• Journal of KIISE:Computer Systems and Theory
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• v.27 no.6
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• pp.541-548
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• 2000

An area light source in the three dimensional space shines past a scene polygon, to generate two types of shadow volumes for each scene polygon, i.e., one with partial occlusion and the other with the complete occlusion. These are called, penumbra and umbra, respectively. In this paper, consider the problem for computing the umbra of a convex polygon from convex quadric light sources such as circles, ellipses, spheres, ellipsoids and cylinders. First, we give characteristics of the boundary surfaces of the umbra and then propose an algorithm for generating the umbra using them.

• Journal of Information Display
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• v.2 no.4
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• pp.46-51
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• 2001

Using ray-optics code incorporated with three-dimensional PDP cell simulation, we have analysed the energy flow in the PDP cell from the electric power input to the visible light output. Also, the visible light output profile and viewing angle distribution were obtained. We applied our code to the analysis of the barrier rib height effect on the visible light luminance and efficiency of the sustaining discharge. Although cells with higher barrier rib generate more VUV photons, less ratio of visible photons are emitted toward front panel due to the shadow effect. Thus, there exists optimal barrier rib height giving the highest visible luminance and efficiency. This kind of code can be a powerful tool in designing cell geometry.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.9
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• pp.83-90
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• 2009

In this paper, a method for reduction of error ratio by external light noise is proposed, which separates error moving component caused by external light noise from moving component of an object, using depth information of stereo image. If measured depth information change of extracted moving component is insignificant, the moving component is considered as external light noise, which concludes that there is no moving object. Experimental results assert the usefulness of the proposed method which makes error ratios by external light noise and by false image as shadow diminish.

• Journal of The Korea Institute of Healthcare Architecture
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• v.24 no.4
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• pp.69-87
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• 2018

Purpose: This study has been started with the awareness that light and color are the main visual sensors of the multi-sensory stimulation environment to achieve the therapeutic environment for demented elderly. The purpose of this study therefore is for clarifying the application characteristics of therapeutic light and color for dementia care facilities. Methods: Internal and external literature reviews have been conducted for the investigation into a)disorders and visual system in demented elderly, b)therapeutic effects of light and color, c)heliotherapy, light therapy and color therapy to deduce the therapeutic characteristics of light and color for demented elderly, and finally into d)the application characteristics of it for dementia care facilities. Results: The application characteristics of the therapeutic light and color for dementia care facilities are classified into both qualitative and quantitative characteristics. Qualitative application characteristics of light represented using of daylight, using of lighting approximate to daylight, expansion of iluminance level, equality in iluminance Level, reduction of shadow, and as well as exclusion of blare. Quantitative application characteristics of it represented iluminance level, color temperature and color rendering index prescribed in international lighting standards. Qualitative application characteristics of color represented non-monochromatic color, color contrast, long wavelength of yellow-red colors, exclusion of short wavelength of blue colors and patterns, and as well as different colors for idenfication. Quantitative application characteristics of it represented kontrast(K) prescribed in DIN32975:2009 and light reflectance value(LRV) prescribed in BS8300:2009. Implications: To form dementia care facilities as therapeutic environment both qualitative and quantitative application characteristics of therapeutic light and color in dementia care facilities are needed.

• Journal of the Korea Computer Graphics Society
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• v.2 no.2
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• pp.1-9
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• 1996

It is important issue to increase the efficiency of visibility operations in rendering since the most of rendering time is spent for performing visibility operations. In this paper, we present light buffers of area light sources, which provide efficient visibility operations from the sources. The light buffers are extended to support visibility operations not originated from the sources. We also explore their applications such as shadow generation, ray tracing and radiosity. Our experimental results show that the light buffers support more efficient visibility operations than the previously developed data structures including BSP trees, linear grids, and octrees.

