• Tunnel and Underground Space
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• v.30 no.3
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• pp.214-225
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• 2020

Uniaxial compressive strength (UCS) of rock is one of the important factors to determine the advance speed during shield TBM tunnel excavation. UCS can be obtained through the Geotechnical Data Report (GDR), and it is difficult to measure UCS for all tunneling alignment. Therefore, the purpose of this study is to predict UCS by utilizing TBM machine driving data and machine learning technique. Several machine learning techniques were compared to predict UCS, and it was confirmed the stacking model has the most successful prediction performance. TBM machine data and UCS used in the analysis were obtained from the excavation of rock strata with slurry shield TBMs. The data were divided into 8:2 for training and test and pre-processed including feature selection, scaling, and outlier removal. After completing the hyper-parameter tuning, the stacking model was evaluated with the root-mean-square error (RMSE) and the determination coefficient (R²), and it was found to be 5.556 and 0.943, respectively. Based on the results, the sacking models are considered useful in predicting rock strength with TBM excavation data.

• Journal of Chest Surgery
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• v.16 no.2
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• pp.139-146
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• 1983

Between 1974 and 1982, 31 patients from 7 to 15 years of age have undergone valve replacement for their acuqired cardiac valvular diseases at Seoul National University Hospital. Furteen patients (45.2%) had a definite history of rheumatic fever and only 4 patients (12.9%) had atrial fibrillation on their preoperative electrocardiograms. Characteristically, the valvular lesions were ones of insufficiency with or without associated stenosis in all patients except only one whose mitral valve was tightly stenotic. Thrity-seven valves were replaced in 31 patietns including a case of successful replacement of his failed xenogragt mitral valve : 4 mechanical valves were used in 3 patients and 33 xenograft valves were used in the remaining 28 patients. The size of the valves were not the major problem at the time of opertion because most of the patients had a dilated heart from disease. There were 3 diaths within 30 days of surgery (9.7% operative mortality rate) and 3 late deaths (9.7% late mortality rate) with an overall mortality rate of 19.4%. Twenty-eight early survivors were followed up for a total of 488 patient-months. Thromboembolic complications occurred in 5 patients with 2 deaths: cmbolic rate of 17.9% or the actuarial embolic incidence of 12.29%/patients-year. four xenograft tissue valves in 4 patients had failed during the period from 19 to 41 months of surgery with an overall valve failure rate of xenograft of 14.3% or the actuarial incidence of 9.84% failure/patient-year. One of these 4 patients had required replacement of his failed mitral xenograft valve which had severe calcification and tissue disruption with primary tissue failure rate of 3.6% or the actuarial incidence of 3.13% failure/patient-year. The actuarial survial including the operative morality was 50.0% at 5 years of surgery. /the actuarial incidence free from thromboembolism in bioprosthetic group was 85.4% at 42 months, while it was 33.4% in mechanicial group at 60 months after operation. The actuarial incidence free from overall valve failur of 100.0% until 18 months after surgery was followed by a rapid decrease during the next 2-year period, and it was only 17.8% at the follow-up end of 42 months after surgery. It was suggested that the major advantage of low thrombogenecity with xenograft valve should be balanced against the high incidence of accelerated valve failure when it is used in children whose age is younger than 15 years old. The possible role of recurrent rheumatic attacks to the early failure of xenograft tissue valve was also discussed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.11
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• pp.984-997
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• 2015

Chang'e-3 consisting of a lunar lander and exploration rover was launched on December 1, 2013 aboard a Long March 3B rocket flying from Xichang space launch center. Chang'e-3 was inserted into the lunar orbit after about a 5-day transit to the Moon and landed on the targeted landing site after orbiting around the Moon for 8 days. The successful landing of the Chang'e-3 gives a lot of help to analyze the future needs of the subsystem technologies and to figure out the trajectory from launch to lunar landing as well as operation sequences in the development of Korean lunar exploration is scheduled. Therefore, the configuration and analysis of overall mission of Chang'e-3 is performed based on the public information from the press and website. As a result, overall mission trajectory is reconstructed by solving boundary condition and then estimating control variable. Visibility status and eclipse status also analyzes so communication and power charge condition is as good as to operate lunar lander. Mass budget of the lander is derived using ${\Delta}V$ according to specific impulse.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.3
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• pp.73-82
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• 2012

In order to carry out efficient investment and successful business in national geo-spatial industry, economic assessment on the field of 3D geo-information has recently emerged as a serious issue. Therefore, this study is intended to offer cost-effective evaluation scheme which are proper for 3D geo-spatial information, especially focusing on development of orthophoto and DEM. The study is organized as follows. The first section clarifies preliminary rules for feasibility by defining target work and category in order to estimate benefit. Then, this paper will be limited to consideration of production of digital mapping for target business which is expected to create high value and its benefit from cost reduction is suggested. Drawing from the AHP(Analytic Hierarchy Process) methods, this study comprehensively described final result and implication to examine business value. Consequently, this study can suggest economical evaluation methods on 3D geo-spatial information industry, which takes up a considerable part of immaterial benefit and has difficulties in economic assessment and estimation. preventing a variety of errors in system operation in advance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.3 s.106
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• pp.239-248
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• 2006

