• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.65-74
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• 2000

A five path ultrasonic and/or magnetic flowmeter were installed after valve. Five path ultrasonic flowmeter were tested to obtain it's performance in a water flow standard system and magnetic flowmeter. It's varied with straight pipe length(nD), install direction and valve position. All the results are summerized. The multi-path flowmeters(MUF) showed up to $\pm0.5{\%}$ at a 2, 4, 8, 15D spacing : the MUF was significantly better than magnetic flowmeter at disturbed flow conditions.

• Journal of Advanced Navigation Technology
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• v.20 no.3
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• pp.196-202
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• 2016

In this paper, a stationary wavelet transform method is proposed for improving the altitude control performance of quadrotor UAV using an ultrasonic rangefinder. A ground tests are conducted using an ultrasonic rangefinder that is much used for vertical takeoff and landing. An ultrasonic rangefinder suffers from signal's spike due to specular reflectance and acoustic noise. The occurred spikes in short time span need to be analyzed at both sides time and frequency domain. It was known that stationary wavelet transform is the transferring solution to the problem occurred by down sampling from DWT also more efficient to remove noise than DWT. The analyzed spikes of the ultrasonic rangefinder using a stationary wavelet transform and experimental results show that it can effectively remove the spikes of the ultrasonic rangefinder.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.749-756
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• 2013

This paper presents an algorithm concerning the ground altitude measurement using a laser altimeter and an ultrasonic rangefinder for UAV(Unmanned Aerial Vehicle). A simple ground test conducted using the laser altimeter and ultrasonic rangefinder that are used for conducting the low altitude measurement of UAV and identify the characteristics of each sensor. Especially, the disadvantages of the laser altimeter were checked through the ground test. After that who those are participated in this paper planned the algorithm which is complemented by the ultrasonic rangefinder and the experiment was conducted. The laser altimeter and the ultrasonic rangefinder were fused by a loosely coupled method by Kalman filter. The paper shows that stable value of altitude complemented by the ultrasonic rangefinder that covers the laser altimeter's drawbacks can be measured through the ground test.

• Journal of Chest Surgery
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• v.37 no.12
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• pp.999-1002
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• 2004

Thirteen year old boy who had been stabbed in his left chest by the knife was transferred to our department from a general hospital, because of the massive bleeding from the intercostal tube drainage. Chest X-ray showed homogeneous density in the left lung field. He was confused and his vital signs were unstable. He was moved into a operating room as soon as possible. After resuscitation, his lacerated left ventricle wound was sutured through median sternotomy. The interventricular shunt was detected with intraoperative transesophageal echocardiography. The traumatic ventricular septal defect was closed via left ventricle using Dacron patch. His postoperative course was uneventful, and he was discharged with small residual shunt.

• Journal of Chest Surgery
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• v.37 no.5
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• pp.448-451
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• 2004

Report of right atrial thrombus complicating pulmonary embolism after cardiac surgery is rare. A 54-year-old woman operated on the atrial septal defect 10 months ago was admitted for left pleuritic pain and dyspnea. Multiple segmental perfusion defects were detected in lung perfusion scan. Transesophageal echocardiography showed a large mobile right atrial mass attached to the free wall of the right atrium with a stalk. Despite the intravenous heparinization for 13 days, follow-up echocardiography revealed the right atrial mass had not diminished in size. The mass which was confirmed as an organizing thrombus was excised under cardiopulmonary bypass. The patient recovered uneventfully and was discharged on warfarin therapy.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.3
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• pp.228-235
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• 2024

Using transcranial doppler ultrasonography (TCD) to measure the presence or absence of abnormalities in patent foramen ovale (PFO) is more effective than transesophageal echocardiography (TEE) because it is simple, inexpensive, and non-invasive. Thus, it can be a good alternative test in cases where it is difficult to perform TEE or in groups at a high risk of complications. Therefore, in this study, we sought to assist in arriving at a diagnosis by suggesting an appropriate method through the comparison of empirical results according to the presence or absence of blood use and varying patient posture. The results were compared depending on the patient's posture and whether blood was used. Patients in whom both middle cerebral arteries were observed were targeted. In cases where the temporal window was defective, it was replaced with basilar artery and compared. There were higher positivity rate and accuracy for sitting position using valsalva maneuver (VM) than for Resting and supine position using VM. Therefore, if it is possible to perform a sitting position using VM with a mixture of blood, it would be a good idea to perform it.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.201-208
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• 2007

Purpose: We investigated whether the diagnostic performance of SPECT scintimammography (SMM) can be improved by adding computer-aided diagnosis (CAD) of ultrasonography (US). Materials and methods: We reviewed breast SPECT SMM images and corresponding US images from 40 patients with breast masses (21 malignant and 19 benign tumors). The quantitative data of SPECT SMM were obtained as the uptake ratio of lesion to contralateral normal breast. The morphologic features of the breast lesions on US were extracted and quantitated using the automated CAD software program. The diagnostic performance of SPECT SMM and CAD of US alone was determined using receiver operating characteristic (ROC) curve analysis. The best discriminating parameter (D-value) combining SPECT SMM and the CAD of US was created. The sensitivity, specificity and accuracy of combined two diagnostic modalities were compared to those of a single one. Results: Both SPECT SMM and CAD of US showed a relatively good diagnostic performance (area under curve = 0.846 and 0.831, respectively). Combining the results of SPECT SMM and CAD of US resulted in improved diagnostic performance (area under curve =0.860), but there was no statistical differerence in sensitivity, specificity and accuracy between the combined method and a single modality. Conclusion: It seems that combining the results of SPECT SMM and CAD of breast US do not significantly improve the diagnostic performance for diagnosis of breast cancer, compared with that of SPECT SMM alone. However, SPECT SMM and CAD of US may complement each other in differential diagnosis of breast cancer.

