• Smart Structures and Systems
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• 제29권3호
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• pp.485-498
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• 2022

In near-fault earthquake prone areas, the velocity pulse-like seismic waves often results in excessive horizontal displacement for structures, which may result in severe structural failure during large or near-fault earthquakes. The recently developed isolator-gap damper (IGD) systems provide a solution for the large horizontal displacement of long period base-isolated structures. However, the hysteresis characteristics of the IGD system are significantly different from the traditional hysteretic behavior. At present, the hysteretic behavior is difficult to be reflected in the structural analysis and performance evaluation especially under random earthquake excitations for lacking of effective analysis models which prevent the application of this kind of IGD system. In this paper, we propose a mathematical hysteretic model for the IGD system that presents its nonlinear hysteretic characteristics. The equivalent linearization is conducted on this nonlinear model, which requires the variances of the IGD responses. The covariance matrix for the responses of the structure and the IGD system is obtained for random earthquake excitations represented by the Kanai-Tajimi spectrum by solving the Lyapunov equation. The responses obtained by the equivalent linearization are verified in comparison with the nonlinear responses by the Monte Carlo simulation (MCS) analysis for random earthquake excitations.

• Journal of the Korean Data and Information Science Society
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• 제19권3호
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• pp.893-901
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• 2008

The disconfirmation paradigm is the earliest researched and the most deeply researched of all the paradigms in marketing. Disconfirmation paradigm deals with the influence of expectation, perceived product performance, and the discord between the two on consumer satisfaction. The GAP-Model is based on the disconfirmation paradigm that tries to understand the effect of the gap between before purchase expectations and after purchase perceptions of the product performance on dependent variables such as customer satisfaction. The purpose of this research is to test whether regression coefficients of a P-Model(performance only model), an E-Model(expectation only model) and GAP(P-E)-Model are equivalent in explaining service value and loyalty. The Chow's F-Test is used to test the excellence of the 3 models. As a result of comparison and analysis, P-Model showed more excellence of service value and loyalty than E-Model or GAP-Model.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권3호
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• pp.139-144
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• 2005

[ $SF_6$ ] gas circuit breakers are widely used short circuit current interruption in EHV or UHV power system. For a $SF_6$ gas circuit breaker development, the $SF_6$ gas velocity measurement is necessary during $SF_6$ circuit breaker's trip operation. Small-gap flashover characteristics are used for this measurement. So, small-gap measuring system which will be used to develope GCB should be developed. This study shows the characteristic analysis and experimental results of small-gap measuring system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.202-207
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• 2003

In the paper, the noise reduction characteristics of a double-gap resonator, which is installed inside an enclosed cavity and is composed of two air-gaps and two partition sheets, are introduced by theoretical analyses and experimets. Analysis for a simple, theoretical model reveals that the double-gap resonator is more effective than the single-gap resonator that consists of an air-gap and a partition sheet, in that the former requires a smaller space than the latter. Furthermore, this theoretical conclusion is verified by comparison experiments using an actually manufactured enclosed cavity, of which the boundary surfaces are made of thick, stiff panels that can be assumed as rigid walls.

• 대한전기학회논문지
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• 제40권7호
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• pp.643-655
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• 1991

The analysis method on air gap permeance distribution, air gap MMF distribution, air gap flux density distribution, cogging torque and BEMF about the skewed stator slots or the skewed rotor magnet segments for BLDCM, respectively, is studied as a function of the skew ratio. The proposed method describes the differences between the skewed stator slots and teh skewed rotor magnet segments for the air gap permeance distribution, air gap MMF distribution and air gap flux density distribution. The reliability of the method is also confirmed by the waveform of the cogging torque and BEMF through experiments. And the result shows that the effects on the cogging torque and BEMF due to the skewed stator slots or the skewed rotor magnet segments are the same. In case of the skewed stator slots, the effects of the variations of the winding resistance and inductance are also studied.

• 대한화학회지
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• 제67권3호
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• pp.175-180
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• 2023

Tetra-aryl substituted A4-type porphyrins (TP, TD, TA) and trans-A2B2 porphyrins (DDP1, AAP1) with electron-donating or withdrawing groups were synthesized. The band gap energy of those porphyrins was calculated from their UV-Vis spectra and CV data. With an electron-withdrawing group, the band gap energy of porphyrin TA increased via the LUMO energy up. Meanwhile, the introduction of an electron-donating group decreased the band gap of porphyrin by HOMO level up as as in the case of porphyrin TD. The band gap (2.19-2.28 eV) of metalloporphyrin PP-Ni was greater than those (1.81-2.06 eV) of non-metalloporphyrins PP due to the LUMO level up.

