• Journal of Chest Surgery
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• v.22 no.1
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• pp.106-115
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• 1989

Clinical results with the xenograft cardiac valves were reviewed for 212 patients who underwent heart valve replacement from January 1981 to December 1987. One hundred and twenty-four Carpentier-Edwards k 88 Ionescu Shiley valves were used. Overall operative mortality was 11 out of 212[5.1%]: 5 out of 153[3.39o] for mitral valve replacement [MVR], 2 out of 34[5.9%] for aortic valve replacement [AVR], 0 out of 4[0%] for Tricuspid valve replacement [TVR], and 4 out of 21[19.1%] for double valve replacement [DVR;MVR+ AVR]. Two hundred and one operative survivors were followed up for a total of 824.3 patient-years [a mean 3.9*1.8 yrs], and the follow up was 78.1%. The linealized complication rates were 0.1% emboli / patient-year, 1.0% endocarditis/ patient-year and 2.2% overall valve failure / patient-year. A linealized rate of primary tissue failure was 0.7*/o/ patient-year. The actuarial survival rates including the operative mortality were 92*2.8% at 4 years and 85*4.3% at 7 years after surgery using the Xenograft cardiac valves. Probabilities of freedom from thromboembolism and overall valve failure were 73*11.0% and 69*2.4% at 7 years after surgery using the Xenograft cardiac valves respectively. The intrinsic durability of the Xenograft cardiac valves appears to be relatively well satisfactory over the long term [4 to 7 years] and the risk of failure appears well balanced by the advantages of a low incidence of thromboembolism and no mandatory anticoagulant therapy.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.2
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• pp.137-146
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• 2012

Black porgy and fat greenling are commercially important fish species due to the continuously increasing demand in Korea. When estimating acoustically the fish length by a fish sizing echo sounder, it is of crucial importance to know the target strength (TS) to length dependence. In relation to these needs, the target strength experiments for live fishes were conducted in an acrylic salt water tank using two split-beam echo sounders operating at 70 and 120kHz. The target strength under well-controlled laboratory conditions was simultaneously measured with the swimming movement by digital video recording (DVR) system and analyzed as a function of fish length (L) and frequency (or wavelength ${\lambda}$). Equations of the form TS-alog (L)+blog (1)+c were derived for their TS-length dependence. The best fit regression of TS on fork length for black porgy was TS=20.62 log (L, m)-0.62 log (${\lambda}$, m)-30.68 ($r^2$=0.77). The best fit regression of TS on fork length for fat greenling was TS=12.06 log (L, m)-5.85 log (${\lambda}$, m)-22.15 ($r^2$=0.44).

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.253-263
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• 2016

Chrysanthemum production would benefit from crop growth simulations, which would support decision-making in crop management. Chrysanthemum is a typical short day plant of which floral initiation and development is sensitive to photoperiod. We developed a model to predict phenological development and leaf appearance of chrysanthemum (cv. Baekseon) using daylength (including civil twilight period), air temperature, and management options like light interruption and ethylene treatment as predictor variables. Chrysanthemum development stage (DVS) was divided into juvenile (DVS=1.0), juvenile to budding (DVS=1.33), and budding to flowering (DVS=2.0) phases for which different strategies and variables were used to predict the development toward the end of each phenophase. The juvenile phase was assumed to be completed at a certain leaf number which was estimated as 15.5 and increased by ethylene application to the mother plant before cutting and the transplanted plant after cutting. After juvenile phase, development rate (DVR) before budding and flowering were calculated from temperature and day length response functions, and budding and flowering were completed when the integrated DVR reached 1.33 and 2.0, respectively. In addition the model assumed that leaf appearance terminates just before budding. This model predicted budding date, flowering date, and leaf appearance with acceptable accuracy and precision not only for the calibration data set but also for the validation data set which are independent of the calibration data set.

• IEMEK Journal of Embedded Systems and Applications
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• v.1 no.2
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• pp.90-103
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• 2006

There are many file systems in various operating systems. Those are usually designed for server environments, where the common cases are usually 'multiple active users', 'great many small files' And they assume a big main memory to be used as buffer cache. So the existing file systems are not suitable for resource hungry embedded systems that process multimedia data streams. In this study, we designed and implemented a new file system which efficiently stores and retrieves multimedia data steams. The proposed file system has a very simple disk layout, which guarantees a quick disk initialization and file system recovery. And we introduced a new indexing-scheme, called the time-based indexing scheme, with the file system. With the indexing scheme, the file system maintains the relation between time and the location for all the multimedia streams. The scheme is useful in searching and playing the compressed multimedia streams by locating exact frame position with given time, resulting in reduction of CPU processing and power consumption. The proposed file system and its APIs utilizing the time-based indexing schemes were implemented firstly on a Linux environment, though it is operating system independent. In the performance evaluation on a real DVR system, which measured the execution time of multi-threaded reading and writing, we found the proposed file system is maximum 38.7% faster than EXT2 file system.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.510-514
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• 2002

