• Current Optics and Photonics
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• v.2 no.5
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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.

• Journal of Astronomy and Space Sciences
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• v.15 no.2
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• pp.297-306
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• 1998

Photoelectric observations of the neglected eclipsing binary VZ Cep were made on four night during the observing season of 1984 at Sobaeksan Astronomy Observatory. The UBV light curves were secured incompletely with the gap in 0.35-0.75 phases. From the observations three times of minimum lights were determined in three band-passes, which formed one weighted minimum epoch (JD Hel 2446009.0453). With our observations, and improved light elements for VZ Cep is determined using all the photoelectric and CCD times of minimum lights published so far. The (O-C) resid-uals calculated with our light elements show small varying scatters which cannot be negligible. From the analyses of all the times of minima with the Scargle’s(1982)period-searching and a curve fitting methods, we found possible periodic oscillations of the (O-C) residuals with the period of 1. y26 and the amplitude of 0.d0032. These results, however, have to be considered as a preliminary values until complete analysis for the minimum lights of VZ Cep with enough observational data. Future observations of this binary system are urgently prompted.

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.135-136
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• 2009

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.2
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• pp.193-204
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• 2002

Many fashion forecasting companies propose the fashion colors in every season. Modern fashion consumer respond to fashionable trends with utmost sensitivity. Therefore to satisfy the consumer with an trendy image, the fashion design must be found first, as image matters, followed by an analysis of each design element's effect on the total image composition. In previous studies of fashion image, has been discussed the positive correlation between fashion design elements of color, fabric, and form as the central issue. In this thesis, two of the fashion design elements, color and fabric are simultaneously considered to classify the image of fabric in fashion. For the color variables, 10 hues are selected from Munsell's system of color notation, and 12 tones from PCCS color notation., which are currently used in the domestic fashion industry. Texture variables used in this survey are classified by luster, prominence-depression of surface, thickness, and density of fabric. Graduate students from 20 to 50 years old and the specialists in fashion companies participated in the survey. The results of this survey are as follows: 1. The fashion fabric image is classified as 5 main images: 'elegant', 'comfortable', 'characteristic', 'light'and 'simple'. 2. The influence of hue, tone and texture is significant to the fashion fabric image. Following colors, yellow-red, red hues and light grayish, dark grayish tones convey the elegant image. The texture property for the elegant image is luster, thin and low density. Properties of fabric conveying the comfortable image are yellow-red and green-yellow hue, soft, light tones, matte and high density. Furthermore, hue turned out to be a insignificant variables for the unique image, whereas dark grayish, grayish tone, luster and prominent texture convey a unique image. For light image, properties of fabric are blue-green, purple hues, light, bright tones with thin, low density texture. Properties of fabric conveying the simple image are blue-green, purple-blue, green-yellow hues, and strong, vivid tones, with luster and flat texture.

• Journal of The Korean Astronomical Society
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• v.51 no.2
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• pp.27-36
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• 2018

In a solar coronagraph, the most important component is an occulter to block the direct light from the disk of the sun. Because the intensity of the solar outer corona is $10^{-6}$ to $10^{-10}$ times of that of the solar disk ($I_{\odot}$), it is necessary to minimize scattering at the optical elements and diffraction at the occulter. Using a Fourier optic simulation and a stray light test, we investigated the performance of a compact coronagraph that uses an external truncated-cone occulter without an internal occulter and Lyot stop. In the simulation, the diffracted light was minimized to the order of $7.6{\times}10^{-10}I_{\odot}$ when the cone angle ${\theta}_c$ was about $0.39^{\circ}$. The performance of the cone occulter was then tested by experiment. The level of the diffracted light reached the order of $6{\times}10^{-9}I_{\odot}$ at ${\theta}_c=0.40^{\circ}$. This is sufficient to observe the outer corona without additional optical elements such as a Lyot stop or inner occulter. We also found the manufacturing tolerance of the cone angle to be $0.05^{\circ}$, the lateral alignment tolerance was $45{\mu}m$, and the angular alignment tolerance was $0.043^{\circ}$. Our results suggest that the physical size of coronagraphs can be shortened significantly by using a cone occulter.

• Korean Institute of Interior Design Journal
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• v.24 no.4
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• pp.43-50
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• 2015

In lighting design and lighting in the light of how the physical space rather than the amount of light metering is implemented in the same space as horizontal illuminance and luminance study of the spatial analysis as a basis for improving the quality of scientific and cognitive aspects analyzed the vertical component of the light. Vertical component of the light and the ability to interpret the information space can be secured more easily sense the brightness of a small area compared to the horizontal components of electrical energy, due to the contrast between the dark and the surrounding induce customers to public facilities or commercial space The pedestrian aids to facilitate the determination of the copper. In addition, to secure the brightness of the overall sense of space allows to have a sense of comfort to lower the tension of the space. The vertical component of light also has a deep relationship to improving the quality of light in electrical energy savings increase the accessibility of space, space, nightscape in the humanities also contribute to environmental and looking for one trillion people in the city in terms of cultural development and identity There.

