• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.724-730
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• 2000

Although there have been many investigations employing the continuous wavelet transform for the analysis of dispersive waves, they seem to lack theoretical justifications for the effectiveness of the continuous wavelet transform over other time-frequency analysis tools such as the short-time Fourier transform. The goal of this paper is to answer this question by investigating theoretically the performance of the continuous wavelet transform and the short-time Fourier transform in tracing rapidly time-varying flexural waves. As a specific example, the performance of the two transforms is compared in a problem dealing with flexural waves generated by an impact in a solid circular cylinder.

• 한국가시화정보학회지
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• 제2권2호
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• pp.38-44
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• 2004

Theoretical and numerical studies are given to the sink flows within a rotating circular tank driven by the fluid withdrawal from a bottom circular hole. It was found that, when the upper free surface was set with no-slip boundary conditions, the Ekman boundary-layer develops not only above the bottom surface but under the top surface. The sink fluid is coming from the two Ekman layers, and the mass transfer from the bulk, inviscid region is dependent on the rotational speed. It is also remarkable to see that all the fluid gathered along the axis flows in a form of rapidly rotating fluid column haying almost the same diameter as the bottom hole.

• 한국생활과학회지
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• 제5권2호
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• pp.53-72
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• 1996

This article reviewed the research on factors associated with marital quality and stability. Three major categories of factors were described, including background and context, individual traits and behaviors, and couple interactional processes. This review highlighted findings from cross-sectional and longitudinal studies of the prediction of marital quality and stability. Particular attention was given to marital instruments and procedures that had a solid empirical foundation for understanding the concepts related to measure of marital quality and stability. Also, empirically based intervention programs that had been designed to prevent marital distress and divorce were investigated to figure out the relationship between communication factors and conflict resolution styles. Finally, three theoretical frameworks were drawn from empirical literatures, marital measurment instruments, and programs for marital strength to predict factors associated with the marital quality and stability. Recommendations for future research and implications were described.

• Korean Journal of Mathematics
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• 제22권4호
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• pp.645-658
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• 2014

Many projection methods have been progressively constructed to find more accurate and efficient solution of the Navier-Stokes equations. In this paper, we consider most recently constructed projection methods: the pressure correction method, the gauge method, the consistent splitting method, the Gauge-Uzawa method, and the stabilized Gauge-Uzawa method. Each method has different background and theoretical proof. We prove equivalentness of the pressure correction method and the stabilized Gauge-Uzawa method. Also we will obtain that the Gauge-Uzawa method is equivalent to the gauge method and the consistent splitting method. We gather theoretical results of them and conclude that the results are also valid on other equivalent methods.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제5권1호
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• pp.77-86
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• 2001

The purpose of this study is to examine a theoretical framework for the interactions of learning in a small group setting of mathematical problem solving. Many researchers already have described the theoretical background for the small group settings in problem solving. However, most of the literatures merely have reported findings of achievement and rising of test scores. They ignored the observation of process taken during the small group work and have not determined how various psychological, social and academic effects are created. As results of the study, two types, mutual collaboration and asymmetric collaboration, of interactions are observed as the interactions of learning, which are conceived as the cores of authentic mathematical activities.

• 천문학회보
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• 제39권1호
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• pp.32.1-32.1
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• 2014

Astronomical observations strongly suggest that the expansion rate of our universe is currently under acceleration. The nature of the so-called dark energy causing the acceleration is unknown, and it is one of the fundamental mysteries in the present day theoretical cosmology. Here we briefly review the current state of cosmic dark energy research in both theoretical and observational sides. Constraints on dynamical dark energy models (e.g., w-fluid, quintessence, and modified gravity) with recent observational data from type Ia supernovae, cosmic microwave background radiation, and large-scale structures in the universe indicate a preferred direction toward the simplest ${\Lambda}$CDM world model. We also discuss some issues regarding the early dark energy model and the spherical collapse of matter in the presence of dark energy.

• 한국실내디자인학회논문집
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• 제23권4호
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• pp.129-139
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• 2014

The objective of this research is to suggest new geometric possibilities in digital architecture by investigating the characteristics of hybridization in digital geometry. The research begins with theoretical background research such as defining hybridization, investigating hybrid thinking, and studying the theory of digital geometry, along with the four conceptual characteristics of hybridization that could be drawn, such as temporality, liquidity, complexity, and connectivity. Based on these characteristics, the generative method of hybrid digital geometric languages such as Blob, Particle, Morph, Loft, and Boolean was analyzed with case research in contemporary digital architecture. As a result, diverse hybrid geometric keywords were extracted; these keywords suggest potential meanings of hybridization such as accidentality, mobility, diversity, and identity. Different elements represent the "mobility" in time by the force and wave, and they are "accidentally" combined in gradual change. The united species in "diverse" characters are seamlessly connected and emerge as a new "identity." The research maximizes the generative possibilities in digital geometry and provides a theoretical basis to apply the digital hybrid methods to architectural design by suggesting the potential meanings and possibilities in hybridization.

• 복식문화연구
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• 제14권6호
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• pp.877-886
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• 2006

The Purpose of this study were to study Retro-hat design. To do these purposees, the focus of theoretical approach was literature research, and hat design was attempted on the basis of the research. The focus of theoretical background was on previous research and fashion-related literature. Photo materials to analyze retro-hat design is Haute-Couture collection in paris from the 1990's to 2004 and some designer's collections. Then Retro hat design is 85 in 1,381 hat photos. The results obtained through this process were as follows. In the hats of Retro, the past style such as an Egyptian wig, a snake-shaped hat in Crete, a Medieval knight hat, Liripipe, Tricorn hat, or Bicorn hat was reinterpreted and expressed. Since 2003, Retro characteristics has became strong and frequent. By designing a hat on the basis of the direction of hat design, this study intended to find out the development direction of hat design.

• Nuclear Engineering and Technology
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• 제14권2호
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• pp.64-69
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• 1982

동시섬광분석기를 써서, 각도범위 90$^{\circ}$에서 180$^{\circ}$에 대하여, Co-60 및 Cs-134 감마선의 방향상관을 측정하였다. 그리고, 방향-편극상관의 측정에는 컴프턴산란효과를 응용한 감마선 편광분광기를 병용하였다. 이론적인 배경과 더불어 실험방법이 기술되었으며, 측정값이 이론적인 개산치와 일치함을 보이기위해 실험결과를 도식적으로 나타내었다.

• 디지털산업정보학회논문지
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• 제20권1호
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• pp.119-131
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• 2024

The purpose of this study is to examine the operational performances by the investment level of information security in companies. The theoretical background summarized the meaning of information security, management information security, and network security. The research process was carried out in four stages. As a result of the analysis, the level of information security was classified into four groups, and the difference in operational performance was confirmed. According to the categorical regression analysis of the three dependent variables, independent variables such as network threats, non-network threats, executive information security awareness, industry, organizational size, and information security education all affected information security regulations, in-house information security checks, and information security budget investments. The theoretical implications of this study have contributed to updating the latest information security theory. Practical implications are that rational investments should be made on the level of information security of companies.