• Journal of Astronomy and Space Sciences
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• v.32 no.4
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• pp.357-366
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• 2015

By using the Optical Wide-field Patrol (OWL) network developed by the Korea Astronomy and Space Science Institute (KASI) we generated the right ascension and declination angle data from optical observation of Low Earth Orbit (LEO) satellites. We performed an analysis to verify the optimum number of observations needed per arc for successful estimation of orbit. The currently functioning OWL observatories are located in Daejeon (South Korea), Songino (Mongolia), and Oukaïmeden (Morocco). The Daejeon Observatory is functioning as a test bed. In this study, the observed targets were Gravity Probe B, COSMOS 1455, COSMOS 1726, COSMOS 2428, SEASAT 1, ATV-5, and CryoSat-2 (all in LEO). These satellites were observed from the test bed and the Songino Observatory of the OWL network during 21 nights in 2014 and 2015. After we estimated the orbit from systematically selected sets of observation points (20, 50, 100, and 150) for each pass, we compared the difference between the orbit estimates for each case, and the Two Line Element set (TLE) from the Joint Space Operation Center (JSpOC). Then, we determined the average of the difference and selected the optimal observation points by comparing the average values.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.8
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• pp.54-61
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• 2001

A fully on-chip open-drain CMOS output driver was designed for high bandwidth DRAMs, such that its output voltage swing was insensitive to the variations of temperature and supply voltage. An auto refresh signal was used to update the contents of the current control register, which determined the transistors to be turned-on among the six binary-weighted transistors of an output driver. Because the auto refresh signal is available in DRAM chips, the output driver of this work does not require any external signals to update the current control register. During the time interval while the update is in progress, a negative feedback loop is formed to maintain the low level output voltage ($V_OL$) to be equal to the reference voltage ($V_{OL.ref}$) which is generated by a low-voltage bandgap reference circuit. Test results showed the successful operation at the data rate up to 1Gb/s. The worst-case variations of $V_{OL.ref}$ and $V_OL$ of the proposed output driver were measured to be 2.5% and 7.5% respectively within a temperature range of $20^{\circ}C$ to $90^{\circ}C$ and a supply voltage range of 2.25V to 2.75V, while the worst-case variation of $V_OL$ of the conventional output driver was measured to be 24% at the same temperature and supply voltage ranges.

• Journal of Biomedical Engineering Research
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• v.22 no.5
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• pp.403-412
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• 2001

The Present study analyzed the pressure-flow characteristics of a Korean shunt valve. Changes in the characteristic currie depending on the design parameters were also investigated. The Korean shunt valve used in the present study was constant pressure type and our analyses were validated through experiments. We applied fluid-structure interaction to solve the flow dynamic Problem because the small diaphragm in the valve was made from flexible silicone elastomers. Considering the material nonlinearity of the hyper-elastic material. the Mooney-Rivlin approximation was employed. The results of the numerical analyses were close to the experimental results The major Pressure drop was observed to happen in the small diaphragm. The slope of the pressure-flow characteristic curve was computed to be 0.37mm$H_2O$.hr/cc, which was similar to the average value of commercial shunt valves. 0.40mm$H_2O$.hr/cc. Therefore. our valves analyzed in the Present study showed a Proper Pressure control characteristics of the constant pressure type shunt valves. The opening pressure could be controlled by adjusting the amount of predeflection of the valve diaphragm. In order to obtain opening pressures of 25mm$H_2O$ and 80mm$H_2O$, respectively, and the required predeflection was found to be 10.2$\mu$m and 35.3$\mu$m. The flow orifice size was found to be within 10$\mu$m during valve operation Therefore, Precision design and manufacturing techniques are necessary for successful operations of the shunt valve. The study indicated the amount of predeflection as well as the magnitude of corner rounding of the diaphragm edge are important design parameters to influence the slope of the pressure-flow characteristic curve.

• Journal of Periodontal and Implant Science
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• v.47 no.5
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• pp.312-327
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• 2017

Purpose: This study assessed marginal bone remodeling and soft tissue esthetics after the loading of single bone-level implants in the anterior maxilla. Methods: An open, single-arm observational clinical trial with 3 years of follow-up was performed, including 22 implants. The patients presented with a single tooth gap in the anterior maxilla (tooth positions 14-24), with natural or restored adjacent teeth. An implant was placed at least 8 weeks post-extraction and healed submerged for 6 weeks. After the second-stage operation, a fixed provisional prosthesis was provided. The final restoration was placed 6 months after the provisional restoration. The time of the provisional crown connection was considered to be the baseline in this study. Esthetic parameters and the marginal bone level were assessed at 6, 12, 24, and 36 months. Results: All implants were well integrated in the bone. A statistically significant increase was found in the mean implant stability quotient between the time of the provisional prosthesis and the time of the final prosthesis. Most implants (95.5%) revealed marginal bone resorption (<0.5 mm), and just 1 implant (4.5%) showed a change of 2.12 mm from baseline to 36 months (mean $0.07{\pm}0.48mm$), while the crestal bone level decreased significantly, from $2.34{\pm}0.93mm$ at baseline to $1.70{\pm}1.10mm$ at 36 months. The facial gingival margin and papilla were stable and the esthetic scores indicated high patient and dentist satisfaction. Conclusions: Platform-switching bone-level implants placed in maxillary single-tooth gaps resulted in successful osseointegration with minimal marginal bone resorption. The peri-implant soft tissue was also esthetically satisfying and stable.

