• Current Optics and Photonics
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• 제2권5호
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• pp.482-487
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• 2018

We investigate the radiation characteristics of radially polarized light and azimuthally polarized light through plasmonic subwavelength-scale annular slit (PSAS) structures, by means of both theoretical and numerical methods. Effective-medium theory was utilized to analyze the characteristics of PSAS structures, and the corresponding results showed that PSAS structures can function as a metallic medium for azimuthally polarized light, or as a low-loss dielectric medium for radially polarized light. Numerical calculations based on the finite-element method were also performed, to verify the theoretical analyses. It turned out that the numerical results supported the theoretical results. Moreover, we exploited the PSAS structures in novel nanophotonic elements with dual functionalities that could selectively focus or pass/block incident light, depending on its polarization state. For example, if PSAS structures were implemented in the dielectric region of a metallic Fresnel zone plate, the modified zone plate could function as a blocking element to azimuthally polarized light, yet as a focusing element to radially polarized light. On the contrary, if PSAS structures were implemented in the metallic region of a metallic Fresnel zone plate (i.e. the inverted form of the former), it could function as a focusing element to azimuthally polarized light, yet as a simple transparent element to radially polarized light.

• 비교문화연구
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• 제45권
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• pp.497-517
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• 2016

This paper interrogates the theoretical foundations of Cross-Cultural Studies across the Social Sciences through an examination of the field ELT. Through an examination of ELT's major theoretical and pedagogical moves, this paper illustrates how ELT is by nature a field of cross-Cultural Studies. A closer examination of the history of ELT shows how the colonial genesis of the field indicates a skewed representation of power between native English speaking nations and non-native speaking nations both in terms of academic theories and pedagogies, as well as socio-cultural relations of power. A further analysis of how the field theorizes and represents various relations of power between disparate cultures in ELT literature explicates the dilemma of the objectivity and neutrality of Cross-Cultural research in ELT. In doing so, the analyses included in this paper thus necessarily raises questions regarding the theoretical foundations of research methodologies of Cross-Cultural Studies in terms of the reflexivity of researchers and the problematic of how, or if, relations of power are included in the studies. This paper questions whether studies that do not include these research perspectives properly represent the disparate cultures under study, or are more of a biased, or Orientalized (Said, 1979) interpretation of cultures.

• Steel and Composite Structures
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• 제47권4호
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• pp.455-466
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• 2023

To investigate the load bearing capacity of axially preloaded circular hollow section (CHS) stub columns strengthened by carbon fiber reinforced polymer (CFRP), theoretical analysis is carried out. The yield strength and the ultimate strength of a CFRP strengthened preloaded CHS stub column are determined at the yielding of the CHS tube and at the CFRP fracture, respectively. Theoretical models are proposed and corresponding equations for calculating the static strengths, including the yield strength and the ultimate strength, are presented. Through comparison with reported experimental results, the theoretical predictions on the static strengths are proved to be accurate. Through finite element (FE) analyses, parametric studies for 258 models of CFRP strengthened preloaded CHS stub columns are conducted by considering different values of tube diameter, tube thickness, CFRP layer and preloading level. The static strengths of the 258 models predicted from presented equations are proved to be in good agreement with FE simulations when the diameter-to-thickness ratio is less than 90ε². The parametric study indicates that the diameter and the thickness of the steel tube have great effects on CFRP strengthening efficiency, and the recommended ranges of the diameter and the thickness are proposed.

• 대한조선학회논문집
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• 제59권6호
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• pp.400-412
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• 2022

This paper provides the results of numerical and theoretical predictions of oil outflows from damaged single-hull and double-hull ships.Theoretical equations derived from the unsteady Bernoulli equation and a CFD method for multi-phase flow analysis were used to estimate the oil outflow rate from cargo tank. The predicted oil outflow rate from a single-hull cargo tank damaged due to grounding and collision accidents showed a good agreement with the available experimental results in both numerical and theoretical analyses. However, in the case of the double-hull conditions, the time variation of the amount of water and oil mixture inside the ballast tank predicted by the theoretical equation showed some different behavior from the numerical results. The reason was that the interaction of the oil flow with the water inflow in the ballast tank was not reflected in the theoretical equations. In the problems of the initial pressure condition in the cargo and ballast tanks, the oil outflow and water inflow were delayed at the pressure condition that the tanks were sealed. When the flow interaction between the oil and water in the ballast tank was less complicated, the theoretical and the numerical results showed a good agreement with each other.

• 대한전자공학회논문지SD
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• 제38권11호
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• pp.781-790
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• 2001

실리콘 웨이퍼 두께에 따른 PZT 박막 적외선 감지소자의 성능변화를 이론적 해석 및 실험적 검증을 통하여 분석하였다. 실리콘이 모두 식각되었을 때 최대값을 보이는 전류응답도는 소자의 뒷면에 남아있는 실리콘의 두께가 50㎛로 두꺼워질 때까지 기하급수적으로 줄어들다가, 그 이상의 두께에서는 전류응답도의 감소폭이 현저히 줄어들었다. 실리콘이 모두 식각된 적외선 감지소자는 450㎛두께의 실리콘이 남아있는 소자에 비해 100배 이상의 높은 전류응답도를 보였다. 이러한 이론적인 해석을 검증하기 위하여 실리콘 기판미세가공법을 이용하여 세 가지 다른 실리콘 두께를 가진 적외선 감지소자를 제작하였다. 제작한 소자에서 측정한 전류응답도의 변화는 이론적 해석값과 좋은 일치를 보였다. 한편, 실험을 통하여 실리콘 두께가 소자의 전류응답도 뿐만 아니라 응답속도에도 큰 영향을 준다는 것을 확인하였다.

