• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.2944-2953
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• 1994

Active range finders using laser beam have been widely used for the factory automation and quality assurance, but they may be unreliable if the object' slope is steep or its surface is specular. The reliability of an active range finder was analyzed for the variation of the reflected laser beam intensity. First, the properties of the object's reflection were modeled by using the bidirectional reflectance-distribution function(BRDF), and then the variation of the laser beam brightness was formulated for the different configuratioin of the object and sensor. The experimental data of the laser beam reflection were obtained for two materials, mild steel and stainless steel. The parameters of the proposed model were obtained by fitting the data of the mild steel to the model and it was found that the results calculated from the proposed model were in good agreement with the experimental data.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04b
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• pp.89-92
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• 2002

Carbon nano tubes(CNTs) have been reported as field emission source because has a sharp tip, a high aspect tip, high chemical stability, high mechanical strength and low work function properties. In this study, we fabricated successfully the back-lamp of the I-inch flat type using CNTs, which was grown directly on cathode substrate of sodalime glass at low temperature. The brightness of CNT back-lamp is measured to $14 Kcd/m^{2}$ at $2000V_{dc}$ in spacing of $500{\mu}m$. And, the emission properties of packaged CNT back-lamp was analyzed as function of applying voltage and times.

• Journal of IKEEE
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• v.17 no.4
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• pp.478-483
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• 2013

This paper presents an adaptive Retinex algorithm for improving dynamic range of image representation. The proposed Retinex algorithm detects degraded brightness by using skewness and the degraded components are compensated with local statistics. In particular, we propose a new compensation function for dynamic range so that effectinve image representation can be achieved. Experimental results show that the proposed algorithm has the capability to improve the dynamic range with reduction of color degradation.

• International journal of advanced smart convergence
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• v.1 no.1
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• pp.6-13
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• 2012

An improved algorithm for image quality assessment is presented. First a simple model of human visual system, consisting of a nonlinear function and a 2-D filter, processes the input images. This filter has one user-defined parameter, whose value depends on the reference image. This way the algorithm can adapt to different scenarios. In the next step the average value of locally computed correlation coefficients between the two processed images is found. This criterion is closely related to the way in which human observer assesses image quality. Finally, image quality measure is computed as the average value of locally computed correlation coefficients, adjusted by the average correlation coefficient between the reference and error images. By this approach the proposed measure differentiates between the random and signal dependant distortions, which have different effects on human observer. Performance of the proposed quality measure is illustrated by examples involving images with different types of degradation.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1356-1358
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• 2003

In the paper, a method making use of the characteristics of Dyad Green Function (DGF) and Fluctuation-Dissipation Theorem to get the brightness temperature of layered medium is introduced. Based on the approach and the measured data of multi-channel radiometer and Least Square Method (LSM), the thickness of lunar soil can be retrieved. These methods are significant to study on materials on lunar surface.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.12
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• pp.1054-1064
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• 2012

HDR (high dynamic range) tone mapping algorithms are used in image processing that reduces the dynamic range of an image to be displayed on LDR (low dynamic range) devices properly. The retinex is one of the tone mapping algorithms to provide dynamic range compression, color constancy, and color rendition. It has been developed through multi-scale methods and luminance-based methods. Retinex algorithms still have drawbacks such as the emphasized noise and desaturation. In this paper, we propose a multi scale tone mapping algorithm for enhancement of contrast, saturation, and noise of HDR rendered images based on visual brightness functions. In the proposed algorithm, HSV color space has been used for preserving the hue and saturation of images. And the algorithm includes the estimation of minimum and maximum luminance level and a visual gamma function for the variation of viewing conditions. And subjective and objective evaluations show that proposed algorithm is better than existing algorithms. The proposed algorithm is expected to image quality enhancement in some fields that require a improvement of the dynamic range due to the changes in the viewing condition.

