• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1066-1071
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• 2005

This paper presents the two lossless auxiliary inductors-assisted voltage source type half bridge (single ended push pull: SEPP) series resonant high frequency inverter for induction heated fixing roller in copy and printing machines. The simple high-frequency inverter treated here can completely achieve stable zero current soft switching (ZCS) commutation for wide its output power regulation ranges and load variations under its constant high frequency pulse density modulation (PDM) scheme. Its transient and steady state operating principle is originally described and discussed for a constant high-frequency PDM control strategy under a stable ZCS operation commutation, together with its output effective power regulation characteristics-based on the high frequency PDM strategy. The experimental operating performances of this voltage source SEPP ZCS-PDM series resonant high frequency inverter using IGBTs are illustrated as compared with computer simulation results and experimental ones. Its power losses analysis and actual efficiency are evaluated and discussed on the basis of simulation and experimental results. The feasible effectiveness of this high frequency inverter appliance implemented here is proved from the practical point of view.

• Imaging Science in Dentistry
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• 제46권3호
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• pp.211-216
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• 2016

Purpose: The use of electronic tools in teaching is growing rapidly in all fields, and there are many options to choose from. We present one such platform, Learning Catalytics$^{TM}$ (LC) (Pearson, New York, NY, USA), which we utilized in our oral and maxillofacial radiology course for second-year dental students. Materials and Methods: The aim of our study was to assess the correlation between students' performance on course exams and self-assessment LC quizzes. The performance of 354 predoctoral dental students from 2 consecutive classes on the course exams and LC quizzes was assessed to identify correlations using the Spearman rank correlation test. The first class was given in-class LC quizzes that were graded for accuracy. The second class was given out-of-class quizzes that were treated as online self-assessment exercises. The grading in the self-assessment exercises was for participation only and not accuracy. All quizzes were scheduled 1-2 weeks before the course examinations. Results: A positive but weak correlation was found between the overall quiz scores and exam scores when the two classes were combined (P<0.0001). A positive but weak correlation was likewise found between students' performance on exams and on in-class LC quizzes (class of 2016) (P<0.0001) as well as on exams and online LC quizzes (class of 2017) (P<0.0001). Conclusion: It is not just the introduction of technological tools that impacts learning, but also their use in enabling an interactive learning environment. The LC platform provides an excellent technological tool for enhancing learning by improving bidirectional communication in a learning environment.

• 대한구순구개열학회지
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• 제6권2호
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• pp.91-105
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• 2003

There are significant limitations in the precision of mandibular distraction in setting a desired occlusal and facial esthetic outcome. The purpose of this study is to present the simulation method for the distraction osteogenesis treatment planning. 3-D surgery simulation software programs V-works and V-Surgery(Cybermed, Seoul, Korea) were used from the 3D CT data in addition to the conventional data facial photography, panorama and cephalogram, dental cast model. We have utilized already for the various surgical procedures to get information preoperatively for the maxillofacial surgery like cancer localization and reconstructive surgery, orthognathic surgery and implant surgery in the department of Oral and Maxillofacial surgery, Seoul National University Hospital. On the software, bone cutting can be done at any place and any direction. Separated bone segment can be mobilized in all 3 dimensional direction. After the 3D simulation on the software program, mock surgery on the RP model can be performed. This planning method was applied to two hemifacial microsomia patients. With this protocol, we could simulate the movement of bony segment after maxillofacial distraction osteogenesis

• Structural Monitoring and Maintenance
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• 제2권1호
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• pp.19-34
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• 2015

