• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.3
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• pp.50-55
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• 1999

Brushless DC Motor(BLDCM) has high efficiency. But this type of motor needs a rotor sensor which complicates the motor configuration. Rotor position sensor degrades system reliability in the severe environmental condition. In this paper, we study a controller which permits the determination of the rotor position by the back EMF to eliminate the rotor position sensor Also, since the back EMF is zero at standstill, a starting technique which permits the starting of an asynchronous motor without a sensor is described. The controller is implemented using microcontroller for minimal external component.

• Journal of Korean Society on Water Environment
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• v.35 no.6
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• pp.567-573
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• 2019

DABF(Dissolve Air Flotation with Ball Filter) is developed as the DAF with the addition of a fiber ball at the lower part of the DAF. The DABF with a capacity of 4,500 ㎥/h was constructed at Gijang SWRO plant in Busan. Since the ball filter has high filtration rate, the loading rate of DABF was designed from 20 to 42 ㎥/h/㎡. When one DABF basin is in the back washing mode, the loading rate of other two DABF basins is increased to 42 ㎥/h/㎡. Turbidity at the BF outlet in DABF is <2 NTU at turbidity of 5-10 NTU at the BF inlet. If there is no algae bloom and turbidity is low in raw seawater, only BF in DABF is operated and meets <2 NTU at the BF outlet. Even if BF is operated at high hydraulic loading rates, no significant differential pressure increases and reduction in the turbidity removal rate is minimal in a day. Thus, DABF is the pre-treatment technology that provides stable water quality even with BF onlyoperation without DAF operation. Compared with the DAF, DABF requires additional facilities such as valves, piping, and drainage systems for backwashing the BF. But in terms of footprint and operating costs, DABF has more advantages than DAF. With DABF application, the load of the downstream filtration equipment is decreased so that the capacity of the filtration equipment can be reduced. Also, if the downstream filtration equipment is to be maintained the same regardless of DABF, the operating cost of DABF is less than DAF.

• Journal of Korean Foot and Ankle Society
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• v.8 no.1
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• pp.86-91
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• 2004

Purpose: To evaluate the methods and results of the surgical treatment in the trimalleolar fracture of the ankle. Materials and Methods: We analysed the results of the ankle trimalleolar fracture which were treated with open reduction and internal fixation from January 1999 till September 2003. There were 45 patients who had at least six months follow up, 16 men, and 29 women. We have analysed the mechanism of injury, methods of operation and postoperative complications. Results: The results were assessed on ankle AP, lateral and mortise X-rays and retrospective chart review. There were 30 supination-external rotation, 13 pronation-external rotation, 2 pronation-abduction in the mechanism of injury by Lauge-Hansen classification. Cases of the posterior malleolar fracture which involved more than 25% of the weight bearing surface were 7 (15.6%). Medial malleolar mono-fixation was done in 5 cases, fibular mono-fixation in 2 cases, bimalleolar fixation in 32 cases, trimalleolar fixation in 6 cases. 38 cases (84.4%) were good or excellent in clincal assessment and 39 cases (86.7%) were good or excellent in radiological assessment according to the criteria of the Meyer. There was no difference of results among the surgical treatment methods. Conclusion: The results of our study indicate that the rigid fixation with early ankle motion and weight bearing is needed in ankle trimalleolar fracture. But minimal fixation is not bad in slight displaced fracture. Both anterior approach and posterior approach were useful methods to stabilization the posterior malleolar fracture. And pre-operative evaluation to detect the hidden soft tissue injuries and fracture mechanism is very important to avoid the failure.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.84.1-84.1
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• 2013

We present a python-based data reduction pipeline for the Immersion GRating INfrared Spectrograph (IGRINS). IGRINS covers the complete H- and K-bands in a single exposure with a spectral resolving power of greater than 40,000. IGRINS is designed to be compatible with telescopes of diameters ranging from 2.7-m (the Harlan J. Smith telescope at McDonald Observatory) to 8-10m. Commissioning and initial operation will be on the 2.7-m telescope from late 2013. The pipeline package is a part of the IGRINS software and designed to be compatible with other package that maneuvers the spectrograph during the observation. This package provides high-quality spectra with minimal human intervention and the processes of order extraction, distortion correction, and wavelength calibration can be automatically carried out using the predefined functions (e.g. echellogram mapping and 2D transform). Since the IGRINS is a prototype of the Giant Magellan Telescope Near-Infrared Spectrometer (GMTNIRS), this pipeline will be extended to the GMTNIRS software.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.7
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• pp.1230-1251
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• 2011

