• Journal of Chest Surgery
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• v.22 no.6
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• pp.1036-1043
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• 1989

Seventy eight patients underwent operation for combined multiple valve disease, with an overall early mortality of 14.1 % from January, 1983 to September, 1988 in the department of thoracic and cardiovascular surgery of Pusan National University Hospital. All of the above cases had combined multiple valve procedures. There were 33 mitral valve replacements and tricuspid annuloplasties, 33 aortic and mitral valve replacements, 5 aortic and mitral valve replacements with tricuspid annuloplasties, 3 aortic valve replacements and mitral annuloplasties, 1 open mitral commissurotomy and tricuspid annuloplasty and, 1 mitral valve replacement and primary closure of tricuspid valve cleft, 1 mitral valve replacement and aortic commissurotomy, 1 mitral, aortic and tricuspid valve replacement were done. 44 were male and 34 were female and the age distribution was from 14 to 57 with mean 38 year old. According to NYHA[New York Heart Association] classification, 49 patients were class I, 19 patients were class Il and 10 were class IV. Average perfusion time was 205.3 minutes. The live patients perfusion time was 178.7 minutes while that of dead ones was 272.0 minutes. Early deaths within 30 days from operation were 11 cases, 6 of which were due to low cardiac output, 3 were acute renal failure and 2 were cardiac rupture. The 65 patients were followed up from 2 to 30 months for a total 20.6 patient years. 1 patient committed suicide because of postoperative depression 1 year after operation. All of the survivors were enjoying their daily life and their NYHA class was superior to the preoperative ones.

• Journal of Chest Surgery
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• v.17 no.2
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• pp.212-222
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• 1984

A total of and consecutive 291 patients underwent isolated mitral valve replacement using the Ionescu-Shiley bovine pericardial xenograft valve during the 5-year period between October 1978 and June 1983. Thirty-two patients were the children under 15 years of age. There were 15 deaths within 30 days after surgery [operative mortality, 5.2%]. All early survivors except 6 children were placed on the long-term oral anticoagulation longer than postoperative 3 months. A total follow-up period extended for 398.2 patient-years, and 12 patients died [late mortality, 4.1%, or 3.0%/patient- year]. Ten patients experienced the thromboembolic complication [2.51%/patient-year], occurring in 8 patients within the first 3 postoperative months, and 4 died. Three patients had the late prosthetic valve endocarditis [0.75%/patient-year] and 2 died. The incidence of overall valve failure according to the criteria was 3.01%/patient-year, or 12 patients, and 2 had replacement of the failed bioprostheses [primary tissue failure, 0.5%/patient-year]. The long-term survival rate was 87.8%\ulcorner2.6% at 5 years postoperatively, and 84% of the late survivors were in NYHA Class I at the end of the follow- up. The probability remaining free from thromboembolism and overall valve failure was 89.8%\ulcorner6.3% and 81.2%\ulcorner.8% at 5 years respectively. These clinical results confirm the safety of mitral valve replacement. The only remaining clinical problem is the structural and functional durability of the bovine pericardial xenograft valve, and its use in young patients may be stopped in preference to the mechanical prosthetic valves.

• Journal of Chest Surgery
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• v.27 no.4
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• pp.313-317
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• 1994

Surgical treatment is possible for the obstructive form of hypertrophic cardiomyopathy and transaortic left ventricular septal myectomy and myotomy has been the procedure of choice. If coexisting intrinsic mitral valve disease exists, mitral valve replacement has been performed. But abnormal systolic anterior motion of anterior mitral leaflet[SAM] with intrinsic normal mitral valve disease is the typical feature of IHSS and we prefer not to replace mitral valve. 3 patients underwent transaortic myotomy and myectomy for IHSS with mitral regurgitation. 2 patients of them have coexisting intrinsic mitral valve diseases such as mitral valve vegetation and chorda rupture. Concomittent mitral valve replacement were performed. 1 patient shows SAM of mitral anterior leaflet but has intrinsic normal mitral valve morphologically and transepicardial echocardiogram and direct monitoring of pressure gradient during the operative procedure gives better information for subsided mitral regurgitation. Post operative course during the 12 months follow-up was uneventful.

