• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.3
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• pp.257-262
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• 2009

The unified power flow controller(UPFC) is one of the most effective devices in the FACTS family. This paper concerns about a filtering technique for reducing the computer calculation to determine the optimal location of UPFC in a power system. The sensitivities of the power generation cost for UPFC control parameters are evaluated. This technique requires that only one optimal power flow is run to get UPFC sensitivities for all possible transmission lines. To find out a optimal locating of a single UPFC in power system, an ideal transformer model which consists of a complex turns ratio and a variable shunt admittance was used. In this model, the UPFC control variables do not depend on UPFC input and output currents and voltages. The sensitivity method was tested on a 5-bus system derived from the IEEE 14-bus system and IEEE 14-bus system to establish its effectiveness.

• Archives of Reconstructive Microsurgery
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• v.10 no.2
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• pp.105-110
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• 2001

Breast reconstruction is an aesthetically critical procedure and should be peformed to match the opposite breast in shape, contour, and position. Many methods were introduced to reconstruct the breast with autogenous tissue. But, free tissue transfer for breast reconstruction has become common method. The transverse rectus abdominis myocutaneous flap technique has been a widely accepted method of breast reconstruction after mastectomy, since the first introduction of free abdominoplasty flap in 1979. In breast reconstruction with a free flap the selection of suitable recipient vessels remains one of the most critical decision for surgeon. The most common recipient site for free flap breast reconstruction is the axillar system. But, the use of the axillary system as a recipient site limits flap movement and flexibility in breast shaping. The use of internal mammary vessels as a recipient site be able to achieve ideal breast symmetry, but that technique require the rib resection. The selection of suitable recipient vessels is most important for successful free tissue transfer. We have performed breast reconstruction with TRAM flaps anastomozed to the internal mammary vessel perforator. We came to the conclusion that this vessel perforator is useful as a recipient site in cases of immediate breast reconstruction with free TRAM flap.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.867-872
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• 2009

Peak expiratory flow rate(PEF) is one of the most important diagnostic parameters in spirometry. PEF occurs in a very short duration during the forced expiratory maneuver, which could lead to measurement error due to non-ideal dynamic characteristic of the transducer. In such case the initial slope of the flow rate signal determines the accuracy of the measured PEF. The present study considered this initial slope as a parameter to compensate PEF. The 26 standard flow rate signals recommended by the American Thoracic Society(ATS) were flown through the air flow transducer followed by simultaneous measurements of PEF and maximum transducer output$(N_{PEF})$. $N_{PEF}$-PEF satisfied a quadratic equation in general, however, two signals (ATS #2 and #26) having large initial slopes deviated from the fitting equation to a significant degree. The relative error was found to be in a linear relationship with the initial slope, thus, $N_{PEF}$ was appropriately compensated to provide accurate PEF with mean relative error less than only 1%. The 99% confidence interval of the mean relative error was less than a half of the error limit of 5% recommended by ATS. Therefore, PEF can be very accurately determined by compensating the transducer output based on the initial slope, which should be a useful technique for air flow transducer calibration.

• Archives of Plastic Surgery
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• v.32 no.4
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• pp.428-434
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• 2005

Extensive and complicated defects on the body call for an omnipotent tool for a perfect reconstruction. Flaps derived from the omentum has many advantages over the conventional flaps. From 1999 to 2004, Omental flaps were applied for various soft tissue reconstructions. Among total 20 total 7 cases were for immediate reconstruction, 2 cases for chronic infection, 3 cases for simultaneous reconstruction of two defects, 4 cases for functional joint reconstruction and 4 cases were for flow- through revascularization. Among these cases, 3 cases were operated with minimal incision harvest technique. There were no complete flap failures, partial necrosis of the distal parts were noted on three cases. The omental flap is indicated on a large contaminated defect reconstruction due to its large size, well-vascularized, and malleable properties. The omental flap provides several additional advantages over other flaps, which are; the availability of the one staged simultaneous reconstruction of two defects with one flap, providing gliding function for the joint motion, and a flow-through characteristics with long vascular pedicle. But there are some serious shortcomings, including a long abdominal scar and intraabdominal problems. However, these are rare and can be minimized with our minimal incision technique. Due to its unique characteristics. the omentum is one of the ideal tissues for the reconstruction of the complicated soft tissue defects due to its unique characteristics.

• Journal of Korean Neurosurgical Society
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• v.57 no.6
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• pp.460-464
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• 2015

Objective : Bilateral C1 lateral mass and C2 pedicle screw fixation (C1LM-C2P) is an ideal technique for correcting atlantoaxial instability (AAI). However, the inevitable situation of vertebral artery injury or unfavorable bone structure may necessitate the use of unilateral C1LM-C2P. This study compares the fusion rates of the C1 lateral mass and C2 pedicle screw in the unilateral and bilateral methods. Methods : Over five years, C1LM-C2P was performed in 25 patients with AAI in our institute. Preoperative studies including cervical X-ray, three-dimensional computed tomography (CT), CT angiogram, and magnetic resonance imaging were performed. To evaluate bony fusion, measurements of the atlanto-dental interval (ADI) and CT scans were performed in the preoperative period, immediate postoperative period, and postoperatively at 1, 3, 6, and 12 months. Results : Unilateral C1LM-C2P was performed in 11 patients (44%). The need to perform unilateral C1LM-C2P was due to anomalous course of the vertebral artery in eight patients (73%) and severe degenerative arthritis in three patients (27%). The mean ADI in the bilateral group was 2.09 mm in the immediate postoperative period and 1.75 mm in 12-months postoperatively. The mean ADI in the unilateral group was 1.82 mm in the immediate postoperative period and 1.91 mm in 12-months postoperatively. Comparison of ADI measurements showed no significant differences in either group (p=0.893), and the fusion rate was 100% in both groups. Conclusion : Although bilateral C1LM-C2P is effective for AAI from a biomechanical perspective, unilateral screw fixation is a useful alternative in patients with anatomical variations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11C
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• pp.1119-1126
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• 2007