• Korean Journal of Remote Sensing
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• v.32 no.3
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• pp.323-330
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• 2016

Communication, Ocean and Meteorological Satellite (COMS) was launched in 2010 with three payloads that include Ka-band communication payload developed by Ministry of Science, ICT and Future Planning (MSIP) and Electronics and Telecommunications Research Institute (ETRI). This study introduces a real-time remote vessel monitoring system built in the Socheongcho Ocean Research Station using the Ka-band communication satellite. The system is composed of three steps; real-time data collection, transmission, and processing/visualization. We describe hardware (H/W) and software systems (S/W) installed to perform each step and the whole procedure that made the raw data become vessel information for a real-time ocean surveillance. In addition, we address functional requirements of H/W and S/W and the important considerations for successful operation of the system. The system is now successfully providing, in near real-time, ship information over a VHF range using AIS data collected in the station. The system is expected to support a rapid and effective surveillance over a huge oceanic area. We hope that the concept of the system can be fully used for real-time maritime surveillance using communication satellite in future.

• Journal of Chest Surgery
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• v.31 no.6
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• pp.598-603
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• 1998

Excessive sweating of the palms, axillae, and face has a strong negative impact on the quality of life for many people. The existing non-operative therapeutic options seldom give sufficient relief and have a transient effect. But a definitive cure can be obtained by upper thoracic sympathectomy. From June 1997 to October 1997, 117 cases of the needle (2 mm) thoracoscopic thoracic sympathectomies were performed in the Department of Thoracic and Cardiovascular Surgery in the Respiratory Center Yong-dong Severance Hospital in Seoul, Korea. We have followed up on 94 cases which include palmar hyperhidrosis (n=85), facial hyperhidrosis(n=5) and axillary hyperhidrosis(n=4). There were 42 males and 52 females whose ages ranged from 14 to 63 years(median:23 years). The T2 ganglia and T3-4 ganglia were excised by electrocuting with a hook and endoscissors and were removed for histologic examination. There have been no mortalities or life-threatening complications. The surgical results were classified as excellent(much improvement,very dry) in 93.6%, good(some improvement, minimally wet) in 2.1%, and fair(slight improvement, still wet) in 4.2%. Five patients(5.3%) required closed thoracostomy drainage because of pneumothorax in the immediate postoperative day. Horner's syndrome occurred in one case. The compensatory sweating occurred in 67 cases(71.2%) and was embarrassing in 21 cases(22.3%) and disabling in 9 cases(9.6%) of these cases. Primary failure occurred in one case. The patient with primary failure underwent successful operation. Fifty-one patients had concomitant hyperhidrosis. Our experiences indicate needle thoracoscopic sympathectomy is a very effective, safe, and time- saving procedure for essential hyperhidrosis.

• Management & Information Systems Review
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• v.28 no.4
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• pp.175-197
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• 2009

Numerous researches related to internet shopping malls have been researched by numerous researchers. Such as, establishing criteria to evaluate service quality of electronic commerce, identifying factors affecting successful internet shopping mall operation, and examining relationships among the factors in electronic commerce based shopping mall needed to be focused on. However, most researches that have been undertaken only consider the service quality model or basic functional dimension. In accordance with this indispensability, the integrated structural relationship among variables, which are potentially inherent in customer's perception and affect personnel royalty on internet shopping mall needs to be acknowledged. The purpose of this study is to examine which factors should be able to facilitate performance of internet shopping mall. Based on the relevant literature, it has been empirically analyzed how corporate image, system quality, service quality and delivery quality affect customer satisfaction as well as customer royalty. The research's problem is that it was tested with data collected from 212 respondents. This study developed and empirically analyzed a model representing the relationship by using the Structural Equation Model. The major findings of this study are, firstly, that the higher corporate image is positively affecting the system quality and delivery quality. Secondly, the higher delivery quality is positively affecting the service quality. Thirdly, the higher service quality is positively affecting the customer satisfaction. Finally, the higher customer satisfaction is affecting the customer royalty.