• Korean Institute of Interior Design Journal
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• v.18 no.2
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• pp.41-49
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• 2009

Contemporary design environment is formed with image-centered trend based on pluralism. In this point of view, enterprises' building lobbies are public places containing the equivocal meaning, actively utilizing light as a design element to express the image of enterprises' identifications. Light is an immaterial entity having unlimited possibilities and potentials on space. It also acts as media to activate spaces and create new images in connection with formative elements of space. This study is to figure out how lightings are expressed and affected the formative characteristics of office lobby spaces and activate the specific characteristics of spaces. As a result, we drew conclusions as follows. First, as state-of-the-art technology and media are introduced, light is expressed on spaces as floating, direction, rhythm, silhouette, metaphor and allusion, sense of depth and volume. Second, expressive aspects of light in lobby space are embodiment of light, substantiation of immateriality, standing of materiality from the perspective of spatial aesthetics, and distortion/transformation of shape, pluralism phenomena of space from the perspective of spatial structure. In this way, light on building lobbies which are greatly required design differentiation strategy, specializes space and also integrates all the designs as not only a functional element but also a mental, psychological, formative element. Consequently, light on lobby spaces induces communication between spaces and users, makes formative value of existence in itself, and presents the characteristics of differentiated enterprises' identities.

• Journal of the Korean housing association
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• v.28 no.1
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• pp.19-26
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• 2017

The purpose of study developing Development evaluation methods of light environment for indoor of middle school based on 'Biophilia'. This study is mainly based on literary review and survey research. To construct structural questionnaire based on 'Light and Space' of Biophilic Design for well being lighting environmental evaluation. We construct structural questionnaire that have 10 evaluation factors and 60 detail evaluation items to evaluate lighting environment for indoor of middle school based on biophilia theory. To survey students' subjective evaluation, the participant of study has been selected with the total number of 232 middle school students. The data were analyzed using Multiple Regression Analysis by IBM SPSS statistics 21. The result of pearson correlation analysis between satisfaction of indoor light environment and school life satisfaction, satisfaction of the whole indoor light environment was found showing positive relationship with school life satisfaction. The results of light environmental evaluation were factor 3,6,8,9 was lower than others. This study was designed to suggesting an evaluation method of light environment of the school. Biophilia theory said when 10 evaluation factor are in harmony, light environment can be well-being. So, factor 3,6,8,9 that are important elements to increase the satisfaction of lighting environment are consider carefully for the plan of indoor lighting environment.

• Korean Institute of Interior Design Journal
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• v.17 no.4
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• pp.42-49
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• 2008

Design concepts of light can be divided into two respects, visual plastic and metaphysical meaning. The current research focuses on the second respect. The meaning of light is abstract characteristics(for example, divinity, spirituality, or image) ultimately expressed by visual plastic. Because it makes architectural space abundant, it have been expressed frequently in architectural space until now. The purpose of this paper is to conceptualize and explain and arrange the meanings of light in the category that have been expressed in architectural space from ancient to current. The method of this study is content analysis and case study, and this is supplement by theoretical consideration on the meaning of light(relationship between perception and meaning, elements to form meaning etc.). This study consists of three steps. Firstly, through the content analysis of existing literature and documents, 17 meanings of light are confirmed. Secondly, these 17 meanings are defined and explained in 3 categories(symbolic, esthetic, and experiential character). Thirdly, they are additionally explained and articulated by case study. In the result, various meanings of light that have been fragmentarily expressed in architectural space until now is clearly arranged at a glance. Those suggested design concepts will be basic conferential material, available to the interior designers and students who want to utilize the organised study concepts.

• Structural Engineering and Mechanics
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• v.65 no.6
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• pp.657-678
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• 2018

Sandwich structures are well known for their use in aircraft, naval and automobile industries due to their high strength resistance with light weight and high energy absorption capability. Sandwich beams with soft core are very common and simple structures that are employed in day to day general use appliances. Modeling and analysis of sandwich structures is not straight forward due to the interactions between core and face sheets. In this paper, formulation of Super Convergent finite elements for analysis of the sandwich beams with soft core based on Euler Bernoulli beam theory are presented. Two elements, Eul4d with 4 degrees of freedom assuming rigid core in transverse direction and Eul10d with 10 degrees of freedom assuming the flexible core were developed are presented. The formulation considers the top, bottom face sheets and core as separate entities and are coupled by beam kinematics. The performance of these elements are validated by results available in the published literature. Number of studies are performed using the formulated elements in static, free vibration and wave propagation analysis involving various boundary and loading conditions. The paper highlights the advantages of the elements developed over the traditional elements for modeling of sandwich beams and, in particular wave propagation analysis.