• Transactions on Electrical and Electronic Materials
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• 제18권5호
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• pp.303-309
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• 2017

The flexible AC transmission system (FACTS) provides a new advanced technology solution to improve the flexibility, controllability, and stability of a power system. The unified power flow controller (UPFC) is outstanding for regulating power flow in the FACTS; it can control the real power, reactive power, and node voltage of distribution networks. This paper investigates the performance of the UPFC for power flow control with a series of step changes in rapid succession in a power system steady state and the response of the UPFC to distribution network faults and islanding mode. Simulation was carried out using the MATLAB's simulink sim power systems toolbox. The results, which were carried out on a 5-bus test system and a 4-bus multi-machine electric power system, show clearly the effectiveness and viability of UPFC in rapid response and independent control of the real and reactive power flows and oscillation damping [6].

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1188-1200
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• 2015

A unified numerical method for computing the quadrature weights, integration matrix, and differentiation matrix is newly developed in this study. For this purpose, a spline-like interpolation using piecewise continuous polynomials is converted into a global spline interpolation formula, with which the quadrature formulas can be derived from integration and differentiation of the transformed function in an exact manner. To prove the usefulness of the suggested approach, both the Lagrange and tension spline interpolations are represented in exactly the same form as global spline interpolation. The applicability of the proposed method on arbitrary nodes is illustrated using two different sets of nodes. A series of validations using three test functions is conducted to show the flexibility in selecting computational nodes with the present method.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권3호
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• pp.313-320
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• 2013

The fractional slot windings are widely used in rotating machine in order to increase the flexibility of design and improve the voltage waveform. However, the MMF wave of fractional-slot windings are found to contain unique harmonic component, which are designated as even order space flux harmonics, fractional number flux harmonics, or both. They may cause stray loss and stator core vibration. This paper proposes new winding methods "novel interspersed windings" and "expanded group windings" to reduce these harmonics. The advantages of two proposed windings are verified by using numerical analysis and measurement test of winding model.

• 한국도로학회논문집
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• 제3권3호
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• pp.135-146
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• 2001

기존의 교면포장공법의 근본적인 문제점으로 인해 새로운 교면포장 공법이 점차 부각되고 있는 실정이며, 새로운 교면포장 공법으로 연구되고 있는 것이 라텍스 개질 콘크리트를 이용하는 것이다. 따라서, 본 연구에서는 신설 콘크리트 교량 교면포장으로 덧씌우기된 LMC의 강도발현 특성과 덧씌우기 될 때의 기존콘크리트와의 부착특성을 파악하고자 하였다. 이런 연구를 위해 라텍스 혼입률에 따른 라텍스 개질 콘크리트의 압축강도와 휨강도, 그리고 기존콘크리트와의 부착강도를 측정하였다. 본 연구결과 라텍스 혼입량 증가로 폴리머 입자들의 볼베어링 작용, 연행된 공기 및 라텍스 안에 있는 계면활성제의 분산작용에 의하여 LMC의 작업성과 휨강도를 증가시킨다는 사실을 파악 할 수 있었고, LMC와 기존 콘크리트 슬래브와의 부착강도는 크게 증진함을 알 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.218-221
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• 2009

Solid oxide fuel cells (SOFCs), as high-temperature fuel cells, have various advantages. In some merits of SOFCs, high temperature operation can lead to the capability for internal reforming, providing fuel flexibility. SOFCs can directly use CH4 and CO as fuels with sufficient steam feeds. However, hydrocarbons heavier than CH4, such as ethylene, ethane, and propane, induce carbon deposition on the Ni-based anodes of SOFCs. In the case of the ethylene steam reforming reaction on a Ni-based catalyst, the rate of carbon deposition is faster than among other hydrocarbons, even aromatics. In the reformates of heavy hydrocarbons (diesel, gasoline, kerosene and JP-8), the concentration of ethylene is usually higher than other low hydrocarbons such as methane, propane and butane. It is importatnt that ethylene in the reformate is removed for stlable operation of SOFCs. A new methodology, termed post-reforming was introduced for removing low hydrocarbons from the reformate gas stream. In this work, activity tests of some post-reforming catalysts, such as CGO-Ru, CGO-Ni, and CGO-Pt, are investigated. CGO-Pt catalyst is not good for removing ethylene due to low conversion of ethylene and low selectivity of ethylene dehydrogenation. The other hand, CGO-Ru and CGO-Ni catalysts show good ethylene conversion, and CGO-Ni catalyst shows the best reaction selectivity of ethylene dehydrogenation.