In this paper, we examine the scheme that the CR (Cognitive Radio) user can coexist with primary user with obeying the concept of interference temperature proposed by FCC. Regarding to the capability of classifying the signals of primary user after the spectrum sensing, the interference temperature model can be discriminated by the ideal and generalized ones. And then, about each model, it can optimize the bandwidth and transmit power with satisfying predetermined capacity of CR user. Especially, it has been considered to allocate to CR user not to interfere to primary users for proper coexistence in conventional interference temperature multiple access technique, proposed by T. Clancy, but this paper proposes the scheme that considering QoS of not only primary users, but also CR user. The hill-climbing algorithm is employed to produce the bandwidth and transmit power subject to satisfying the required capacity.

• Proceedings of the KWS Conference
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• 2000.10a
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• pp.13-18
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• 2000

Welding is critical technique for the joining of materials in the nation's major Manufacturing industries. Since 1998, leaders in welding industry have defined a vision of the issues and opportunities that it will face in 2020. In developing this vision document, more than 25 senior managers and respected experts from various segments of the welding community met to begin a dialog about the future of the welding industry. They were brought together to develop a long-range business plan for their industry that would identify how it would meet the needs of manufacturers, of the marketplace, and of society in 2020. In essence, these decision makers created an ideal vision of the state of their industry in 20 years, and the strategy to reach it. Welding is a precise, reliable, and cost-effective, method for joining materials. No other technique is as widely used by manufacturers to join metals and alloys efficiently. Most of the familiar objects in modern society, form buildings and bridges, to vehicles, computers, and medical devices, could not be produced without the use of welding. Despite the importance of welding to the manufacturing industry, the leaders in this area felt that welding was not appreciated as much as it should be from the society. The welding industry consists of the “users” of welding techniques as well as the companies, universities and other organizations that industry look for improvements in their operations by 2020, and should find their interest addressed in this document. A major economic impact study co sponsored by AWS and EWI and supported by US Navy, State of Ohio, US Department of Commerce, and major companies was kicked off. This two-year study will determine the economic impact of welding on the United States economy. The objective of this study is to break a paradigm about welding-those of us who are heavily involved in welding, believe strongly that much of our gross domestic product is directly dependent on welding. Furthermore, continued advances in the field of welding are necessary to achieving further increases in productivity that makes our economy strong. Yet, despite intuition, anecdotal information, and fragmented analyses, the completing quantitative information that would proved the justification for strategic actions to further develop this critical field is not currently available.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.102-115
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• 2019

This study aims to establish and apply a drought vulnerability assessment plan including various factors related to drought. The evaluation technique consisted of three stages: evaluation factor and weight selection, evaluation data database construction, evaluation data and weight combination, and Delphi investigation method was applied to evaluation factor and weight selection. As the evaluation method, the TOPSIS method, which is a widely used MCDM method, was used. The results of the drought vulnerability assessment were applied to the administrative districts of Sigun-gu, Korea from March 2016 to September 2019. As a result of the evaluation, drought vulnerable areas were identified in Chungcheongbuk-do, Gyeongsangnam-do, and Jeollanam-do, and it was analyzed that it is necessary to establish drought response plans for these areas.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.1
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• pp.16-23
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• 2011

This paper suggests a motion compensation technique using GPS/IMU data in order to compensate for phase error caused by undesired motion of radar platform. An actual flight trajectory would be deviate from an ideal straight-constant trajectory with a constant velocity for SAR imaging, due to pitch, roll and yaw motion of aircraft caused by turbulence. This leads to blurred SAR images due to inter-pulse phase errors as well as along-track velocity errors. If the motion compensation is carried out to reduce those errors, SAR image quality can be significantly improved. Simulation results show that the motion compensation technique introduced in this paper is an effective tool to improve SAR image quality against severe motion of radar platform.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.3
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• pp.196-207
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• 2018

An accurate implant placement with ideal location is significant for long-term success of the implant. An exact evaluation of nearby anatomic structures such as quality of residual bone, an inferior alveolar bone and a maxillary sinus is required. For a prosthetic-driven treatment, planned surgery, precise prosthesis and communication with the patient are significant requisites especially for full-mouth rehabilitation. In this case, the patient with severe alveolar bone resorption had a CT guided surgery supported by CT data and the data from scanning diagnostic wax-up. Afterward, edentulous area was restored by full mouth implant-supported prosthesis by using monolithic zirconia and CAD/CAM technique. This paper reports the outcome of the procedure which was remarkable both esthetically and functionally.