• Journal of Astronomy and Space Sciences
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• v.32 no.3
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• pp.209-219
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• 2015

The Accurate Ranging System for Geodetic Observation - Mobile (ARGO-M) was successfully developed as the first Korean mobile Satellite Laser Ranging (SLR) system in 2012, and has joined in the International Laser Ranging Service (ILRS) tracking network, DAEdeoK (DAEK) station. The DAEK SLR station was approved as a validated station in April 2014, through the ILRS station "data validation" process. The ARGO-M system is designed to enable 2 kHz laser ranging with millimeter-level precision for geodetic, remote sensing, navigation, and experimental satellites equipped with Laser Retro-reflector Arrays (LRAs). In this paper, we present the design and development of a next generation high-repetition-rate SLR system for ARGO-M. The laser ranging rate up to 10 kHz is becoming an important issue in the SLR community to improve ranging precision. To implement high-repetition-rate SLR system, the High-repetition-rate SLR operation system (HSLR-10) was designed and developed using ARGO-M Range Gate Generator (A-RGG), so as to enable laser ranging from 50 Hz to 10 kHz. HSLR-10 includes both hardware controlling software and data post-processing software. This paper shows the design and development of key technologies of high-repetition-rate SLR system. The developed system was tested successfully at DAEK station and then moved to Sejong station, a new Korean SLR station, on July 1, 2015. HSLR-10 will begin normal operations at Sejong station in the near future.

• Archives of Plastic Surgery
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• v.42 no.5
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• pp.588-595
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• 2015

Background Radiotherapy treatment after keloidectomy is known to be an effective method for reducing the rate of recurrence. However, to date, the appropriate total radiation dose and fractionation have not yet been confirmed. The authors performed a retrospective analysis to identify the appropriate radiation dose and fractionation in post-keloidectomy radiotherapy. Methods From May 2000 to February 2011, postoperative radiotherapy was performed on 39 lesions in 28 patients after total keloidectomy. The keloid lesions were confined to the ear lobes. Between May 2000 and May 2004, 14 keloids were treated with surgical excision, followed by a total radiation dose of 1,200 cGy in three fractions over four to five days (group 1). Between June 2004 to February 2011, 25 keloids were treated with surgical excision, followed by a total radiation dose of 1,500 cGy in three fractions over four to five days (group 2). Patients were given a survey asking them to report their experiences regarding reoperation, recurrence of symptoms, recurrence of the lesion, and satisfaction with the operation. Results Of the 28 patients who were treated, 20 underwent follow-up. Group 2 had more cases showing elevation with erythematous changes, whereas group 1 had more cases showing progressive stages of elevation than group 2. These differences were statistically significant. Moreover, a correlation was observed between the level of keloid elevation and the extent of symptoms. Conclusions We suggest 1,500 cGy of radiation in three fractions following keloidectomy for ear lobe keloids. A further randomized study is needed to assess the recurrence of keloids after radiotherapy.

• Clinics in Shoulder and Elbow
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• v.18 no.2
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• pp.75-79
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• 2015

Background: This retrospective comparative study aims to evaluate the surgical outcomes and complications of two surgical methods for simple fractures of the humeral shaft; minimally invasive anterior plating and open reduction combined with internal fixation. Methods: A total of 26 patients with humeral shaft simple fractures, who had surgery between June 2009 and September 2013 and were followed-up at least 12 months, were included in our analysis. They were divided into two groups; group 1 comprised of 12 patients who underwent minimally invasive anterior plating and group 2 comprised of 14 patients who underwent an open reduction and internal fixation. The clinical outcomes, radiological results, and complications were compared and analyzed. Results: We found that bone union was achieved in all patients, and the mean union periods were $20.7{\pm}3.34$ and $20.3{\pm}3.91$ weeks for groups 1 and 2, respectively. In most patients, we found that shoulder and elbow functions were recovered. At 12 months post-operation, we found that the Korean Shoulder Scoring system, the University of California at Los Angeles score and Mayo elbow performance score were $91.4{\pm}7.97$, $33.4{\pm}1.15$, and $90.8{\pm}2.23$ for group 1, and $95.2{\pm}1.53$, $33.3{\pm}1.43$, and $90.17{\pm}1.85$ for group 2. In terms of complications, we found that 2 patients had radial nerve palsy after open reduction and internal fixation, but all cases spontaneously resolved within 6 months. Complications such as infection and loss of fixation were not reported. Conclusions: Both minimally invasive anterior plating and open reduction with internal fixation produced satisfactory outcomes in the treatment of simple fractures of the humeral shaft.

