• 한국조명전기설비학회지:조명전기설비
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• 제7권1호
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• pp.30-36
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• 1993

본 연구는 정류기의 입력전류에 포함되어 있는 고조파성분을 제거하고 입력역률을 개선하기 위해 무손실 저항(Loss Free Resistor) 개념에 기본을 둔, PC, 가전기기 및 형광등용 전자안정기등과 같은 저전력 전원설비에 적합한 불연속 도통모드(DCM) 플라이백 방식의 능동역률 보정기의 등가회로모델 및 설계법을 제시하였다. 이 개념에 의하여 능동역률 보정기의 등가입력저항, 출력전력원 특성을 정확하게 나타낼 수 있었으며 또 설계방정식을 유도하여 능동역률 보정기를 설계 시험한 결과, 적은 부품으로 정류기의 입력교류 전류에 포함되어 있는 고주파를 제거하였고 따라서 0.98의 고입력역률의 정류를 할 수 있었다.

• 디지털융복합연구
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• 제10권7호
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• pp.115-121
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• 2012

본 연구는 소비자들이 왜 위조명품을 구매하고 사용하는가에 대한 의문을 해결하고자 하였다. 이를 위해 소비자들이 위조품을 사용하면서 느낀 혜택이나 이익이 무엇인가? 또한 위조품을 사용하면서 느낀 손실이나 불만족은 무엇인가? 에 대한 선행연구 결과를 토대로 위조품 사용동기, 사용혜택 및 사용손실 요인을 알아보고 이러한 위조품 사용행동과 관련된 동기, 혜택 및 손실 요인 각각이 위조품 제품태도와 구매의도에 어떠한 영향을 미치는 가를 확인하였다. 연구결과 첫째, 위조품 사용동기요인은 과시성, 경제성, 만족감, 실용성이다. 위조품 태도에는 과시성과 품질 동기가 유의미한 영향을 미쳤으며, 위조품 구매의도에는 경제성, 만족감 및 품질동기가 유의미한 영향을 미쳤다. 둘째, 위조품 혜택요인은 개인적 혜택과 경제적 혜택으로 나타났다. 위조품 태도에는 개인적 혜택요인이 유의미한 영향을 미치는 것으로 나타났으며, 위조품 구매의도에는 경제적 및 개인적 혜택이 유의미한 영향을 미쳤다. 셋째, 위조품 손실요인은 개인적손실, 품질손실, 물질적손실 및 사회적손실으로 나타났다. 위조품 태도에는 유의미한 영향을 미치는 요인은 없으며, 구매의도에는 사회적 손실 요인이 유의미한 영향을 미쳤다. 이러한 연구결과는 소비자의 위조품 사용행동에 대한 심층적 이해를 통해, 향후 위조품 사용을 줄이는 캠페인에 활용할 수 있는 자료를 제공해 줄 것으로 기대한다.

• International Journal of Automotive Technology
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• 제7권4호
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• pp.423-439
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• 2006

This paper proposes a hybrid analytic method for the prediction of vibrational and acoustic responses of reverberant system in the medium-to-high frequency ranges by using the PFA(Power Flow Analysis) algorithm and SEA(Statistical Energy Analysis) coupling concepts. The main part of this method is the application of the coupling loss factor(CLF) of SEA to the boundary condition of PFA in reverberant system. The hybrid method developed shows much more promising results than the conventional SEA and equivalent results to the classical PFA for various damping loss factors in a wide range of frequencies. Additionally, this paper presents applied results of hybrid power flow finite element method(hybrid PFFEM) by formulating the new joint element matrix with CLF to analyze the vibrational responses of built-up structures. Finally, the analytic results of coupled plate structures and an automobile-shaped structure using hybrid PFFEM were predicted successively.

