• Journal of the Korean Society for Precision Engineering
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• v.29 no.6
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• pp.693-701
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• 2012

In this study, a small wind turbine airfoil specialized for national wind condition was designed in order to develop the furling control type HAWT. And then a flow analysis was carried out based on the blade drawing which was designed to characterize of the developed airfoil. The result of the flow analysis showed that the torque on the 3 blades was 180.23N.m. This is equivalent to an output power of 5.66kw and an output efficiency of 0.44. Then we produced and constructed a 3kW - furling control type HAWT by getting the system unit design technology such as the specialized furling control device. By operating this turbine, we could get 3kW of the rated power at a wind speed of 10.5m/s through the ability test. Cut-in wind speed was 2m/s, generator efficiency was 92% at the rated power output. Sound power level was 87.2dB(A). Also we observed that the output power was limited to 10.5m/s with furling system operation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9A
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• pp.991-997
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• 2004

In this paper, we propose the architecture of modem receiver to fabricate HomePNA 2.0 chip. HomePNA suffers from inferior channel because of bridge tap, the effect of amateur HAM band and so on. To transfer data over such channel, HomePNA 2.0 uses training sequence to equalize channel and uses FD-QAM optionally as modulation method. So modem receiver demodulate QAM based signal and needs optimum architecture that fully uses these transmission feature. As a result of research, we define 2 mode function of modem receiver depending on TX/RX state. In this paper, particularly, we show the algorithm of equalizer, carrier phase recovery and frame synchromzationblock and propose architecture that improve the performance of channel equalization and is stable in operation. In the end, we estimate the performance of proposed HomePNA2.0 modem receiver over HomePNA TEST LOOP using SPW program.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.297-305
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• 1979

Occlusive coronary artery disease presents a potential threat to a significant population in the United States. According to many case reports, the increasing incidence of coronary artery disease due to atherosclerosis is noted in Korean, recently. Operative vascular procedures have increased steadily in number over the past 20 years in the United States. There have been many isolated case reports about coronary artery surgery, but these had little clinical impact. Nowadays, major three coronary bypass surgery has developed principally at three cardiac centers in the United States since 1967. Among three coronary bypass operation, the aorta-coronary artery saphenous vein bypass graft was first demonstrated by Favolaro and Effler at the Cleveland Clinic in 1967. We experienced one case of coronary artery disease, which was treated successfully by aorta-coronary saphenous vein graft with mild hypothermia under extracorporeal circulation in May, 1977. Saphenous vein was removed from above the knee and was 2.5 mm in diameter. The left ventricle was not vented for the left ventricle was not overdistended. Temporary artificial pace-maker-Medtronic-was implanted for the prevention and treatment of post-operative arrhythmia and heart block in post-operative first day. He is a 57 year old male businessman who had been suffered from hypertension [200 mmHg in systolic pressure] since 4 years ago, who had intermittent conservative treatment at local clinic. He had been afflicted with severe chest pain with choking sensation for 50 days. This symptom was aggravated exposing cold weather, or cold water, but was respond to rest. Pre-operative ECG revealed no any other ischemic sign except sinus bradycardia. Significant S-T segment depression was noted at lead II, AVF after double 5 minutes exercise, indicating positive Master`s test. Serum cholesterol was slight elevated to 253 mg/dl. Final pre-operative diagnosis was made by coronary arteriogram, which showed about 1.0-cm segmental 90 % occlusive atherosclerotic lesion in the proximal part of right coronary artery above the origin of acute marginal artery. Left coronary artery revealed good patency and there was no collateral circulation between right and left coronary artery .Hospital course was not eventful. He was discharged with good result on the post-operative day. He has been free from chest pain for longer than 2 years. And also the arterial flow in the coronary bypass graft is auscultated with the pocket-sized ultrasonic velocity detector, which shows the patency of the coronary bypass graft good.

