• Journal of Biosystems Engineering
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• v.20 no.4
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• pp.368-375
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• 1995

A computer vision system was built to generate images of a stationary egg. This system includes a. CCD camera, a frame grabber, and an incandescent back lighting system An image processing algorithm was developed to accurately detect surface holes and surface cracks on eggs. With 20W of incandescent back light, the detection rate was shown to be the highest. The Sobel operator was found to be the best among various enhancing filters examined. The threshold value to distinguish between the crack and the translucent spots was found to be linear with the average gray level of a whole egg image. Those values of both gray level and area were used as criteria to detect holes in egg and those values of both area and roundness were used to detect cracks in egg. For a sample of 300 eggs, this system was able to correctly analyze an egg for the presence of a defect 97.5% of the time. On the average, it took 59.5 seconds to analyze an egg image and determine whether or not it was defected.

• Elastomers and Composites
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• v.50 no.1
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• pp.1-6
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• 2015

Polybutadiene rubber (BR) has been well known that its physical and chemical properties are changed when it is exposed to ultraviolet light undergoing photooxidation. In this study, photooxdiation process of BR vulcanizate was investigated using a high pressure mercury lamp used as an outdoor lighting, which has high UV radiation efficiency and reasonable cost. Discoloration and crack formation of photooxdized BR vulcanite surface were examined using an image analyzer. Change of chemical functional groups of BR vulcanite surface by photooxidation was investigated using ATR-FTIR, and variation of the crosslink density with the UV irradiation time was investigated. By increasing the UV irradiation time, the crosslink density steeply increased after a period of time and did not increase any more. Formation of hydroxyl (~OH) and carbonyl (~C=O) groups on the BR vulcanizate surface increased and the1,4-cis unit was converted to the 1,4-trans unit as the photooxidation was proceeded.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1581-1583
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• 2000

In this paper, we proposed a surface discharge FFL with the new electrode structure like the needle shaped electrode as the variation of cell structure to high luminance and low power consumption. In comparison with different electrode structure it has low discharge voltage and current and good optical characteristics. So it has better discharge characteristics than different surface discharge FFL and can be fungible of backlight as a lighting source in LCDs.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.11
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• pp.559-569
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• 2017

Various studies examining how to conserve building energy have been conducted recently. From such studies it has been determined that insulation performance of an aircap is viable and therefore aircaps are used as material for improving insulation performance of windows. However, the aircap for improving insulation performance of a window is attached on the front, causing infringement of the prospect right. Therefore, the purpose of this study is to develop an aircap module attached to the window through rolling, conducting performance verification throughfull-scale testbed and verifying its effectiveness. Findings of this study are as follow : 1) The module suggested in this study enables setting of an area wherein the aircap is attached through rolling so that the aircap rolls up using Velcro tape, and an insulation bar is suggested to block the gap between the aircap and window glass. 2) When the aircap is applied to the window, consumption of lighting energy increased during summer and winter by 2.8%~16.4% and 0%~76.2% respectively in comparison to no aircap application, indicating that it is unsuitable for conserving lighting energy. 3) In terms of conserving cooling and heating energy, an advantageous or effective aircap attachment method is the method whereby an aircap is attached to the front surface of a window. However, the method whereby an aircap is attached to a part of a window and where no aircap is attached increases consumption of cooling and heating energy during summer and winter by 6.0%~35.7% and 2.7%~41.6% respectively in comparison to the method wherein an aircap is attached to the front surface of a window. 4) In consideration of conserving cooling, heating and lighting energy, the attachment of an aircap to the front surface of window is the most appropriate method, and it is appropriate to attach the aircap at a position that is 1,500 mm or higher from the floor to secure the prospect right and minimize energy loss.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.10
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• pp.875-880
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• 2016

In this study, we proposed an effective and simple way to directly generate wrinkle patterns on a curved surface. A curved surface was prepared using a 3D printer and an UV (Ultraviolet)-lighting system was utilized to weakly polymerize the UV-curable thin resin layer coated on the surface, resulting in a gradient of material properties in the layer thickness. Subsequently, a thermal curing process was conducted to generate microscale wrinkles by compressive forces that were generated during complete curing. Wrinkle shapes from 5, 15, 25 sec of UV-light exposure were compared. With increasing UV-exposure, the line-width of wrinkles became thicker due to much higher strength of skin zone. The results indicated that the proposed fabrication process could be utilized for surface modification in diverse research fields.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.11
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• pp.53-62
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• 1994