This document specifies a new IPv6 deployment protocol called CHANC, which stands for Configuring Hosts to Auto-detect (IPv6, IPv6-in-IPv4, or IPv4) Network Connectivity. The main part is an application level tunneling protocol that allows Internet Service Providers (ISPs) to rapidly start deploying IPv6 service to their subscribers whom connected to the Internet via IPv4-only access networks. It carries IPv6 packets over HTTP protocol to be transmitted across IPv4-only network infrastructure. The key aspects of this protocol are: offers IPv6 connectivity via IPv4-only access networks, stateless operation, economical solution, assures most firewall traversal, and requires simple installation and automatic configuration at customers' hosts. All data packets and routing information of the IPv6 protocol will be carried over the IPv4 network infrastructure. A simple application and a pseudo network driver must be installed at the end-user's hosts to make them able to work with this protocol. Such hosts will be able to auto-detect the ISP available connectivity in the following precedence: native IPv6, IPv6-in-IPv4, or no IPv6 connectivity. Because the protocol does not require changing or upgrading customer edges, a minimal cost in the deployment to IPv6 service should be expected. The simulation analysis showed that the performance of CHANC is pretty near to those of native IPv6, 6rd, and IPv4 protocols. Also, the performance of CHANC is much better than that of D6across4 protocol.

• Archives of Plastic Surgery
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• v.35 no.3
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• pp.255-260
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• 2008

Purpose: Tongue cancer is the most common malignant tumor of the oral cavity and the ultimate goal in treatment of the cancer is not only complete excision and meticulous closure of the wound, but also, reconstruction of a demensional and functional tongue. Our study focuses on various factors, such as defect size, extent of tumor, age, application of mandibulectomy or radiotherapy, and their influences on postoperative speech and swallowing function. Methods: Our study was based on 59 patients who underwent tongue cancer operation and reconstruction of the tongue. Speech and swallowing were evaluated according to categories documented by Sultan and Teichgraeber. Patients were classified into 3 groups as partial glossectomy, hemiglossectomy and total glossectomy groups for evaluation. The average age of the patients were 51, and the mean follow-up period was 4 years 2 months. Results: The partial glossectomy group showed statistically relevant results for speech articulation and swallowing abilities compared to the total glossectomy group. In cases of defects involving the mouth floor, the group showed decreased results compared to the group without mouth floor involvement. Increased age showed decreased postoperative results with statistical significance, while mandibulectomy and radiotherapy revealed no statistically significant data. Analysis according to TNM staging resulted in decreased functional result with advanced staging without statistical significance. Conclusion: To summarize the factors influencing the functional outcome in tongue reconstruction, younger patients and early stage cancer with minimal surgical extent revealed more satisfying results while mandibulectomy and radiation did not have influence on our analysis. Addition of various influencing factors and studies with longer follow up periods on our patient groups may provide effective data for more satisfying functional outcomes in the future.

• Archives of Plastic Surgery
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• v.37 no.3
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• pp.289-292
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• 2010

Purpose: Mycobacterium abscessus belongs to the group of rapid-growing atypical mycobacterium. The organism is ubiquitous and is found in soil, dust, and water. Although it rarely causes disease in humans, Mycobacterium abscessus has been associated with soft tissue infection. To the best of our knowledge, this is the first case report of facial soft tissue Mycobacterium abscessus infection in a healthy child in Korea. Methods: A 12-year-old girl presented with an erythematous skin lesion with serous discharge on her chin, which had been present for 3 weeks. On her history, she had a laceration wound on her chin at public bath and the lesion was repaired at emergency department immediately. Although conventional soft tissue infecton treatment, her lesion remains unhealed state and had serous discharge for 2 months. Moreover, we found a 1 cm sized nodular mass on her chin. Therefore we performed excision operation and referred the specimen to the laboratory for microbial and histopathologic study. Results: Pathology report confirmed the mass was enlarged lymph node with chronic necrotizing granulomatous inflammation with central microabscess. Non-Tuberculous mycobacterium identification test through tissue specimen resulted Mycobacterium abscessus. We prescribed clarithromycin for three weeks by oral administration as well as performed wound debridement and mass excision via previous wound. This way, her lesion appeared to be complete healing with minimal scarring. There were no evidence of inflammation sign or palpable mass. Conclusion: Although the prevalence is rare, Mycobacterium abscessus infections of soft tissue should be considered even in a healthy child with a lesion caused by trauma or which fails to respond to conventional treatment.

