• Earthquakes and Structures
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• 제9권5호
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• pp.1091-1114
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• 2015

The adequacy of a number of advanced earthquake Intensity Measures (IMs) to predict the structural damage of earthquake resistant 3D R/C buildings is investigated in the present paper. To achieve this purpose three symmetric in plan and three asymmetric 5-storey R/C buildings are analyzed by nonlinear time history analysis using 74 bidirectional earthquake records. The two horizontal accelerograms of each ground motion are applied along the structural axes of the buildings and the structural damage is expressed in terms of the maximum and average interstorey drift as well as the overall structural damage index. For each individual pair of accelerograms the values of the aforementioned seismic damage measures are determined. Then, they are correlated with several strong motion scalar IMs that take into account both earthquake and structural characteristics. The research identified certain IMs which exhibit strong correlation with the seismic damage measures of the studied buildings. However, the degree of correlation between IMs and the seismic damage depends on the damage measure adopted. Furthermore, it is confirmed that the widely used spectral acceleration at the fundamental period of the structure is a relatively good IM for medium rise R/C buildings that possess small structural eccentricity.

• 대한기계학회논문집
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• 제17권7호
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• pp.1710-1718
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• 1993

This paper investigates the problem of a crack approaching two circular holes in an orthotropic infinite plate. The stress intensity factors were obtained by using the modified mapping-collocation method. The present results show excellent agreement with existing solutions for a crack approaching two circular holes in an isotropic infinite plate. In the numerical examples, various types of cross-ply laminated composites were considered. To investigate the effect of orthotropy and geometry(d/R and a/(d-R)) on crack tip singularity, stress intensity factors were considered as functions of the normalized crack length. It is expected that the modified mapping-collocation method can be applied to the analysis of various kinds of cracks existing around the stress-concentration region of composite laminate.

• 마이크로전자및패키징학회지
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• 제23권3호
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• pp.37-41
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• 2016

본 논문에서는 긴 작동거리(working distance, WD)를 가지는 근적외선 형광 이미징 시스템을 소개하고, gain, 노출시간, 작동거리, 확대배율 등 측정 변수에 의한 형광 영상의 차이에 대해 분석하였다. 노출시간이 길수록, 확대배율이 클수록 형광신호는 더욱 강해지고, gain이 클수록 형광신호도 강해지지만, 배경신호도 함께 증가하여 SBR은 나빠질 수 있다. 제안한 시스템은 레이저 조사 방식으로 인해 작동거리가 짧은 경우 레이저 조사 영역의 강도 분포가 균일하지 못해서 형광신호가 약해지며, 그에 따른 해결방안을 제안하였다.

• 서비스연구
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• 제13권1호
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• pp.1-26
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• 2023

본 연구는 스마트공장 도입의 효과와 관련 요인을 분석하였다. 이를 위해 도입기업과 비도입기업의 표본 데이터를 median-size-industry matching method로 각각 110개, 325개를 수집했다. 도입 전년부터 도입 후 4년도까지 재무제표 데이터(ROA 등)를 활용했는데 event study method에 따른 abnormal operating performance, annual abnormal changes를 구한 뒤 Wilcoxon signed-rank test와 t-test로 분석했다. ROA와 매출증가율은 도입 후 단기적인 효과가 나타났으나 장기적으로 이어지지는 않았다. 또한 도입효과에 인력비중, 연구개발 수준, 이전 재무 성과 세 가지 요인이 조절효과로 영향이 있는지 회귀분석을 한 결과 연구개발 수준과 이전 재무 성과의 조절효과를 확인했다. 도입 효과에 도입시기의 영향과 이와 관련된 요인으로 이전 재무 성과와 기업규모의 조절효과가 있는지 회귀분석을 한 결과 장기에 도입시기가 늦을수록 도입효과가 더 커졌고, 이전 재무 성과와 기업규모의 조절효과를 확인했다.