In this paper, the cryogenically cooled low noise amplifier module for radio telescope receiver front-end using pHE-MT MMIC is designed and fabricated. In the selection of MMIC, the MMIC fabricated with the pHEMTS providing successful cryogenic operation are chosen. They are mounted in the housing using the thin film substrate. In the design of the housing, the absorber and the elimination of the gap between the carrier and the housing as well removed the unnecessary oscillations by its structure. The mismatch is improved by ribbon-tuning to provide the best performance at room temperature. The fabricated module shows the gain of $35dB{\pm}1dB$ and the noise figure of $2.37{\sim}2.57dB$ at room temperature over $21.5{\sim}23.5GHz$. In the cryogenic temperature of $15^{\circ}K$ cooled by He gas, the measured gain was above 35 dB and flatness ${\pm}2dB$ and the noise temperatures of $28{\sim}37^{\circ}K$.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.2
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• pp.189-198
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• 1998

Since the male sterilization (vasectomy) has been performed on a large scale as an accepted family planning in Korea on 1980s and this, in turn, has been followed by an increase in the number of patients requesting vasovasostomy. We studies 1000 consecutive cases of vasovasostomy performed from January 1975 to July 1995 in Pusan National University Hospital. In this report, we are going to present serial studies of vasovasostomy through which we attempted to find out what factors are of impotence in influencing the successful outcome of vasovasostomy operation. We inquired the operative results data through the questionnaire and telephone interview with survey of medical records. A total of 259 cases was excluded due to the loss of follow-up. The overall patency and pregnancy rates of 741 cases were 86.9% and 51.1%, respectively. The age of man at the time of anastomosis ranged from 23 to 57 years old with an average of 34.9. The most frequent reason for requesting vasovasostomy was the desire to have more children (43.4%). The average obstructive interval was 60.6 months with range from 1 to 264 months. If the obstructive interval had been less than 5 years patency rate was 92.4% and pregnancy rate 64.8%, but 6 years or more 84.1% and 48.5% (p<0.01, p<0.01). Patency and pegnancy rates according to intraoperative vas fluid were 93.1% and 62.8% for presence and 83.7% and 53.1% for absence (p<0.01, p<0.05). Patency and pregnancy rates according to histologically proven sperm granuloma at vasectomy site were 87.7% and 49.2% for presence and 86.9% and 50.6% for absence (p>0.05, p<0.05). Patency and pregnancy rates were not significantly different between microscopic standard vasovasostomy (88.4%, 64.3%) and modified vasovasostomy (89.5%, 56.3%)(p>0.05, p>0.05). Both patency and pregnancy rates according to level of anastomosis were 89.8% and 59.8% in cases of straight vas and 91.5%, 60.1% in cases of convoluted vas (p>0.05, p>0.05). Patency and pregnancy rates according to the kind of suture materials were 91.5% and 56.2% for absorbable, 91.0% and 64.2% for non-absorbable and 93.3% and 53.3% for absorbable plus non-absorbable, respectively (p>0.05, p<0.05). Thus it is suggested that the important factor influencing the success rate of vasovasostomy is the interval of obstruction and vasal ooze with surgical skills.

• Proceedings of the Safety Management and Science Conference
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• 2011.04a
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• pp.731-746
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• 2011

The successful and sustainable growth of SMEs depends on their ability of strengthen their competitiveness in quality and cost and service more than anything else as a fundamental of operation. Among these key competitive factors of SMEs, quality is the most critical factor in manufacturing business fields. Because quality strongly influence cost and service performance on this manufacturing business field. There are many different ways to improve the quality performance but it needs proper management decision to choose the best way what can maximize outputs with minimum inputs. And it needs effective measurement methods and some indicators to analysis the quality performance properly. The quality cost is one of the simplest key indicators to measure the quality performance and the effectiveness of quality related management decisions. The major purpose of this study is to diagnose the categorized current level of actual quality cost of local SMEs to maximize their quality management effectiveness through comparing their level with others what's expressed in early studies. In this study, through survey on local SMEs, we found that their average annual quality cost ratio versus turnover - Total amount of annual quality cost divided by annual turnover - is around 3.69% excluded some SME's performances what have different quality control measures with others. And we found some results what corresponded with the early studies on the correlations between those categorized quality costs factors and some discrepancies between some of the literature model and the early case study results as follows. There were negative correlations between the Prevention costs and the External failure costs, and the Appraisal costs and the External failure costs, and there was positive correlation between the Appraisal costs and Internal failure costs same as early studies. But, we couldn't found any strong negative correlations between the Cost of control - Preventive costs & Appraisal costs - and the Cost of Failure of control - Internal & External failure costs -. It reveals not only the lack of effectiveness on their preventive or appraisal activities but also it can reveal there were so many effective ways to prevent the failure costs properly such as some innovative investment on Factory automation includes Error Proofing and more preventive actions to improve the effectiveness of the typical management methods likes CE (Concurrent Engineering), APQP (Advanced Product Quality Planning), FMEA (Failure Mode & Effect Analysis) etc.