Power Quality and reliability are becoming important issues for critical and sensitive loads. The recent growth in the use of impactive and nonlinear loads has caused many power quality problems such as voltage flicks, harmonics and unbalances, which may cause the modem automatic devices to fail, misoperate, or shut down. This paper deals with 7-Level H-Bridge Line-Interactive Dynamic Voltage Restorer (LIDVR) system. It has the power factor near to unity under normal source voltage, can compensate the harmonic current of the load and instant interruption, and has the fast response. Currently, most of the DVR design studies are based on the assumption of the balanced three-phase system. But, actually line fault occurred $1{\phi}\;{sag}\;or\;2{\phi}$ sag. Hence, proposed new control scheme compensate asymmetry input voltage. Finally, simulation results verify the proposed 7-Level H-Bridge LIDVR system.

• Journal of Chest Surgery
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• v.30 no.4
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• pp.423-427
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• 1997

Hemoptysis occurs quite frequently as a consequence of mitral stenosis, but massive, lirE threatening pulmonary hemorrhage is distinctly unusual. We report a 30 year old female who underwent cmcrgcncy rcdo double valve replacement for intractable pulmonary hemorrhage. she underwent mitral valve replacement (lonescu Shirley 27 mm) due to rheumatic valvular heart disease in 1984 and tricuspid valve annuloplasty (Carpentier's rlng 30mm) two years later She was admitted for massive hcmoptysis and dyspnea on the 26th of December, 1995. Medical treatment including transarterial embolization was given but was not satisfactory. Emergency valve replacement (Mitral valve , 51. Judc 29mm and tricuspid valve ; 51. Jude 33mm) was performed and hemoptysis was controlled dramatically 24 hours after surgery.

• Journal of Chest Surgery
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• v.41 no.4
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• pp.430-438
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• 2008

Background: All the patients with mechanical valves require warfarin therapy in order to prevent them from developing thromboembolic complications. According to the ACC/AHA practice guidelines, after AVR with bileaflet mechanical prostheses in patients with no risk factors, warfarin is indicated to achieve an INR of 2.0 to 3.0. After MVR with any mechanical valve, warfarin is indicated to achieve an INR of 2.5 to 3.5. But in our clinical experience, bleeding complications (epistaxis, hematuria, uterine bleeding, intracerebral hemorrhage etc.) frequently developed in patients who maintained their INR within this value. So, we retrospectively reviewed the patients with bileaflet mechanical heart valve prosthesis and we determined the optimal anticoagulation value. Material and Method: From January 1984 to February 2007, 311 patients have been followed up at a national medical center. We classified the AVR patients (n=60) into three groups as follows: an INR from 1.5 to 2.0 in Group I, an INR from 2.0 to 2.5 in Group II and an INR from 2.5 to 3.0 in Group III. We classified the MVR (n=171) and DVR (n=80) patients into four groups as follows: an INR from 1.5 to 2.0 in Group I, an INR from 2.0 to 2.5 in Group II, an INR from 2.5 to 3.0 in Group III and an INR from 3.0 to 3.5 in Group III. We compared the groups for their thromboembolic and bleeding complications by means of the Kaplan Meier method. Result: In the AVR patients, 2 thromboembolic complications and 4 bleeding complications occurred and the log rank test failed to identify any statistical significance between the groups for thethromboembolic complication rate, but groups I and II had lower bleeding complication rates than did group III. Thirteen thromboembolic complication and 15 bleeding complication occurred in the MVR and DVR patients, and the log rank test also failed to identify statistical significance between the groups for the thromboembolic complication rate, but groups I and II had lower bleeding complication rates that did groups III and IV. Conclusion: The thromboembolic complication rate was not statistically different between groups I and II and groups III and IV, but the bleeding complication rates of groups I and II were lower than those of groups III and IV. So this outcome encouraged us to continue using our low intensive anticoagulation regime, that is, an INR of 1.5 to 2.5.