• Journal of Chest Surgery
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• v.27 no.12
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• pp.1002-1007
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• 1994

The spontaneous pneumothorax occurs subsequent to a disruption in the continuity of the visceral pleura with escape of free air into the pleural space included primary & secondary pneumothorax that is unrelated to identifiable etiologies such as trauma. In. the 33 year period 1960 to 1993, the 230 cases of open thoracotomy were carried out for definitive treatment of spontaneous pneumothorax, at the Dept. of Thoracic & Cardiovascular Surgery, National Medical Center, Seoul, Korea. There were 193 men & 37 women. They ranged in age from 15 years old to 72 years old. The lesion site was on the right side in 117 and on the left in 97, the 16 cases were in bilateral lesions.Surgical indications included recurrence in 98 cases, persistent air leak in 68 cases, nonexpansion of the lung 37 cases, roentgenologically apparent bullae & blebs in 23 cases, bilateral lesions in 16 cases,combined hemothorax & prevent for recurrence in each 2 cases. The types of operation were bullectomy in 207 cases, wedge resection in 13 cases, decortication & B.P.F. closure in 6 cases,lobectomy in 2 cases, pneumonectomy, plication in each I case. The post operative complication developed in 18 cases[7.8 %], there was I case of death due to sepsis. We believed that open thoracotomy with resection or obliteration of blebs & pleurodes is provided the best protection against recurrence.

• Journal of Chest Surgery
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• v.36 no.8
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• pp.590-594
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• 2003

Vascular injury has been increased with popular outside activities. However there are only a few studies for vascular trauma. We intended to find out the relationships between the vascular trauma and its prognosis. Material and Method: Forty-four patients were diagnosed and operated on for vascular injury in the Gyeongsang National University Hospital from 1992. to 1999. We reviewed their chart and analysed their data retrospectively. We studied to causes, treatments, and prognoses of traumatic vascular injury. Result: The transfer time between accident place and emergency department was mean 3,5 hour, and the operation preparing time was 8.8 hours. Five cases required amputation of extremity. All amputation cases were combined with communited bony fractures. Thirty-eight cases had combined other injuries, and almost combined injuries were muscular and neurological damages, Conclusion: The optimal treatment plan for vascular trauma was prompt diagnosis and quick management. It may decrease amputation rate and post-traumatic complications. Therefore we must be carefully evaluated the multiple traumatic patients for early diagnosis of vascular injury and operate quickly in emergency status.

• Journal of Chest Surgery
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• v.26 no.11
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• pp.851-855
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• 1993

Among elevn consecutive cases having undergone Completion Pueumonectomy[CP]between 1958 and Aug. 1993 at the Dep. of Thoracic & Cardiovascular Surgery in National Medical Center. The patient`s mean age was 43 years[range 28 yrs, to 68yrs.],& they consisted with 10 males and 1 female. The indications for CP were benign diseases in 9 cases & 2 cases of lung cancer. The mean interval between the first operation & CP was 62.3 months[from 17 days to 288 months]. The several special intraoperative procedures such as intrapericardial pulmonary vesselsdivision & suture ligation, reinforcement of bronchial stumpmargin, & applied the Fibrin glue & hemostatics. The mean intra operative bleeding was 3582ml.[1500ml. to 6500ml.] The post orerative complication were developed in 5 cases[45.5%] they were empyema with BPF in 2 cases, empyema in 2 cases, & 1 case of repiratoy insufficiency which leading to death. We concluded that the C P noted high morbidity & mortality compared with ordinary first pulmonary resectional surgery. But, it will be a challenge to improved the morbidity because of increasing trend of completion pneumonectomy in a furture time.

• Journal of Chest Surgery
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• v.44 no.3
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• pp.229-235
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• 2011

Background: Following major lung resection, patients have routinely been monitored in the intensive care unit (ICU). Recently, however, patients are increasingly being placed in a general thoracic ward (GTW). We investigated the safety and efficacy of the GTW care after lobectomy for lung cancer. Materials and Methods: 316 patients who had undergone lobectomy for lung cancer were reviewed. These patients were divided into two groups: 275 patients were cared for in the ICU while 41 patients were care for in the GTW immediately post-operation. After propensity score matching, postoperative complications and hospital costs were analyzed. Risk factors for early complications were analyzed with the whole cohort. Results: Early complications (until the end of the first postoperative day) occurred in 11 (3.5%) patients. Late complications occurred in 42 patients (13.3%). After propensity score matching, the incidence of early complications, late complications, and mortality were not different between the two groups. The mean expense was higher in the ICU group. Risk factors for early complications were cardiac comorbidities and low expected forced expiratory volume in one second. The location of postoperative care had no influence on outcome. Conclusion: Immediate postoperative care after lobectomy for lung cancer in a GTW was safe and cost-effective without compromising outcomes in low-risk patients.