• Korean Institute of Interior Design Journal
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• v.14 no.6 s.53
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• pp.193-201
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• 2005

In this study we analyzed and interpreted the phenomenologlcal characteristics and meanings of water space in religious architecture through field studies and phenomenologlcal approaches, focusing on the religious architecture Introducing water space in contemporary architecture. The phenomenological experience elements of the research ate light, time, place and context. As the results of this study, first, light as a phenomenological element not only induces a contrast and change between light and the shadow in architectural space and various changes of light in inner space, but also operates as an element which expresses building features outward with time. Second, time as a phenomenological perception experience makes us feel changes of the environment and physical properties and experience space visually and physically. The continuity of time shows the change of a day, night and daytime and seasons. Third, water space makes the sense of place more remarkable, connected closely with surrounding nature In outer space, and creates a new space. Fourth, water space is a contextual element which harmonizes with surrounding environment by connecting surrounding natural environment with architectural space. Fifth, water space in religious architecture is a symbolic and central element, and emphasizes the atmosphere of architectural space. In addition, it makes the people who experience water space perceive the place by triggering sensitive response.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.416-418
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• 1996

A $50{\times}50{\mu}m^2$ aluminum micromirror array is fabricated using surface micromachining technology. $50{\times}50$ micromirrors are arrayed two dimensionally. The micromirror plate is supported by a vertical spring structure that is placed underneath the mirror plate. When the mirror plates reflect a light, the micromirror array un have large effective reflecting area. Fabrication of vertical spring uses only one mask and shadow evaporation process.

• Current Optics and Photonics
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• v.2 no.6
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• pp.554-562
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• 2018

This study presents a color 3D scanner based on the laser structured-light imaging method that can simultaneously acquire 3D shape data and color of a target object using a single camera. The 3D data acquisition of the scanner is based on the structured-light imaging method, and the color data is obtained from a natural color image. Because both the laser image and the color image are acquired by the same camera, it is efficient to obtain the 3D data and the color data of a pixel by avoiding the complicated correspondence algorithm. In addition to the 3D data, the color data is helpful for enhancing the realism of an object model. The proposed scanner consists of two line lasers, a color camera, and a rotation table. The line lasers are deployed at either side of the camera to eliminate shadow areas of a target object. This study addresses the calibration methods for the parameters of the camera, the plane equations covered by the line lasers, and the center of the rotation table. Experimental results demonstrate the performance in terms of accurate color and 3D data acquisition in this study.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.9
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• pp.708-713
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• 2010

In this research a ring light was developed so that a partial shadowless shooting for the patient's affected area at the medical treatment room and surgical operation room using high luminance light emitting diode (LED) for which attention is being paid as new lighting parts for medical purpose. LED which was applied to the development used high luminance three color LED for full color for which various color materialization and the adjustment of radiation intensity are possible and we can get white light in order to emphasize the delicate expression for generic tone of shooting object, strong highlight, simple shadow and three dimensional effect at the time of close-up shadowless shooting of the affected area. And at the time of design of ring light, the characteristics of LED and the loss of light at the time of penetrating light diffusion PC were considered so that intensity of illumination for over 150 lx can be obtained. The result of measurement of the intensity of illumination of the ring light that was developed revealed that maximum intensity of illumination of 225.7 lx was obtained, while smoke index was measured to be maximum 78 Ra in the case of Red(50%) Green(100%) and Blue LED(60%). We could confirm that response speed was also very fast as 1.72 ms.

• Korean Institute of Interior Design Journal
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• v.24 no.1
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• pp.152-159
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• 2015

Contemporary architecture is philosophy and art, and science are different that holds the architecture of human thought and behavior based on a variety of physical space. In addition, the technology is used by the new media graphics, lasers, LED, which were possible only in imagination, using tools such as the time-space of the potential for explosion. In particular, it was found in the spacial color of atypical using the nature of light. Such these architecture is space people actively experiencing a sense towards the expansion of its place. Therefore, the study purpose is to explore the Steven Holl's spacial colors to utilize the space is important to the possibility of light. He prefers the connection to the invisible world is inferred from the visible world and other space. He thoughts an idea linked to the concept watercolors which is a tool that holds to the notion of the flexibility of light and shadow. Concept watercolor is the idea space, establish space, recombinant space, and the growthy space. These have shown the no fixed spacial color cause of the combination of the different tones according to the characteristics of the mixed-color development of a concept watercolors demonstrated the spacial color of the replacement. That is to establish a parody of the works light blending spacial color.