• Journal of Chest Surgery
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• v.33 no.1
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• pp.38-44
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• 2000

Background: We analyzed the result of the "Off-Pump" Coronary Artery Bypass grafting (OPCAB) performed to minimize inflammatory responses to cardiopulmonary bypass and myocardial ischemia during the aortic cross-clamp period. Material and Method : The preoperative diagnosis operative procedure mortality complication and postoperative course of the 50 patients who underwent OPCAB between January 1998 and September 1998 were analyzed. There were 34 males and 16 females with mean age of 60$\pm$9 years. Preoperative clinical diagnoses were unstable angina in 31(62%) stable angina in 16(32%) and clinical diagnoses were unstable angina in 31(62%) stable angina in 16(32%) and postinfarction angina in 3(6%) patients. Preoperative angiographic diagnoses were three-vessel disease in 25(50%) two-vessel disease in 5(10%) one-vessel disease in 7(14%) and left main disease in 13(26%) patients. There were elective operation in 37 cases and urgent operation in 13 cases. Result: The mean number of grafts was 3.2$\pm$1.2 per patient. Grafts used were unilateral internal thoracic artery in 43 greater saphenous vein in 37 radial artery in 7 bilateral internal thoracic arteries in 4 and right gastroepiploic artery in 2 cases Forty sequential anastomoses were performed in 18 cases. Vessels accessed were left anterior descending artery in 48 diagonal branch in 41 obtuse marginal branch in 30 right coronary artery in 24 posterior descending artery in 9 ramus intermedius in 5 and posterolateral branch in 5 anastomoses. Predischarge coronary angiography performed in 44 patients demonstrated the patency rate of 89.5%(128/143) Operative mortality was 2%(1/150) Postoperative complications were arrhythmia in 5 graft occlusion that needed reoperation in 4. perioperative myocardial infarction in 2 femoral artery thromboembolism developed after the application of IABP in 1 postoperative transient delirium in 1 peripheral compression neuropathy in 1 case. Sixteen patients(32%) were extubated at the operating room and the other patients were extubated at the mean 13$\pm$20 hours after the operation. Mean duration of stay in intensive care unit was 49$\pm$46 hours. Thirteen patients(26%) required blood transfusions perioperatively and the amount of perioperative blood transfusion was mean 0.70$\pm$1.36 pack/patient. Conclusion: OPCAB is suggested to be the ideal technique with less postoperative complication less hospitalization time and less cost.less cost.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.457-469
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• 2009

Applicability of bioleaching techniques using a sulfur-oxidizing bacteria, Acidithiobacillus thiooxidans, for remediation of shooting range soil contaminated with toxic heavy metals was investigated. The effects of sulfur concentration, the amount of bacterial inoculum and operation temperature on the efficiency of heavy metal solubilization were examined as well. As sulfur concentration and the amount of bacterial inoculum increased, the solubilization efficiency slightly increased; however, significant decrease of heavy metal extraction was observed with no addition of sulfur or bacterial inoculum. Bacteria solubilized the higher amount of heavy metals at $26^{\circ}C$ than $4^{\circ}C$. Lead showed the highest removal amount from the contaminated soil but the lowest removal efficiency when compared with Zn, Cu and Cr. It was likely due to formation of insoluble $PbSO_{4(s)}$ as precipitate or colloidal suspension. Sequential extraction of the microbially treated soil revealed that the proportion of readily extractable phases of Zn, Cu and Cr increased by bacterial leaching, and thus additional treatment or optimization of operation conditions such as leaching time were required for safe reuse of the soil. Bioleaching appeared to be a useful strategy for remediation of shooting range soil contaminated with heavy metals, and various operating conditions including concentration of sulfur input, inoculum volume of bacteria, and operation temperature exerted significant influence on bioleaching efficiency.

• Journal of Chest Surgery
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• v.32 no.2
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• pp.108-118
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• 1999