• The Mathematical Education
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• v.57 no.3
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• pp.247-270
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• 2018

The purpose of this study is to investigate the mathematical disposition and mathematical communication level of elementary school students in the process of applying mathematical journal writing activities. For this study, 21 third grade students in elementary school were observed when they participated in mathematical journal writing activities while studying number and operation area. According to the Mathematical disposition pre-test and post-test results, mathematical confidence, mathematical flexibility, mathematical will, and mathematical reflection increased and it was statistically proved. Expression and explanation level of the mathematical communication writing area also increased as the mathematical journal writing activity continued. Thus, mathematical journal writing activities can help to enhance the core competencies of the 2015 revised mathematics curriculum while make students 'to develop and transform mathematical expressions' and 'to express oneself'. Also, it provides implications of including active writing activities such as mathematical journal writing activities into mathematics classroom. Furthermore, the change in mathematical communication level according to mathematical disposition level was not statistically significant. Therefore, when providing active writing activities including mathematical journal writing activities into classroom, it is necessary to understand students' individual characteristics and to encourage communication to be active rather than giving feedback based on one's mathematical disposition level.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.2
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• pp.73-84
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• 1992

The TIDE, finite element model for the simulation of tidal flow in shallow sea was tested for its applicability at the Saemangeum area. Several pre and post processors were developed to facilitate handling of the complicated and large amount of input and output data for the model developed. Also an operation scheme to run the model and the processors were established. As a result of calibration test using the observed data collected at 9 points within the region, linearlized friction coefficients were adjusted to be ranged 0.0027~0.0072, and water depths below the mean sea level at every nodes were changed to be increased generally by 1 meter. Comparisons of tidal velocities between the observed and the simulated for the 5 stations were made and obtained the result that the average relative error between simulated and observed tidal velocities was 11% for the maximum velocities and 22% for the minimum, and the absolute errors were less than 0.2m/sec. Also it was found that the average R.M.S. error between the velocities of observed and simulated was 0.119 m/sec and the average correlation coefficient was 0.70 showing close agreement. Another comparison test was done to show the result that R.M.S. error between the simulated and the observed tidal elevations at the 4 stations was 0.476m in average and the correlation coefficients were ranged 0.96~0.99. Though the simulated tidal circulation pattern in the region was well agreed with the observed, the simulated tidal velocities and elevations for specific points showed some errors with the observed. It was thought that the errors mainly due to the characteristics of TIDE Model which was developed to solve only with the linearized scheme. Finally it was concluded that, to improve the simulation results by the model, a new attempt to develop a fully nonlinear model as well as further calibration and the more reasonable generation of finite element grid would be needed.

• Journal of Korean Society of Rural Planning
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• v.23 no.3
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• pp.133-145
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• 2017

The purpose of this study is to assess residents' perception of the revitalization projects of the rural center and to evaluate their views of the projects' importance and their levels of satisfaction with how they have been carried out. In this study, we measured the residents' perceptions and preferences regarding these projects by using Importance-Performance Analysis (IPA). Results showed that residents' perceptions and satisfaction were the highest for the projects providing welfare facilities, even though this project has little relevance to the overall project goal. Residents were dissatisfied with construction projects such as the building of cultural facilities and urban parks, even while recognizing their importance. It is necessary to establish what problem the people perceive and to manage them appropriately. Next, the residents did not appreciate the community empowerment projects, nor did they evaluate the contents of the program positively. It can therefore be seen that the community empowerment projects have not been carried out well. Finally, the street landscape improvement project was not successfully implemented compared to other projects. The residents have negatively perceived the installation of facilities that they do not want, rarely use, or are poorly operated. this shows that the evaluation of residents is significant. They become the users of the revitalization project for the rural center. It is necessary to overcome problems such as project items chosen by professionals without local consultation and obvious design in the revitalization project of the local center. There is a need to ascertain the residents' opinion of each project and to encourage them to participate directly in the management operation.