• Journal of the Korean Data and Information Science Society
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• 제26권6호
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• pp.1377-1386
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• 2015

한 나라 전체의 경제활동 수준을 나타내는 경기의 변동과 밀접한 관계를 지닌 지표로서 GDP갭을 꼽을 수 있다. GDP갭은 초과수요압력이나 고용사정에 대한 정보를 제공하기 때문에 중앙은행의 통화정책 수행시 중요한 고려변수로 꼽히고 있다. 그러나, GDP갭 총량만으로는 최근의 경제구조 변화라든지 대내외 경제여건의 영향 등을 살펴볼 수 없는 등 제한적인 부분이 있다. 본 논문에서는 통계적 필터링 기법에 의해 새로운 갭을 추정하고 다양한 물가영향 모형을 설정하여 각 요인들이 인플레이션에 미치는 영향력을 추정하는 한편 동 요인들의 영향력이 시간에 따라 변화하는지도 분석하였다. 분석결과, GDP갭의 물가영향력이 2000년대 들어 대체로 그 영향력이 축소되는 것으로 추정된 반면, 글로벌갭이 국내 물가에 미치는 영향력은 증대된 것으로 나타났다. 이러한 변화는 최근의 저물가 현상이 국내요인과 더불어 세계 경기침체에서 비롯된 수출의 둔화와 같은 국외여건에 영향을 받았다는 것을 의미한다.

• 한국건설관리학회논문집
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• 제13권5호
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• pp.125-134
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• 2012

건설산업에 있어서 녹색 또는 그린(Green)은 차세대 신 성장동력의 핵심적인 키워드로 부상하고 있다. 녹색건설 경쟁력을 갖추는 것은 건설기업의 생존과 발전을 위해 중요하며 이를 위해 녹색건설 경쟁력 요인에 대한 이해는 필수적이다. 본 연구의 목적은 건설기업이 녹색건설 경쟁력을 확보하기 위해 요구되는 경쟁력 요인을 발굴하고 Gap 분석 기법을 통해 경쟁력 요인의 중요도와 현 수준을 분석하여 주요 특징과 시사점을 도출하는데 있다. 녹색건설 경쟁력 요인에 대한 이해는 건설기업의 녹색건설 전략 수립을 위한 선행 작업이며 동시에 녹색건설 관련 정책 및 제도 수립에 있어 건설기업에게 어떤 동기부여를 해야 하는지를 이해하기 위해 필수적이다. 본 연구를 통해 나타난 주요 결과를 요약하면, 첫째, 녹색건설 경쟁력의 중요도와 현 수준을 분석한 결과 중요도와 비교하여 현 수준이 모두 낮은 것으로 나타났다. 둘째, 녹색건설 경쟁력의 중요도와 현 수준 관점에서 CEO 역량 부문은 큰 격차가 없는 것으로 나타났지만 기업 역량 부문에서는 큰 격차가 있는 것으로 나타났다. 셋째, 녹색건설의 R&D 전략과 녹색건설 협력업체의 보유 및 협업 역량이 중요도와 현 수준의 차이(Gap)가 가장 크게 나타났다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.943-946
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• 2007

The vibration and noise characteristic of the Axial-gap motor for an air conditioner were analyzed. Experimental Modal Analysis was performed to understand the vibration characteristic of the motor. The noise of motor was measured in a dead room. Finite Element Method was performed to find the vibration characteristic of the motor by using ABAQUS program.

• 대한기계학회논문집A
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• 제33권10호
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• pp.1038-1044
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• 2009

In this study, vibrations of an electric motor are analyzed when the motor has the interaction between mechanical and electromagnetic behaviors. For this vibration analysis a 3-phase 8-pole brushless DC motor is selected. Vibrations of the motor are influenced by coupled electromechanical characteristics. The variation of air-gap induced by vibration has an influence on the inductance of the motor coil. To analyze dynamic characteristics of the rotor, we studied inductance by the variation of an air-gap. After obtaining the kinetic, potential and magnetic energies for the motor, the equations of motion are derived by using Lagrange's equation. By applying the Newmark time integration method to the equations, the dynamic responses for the displacements and currents are computed.