• Journal of Chest Surgery
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• v.27 no.12
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• pp.1031-1035
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• 1994

Mechanical valve thrombosis is a serious and potential lethal complication unless early diagnosis & prompt therapy are made. We have been experienced 3 cases of valve thrombosis. From Aug. 1988 to July 1994, reoperations of mitral valve replacement [MVR] with mechanical prostheses [all mitral] were performed in three patients[2 men, 1 woman] due to valve thromboses. All three patients were diagnosed by means of cineradiography. Preoperative status of was shock status and he was applied intra-aortic balloon pump [IABP]. All three cases of prosthetic valve failure [PVF] were treated by Redo-MVR. Time intervals of reoperations were 5months, 40months, and 35months, respectively. In all cases, valve thromboses were excised successfully. Cineradiography provided an accurate diagnosis in all cases, which was utilized as safe, reliable & noninvasive imaging modalities. There were no operative death & complication. All three patients were fully recovered and returned to their employements, and active lives.

• Journal of Drive and Control
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• v.10 no.3
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• pp.27-33
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• 2013

Solenoid valve has used in various industrial field extensively. A solenoid valve has different size, shape and method of operation accordantly to industrial field. Many researchers study on kinds of solenoid valve such as flow rate, dynamic, magnetic field, valve shape and operating method. But the flow rate characteristic and dynamic response time performance on the diaphragm valve are not studied. This paper describes the flow rate characteristic and dynamic response time performance on the diaphragm valve. At first, the diaphragm valve is simulated in AMESim simulation tool. AMESim model found that an effect of valve performance depends on parameter. The parameter is the diaphragm orifice area. And the performance test bench confirms the effect in this parameter. Finally, it finds out the flow rate characteristic and dynamic response time performance on the diaphragm valve.

• Journal of Chest Surgery
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• v.18 no.3
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• pp.446-455
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• 1985

A total and consecutive 156 patients have undergone cardiac valve surgery including 13 closed mitral commissurotomy, 13 open mitral commissurotomy, one mitral annuloplasty, 75 mitral valve replacement, one aortic annuloplasty, 24 aortic valve replacement, 3 tricuspid valve replacement, 25 double valve replacement and one triple valve replacement. 155 prosthetic valves were replaced in a period between September 1976 and August 1985. There were 68 males and 88 females with age range from 8 to 69 yrs [mean 36.5 yr]. Out of replaced valves, 61 was tissue valve including 54 Carpentier-Edwards, and 4 was mechanical valves including 74 St. Jude Medical, and the position replaced was 101 valves for mitral, 46 for aortic and 8 for tricuspid. Single valve replacement in 102 cases, double valve replacement in 25 cases [17 for AVR+MVR, and 8 for MVR+TVR], and only one case was noted in the triple valve replacement. Early mortality within 30 days after operation was noted in 11 cases [7%]; 7 after MVR, 2 after DVR, and each one after open mitral commissurotomy and mitral annuloplasty. Cause of death was valve thrombus, cerebral air embolism, low output syndrome, uncontrollable arrhythmia, parapneumonic sepsis, acute cardiac tamponade and left atrial rupture. 7 late deaths were noted during the follow-up period from 1 to 104 months [average 48 month]; three due to valve and left atrial thrombus formation, two due to CVA from overdose of warfarin, and each one due to congestive heart failure and chronic constrictive pericarditis, Anticoagulants after prosthetic valve replacement were maintained with warfarin, dipyridamole and aspirin to the level of around 50% of normal prothrombin time in 79 cases, and Ticlopidine with aspirin in 47 cases to compare the result of each group. There were 11 major thromboembolic episodes including 3 deaths in the warfarin group. Two cases of CVA due to overdose of warfarin was noted in the warfarin group. In the ticlopidine group, there was only one left atrial thrombus confirmed at the time of autopsy. Among the survived 138 cases, nearly all cases[136 cases] were included in NYHA functional class I and II during the follow-up period. In conclusion, surgical treatment of the cardiac valve disease in 156 clinical cases revealed excellent result with acceptable operative risk and late mortality. Prevention of thrombus formation with anti-platelet aggregator Ticlopidine has better result than warfarin group presently with no specific side effect such as bleeding or gastrointestinal trouble.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.77-86
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• 2015

It is difficult to extract small valve automatically in noisy 3D point cloud obtained from LIDAR because small object is affected by noise considerably. In this paper, we assume that the valve is a complex model consisting of torus, cylinder and plane represents handle, rib and center plane to extract a pose of the valve. And to extract the pose, we received additional input: center of the valve. We generated histogram of distance between the center and each points of point cloud, and obtain pose of valve by extracting parameters of handle, rib and center plane. Finally, the valve is reconstructed.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.51-58
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• 2002