• Journal of The Korean Society of Clinical Toxicology
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• v.11 no.1
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• pp.9-18
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• 2013

Purpose: Antidotes for toxicological emergencies can be life-saving. However, there is no nationwide stocking and delivery system for emergency antidotes in Korea. We report on a two-year experience of a nationwide stocking and delivery trial for emergency antidotes at emergency departments in Korea. Methods: An expert panel of clinical toxicologists reviewed and made a list of 15 stocked antidote. These antidotes were purchased or imported from other countries and delivered from 14 antidote stocking hospitals nationwide 24 hours per day, seven days per week. Results: From August 1, 2011 to April 30, 2013, 177 patients with acute poisoning, with a median age of 48.5 years, were administered emergency antidotes. The causes of poisoning were intentional in 52.0% and 88.0% were intentional as a suicide attempt. Regarding clinical severity, using the poisoning severity score, 40.7% of patients had severe to fatal poisoning and 39.0% had moderate poisoning according to clinical severity. The most frequent presenting symptom was neurologic deficit, such as altered mentality (62.7%). alerted mentality (62.7%). Emergency antidotes were administered as follows: methylene blue (49 cases), flumazenil (31), N-acetylcysteine (25), glucagon (17), 100% ethanol (15), cyanide antidote kit (12), anti-venin immunoglobulin (5), pyridoxine (4), hydroxocobalamine (2), and deferoxamine (1). The median time interval from antidote request to delivery at the patient's bedside was 95 minutes (interquartile range 58.8-125.8). Conclusion: Findings of this study demonstrated the possibility of successful operation of the nationwide system of emergency antidotes stocking and delivery in Korea.

• Radiation Oncology Journal
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• v.16 no.3
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• pp.245-250
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• 1998

Purpose : This study was to evaluate survival, failure patterns, and prognostic factors of stage I squamous cell carcinoma of the glottic larynx after curative radiation therapy. Materials and Methods : A retrospective analysis was done for 57 patients with glottic cancer who were treated with curative radiation therapy from June 1985 to November 1992. There were 55 male and two female patients. Patients' age ranged from 17 to 71 years(median 39 years). Radiation therapy was delivered five times a week, 2 Gy daily, total 66 Gy using 6 MV X-ray. Results : Complete response(CR) was noted in 51 out of 57 patients (89.5%) and persistent disease (PER) in six out of 57 patients(10.5%). The disease-free survival rates at 3 and 5 years were 72.9% and 63.8%, respectively. Seven failures were observed among 51 CR patients during follow-up. Salvage total laryngectomy for six recurred patients and partial laryngectomy for one recurred patient were done with successful results, i.e., all of them were actually salvaged. Among six PER patients, salvage total laryngectomy for two patients and partial laryngectomy for two patients were done and two patients refused operation. Following salvage surgery for the four PER patients, three were salvaged and one failed locoregionally. Among the 13 failures 10(76.9%) were salvaged with surgery. The ultimate local control rate at 5 years was 92.3% and overall 47 out of 57 (82.5%) patients were able to preserve their larynx. The 5-year disease-free survival rates were 85.5% for posterior lesions, and 61.6% for anterior lesions(P<0.05). Cord mobility, involvement of anterior commissure, field size, and T stage did not impact on disease-free survival. Conclusion : Considering the high percentage of voice preservation with initial radiotherapy, radiotherapy should be the first choice in the treatment of stage 1 glottic carcinoma.

• The Journal of the Korea Contents Association
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• v.15 no.2
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• pp.151-162
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• 2015

A theme park is a complex space, in which held is a performance & exhibition event created to make visitors feel fun and a deep impression through a certain theme. Recently, local governments are increasingly planning for theme parks with the aim of local economy revitalization. Accordingly, this paper set up a development model for a Korean culture theme park after deducting success factors for creating a successful theme park through the case of Korean culture theme park. To be concrete, this paper deducted the success factors through literature research and case research as follows: Setting of themes having identity and consistency; programs that can give fun and a deep impression; convenient support facilities reflecting customers' needs; differentiated marketing for progress in customer attraction power; location linked with cultural resources around a theme park and a space for communicating a message; privately-initiated project promotion and the main body of operation; target setting consequent on market segmentation, and demand forecast, etc. A theme park cannot be successfully operated to contribute to local economy revitalization until such success factors should be closely linked and harmonized with each other. In addition, in order for a theme park to make a continued growth, it's required that problems occurring at the operational stage should be endlessly improved, and contents strengthening should be continuously done in line with circumstances of the times and viewers' eye level.