This paper presents a new approach of analyzing errors resulting from nonideal general-purpose lighting environment when the Photometric Stereo Method (PSM) is applied to estimate the surface-orientation of a three-dimensional object. The approach introduces the explicit modeling of the lighting environment including a circular-disk type irradiance object plane and the direct simulation of the error distribution with the model. The light source is modeled as a point source that has a certain amount of beam angle, and the luminance distribution on the irradiance plane is modeled as a Gaussian function with different deviation values. A simulation algorithm is devised to estimate the light source orientation computing the average luminance intensities obtained from the irradiance object planes positioned in three different orientations. The effect of the nonideal lighting model is directly reflected in such simulation, because of the analogy between the PSM and the proposed algorithm. With an instrumental tool designed to provide arbitrary orientations of the object plane at the origin of the coordinate system, experiment can be performed in a systematic way for the error analysis and compensation. Simulations are performed to find out the error distribution by widely varying the light model and the orientation set of the object plane. The simulation results are compared with those of the experiment performed in the same way as the simulation. It is confirmed from the experiment that a fair amount of errors is due to the erroneous effect of the general-purpose lighting environment.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1998.11a
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• pp.147-150
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• 1998

도로 표면의 반사특성의 측정은 휘도 계산에 있어서 매우 중요하다. 이 연구에서는 도로 면의 반사특성을 측정할 수 있는 장치를 개발하고, 이를 이용하여 콘크리트 시료의 반사 특성을 측정하였다. 측정 결과를 이용하여 도로조명에 의한 휘도 분포를 계산한 결과, 측정값에 가까운 결과를 얻었다.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.333-336
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• 2009

A series of microcavity plasma devices having various electrode geometries were investigated for the display and lighting applications. Addressable, self-assembled Al/$Al_2O_3$ electrodes were fabricated in a thin, flexible single sheet of Al foil. And, enhanced luminance and efficient microplasmas are achieved by precise control of the cross-sectional geometry and surface morphology of the cavities within the microplasma devices. New microdischarge system fabricated in various substrates will be introduced.

• Journal of Environmental Science International
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• v.24 no.4
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• pp.359-369
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• 2015

This study analyzed the velocimetry of runoff and measured the flood discharge by applying the SIV (Surface Image Velocimetrer) to the daytime and nighttime flow image data with special reference to Seong-eup Bridge at Cheonmi stream of Jeju during the flow by the severe rainstorm on May 27, 2013. A 1000W lighting apparatus with more than 150 lux was installed in order to collect proper nighttime flow image applied to the SIV. Its value was compared and analyzed with the velocity value of the fixed electromagnetic wave surface velocimetry (Kalesto) at the same point to check the accuracy and applicability of the measured velocity of flow. As a result, determination coefficient $R^2$ values were 0.891 and 0.848 respectively in line with the velocity distribution of the daytime and nighttime image and the flow volume measured with Kalesto was approximately 18.2% larger than the value measured with the SIV.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.1
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• pp.277-290
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• 2019

The demand for indoor positioning is increasing day by day. However, the widely used positioning methods today cannot satisfy the requirements of the indoor environment in terms of the positioning accuracy and deployment cost. In the existing research domain, the localization algorithm based on three-dimensional space is less accurate, and its robustness is not high. Visible light communication technology (VLC) combines lighting and positioning to reduce the cost of equipment deployment and improve the positioning accuracy. Further, it has become a popular research topic for telecommunication and positioning in the indoor environment. This paper proposes a surface centroid TOA localization algorithm based on the VLC system. The algorithm uses the multiple solutions estimated by the trilateration method to form the intersecting planes of the spheres. Then, it centers the centroid of the surface area as the position of the unknown node. Simulation results show that compared with the traditional TOA positioning algorithm, the average positioning error of the surface centroid TOA algorithm is reduced by 0.3243 cm and the positioning accuracy is improved by 45%. Therefore, the proposed algorithm has better positioning accuracy than the traditional TOA positioning algorithm, and has certain application value.