drawn out of PPG signal, systolic blood pressure, mean blood pressure, and diastolic blood pressure were $-0.6{\pm}4.4mmHg,\;-1.0{\pm}3.9mmHg$ and $-1.3{\pm}5.4mmHg$, respectively, indicating that mean of the whole measurement errors was greatly improved, and standard deviation was decreased.

• Journal of Chest Surgery
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• 제22권2호
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• pp.234-245
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• 1989

Between January 1984 and December 1986, sixty nine patients, aged 16 months to 25 years [mean age 10.05*6.40 years], underwent total correction of tetralogy of Fallot in Kyungpook national university hospital. In 66 hospital survivors, 30 patients were followed up for 12 to 48 months [mean 30.10*10.26 months]. These 30 patients were classified in two groups, TAP [transannular patch] and Non-TAP group. There were 9 patients in TAP group, and 21 in Non-TAP group. There were no significant differences between two groups in terms of age at operation, follow up duration, ACC time, and bypass time. All patients were evaluated by two dimensional echocardiography, Doppler echocardiography, standard 12-lead electrocardiography, and plain chest X-ray. Right ventricular systolic pressure, pulmonary arterial systolic pressure, pressure gradient between the right ventricle and the pulmonary artery, presence or absence of pulmonary regurgitation and its grading, fractional shortening of the left ventricle, and Qp/Qs in case of remnant ventricular septal defect were obtained by echocardiographic examination. Cardiothoracic ratio was measured by plain chest film, and ventricular dysrrhythmia was detected by electrocardiogram. Comparing the data between two groups, there was significant difference in incidence of postoperative pulmonary regurgitation [p< 0.05], 100%[9/9] in TAP group and 47.6 %[10/21] in Non-TAP group, but all the regurgitations were not severe. There were no significant differences in other comparisons, despite of higher incidence of cardiomegaly in TAP group [CT ratio: 59.3*5.3% VS 54.7*6, 4 %].

• 한국측량학회지
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• 제27권5호
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• pp.535-544
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• 2009

GPS 위성으로부터의 신호는 위성과 지상의 수신기 사이의 경로에 걸쳐서 누적된 양의 수증기나 가강수량으로 복원하기 위해 이용되고 있다. GPS 위성 신호의 대류권 지연으로부터 가강수량으로 복원하기 위해서는 대류권의 총 지연량으로부터 실제 습윤 지연량을 계산하기 위하여 표면 기압 관측을 통해 결정된 실제 건조 지연량의 계산이 필요하다. 그러나 기압 정보를 얻기 위한 기압계가 모든 GPS 상시관측소와 동일한 지점에 위치하고 있지 않기 때문에 지상 기상 관측소로부터 획득한 해면 경정된 기압 정보를 이용하곤 한다. 이러한 기압의 직접 이용은 GPS를 이용한 수증기 복원 능력을 저하시키는 원인이 된다. 본 연구에서는 우리나라에 적합한 기압의 역해면 경정 보정 방안을 제시하고 이를 이용한 GPS 수증기의 정확도를 레디오존데 PWV와 평가하고 GPS로 추정한 수증기의 복원 능력의 개선 방안을 제시하였다.