• Journal of Mechanical Science and Technology
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• 제20권3호
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• pp.319-328
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• 2006

A simple approximation method for the stress intensity factor at the tip of the axial semielliptical cracks on the cylindrical vessel is developed. The approximation methods, incorporated in VINTIN (Vessel INTegrity analysis-INner flaws), utilizes the influence coefficients to calculate the stress intensity factor at the crack tip. This method has been compared with other solution methods including 3-D finite element analysis for internal pressure, cooldown, and pressurized thermal shock loading conditions. For these, 3-D finite-element analyses are performed to obtain the stress intensity factors for various surface cracks with t/R=0.1. The approximation solutions are within $\pm2.5%$ of the those of finite element analysis using symmetric model of one-forth of a vessel under pressure loading, and 1-3% higher under pressurized thermal shock condition. The analysis results confirm that the approximation method provides sufficiently accurate stress intensity factor values for the axial semi-elliptical flaws on the surface of the reactor pressure vessel.

• 한국경영과학회지
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• 제11권2호
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• pp.7-12
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• 1986

The problem of strategic R & D investment is formulate as a differential game model and solved explicity for a special case. It is shown that, at equilibrium, an increase in the intensity of market competition or a decrease in the role of technology transfer results in an increase in the initial rate of investment by competing tfirms. The increased initial investment rate may enhance the rate of technology development. This dynamic model can be used to propose non cooperative R & D investment policies in technologically competitive situation.

• 품질경영학회지
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• 제42권3호
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• pp.477-496
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• 2014

Purpose: This paper has examined the impact of open innovation business model in technology commercialization with the data from 30 companies of manufacturing firms in South Korea. Methods: The findings provide support for distinguishing five hypotheses relating to development time, IP management, sales, firm size and R&D intensity. To test the hypotheses, data were collected using via e-mail and fax. Small and medium-sized (less than 300 employees) and large industrial firms were chosen for this study. Results: The result shows that openness in its business model is positively associated with successful technology commercialization. Conclusion: The major findings and the implications are: First, as the business model gets more open, development period of technology will be more favorable which gets benefit from rising costs of innovation. Second, as the business model gets more open, large portion of sales are created from new products. Thus, the problem of shorter product life in the market which affects large portion of market revenue can be solved through an open business model. Third, in general, R&D intensity, firm size and the level of IP management affect determination of business model types. The findings also suggest that companies need to increasingly address their external technology exploitation process instead of focusing on their internal innovation processes.

• 기술혁신학회지
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• 제13권1호
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• pp.124-139
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• 2010

본 연구는 과학기술정책연구원이 지난 2008년도에 조사한 '기술혁신조사(KIS) 2008'의 원자료를 활용하여, 2005년부터 2007년까지 국내 제조업 기업들이 이루어낸 혁신의 결정요인에 대해 분석하였다. Probit 모형을 활용한 실증분석 결과 기업규모와 시장집중도가 기업의 기술혁신 활동을 유인하는 주요 결정요인이라는 슘페터 가설을 지지하는 연구결과를 얻었다. 또한 기업이 수행하는 연구개발 활동 역시 혁신을 촉진할 수 있는 요인으로 나타났다. 이와 함께 시장에 있어서 소비자지향성의 척도라 할 수 있는 광고 선전비 집약도가 혁신이 일어날 확률에 긍정적인 영향을 주는 것으로 추정되었다.

• 센서학회지
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• 제30권1호
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• pp.56-60
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• 2021

In this study, the relationship between the transmitted light intensity and full-width-at-half-maximum (FWHM) of a Fabry-Perot filter was investigated. The measured refractive indices and absorption coefficients of the fabricated thin films were applied to the Fabry-Perot filter via simulations using optical software. Although considerable research has been conducted on Fabry-Perot filters, this study focused on the usefulness of 4.26-㎛ infrared filtering in carbon dioxide detection. Optical analysis was performed considering the effects of the thickness, refractive indices, and number of thin films in a distributed Bragg reflector. Ultimately, a clear trade-off relationship was observed wherein the transmitted light intensity decreased as the number of multilayers increased; however, the FWHM was observed to be narrower.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.167-170
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• 2002

We have proposed new pixel structures for Active Matrix OELD (AMOELD) to improve the uniformity of luminance and manufactured a full-color 3.6-inch QVGA AMOELD. The proposed pixel structures, composed of four TFTs and one capacitor, can display 64 gray scales by compensating threshold voltage (Vth) variation of driving TFTs. Nonuniformity and peak intensity of measured luminance are under 14% and over $200cd/m^2$, respectively.