• Journal of Chest Surgery
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• v.36 no.12
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• pp.928-928
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• 2003

승모판성형술 직후에 시행한 재수술에 대한 연구보고는 많지 않다. 저자들은 승모판성형술 직후 성형술 실패로 판단되는 환자에서 즉시 시행한 재수술 결과에 대해 알아보았다. 대상 및 방법: 1995년 4월부터 2001년 7월까지 세종병원에서 승모판성형술을 받은 환자 중 체외순환 이탈 직후 시행한 경식도초음파 검사에서 승모판막폐쇄부전 혹은 협착이 의미있게 잔존하거나 다른 이유로 재수술이 즉시 필요하였던 18명을 대상으로 후향적으로 조사하였다. 남녀비는 5 : 13이었고 평균 연령은 44세였다. 승모판막 질환은 폐쇄부전 12명, 협착 3명, 그리고 혼합형이 3명이었다. 원인은 류머치스성 9명, 퇴행성 8명, 그리고 심내막염이 1명이었다. 재수술의 원인은 잔존 승모판폐쇄부전 13명, 협착 4명, 그리고 좌심실천공이 1명이었다. 14명(77.8%)에서 재성형술을, 4명에서는 인공기계판막치환술이 시행되었다. 결과: 조기사망은 없었다. 조기결과는 승모판막치환을 한 4명을 제외한 14명 중 13명(92.9%)에서 0-I도의 폐쇄부전을 보였고 협착은 14명 모두 경도 이하 상태였다. 평균 33개월을 추적조사 한 결과 1명이 술 후 4개월 후 심기능부전으로 사망하였다. 승모판폐쇄부전은 9명(64.3%)에서 0-I도를, 승모판협착은 11명(78.6%)에서 경도 이하였고 재수술은 1명에서 시행되었다. 6년 생존율과 재수술로부터의 자유도는 각각 94%와 90%였다. 4년 후 승모판폐쇄부전 및 협착 재발로부터의 자유도는 각각 56%와44%였다. 결론: 승모판막성형술 직후 재수술은 양호한 조기 및 중기 생존율을 보이며 일차성형술 실패 후에도 높은 빈도에서 재성형술이 가능하다. 하지만 재성형술 시 특히 류머치스성 판막질환에서는 판막 기능부전 발생률이 높기 때문에 성형술 후 판막부전의 재발을 줄이기 위해서는 성형술의 적절한 적용 및 적응증 선별이 중요할 것으로 생각된다.

• Journal of Chest Surgery
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• v.30 no.2
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• pp.146-151
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• 1997

Between December 1993 and March 1996, 75 patients had undergone ubannular procedures in mitral valve reconstruction. Their mean age was 45 years and they consisted of 28 males and 47 females. The cause of mitral disease in 75 patients were classified as follow : 29 cases were degenerative, 40 cases were rheumatic, 3 cases were congenital, 2 cases were infectious and 1 case was ischemic. Average number of mitral anatomical lesion per patient was 3.1 and we used average 1.5 procedures on subannular structure in mitral valve per patient. Subannular procedures were chordae shortening 21, chordae transfer 22, new chordae formation 20, papillary muscle splitting 33, shortening of papillary muscle 2. Intraoperative transesophageal echocardiography was carried out for providing an immediate and accurate assessment of the adequacy of the reconstruction. There was no operative death. Patients have been followed up from 2 to 29months, mean 12.5. There were two failures that necessitated reoperation. The mean functional class (NYHA) was 3.19 preoperative and improved to 1.12 postoperatively. After mitral valve repair, the patients were improved hemodynamic, echocardiographic data. In conclusion, subannular procedure in mitral valve repair when feasible is stable and safe with a low prevalence of reoperation.

• Journal of Chest Surgery
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• v.38 no.7 s.252
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• pp.483-488
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• 2005

Aortic valve-sparing procedures could reduce valve-related morbidity, but may increase operative risks; therefore, these procedures could not be performed routinely. We attempted to find out the early results while focusing on the operative risks associated with these procedures in our hospital. Material and Method: From May 1996 to July 2003, 26 patients underwent these procedures including 15 patients with Marfan syndrome and 1 patient with Behcet disease. There were 17 men and 9 women with mean age of $37.9\pm19.2$ years (range: 6 months-74 years). Ten patients had ascending aortic dissection, 18 patients had more than moderate degree of aortic valve insufficiency (AI). Two types of valve-sparing procedures were performed: valve reimplantation in 14 and root remodeling in 12 patients. Associated procedures were performed as follows: aortic valve plasty in 6, mitral valve plasty in 5, hemi-arch replacement in 4, total arch replacement in 2, coronary artery bypass surgery in 1 and Maze procedure in 1 patient(s). Result: In four patients, valve-sparing procedures were converted to Bentall procedures during operation. Including these patients, there was no operative deaths, 3 patients underwent re-operation due to bleeding, 1 patient had permanent pacemaker. The median duration of ICU stay was 45.5 hours, the median duration of hospital stay was 10.5 days. In 22 patients excluding 4 converted patients, intraoperative transesophageal echocardiogram (TEE) showed less than mild degree of AI in all except one who had not received intra-operative TEE in the beginning and showed moderate degree of AI at discharge. The mean duration of follow-up was $21.2\pm27.4$ months. All patients were alive except one who died during other departmental surgery. In 3 patients, more than moderate degree of AI was recurred, but there were no reoperation. Conclusion: Aortic valve-sparing procedures could be performed relatively safely in selected patients who had annuloaortic ectasia.