A simulation model has been developed to predict the performance of 5-valve gasoline engine by gas exchange process with combustion model. In this study, we simulated the intake flow characteristics and performance of 5-valve engine with entwine speed and we compared the 5-valve engine performance with that of 4-valve engine. As a result. the calculated value was in consistency with the measured value relatively. The performance of 5-valve engine was higher than that of 4-valve engine in high engine speed region.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.24 no.4
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• pp.172-179
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• 1988

A cartridge type hydraulic logic valve consists of simple two port valve whose poppet is closed or opened by means of pressure signal of a pilot line. Accordingly, the logic valve can be used not only for direction, flow and pressure control purpose but also for versatile function valve which enables all above mentioned functions. In addition, the valve has little internal leakage and pressure loss, superior response characteristics and easiness in making small block type valve. The above mentioned good performances being recognized recently, the logic valve has been used widely in the large scale hydraulic system such as a hydraulic press system, for the performance requirements of high speed operation and precise control characteristics. However, there are scarce reports until now, except for a few ones from Aachen Institute of Technology in West Germany, so it is necessary to be studied on development and investigation for practical application. This paper showed that the static and dynamic characteristics of a logic valve when the logic valve is used for directional control, to investigate the relations between the valve operating characteristics and the valve design conditions. From the above mentioned procedure, it was ascertained that the valve operation characteristics obtained by numerical analysis showed good agreements with experimental results. The representative results obtained are as follows; 1. During the valve is closing, the poppet velocity is almost constant in the logic valve. 2. The pilot pressure P sub(3) and the resistance R in the pilot line have much influences on the valve operation time. 3. Spring strength have not such a severe influence on the valve operating time. 4. The operation characteristics of the logic valve can be estimated with good accuracy comparatively by numerical analysis with the equations describing poppet motion.

• Journal of Chest Surgery
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• v.13 no.4
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• pp.422-434
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• 1980

Since 1968 up to the end of October 1980, 448 valves were replaced in 354 patients in Seoul National University Hospital. There were 238 mitral, 38 aortic, 7 tricuspid, 45 aortic with mitral, 23 tricuspid with mitral, and 3 triple valve replacement aortic mitral and tricuspid cases. Annual increase of mitral valve replacement cases and decrease of operative maortality were remarkable. Recently operative mortality of mitral valve replacement is about 5%. Sex ratio of mitral valve replacement is almost equal and there were 12 cases of pediatric patients (5%) among 238 cases, and patients under the age of 20 years were 34 (14.3%). Mitral valve replacement was done for 199 single mitral, 38 double valve and one triple valve lesions. Among 238 mitral valve replacement paients left atrial thrombus in 23(9.7%), atrial fibrillation in 132 (55.5%), and reoperation after blind mitral commissurotomy in 12(5%) cases were noted. In recent cases bioprosthetic valves, mainly lonescu-shiley valve were utilized to overcome the difficulties of postoperative late complications in anticoagnuation, especially for the rural patients and pediatric cases, in addition to the hemodynamic advantages of lonesocu valve. Among 354 patients 16 cases were congenital heart anomaly related, 5 ventricular septal defect related aortic and 4 Ebstein related tribuspid valve replacement cases. There were 2 congenital anomaly related mitral valve replacements, one for congenital mitral insufficiency of 7 years old boy and one for corrected transposition of the great vessels associated with mitral insufficiency. Among total 354 valve replacements 49 operative deaths (13.3%) were noted and in 238 mitral valve replacement 24 operative deaths occurred (10.1%). In 39 patients among 354 total valve replacements late complications were found. In 238 mitral valve replacement cases late complications were noted in 26 patients, among whom 16 cases expired. Main late complications were thrombe-embolism, subacute becteerial endocarditis, arrythmia cerebral hemorrhage due to unsatisfactory anticoagulation, and congestive heart failure in the incipient period of valve replacement were also noted. In mitral valve replacement cases long-term survival rate was 83.2% who showed marked clinical improvement. Ther were no evidences of calcification during the 2 years follow-up period for the lonescu-valve replacement cases among 19 pediatric patients. In conclusion 238 cases of mitral valve replacement were done with 24 operative deaths and 26 late complication cases among whom 16 expired. The long term survival was 83.2% of the cases. In pediatric cases in place of coumadin anticoagulation Persantin **** 75 and aspirin were administered after valve replacement. In adult cases who have difficulaties with coumadin anticoagulation and for those even with bioprosthetic heart valve replacement who needs long-term or permanent anticoagulation persantin 75 and aspirin combination regimen were administered with antisfactory results.