• The Journal of the Korean bone and joint tumor society
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• v.17 no.1
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• pp.36-43
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• 2011

Purpose: This study was designed to verify intermediate-term functional and radiological results of limb salvage operation using endoprosthetic replacement system ($MUTARS^{(R)}$) used in patients with a malignant bone tumor. Materials and Methods: Thirty one cases which used $MUTARS^{(R)}$ tumor prosthesis were reviewed. The mean age of the patients was 49.2 years and the mean follow up was 39.8 months. We retrospectively reviewed complications, and evaluated functionally and radiologically by Enneking functional score, ISOLS radiological implants evaluation system at last follow-up. Results: 3 patients had died of disease, distant metastasis was seen in 4 patients and local recurrence was seen in 1 patients. Complications were developed in 12 patients. (infection 6, leg length discrepancy 2, aseptic loosening 2, periprosthetic femoral fracture 1, screw loosening 1) Mean value of total functional scores were 81.2% in proximal femur, 77.4% in distal femur, 78.1% in proximal tibia, and 80.2% in proximal humerus. The overall radiological result was relatively satisfactory. Conclusion: Our results suggest limb salvage with the $MUTARS^{(R)}$ endoprosthesis is successful with good functional and radiological results. But we should be careful with complications such as infection.

• Archives of Plastic Surgery
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• v.37 no.2
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• pp.129-136
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• 2010

Purpose: Anatomically, the foot is provided with insufficient blood supply and is relatively vulnerable to venous congestion compared to other parts of the body. Soft tissue defects are more difficult to manage and palliative treatments can cause hyperkeratosis or ulcer formation, which subsequently requires repeated surgeries. For weight bearing area such as the heel, not only is it important to provide wound coverage but also to restore the protective senses. In these cases, application of flaps for hind foot reconstruction is widely recognized as an effective treatment. In this study, we report the cases of soft tissue reconstruction for which various types of flaps were used to produce good results in both functional and cosmetic aspects. Methods: Data from 37 cases of hind foot operation utilizing flaps performed between from June 2000 to June 2008 were analyzed. Results: Burn related factors were the most common cause of defects, accounting for 19 cases. In addition, chronic ulceration was responsible for 8 cases and so forth. Types of flaps used for the operations, listed in descending order are radial forearm free flap (18), medial plantar island flap (6), rotation flap (5), sural island flap (3), anterolateral thigh free flap (2), lattisimus dorsi muscular flap (2), and contra lateral medial plantar free flap (1). 37 cases were successful, but 8 cases required skin graft due to partial necrosis in small areas. Conclusion : Hind foot reconstruction surgeries that utilize flaps are advantageous in protecting the internal structure, restoring functions, and achieving proper contour aesthetically. Generally, medial plantar skin is preferred because of the anatomical characteristics of the foot (e.g. fibrous septa, soft tissue for cushion). However alternative methods must be applied for defects larger than medial plantar skin and cases in which injuries exist in the flap donor / recipient site (scars in the vicinity of the wound, combined vascular injury). We used various types of flaps including radial forearm neurosensory free flap in order to reconstruct hind foot defects, and report good results in both functional and cosmetic aspects.

• The Korean Journal of Pain
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• v.9 no.2
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• pp.399-402
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• 1996

Endoscopic transthoracic sympathectomy (ETS) has recently become estabilished as a successful treatment for severe palmar and axillary hyperhidrosis. Descriptions have been published of neurolytic, operative and alternative endoscopic procedures involving thermocoagulation, laser coagulation, or or nonvideo-assisted ganglionectomy using equipment not widely available, with low morbidity and excellent results. All methods have advantage and disadvantages. A 19-year-old male who suffered from severe hyperhidrosis on face, palms and axillary areas, has been initially treated with stellate ganglion block in other pain clinic. He was transfered to our pain clinic for endoscopic thoracic sympathectomy. The patient was intubated left side 34 Fr. double lumen tube and positioned left semi-lateral position for right sympathectomy. Right side pneumothorax was created by clamping the ipsilateral side of the double lumen tube and aspiration of air. 11-mm trocar was introduced through incision at the third intercostal space in anterior axillary line, and then additional two 11-mm and 5-mm trocar was introduced through second and fifth intercostal space in mid axillary line. The lung was gently retracted and the parietal pleura over the heads of the appropriate ribs excised using 5-mm sharp insulated coagulating microprocesss. The T4, T3, and T2 ganglions, as well as accompanying rami communicantes, and other branchs arising from upper thoracic nerves to the brachial plexus and surrounding tissues were carefully dissected, coagulated. During sympathectomy, skin temperature of middle was continuously monitored. Elevation of palmar skin temperature intraoperatively indicated an adequate sympathectomy with a definite therapeutic effect. A No. 28 Fr. thoracotomy tube was introduced through a troca under video guidance, placed under water seal after the lung was reinflated. the controlateral side was performed same procedure. After bilateral sympathectomy, chest tubes were removed, and then, he was discharged 2 days after operation with great satisfaction. The ETS provides a well-tolerated, cost-effective alternative to thoracic sympathectomy for primary hyperhidrosis and sympathetic mediated neuropathic pain disorder. And T2 ganglion is considered the key ganglion for the treatment of primary hyperhidrosis. The low incidence of compensatory sweating may by explained by the limited extent of the sympathectomy.