• Journal of Chest Surgery
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• v.28 no.12
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• pp.1096-1106
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• 1995

We experienced 7 cases of left single lung transplantation in 14 mongrel dogs and analyzed graft lung function by hemodynamics, blood gas analysis, chest X-ray, biopsy and perfusion lung scan. We performed right pulmonary artery cuff[PA cuff for analysis of graft lung function in 3 cases. The donor lungs were flushed with modified Euro-Collins solution[n=3 or low potassium dextran glucose solution[n=4 and preserved for 4 to 5 hours[n=4 or 24 hours[n=3 at 10o C and implanted to the dogs with similar weight . Assessment of left graft lung was done by occluding the right pulmonary artery for 10 minutes using PA cuff. Assessment for graft lung function was done immediately after an operation and after 3 days, 7days and 3 weeks postoperatively. Four dogs survived for 3days, 7days[2 cases and 3 weeks respectively. Other three dogs expired within 3 hours of reperfusion. Immediate perfusion scans of left lung in four survived dogs after reperfusion were 42.1%, 36% , 11% and 5.9% respectively, and another dog with 4.8% perfusion to left lung was dead due to left atrial thrombi after 3 hours reperfusion. In one case among three acute rejections follow-up perfusion scan was done on 3rd and 11th postoperative day and the result decreased from 36% perfusion immediate postoperatively to 21% and 15% respectively. Three expired dogs postoperatively couldn`t tolerate occlusion of right pulmonary artery with above 40 mmHg of mean pulmonary artery pressure. On the other hand, three survival dogs postoperatively tolerated occlusion of right pulmonay artery with less than 30 mmHg of mean pulmonary artery pressure. and one dog couldn`t tolerate same procedure immediate postopertively but in 2 hours reperfusion later tolerated with 29 mmHg of mean pulmonary artery pressure.In conclusion we couldn`t compare the effect of two flushing solutions but low potassium dextran glucose solution showed relatively safe preservation effect in cases with preservation of more than 20 hours. Also canine left single lung transplantation model with PA cuff indicated useful method for the assessment of graft lung function with effect of lung preservation.

• Journal of Chest Surgery
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• v.30 no.12
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• pp.1247-1250
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• 1997

A 13-year-old boy presented with anterior chest wall depression and dyspnea on exertion(NYHA II). He underwent Ravitch operation for pectus excavatum 7 years ago. A preoperative echocardiographic study revealed secundum atrial septal defect. He had no other abnormality of laboratory test, except FVC and FEVI were decreased into 2.03 L(7 %) and 1.82 L(71 %). He underwent repair of secondary anterior chest wall deformity and secundum atrial septal defect. We used unique method, raising sternum at right angle to secure good operative field for open heart surgery. Acute respiratory insufficiency was developed on postoperative day 1. Mechanical ventilation was applied which could be weaned on postoperative day 6 and thereafter hospital course was uneventful without any other sequale. He was discharged on postoperative day 19.

• Journal of the Korean Vacuum Society
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• v.12 no.2
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• pp.93-104
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• 2003

For evaluation of durability of low vacuum pumps, it is required to examine the performance and degradation of low vacuum pumps. Pump degradation may result from abnormalities associated with the performance in many areas of pump operation. The diagnostics method can be used to monitor the pump performance in the semi-conductor process line. Based on the mechanical defect of the pump, the dynamic response and reliability of the system for performance test, and the dynamic characteristics of the pump were experimentally assessed. The theoretical work rate for the compression process in the pump was calculated, and then the efficiency of the pump associated with the power consumption was evaluated. This analysis will be useful in detecting pump degradation with increasing the power consumption. To determine the predominant factors of pump degradation, it is important to evaluate the entire pumping system. We studied vibration, dynamic pressure, pumping speed, and power consumption of low vacuum pumps. Our results can be utilized for the future research on the evaluating technology of durability of low vacuum pumps.

• Journal of Korea Water Resources Association
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• v.40 no.1 s.174
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• pp.25-38
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• 2007

A grid-based urban surface runoff model for simulating the temporal variation and spatial distribution of overland flow in a drainage area was developed. The process of routing of overland flow is modeled by the nonlinear storage equation which is composed of the continuity equation and the Manning's equation. For model operation, the drainage area is divided into grid areas, and spatially distributed topographical and hydrological information for model inputs is provided. Then overland flow is routed for each of the discretized cells of the area. In order to test the applicability of this model, temporal variations and spatial distributions of flow depth and overland flow was simulated in a fictitious and a real urbanized Kunja drainage area. Results indicate that the model can simulate reasonably well the urban runoff hydrograph.