• 한국항공우주학회지
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• 제42권7호
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• pp.552-560
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• 2014

Pulse Detonation Engine (PDE)는 압축 효과에 따른 효율 증가와 정지 상태로부터 높은 초음속구간까지 작동가능하다는 등의 장점으로 인해 차세대 고속추진기관으로 많은 연구가 진행되고 있다. 본 연구에서는 Chapman-Jouguet 데토네이션 이론과 일정 단면적의 관내 압축성 기연 가스 팽창과정을 연계한 Endo 이론을 바탕으로 실제 추진제에 대한 효율적인 PDE 이론 성능 예측 프로그램을 개발하였다. 성능 예측 프로그램은 탄도진자 측정을 통하여 얻은 실험 결과와 비교를 통하여 검증하였다. 이 프로그램을 이용하여 당량비, 초기압력 및 초기 온도 및 압력에 대한 성능 특성을 살펴보았고 다양한 탄화수소 연료, 산화제 조성에 대한 성능을 해석하여 PDE 이론 성능 데이터베이스를 구축하였다.

• 대한토목학회논문집
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• 제28권2C호
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• pp.133-141
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• 2008

토목섬유보강 성토지지말뚝시스템에서 지반아칭에 의한 하중전이 특성을 규명할 수 있는 이론해석법을 개발하였다. 이론해석 결과, 성토지지말뚝에 토목섬유가 복합시공되면, 말뚝의 효율이 증가하였으며, 효율의 증대효과는 지반아치가 완전히 발달하기 이전인 저성토 구간에서 특히 두드러지게 나타났다. 또한, 이론해석법에 의한 하중전이는 말뚝의 간격, 성토고, 지반정수 및 토목섬유에 크게 영향을 받고 있다. 즉, 말뚝의 간격이 증가하면 말뚝의 효율은 감소하며, 성토고, 성토지반의 내부마찰각 및 토목섬유의 강도가 증가하면 효율이 커지게 된다. 이와같은 해석결과는 본 제안식이 토목섬유보강 성토지지말뚝시스템에서의 지반아칭효과를 잘 설명해주는 합리적인 해석법임을 나타내고 있다.

• 감성과학
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• 제20권2호
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• pp.149-160
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• 2017

가설검증 과정에서 자료 분석 결과 산출된 통계치에 대한 해석은 몇 가지 통계학적 이론을 토대로 분석 결과 산출된 관련 통계치의 이론적 확률 분포에 의해 좌우된다. 예를 들어 실험 조건 간 측정치의 평균 차이에 대한 통계적 유의미성은 대개 전집 특성에 대한 몇 가지 이론적 가정에 기초해 구성된 해당 평균 차이값의 확률 분포(예: Student's t)에 기초해 결정된다. 본 연구는 이러한 이론적 통계치의 분포가 아닌 실측정 자료의 무선 재구성을 통해 얻어진 경험적 통계치의 분포에 기초해 가설 검증을 시도하는 무선재추출법의 기본 논리와 장점을 살펴보고 사건관련전위 분석 상황에서의 응용 가능성을 모색하였다. 더 나아가 무선 추출 원리에 기초한 무선치환법이 적용된 구체적 사례를 소개하고 ERP 자료 분석에 있어서 경험적 통계 분석 적용에 앞서 유의할 점을 살펴봄으로써 뇌파 연구자들의 무선재추출법에 대한 정확한 이해를 도모하였다.

• Computers and Concrete
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• 제11권2호
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• pp.169-182
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• 2013

One of the major benefits of the pre-stressed concrete pavements is the omission of tension in concrete that results in a reduction of cracks in the concrete slabs. Therefore, the life of the pavement is increased as the thickness of the slabs is reduced. One of the most important issues in dealing with the prestressed concrete pavement is determination of the magnitude of the pre-stress. Three dimensional finite element analyses are conducted in this research to study the pre-stress under various load (Boeing 777) and thermal gradient combinations. The model was also analyzed under temperature gradients without the presence of traffic loading and the induced stresses were compared with those from theoretical relationships. It was seen that the theoretical relationships result in conservative values for the stress.

• International Journal of Quality Innovation
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• 제9권1호
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• pp.55-67
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• 2008

Following this introduction, this paper presents two conceptual and theoretical analyses-(i) CSR and its relation to profit and charity (ii) CSR as part of a service business model. The paper then illustrates these concepts using a comparative study of four service firms, with particular emphasis on their different CSR activities and how these affect the mission of each company. All four of the service companies are global actors with strong Service Brands (Edvardsson, Enquist and Hay, 2006) and a leading position in using CSR as a driving force for doing business: IKEA, Starbucks, H&M and the Body Shop. The paper then draws together the conceptual analysis and the case studies in a discussion of how CSR can be a proactive driver in the service business. Because of the limit space for a QMOD paper the focus is on the conceptual and theoretical analysis part and the empirical part and discussion/conclusion has to be further developed.