• KSBB Journal
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• 제8권3호
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• pp.237-242
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• 1993

Chitin 섬유는 인장강도가 기대치 보다 약하며 생 체조직 내에서 흡수도가 너무 빨라 수술 후 2주일 정도의 강도 유지밖에 못하는 단점 등이 었으므로, chitin과 그 구조가 비슷한 cellulose와 혼합하여 인 장력과 유연성이 크게 증대된 Chitulose 섬유를 개 발하였다. 우선 chitin과 cellulose가 잘 용해되어 혼 합펼 수 있는 용매로서 DMAc/LiCl을 탐색하였으며 이 용애계에 용해시킨 Chitulose 용액을 가지고 습 식방사하여 얻은 Chitulose 섬유 중, 용매에 대한 chitin cellulose 함량비가 1.5: 0.2얼 때, Instron 시험결과 강도와 유연성이 가장 좋았으며, 멸균시 autoclave해도 변화되지 않아 열에 매우 안정한 것 으로 나타났다. 이 섬유를 가지고 400-500g되는 백서의 피하조직에 매몰시킨 후, 생체 내 분해흡수 도를 관찰한 결과, 매볼 후 14일부터 분해되기 시작 하여 40일 후에는 완전히 분해흡수되였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1963-1966
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• 2005

Degenerative lumbar spinal stenosis(DLSS) is a disease inducing low back pain, leg pain, convulsion, numbness, and neurogenic claudication from compression of nerve root. Intervertebra fixation was reported to increase the degenerative of neighbor region after treatment. Recently, a new surgical technique of inserting a fixator between interspinous processes has been introduced. The purpose of this study is to design of the interspinous process fixator with flexibility to complement the trouble of using fixator in DLSS. This study evaluated the existing fixator through the mechanical test and modified fixators using the finite element analysis(FEA). Displacement, stiffness and Von-Mises stress were found to have similar values to those obtained from the mechanical test and the FEA in the biomechanical loading condition. Effects of variation in length and thickness were investigated to design an optimal fixator.

• 한국정밀공학회지
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• 제23권3호
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• pp.195-202
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• 2006

The degenerative lumbar spinal stenosis (DLSS) is a disease inducing low back pain, leg pain, convulsion. numbness, and neurogenic claudication from compression of nerve root. Intervertebra fixation was reported to increase the degeneration of neighbor lesion after treatment. Recently, a new surgical technique of inserting a fixator between interspinous processes has been introduced. The purpose of this study is to design the interspinous process fixator with flexibility to complement the trouble of using fixator in DLSS. This study evaluated the existing fixator through the mechanical test and modified it using the finite element analysis (FEA). The evaluation was based on the displacement, stiffness and von-Mises stress obtained from the mechanical test and calculated from the FEA in the biomechanical loading condition. Effects of variation in length and thickness were investigated to design an optimal fixator. Three prototypes were manufactured using FEA results. Mechanical tests under the biomechanical loading condition were performed to select the best one from these three. The selected fixator increased flexiblity by 32.9%.

• 디자인학연구
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• 제19권3호
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• pp.143-154
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• 2006

The primary purpose of this study was to investigate the influence of Cognitive Factors (CF) on the Creative Abilities (CAs) in design. We set up a model of Cognitive Design Process (CDP), which consists of four domains: Concepts, Experience, Five Senses (FS), and Thinking Modes (TM). Here, experience is first perceived by the five senses, and then recognized by intelligence. We regard design as a transforming process from concept to experience. For this study, two major Sensory Modalities (Visual and Kinesthetic), four Thinking Modes (Brain Dominance Profile), and four Creative Abilities (Fluency, Flexibility, Originality, and Elaboration) were reviewed. We hypothesized that idea generation is influenced by different Sensory Modalities (Visual Sense vs. Kinesthetic Sense) and Thinking Modes, and that these have a close relationship with the attributes of CAs. Firstly, we have examined the cognitive thinking model in design. Then, we adapted the Test of Creative Abilities of Design Thinking (TCADT) for measuring CAs. We surveyed the CAs under CF in particular. Finally, we have investigated the influences of the different Sensory Modalities (Visual Sense vs. Kinesthetic Sense) on CAs. It was found that a close relationship between Brain Dominance and CAs, and Sensory Modalities (SM) have different influence on these creative abilities. As a result, a tool for the Test of CAs and a framework for creative idea generation with the effective CF will be presented. These provide the basis for a new approach to creative idea generation in Experience Design.

• 대한통합의학회지
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• 제1권4호
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• pp.67-74
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• 2013

Purpose : The purpose of this study was to investigate the effect of horseback riding exercise for BMI(body mass index) and waist circumference in the obese women. Method : 20 subjects in Y-equestrian were randomly divided two group, horseback machine exercise(HME) group and horseback-riding exercise(HRE) group. Each group carried out 30 minutes exercise two times a week for 8 weeks. BMI were measured for body composition, and evaluation of waist circumference. Result : The results were as follows, the BMI(body mass index) between horseback machine exercise and horseback-riding exercise groups in post-test, were significantly different in measures(p<.05). And there were significant in two group after exercise(p<.05). The waist circumference between horseback machine exercise and horseback-riding exercise groups in post-test, were significantly different in measures(p<.05). And there were significant in two group after exercise(p<.05). Conclusion : These finding revealed that horseback-riding exercise was effective on BMI and waist circumrerence of obese women so that these exercise can be new altematives exercise for obesity management in the obese women.