Background: To evaluate the risk factor and long-term result of arterial switch operation , a retrospective study was done. Material and Method: A retrospective analysis was done to evaluate the early and long-term results on 58 patients who underwent an arterial switch operation(ASO) for transposition of the great arteries(TGA) with intact ventricular septum, between January 1988 and December 1996. Beforesurgery, 36 patients(62.1%) underwent balloon atrial septostomy, 32 patients(51.7%) received PGE1 infusion, and preparatory banding of pulmonary artery was performed on 6 patients(mean LV/RV pressure ratio 0.53$\pm$0.11). Result: The age at operation ranged from 1 to 137 days(mean 24$\pm$26 days) and the weights ranged from 1.8 to 6.8 kg (mean 3.5$\pm$0.8 kg). There were 14 early deaths(24.1%), but of the last 24 patients operated on since 1994, there were only 2 early deaths(8.3%). In the risk factor analysis, the date of operation was the only risk factor for early death(p-value < 0.01). Eight of the 14 early deaths were due to acute myocardial failure(mainly inadequate coronary blood flow). The length of follow-up ranged from 2 months to 8 years, average of 36$\pm$27 months. The follow-up included sequential noninvasive evaluations and 21 catheterizations and angiographic studies performed 5 to 32 months postoperatively with particular attention to the great vessel and coronary anastomosis, ventricular function, valvular competence, and cardiac rhythm. There were 5 late deaths(11.4%), one of thesedeaths was related to the late coronary problems, two to aspiration, one to uncontrolled chronic mediastinitis, and one to progressive aortic insufficiency and heart failure. The most frequent postoperative hemodynamic abnormality was supravalvular stenosis and the degree of pulmonary or aortic obstruction had slowly progressed in some cases, however there were no children who had to undergo a reoperation for supravalvular pulmonary or aortic stenosis. Aortic regurgitation was identified in 9 patients, which was mild in 7 and moderate in 2 and had progressed in some cases. Two patients who had an unremarkable perioperative course were identified as having coronary artery obstructions. The other late survivors were in good condition, were in sinus rhythm, and had normal LV functions. Actuarial survival rate at 8 years was 68.8%. Conclusion: We concluded that anatomic correction will be established as the optimal approach to the TGA with intact ventricular septum, though further long-term evaluations are needed.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.5
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• pp.511-516
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• 2008

Since 1989, Advanced drinking water treatment processes began to build in Korea, especially the water treatment plants around the Nak-dong river stream due to sequential pollutant accidents. Moreover, Advanced drinking water treatment processes, ozone and GAC, are again to be built in water treatment plants around Han-river stream to control taste and odor, micro pollutants. However, there are still a lot of discussion to decide the processes to apply for advanced treatment. Thus there are still need to understand clearly on the cost evaluation of each advanced treatment processes. The cost evaluation was accomplished based on the data of six water treatment plants which are currently being either operating or constructing. Exceptionally, PAC(Powdered Activated Carbon) process was evaluated with cost estimation from construction company. The capital cost per unit volume of ozone process was significantly decreased as the treatment capacity increased. The capital cost was in the order of GAC, ozone and GAC. The operation cost decreased in the order of PAC, GAC and ozone. The total cost considering present value shows that ozone process covers 84% of ozone and GAC process for $30,000m^3/d$ capacity while it covers less than 35% for over 140 thousands $m^3/d$ capacity. Comparing GAC only, and ozone/GAC process, ozone/GAC process is more cost effective for high capacity water treatment plant.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.18-21
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• 2009

In the digital system, ROM has a large power-consumption and a speed-bottleneck. According to gradual growth of system speed, ROM is demanded to have low-power consumption and high-speed operation design. The ROM adapted in FFT or FIR filter needs method of sequential accessed addressing. We proposed a reduction method for the number of storage cells in this paper. The number of storage cells which is connected with bi-line is reduced by the proposed method so that the capacitance value of bit-time is reduced. In this case, delay time, and power consumption are reduced. Design result of ROM in this paper using the proposed method could reduce up to 86.3% of storage cell '1' compare with conventional method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.2
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• pp.69-76
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• 2010

Recently, the natural environment changes drastically and the frequency of occurrence for lightning has gradually been increased. Such lightning delivers high volume of energy along the power line and communication line to the equipment in use. The high volume of energy arising from the lightning surge develops in fast velocity to destroy the facilities in power source and many other facilities in operation in sequential destruction with vast energy. This paper examines the characteristics of ZnO varistor to prevent from thermal runaway. We carry out performance evaluation of electrical characteristics on ZnO varistor. we will develop ZnO varistor Prevented from thermal explosion using test result of this paper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1251-1255
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• 2011

In this paper, we propose an optimal path search algorithm that contains all nodes using genetic algorithm. An object in this approach is formed as an equation related with the Euclidean distance between an intermediate node and the starting node and between an intermediate node and the goal node. Like other genetic algorithm structures, our algorithm defines a fitness function and selects a crossover spot node and a bitwise crossover point. A new node out of such operation survives only if it satisfies the fitness criteria and that node then becomes the starting node for the next generation. Repetition continues until no changes are made in the population. The efficiency of this proposed approach is verified in the experiment that it is better than two other contestants - sequential approach and the random approach.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.12
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• pp.1063-1070
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• 2008