• Archives of Plastic Surgery
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• v.35 no.1
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• pp.56-61
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• 2008

Purpose: There was no controlled study on botox injection and neurectomy for treatments of muscle hypertrophy. Although many studies have shown the clinical effects of each treatment, it was not able to evaluate and compare the effects of each treatment because there was no comparison of the two treatments under the same experimental condition. Hence, the aim of this study is to com Methods: The study was carried out on 21 rabbits. 9 rabbits received botox injection(botox injection group), and neurectomy was performed to another 9 rabbits (neurectomy group). 3 rabbits did not receive any treatment(control group). To compare and analyze the effects of muscular atrophy, muscle was stained with NADH-TR, and the changes in size of the muscle fiber were examined. And the electromyography was examined. In each group, muscle fiber was stained and electromyography was performed 2, 3, and 6 months after injection or operation. Results: In histological test and electromyography, in the neurectomy group, the size of muscular fiber and amplitude of electromyography decreased until 2 months after neurectomy. And decreased results were maintained with the passage of time. It showed irreversible aspect. On the other hand, in the botox injection group, the decrease in the size of muscular fiber and amplitude of electromyography was observed until 2 months after injection. In 3 months after the injection, it was slowly getting back to original size and had almost recovered by 6 months after the injection. It showed reversible aspect. Conclusion: This study shows researches about clinical effect of botox injection and neurectomy coincide with the results of experiment under the same experimental condition.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.201-212
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• 2017

PURPOSES : The objective of this study is to identify the characteristics affecting traffic accidents that have occurred in 564 industrial complexes nationwide from 2011 to 2015. METHODS : The traffic accidents were specified using various factors such as industrial complex type (national VS. general), industrial complex degradation (old VS. non-old), location of complex (capital VS. non-capital), and traffic law violation (speeding, signal violation, and median invasion). The average number of crashes and accident ratio (fatal, severe, and both) in terms of characteristics of industrial complexes were calculated. With a sample of crashes of the industrial complexes for 5 years, statistical significances were tested to analyze and compare the differences based on industrial complex and traffic law characteristics using parametric and non-parametric methods. RESULTS : From statistical results, it is observed that the crash frequency occurring in old industrial complexes is three times higher than that in non-old industrial complexes. Old industrial complexes located in a capital area, old national industrial complexes, and old general industrial complexes are considerably related to higher crash frequency, but the fatal accident ratio appeared to have no statistical difference across industrial complex characteristics. Severe crashes are more likely to occur in non-old industrial complexes on an average. CONCLUSIONS : It is necessary to eliminate potential threats to roads and traffic in the same manner as illegal parking in industrial complexes through the restoration of old industrial complexes. To improve the efficiency of road infrastructure, efforts should be made to improve traffic safety in accordance with industrial characteristics such as planning and operation of relevant local government programs.

• Journal of Korean Society on Water Environment
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• v.21 no.2
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• pp.118-124
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• 2005

The oxygen solubilized device(O.S.D) and standardized microorganism culture system is more efficient than physical and chemical purification techniques in closed water. This study was to determine how the O.S.D and standardized culture system is efficient in purification capacity in closed water based on the lab scale and pilot plant. In the batch test, inducing the quantitative results from pilot plant operation condition, removal efficiency of COD and TN were about 48.3% and 35% respectively, while SS and chlorophyll-a were 94.9% and 68.7%. The pilot plant results showed that suspended solid(SS) and chlorophyll-a removal efficiency were 60% and 59% respectively, due to coagulation characteristics by standardized culture. Total nitrogen(TN) and total phosphorus(TP)showed good effect for the purification of target pond water quality from field data. Additionally, released velocity was determined in control condition of $5.31mgPO{_4}^{3-}{\cdot}m^{-2}{\cdot}day^{-1}$ and $2486.8mgCOD{\cdot}m^{-2}{\cdot}day^{-1}$. Otherwise, phosphate and COD reflux in the aeration and microorganism condition was showed $-9.95mgPO{_4}^{3-}{\cdot}m^{-2}{\cdot}day^{-1}$ and $-397.88mgCOD{\cdot}m^{-2}{\cdot}day^{-1}$. This technology is the most effective not only removal of SS and chlorophyll-a but also control of phosphate and COD release which is very important phenomena in evaluating water quality in closed water like a reservoir and pond.