• International Journal of Air-Conditioning and Refrigeration
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• 제16권3호
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• pp.83-88
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• 2008

A geometrically asymmetric trapezoidal fin is analyzed using the one-dimensional analytic method. Heat loss and thermal resistance are represented as a function of the fin base thickness, base height, fm shape factor, inside fluid convection characteristic number, convection characteristic numbers ratio, fm length and ambient convection characteristic number. The relationship between the fin base height and the shape factor for equal amounts of heat loss is presented. One of the results shows that the variations of the fm base thickness and the inside fluid convection characteristic number give no effect on the thermal resistance.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 춘계학술발표대회 논문집
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• pp.167-170
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• 2000

The flexural vibration of a sandwich beam with partially inserted viscoelastic layer has been studied using the finite element analysis in combination with an experiment. Effects of length and thickness of partial viscoelastic layers on system loss factor(${\eta}_s$) and resonant frequency(${\omega}_r$) were considerably large. The thicker the viscoelastic layer in a sandwich beam, the larger the system loss factor in Mode 1 as compared with that in Mode 2. The loss factor increased almost linearly with increasing the length of partial viscoelastic layer. Effects of thickness of beams were also considered.

• Journal of electromagnetic engineering and science
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• 제5권2호
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• pp.66-71
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• 2005

The purpose of this paper is to present the complex antenna factor of an EMI dipole antenna with a balun consisting of two coaxial feeders(coaxial cable balun) for measuring electromagnetic fields. A new formula of complex antenna factors for an EMI antenna with coaxial cable balun is derived using by power loss concepts. The complex antenna factor shows that the present result in this study was identical with that of the result from S-parameters. The theoretical complex antenna factors derived by power loss concepts are in good agreement with the experiments.

• 한국소음진동공학회논문집
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• 제19권5호
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• pp.530-536
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• 2009

In this paper, the power flow analysis(PFA) has been used to analyze the vibration of a plate covered with a damping sheet. Experiments have been performed to measure the loss factor and frequency response functions of the plate covered with the damping sheet. The data for the loss factor has been used as the input data to predict the vibration of the coupled plates with PFA. The comparison between the experimental results and the predicted PFA results for the frequency response functions has been performed. It showed that PFA can be effectively used to predict structural vibration of a plate covered with a damping sheet in medium-to-high frequency range.

• 한국농공학회논문집
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• 제48권2호
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• pp.59-66
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• 2006

This study is performed to evaluate freezing and thawing properties of polypropylene fiber reinforced eco-concrete using soil, natural coarse aggregate, soil compound and polypropylene fiber. The mass loss ratio is decreased with increasing the content of natural coarse aggregate and soil compound, but it is increased with increasing the content of polypropylene fiber. The ultrasonic pulse velocity, dynamic modulus of elasticity and durability factor are increased with increasing the content of natural coarse aggregate and soil compound, but it is decreased with increasing the content of polypropylene fiber. The mass loss ratio, ultrasonic pulse velocity, dynamic modulus of elasticity and durability factor are $1.49{\sim}3.32%,\;1,870{\sim}2,465\;m/s,\;77X10^2{\sim}225X10^2\;MPa\;and\;84.6{\sim}92.8$ after freezing and thawing 300 cycles, respectively. These eco-concrete can be used for environment-friendly side walk and farm road.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.496-497
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• 2009

In this paper the power flow finite element method (PFFEM) has been used to analyze the vibration of a plate partially covered with a damping sheet. Experiments have been performed to measure the loss factor and frequency response functions of the plate partially covered with the damping sheet. The data for the loss factor has been used as the input data to predict the vibration of the coupled plates with PFFEM. The comparison between the experimental results and the predicted PFFEM results for the frequency response functions has been performed. It showed that PFFEM can be effectively used to predict structural vibration in medium-to-high frequency ranges.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.1192-1196
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• 2001

Damping materials show variant characteristics depend on frequency or temperature condition. Therefore, we need to measure damping material characteristics called a loss factor or a young's modulus varying frequency or temperature condition. In this article, measuring procedure and method has been introduced for damping material using a sticking damping material with a thin steel beam. And it shows a temperature effect to damping materials.