The performance of an acoustic transducer is determined by the effects of many design variables, and mostly the influences of these design variables are not linearly independent of each other. To achieve the optimal performance of an acoustic transducer, we must consider the cross-coupled effects of the design variables. In this study, the variation of the performances of underwater acoustic transducer in relation to its structural variables was analyzed. In addition, the new optimal design scheme of an acoustic transducer that could reflect not only individual but also all the cross-coupled effects of multiple structural variables, and could determine the detailed geometry of the transducer with great efficiency and rapidity was developed. The validation of the new optimal design scheme was verified by applying the optimal structure design of a flextensional transducer which are the most common use for high power underwater acoustic transducer. With the finite element analysis(FEA), we analyzed the variation of the resonance frequency, sound pressure, and working depth of a flextensional transducer in relation to its design variables. Through statistical multiple regression analysis of the results, we derived functional forms of the resonance frequency, sound pressure, and working depth in terms of the design variables. By applying the constrained optimization technique, Sequential Quadratic Programming Method of Phenichny and Danilin(SQP-PD), to the derived function, we designed and verified the optimal structure of the Class IV flextensional transducer that could provide the highest sound pressure level and highest working depth at a given operation frequency of 1 kHz.

• Journal of Trauma and Injury
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• v.29 no.3
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• pp.76-81
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• 2016

Purpose: The purpose of this study was to compare the data comprehensively including not only the clinical and radiographic outcomes but some parameters related to operation between the minimally invasive plate osteosynthesis (MIPO) technique and intramedullary nailing (IMN) for treatment of segmental tibia shaft fractures. Methods: We conducted a retrospective study of 31 patients (mean age, 49.3 years, range, 27-74 years), with a mean follow-up of 14.1 months (range, 12-19 months) with acute segmental tibial fractures (AO 42-C2) who underwent either surgical treatment of MIPO or IMN. In accordance with the Gustilo-Anderson classification, 11 were type I, 5 were type II, and 15 were type III. Initial compartment syndrome was confirmed in 2 cases. Results: There were no statistically significant differences in terms of the patient demographic data between the two groups. The time to definitive fixation was longer in the MIPO group (mean $13.7{\pm}10.9days$; range, 2-27) than in the intramedullary group (mean $5.4{\pm}9.6days$; range, 0-35) with statistically significant difference (p=0.002). Bony union was observed in most of cases but except 5 cases of nonunion were diagnosed (3 in the MIPO vs 2 in IMN, p=0.188). The average bone healing time was 27.1 weeks (10 to 56 weeks) in MIPO group and 23.2 weeks (13 to 66 weeks) in IMN group, respectively (p=0.056). Overall complications were 5 cases in MIPO group and 2 cases in the IMN group. Difference in LEFS was not statistically significant between both groups (p=0.824). Conclusion: This study showed that segmental tibia shaft fractures treated with both MIPO and intramadullary nailing was challenging with relatively high complication rate. A well planned sequential strategy with keeping the soft tissue and personality of fracture in mind is utmost significant as much as the choice of surgical modalities.

• Journal of Chest Surgery
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• v.28 no.5
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• pp.453-463
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• 1995

During 42 month period 91 consecutive patient underwent coronary artery bypass surgery. The mean age of these patient was 57 years [range from 28 to 78 years . There were 57 men and 34 women. The preoperative risk factors that include beyond the 50 % of total patients were male sex, obesity, hypo-high-density lipoproteinemia, smoking, hypercholesterolemia, hyper-low-density lipoproteinemia, hypertriglyceridemia and hypertension. Preoperatively 27 patients had stable angina pectoris and 39 patients of unstable angina pectoris. Twenty five patients had previous myocardial infarction history. The patterns of disease were 8 patients of single vessel involvement, 18 patients of double vessel involvement, 54 patients of triple vessel involvement and 11 patients of left main coronary artery disease. Fifty five patients were in Canadian Cardiovascular Society functional class III. Myocardial revascularization was performed under emergency conditions in 5 patients. Nine percent of patients had previous PTCA history. We performed 16 cases of sequential anastomosis, internal mammary artery harvest in 86 percent of total patients and total 284 distal anastomoses[mean 3.1 anastomosis per patient . The mean ACC time was 60.5 minutes and ECC time was mean 110 minutes. The combined surgeries were 16 cases of endarterectomy, 2 cases of LV aneurysmectomy, 1 case of Bentall operation, 1 case of repair of sinus of Valsalva, 1 case of ligation of coronary AV fistula and 1 case of excision of breast mass. The most common complication was wound infection[12 cases, 13 % . There was one hospital death due to postoperative respiratory failure and low output syndrome in patient with postinfarction VSD, LV aneurysm. Postoperative 88 patients were in Functional class I or II. The 99mTc-MIBI myocardial perfusion scan that used as evaluation of postoperative state was well correlated with patient`s symptoms instead of some disadvantages.