• Journal of Chest Surgery
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• v.37 no.9
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• pp.742-748
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• 2004

The On-X valve was recently introduced. It was the aim of this study to assess the safety and feasibility from the data derived from 28 patients who underwent aortic and/or mitral valve replacement with this prosthesis in National Medical Center. Material and Method： From May 1999 and May 2003, a series of 28 consecutive patients who had been implanted with 32 On-X prosthesis were reviewed, The operative procedure comprised of 12 MVR, 10 AVR and 6 DVR. The study followed the guidelines of AATS/STS. Mean follow-up was 27 months (total 04 patient-years). Result: Early ($\leq$30 days) mortality was 7.44% (2/28) and no late mortality occurred in the study. Total actuarial freedom from mortality at 2 years was 92.86$\pm$4.87% for all cases, 100% for MVR, 90$\pm$9.49% for AVR, and 83.3$\pm$1.52% for DVR. Thromboembolic event occurred in 2 MVR patients and that was the only complication; therefore, the linearized incidence of valve related complications was 3.17%/ patient-years for all cases and 6.5%/patient-years for MVR and the actuarial freedom from valve related complications at 2 years was 84.85$\pm$10.75%. Preoperatively, 24 (85.71%) patients were in NYHA functional class III or IV but postoperatively, 25 (89,29%) patients were in NYHA functional class I or II. The levels of hemoglobin, hematocrit, serum LDH, reticulocyte rate and indirect bilirubin were all within normal range at postoperative 3 month. In mitral position, the peak gradient was 6.1$\pm$1.8 mmHg and the mean gradient was 3.0$\pm$0.6 mmHg and EOA were 2.54$\pm$0.56 $m^2$, 2.39$\pm$0.73 $m^2$, 2.34$\pm$0.55 $m^2$, 2.40$\pm$0.63 $m^2$ at 27 mm, 29 mm, 31 mm, 33 mm respectively. In aortic postion, the peak gradient was 21.1 $\pm$14.12 mmHg and the mean gradient was 12.3$\pm$6.52 mmHg. Conclusion: Since there was no significant difference in the postoperative mortality, valve related complications and echocardiographic hemodynamic data compared to standard bileaflet design and since there was an improvement in the NYHA functional class and normal values of hemolytic indicators, it can be assumed that On-X valve is safe and feasible. However, accumulation of cases and long-term follow-up of this patient group is needed to establish this result.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.626-633
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• 2005

This paper proposes a new 2MVA SSFG(Sag Swell Flicker Generator) injecting voltage by using series inverter. The proposed SSFG composes series inverter, DC capacitor as energy storage, rectifier and voltage clamp circuit. This SSFG is designed to generate typical power disturbances, such as voltage sag/swell, over/under voltage and voltage flicker. Also it is designed to generate unexpected voltage phase jumping waveform by controlling the series inverter. In this paper, three kinds of control methods for the proposed 2MVA SSFG we investigated by PSIM simulation. Also typical voltage sag, swell, flicker waveforms are implemented by adopting effective control method.

• Journal of Chest Surgery
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• v.22 no.6
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• pp.1025-1035
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• 1989

Since we first performed open heart surgery on December 30, 1986, 126 cases were operated on up to August 31, 1989. Among the 126 cases, 65 cases were congenital heart disease of which 63 were acyanotic disease, and 61 cases were acquired heart disease, most of which were valvular heart disease. The age distribution of congenital heart disease was from 1 years 2 months to 48 years, and males had a slightly higher incidence. The age of acquired heart disease was from a minimum of 15 years to a maximum of 68 years, and the male to female ratio was 1;1.5. Midsternotomy was performed in all cases, and the aortic cannula was inserted through ascending aorta and the venous cannula inserted into the SVC and IVC through the right atrium. Vent was inserted through the right superior pulmonary vein. Cardioplegia solution was used in all cases; it was composed of sodium bicarbonate 3.5 ampule, KCL 14 mEq, 2% lidocaine 2.5 ml, 20 % albumin 50 ml and heparin 1000 units mixed to 950 ml with Hartman solution, and was made to 4oC and infused 10 ml per Kg every 20 minutes. The congenital heart disease had a variety of VSD in 32 cases, ASD 23 cases, PS 6 cases, PDA 2 cases, and one case each of Ebsteins anomaly and tricuspid atresia. The operations performed for acquired heart disease were 4 cases of OMC, 33 cases of MVR, and 5 cases of AVR, and 1 case of AVR with CABG. DVR was perfomed in 13 cases, and triple valve replacement was done in 1 case. Other than these, excision of LA myxoma was 2 cases, and repair of traumatic VSD and removal of a pulmonary embolism were one case each. The surgical mortality was 5 cases[4%], all of which occurred in valve replacement cases. Follow-up study revealed 2 late deaths. One died after a traffic accident and one died due to sepsis after he had received a gastrectomy for ulcer bleeding. The remaining patients were in good condition.