• Journal of Trauma and Injury
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• v.24 no.2
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• pp.82-88
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• 2011

Background: The incidence of abdominal trauma with intra-abdominal organ injury or bowel rupture is increasing. Articles on the diagnosis, symptoms and treatment of small bowel perforation due to blunt trauma have been reported, but reports on the relationship of mortality and morbidity to clinical factors for prognosis are minimal. The purposes of this study are to evaluate the morbidity and mortality of patients with small bowel perforation after blunt abdominal trauma on the basis of clinical examination and to analyze factors associated with the prognosis for blunt abdominal trauma with small bowel perforation. Methods: The clinical data on patients with small bowel perforation due to blunt trauma who underwent emergency surgery from January 1994 to December 2009 were retrospectively analyzed. The correlation of each prognostic factor to morbidity and mortality, and the relationship among prognostic factors were analyzed. Results: A total of 83 patients met the inclusion criteria: The male was 81.9%. The mean age was 45.6 years. The mean APACHE II score was 5.75. The mean time interval between injury and surgery was 395.9 minutes. The mean surgery time was 111.1 minutes. Forty seven patients had surgery for ileal perforations, and primary closure was done for 51patients. The mean admission period was 15.3 days, and the mean fasting time was 4.5 days. There were 6 deaths (7.2%), and 25 patients suffered from complications. Conclusion: The patient's age and the APACHE II score on admission were important prognostic factors that effected a patient's progress. Especially, this study shows that the APACHE II score had effect on the operation time, admission period, the treatment period, the fasting time, the mortality rate, and the complication rate.

• Journal of Chest Surgery
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• v.10 no.2
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• pp.281-294
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• 1977

Superior vena cava to pulmonary arterial shunting operation was made between the superior vena cava and the right pulmonary artery in the fashion of end-to-end anastomosis in 20 mongrel dogs. The experimental animals were divided into three group and blood flow in the superior vena cava was occluded for 20, 30 and 60 minutes respectively, and observations were made for the changes in caval pressure and cerebrospinal fluid pressure. And pathologic examinations were also performed. On occluding the caval blood flow, the superior vena caval pressure was sharply and immediately elevated from $103.5{\pm}19.8mmH_2O$ at thoracotomy to $556.4{\pm}86.lmmH_2O$ within 2 minutes to make its plateau thereafter, and the cerebrospinal fluid pressure followed closely the changes of the superior vena caval pressure in its level and pattern being elevated from $102.0{\pm}19.9mmH_2O$ to $490.5{\pm}79.9mmH_2O$. The drops of both the caval and cerebrospinal fluid pressures were definite and marked on opening the shunt flow through the anastomosis, but these postoperative pressures retained still higher ones above their levels measured at thoracotomy. The pathological examinations of the brain and the spinal cord were also performed in six animals. Characteristic changes uniformly seen in all area and in all animals were the findings of capillary congestion and perivascular edema. On the other hand, ischemic nerve cell changes were rather evident, revealing their degrees and extents being related to the prolongation of the time of caval occlusion which has followed by the sustained high pressures in both the superior vena and the cerebrospinal fluid. The experiment suggests the safety of this surgical procedure with minimal, if any, permanent damage as long as the occlusion of the caval blood flow is not prolonged beyond the expected.

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.75-87
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• 2001

The Conditional Access System is the complete system for ensuring that broadcasting services are only accessible to those who are entitled to receive them. Four major parts to this system are scrambling, descrambling, authentication and encryption. For the proper operation, which means hard-to- break and uninterrupted service, secure key management and efficient delivery mechanism are very important design factors to this system. Performance analysis is another important factor to this system that is used in massive subscriber environment. In this thesis, one of the secure and efficient key management mechanisms is proposed. For the secrecy of this mechanism, hierarchical stacking of keys and key generation matrix are proposed. For the proof of efficient delivery of those keys, simulation results and performance analysis. which is based on queuing analysis, are presented. Lastly, optimal key generation and delivery period, maximal and minimal key deliver time, and communication capacity for data collection are presented for various subscriber volume.