One of the main causes of a limited use of nondestructive evaluation (NDE) technologies in bridge deck assessment is the speed of data collection and analysis. The paper describes development and implementation of the RABIT (Robotics Assisted Bridge Inspection Tool) for data collection using multiple NDE technologies. The system is designed to characterize three most common deterioration types in concrete bridge decks: rebar corrosion, delamination, and concrete degradation. It implements four NDE technologies: electrical resistivity (ER), impact echo (IE), ground-penetrating radar (GPR), and ultrasonic surface waves (USW) method. The technologies are used in a complementary way to enhance the interpretation. In addition, the system utilizes advanced vision to complement traditional visual inspection. Finally, the RABIT collects data at a significantly higher speed than it is done using traditional NDE equipment. The robotic system is complemented by an advanced data interpretation. The associated platform for the enhanced interpretation of condition assessment in concrete bridge decks utilizes data integration, fusion, and deterioration and defect visualization. This paper concentrates on the validation and field implementation of two NDE technologies. The first one is IE used in the delamination detection and characterization, while the second one is the USW method used in the assessment of concrete quality. The validation of performance of the two methods was conducted on a 9 m long and 3.6 m wide fabricated bridge structure with numerous artificial defects embedded in the deck.

• 한국의학물리학회지:의학물리
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• 제30권4호
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• pp.112-119
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• 2019

Purpose: The advantages of ocular proton therapy are that it spares the optic nerve and delivers the minimal dose to normal surrounding tissues. In this study, it developed a solid eye phantom that enabled us to perform quality assurance (QA) to verify the dose and beam range for passive single scattering proton therapy using a single phantom. For this purpose, a new solid eye phantom with a polymethyl-methacrylate (PMMA) wedge was developed using film dosimetry and an ionization chamber. Methods: The typical beam shape used for eye treatment is approximately 3 cm in diameter and the beam range is below 5 cm. Since proton therapy has a problem with beam range uncertainty due to differences in the stopping power of normal tissue, bone, air, etc, the beam range should be confirmed before treatment. A film can be placed on the slope of the phantom to evaluate the Spread-out Bragg Peak based on the water equivalent thickness value of PMMA on the film. In addition, an ionization chamber (Pin-point, PTW 31014) can be inserted into a hole in the phantom to measure the absolute dose. Results: The eye phantom was used for independent patient-specific QA. The differences in the output and beam range between the measurement and the planned treatment were less than 1.5% and 0.1 cm, respectively. Conclusions: An eye phantom was developed and the performance was successfully validated. The phantom can be employed to verify the output and beam range for ocular proton therapy.

• 한국의학물리학회지:의학물리
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• 제30권4호
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• pp.94-103
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• 2019

Purpose: To evaluate the clinical feasibility of knowledge-based planning (KBP) for volumetric-modulated arc radiotherapy (VMAT) in spine stereotactic body radiotherapy (SBRT). Methods: Forty-eight VMAT plans for spine SBRT was studied. Two planning target volumes (PTVs) were defined for simultaneous integrated boost: PTV for boost (PTV-B: 27 Gy/3fractions) and PTV elective (PTV-E: 24 Gy/3fractions). The expert VMAT plans were manually generated by experienced planners. Twenty-six plans were used to train the KBP model using Varian RapidPlan. With the trained KBP model each KBP plan was automatically generated by an individual with little experience and compared with the expert plan (closed-loop validation). Twenty-two plans that had not been used for KBP model training were also compared with the KBP results (open-loop validation). Results: Although the minimal dose of PTV-B and PTV-E was lower and the maximal dose was higher than those of the expert plan, the difference was no larger than 0.7 Gy. In the closed-loop validation, D_1.2cc, D_0.35cc, and D_mean of the spinal cord was decreased by 0.9 Gy, 0.6 Gy, and 0.9 Gy, respectively, in the KBP plans (P<0.05). In the open-loop validation, only D_mean of the spinal cord was significantly decreased, by 0.5 Gy (P<0.05). Conclusions: The dose coverage and uniformity for PTV was slightly worse in the KBP for spine SBRT while the dose to the spinal cord was reduced, but the differences were small. Thus, inexperienced planners could easily generate a clinically feasible plan for spine SBRT by using KBP.

• 대한두개안면성형외과학회지
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• 제21권1호
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• pp.64-68
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• 2020

The coexistence of craniofacial cleft and bilateral choanal atresia has only been reported in three cases in the literature, and only one of those cases involved a Tessier number 3 facial cleft. It is also rare for bilateral choanal atresia to be found in adulthood, with 10 previous cases reported in the literature. This report presents the case of a 19-year-old woman with a Tessier number 3 facial cleft who was diagnosed with bilateral choanal atresia in adulthood. At first, the diagnosis of bilateral choanal atresia was missed and septoplasty was performed. After septoplasty, the patient's symptoms did not improve, and an endoscopic examination revealed previously unnoticed bilateral choanal atresia. Computed tomography showed left membranous atresia and right bony atresia. The patient underwent an operation for opening and widening of the left choana with an image-guided navigation system (IGNS), which enabled accurate localization of the lesion while ensuring patient safety. Postoperatively, the patient became able to engage in nasal breathing and reported that it was easier for her to breathe, and there were no signs of restenosis at a 26-month follow-up. The patient was successfully treated with an IGNS.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권5호
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• pp.337-342
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• 2012

The osseous or osteocutaneous free fibula flap has become the gold standard for most mandibular reconstructions because of its favorable osseous characteristics. However, disadvantages, such as the time-consuming reconstructive step, difficulty in performing the osteotomies to precisely recreate the shape of the missing segment of mandible and poor bone-to-bone contact play a role in making the surgeons look for alternative flaps. With the advent of computerized design software, which accurately plans complex 3-dimensional reconstructions, has become a process that is more efficient and precise. However, the ability to transfer the computerized plan into the surgical field with stereolithographic models and guides has been a significant development in advancing reconstruction in the maxillofacial regions. The ability to "pre-plan" the case, mirror and superimpose natural structures into diseased and deformed areas, as well as the ability to reproduce these plans with good surgical precision has decreased overall operative time, and has helped facilitate functional and esthetic reconstruction. We describe a complex case treated with this technique, showing the power and elegance of computer assisted maxillofacial reconstruction from the University of Michigan, Oral and Maxillofacial Surgery.

• 대한간호학회지
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• 제36권8호
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• pp.1324-1330
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• 2006

Purpose. This study developed a web-based wound care course for undergraduate nursing students and evaluated the course's content, system, and student-satisfaction. Methods. This study was done in three stages, the development of the web-based wound care course, the implementation and evaluation of the course. The course was developed based on the ARCS model. 80 under-graduate nursing students to Y University in Korea used the web-based wound care program during four weeks. After that, they completed questionnaires, evaluating the contents, system, and their satisfaction. Results. Eighteen learning objectives were used to create the web-based wound care course and the course was developed with 7 chapters and 20 subsections. The analysis of the questionnaires showed a mean score for content and system-related items of 3.04 each, out of a possible 4 points. Student satisfaction items had a mean score of 2.89. Conclusions. The web-based course allowed students access to the course anytime and anywhere, and according to their own learning abilities. However this advantage would only be possible when nurse educators develop qualitative web-based course to meet the demand of a complex health care system as well as the needs of the students and the effectively incorporate it into traditional lectures.

• 한국인터넷방송통신학회논문지
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• 제13권6호
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• pp.37-45
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• 2013

본 논문에서는 최근 네트워크를 이용한 온라인 원격 진료 서비스가 논의되고 있는 시점에 맞춰 환자에게 적합한 의료기관을 매칭하는 개인 맞춤형 의료서비스 지원 시스템을 제안한다. 본 시스템을 설계하기 위해 개인 맞춤형 의료서비스 지원 시스템의 요구사항을 파악하여 데이터를 표준화하였고 서버와 클라이언트 구조로 아키텍처를 설계하였다. 또한 설계한 시스템을 구현하기 위해 서버와 클라이언트, 온톨로지 저장소의 구조를 정의하고 시스템을 구현하였다. 본 논문에서 설계 및 구현한 개인 맞춤형 의료서비스 지원 시스템을 테스트하기 위해 가정 사항과 시나리오를 작성하여 테스트를 수행한 결과 환자 증상을 선택하면 선택된 증상별로 진료과가 추론이 되고 환자가 원하는 의료기관의 항목에 따라 1차 추론되 진료과에 맞는 의료기관이 추론이 되는 것을 확인하였다.