• Journal of Fashion Business
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• v.13 no.6
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• pp.61-75
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• 2009

The objective of this research is to the enhance the color function of work clothing : to research and analyze the hue and tone of work clothing colors to be used for machinery and heavy industries in national industrial complexes, Through this research, the color using problems which related with safety workers will be revealed. For this project, total 42 sets of work suits were sampled from 12 different companies in the machinery and construction industries in the national industrial complexes of Gyeongsang Namdo Province and 16 sets of work suits currently being sold in the market. The collected work suits samples were classified according to item types and design. Color measurements were taken thus: After calibration according to ASTM D1729 specifications of standardized configuration settings to match standardized luminous source D65(Daylight 6500K) in color cabinet BOTECK SuperLight-VI, the RGB values of the work suits were calculated using PANTONE Color Cue TX. The RGB values of the colors thus derived were converted into V/C values using the Munsell Conversion 9.0.6 and analyzed with Munsell's 10-color system and PCCS. The results were presented according to Munsell's color wheel and color and brightness distributions were expressed in table form, as well as presented as a tone map. Following analysis, color hue distribution was found to be concentrated around PB, and brightness distribution toward the low end and mid range of the scale. Saturation values were distributed mostly around the low end of the scale. Following color tone analysis according to PCCS, it became apparent that colors were mainly distributed around dkg, ltg, and g, at low- and mid-brightness and low-saturation. Therefore, it may be concluded that colors used in work suits in the machinery and heavy industries are mainly cool colors, at low- and mid-brightness and low saturation. It is conjectured that such colors were applied uniformly in the workplace in order to serve certain functions, such as concealment of stains and contamination. Therefore, it follows that the utilization of colors, among other functions served by working clothings, must be taken into consideration in order to enhance safety and efficiency.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.1
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• pp.51-57
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• 2005

In this paper, we propose an adaptive contrast control method for the flat real-time processing. The proposed method has employed probability density function(PDF) in order to control a sudden change in image-brightness. In addition, the proposed algerian obtains the maximum contrast without affecting the processed image. In order to reduce hardware complexity, we have utilized approximated CDF based on sampling values. Visual test and standard deviation of their histogram have been introduced to evaluate the resultant output images of at: proposed method and the original ones.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2031-2039
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• 2015

In the LED lighting industry, the dimming function in the LED lamp is required by demands of many consumers. To drive this LED lighting, various types of power converters have been applied. Among them, an LLC resonant converter could be applied for high power LED lighting because of its high efficiency and high power density, etc. The function of power factor correction (PFC) might be added to it. In this paper, a dimmable single-stage asymmetrical LLC resonant converter is proposed. The proposed converter performs both input-current harmonics reduction and PFC using the discontinuous conduction mode (DCM). Also, the lower voltage stress across switching devices as well as the zero voltage switching (ZVS) in switching devices is realized by the proposed topology. It can reduce cost and has high efficiency of the driver. In addition, the regulation of the output power by variable switching frequency can vary the brightness of a light. In the proposed converter, one of the attractive advantages doesn’t need any extra control circuits for the dimming function. To verify the performance of the proposed converter, simulation and experimental results from a 300W prototype are provided.

• Journal of The Korean Astronomical Society
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• v.39 no.3
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• pp.57-71
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• 2006

We investigated the structural parameters of a sample of 30 dwarf galaxies(15 dEs and 15 dS0s) in the Virgo Cluster using i-band images from the Sloan Digital Sky Survey Data Release 4. Among 28 galaxies for which surface brightness profiles were derived from ellipse fittings, 23 galaxies had a single component that was adequately described by a generalized $S\acute{e}rsic$ function with a shape parameter ranging from n=0.5 to 2, while 5 galaxies(2 dEs and 3 dS0s) had bulge and disk components that were fitted by a generalized $S\acute{e}rsic$ function and an exponential function, respectively. Since the majority of dwarf galaxies in the present sample had a single component, it seems likely that genuine dS0 galaxies that have disk and bulge components are quite rare in the Virgo Cluster. The similarity in structural parameters of genuine dS0 galaxies in the Virgo Cluster with those of Magellanic-type galaxies implies that the progenitors of dwarf lenticular galaxies in the Virgo Cluster were most likely Magellanic-type galaxies if dS0s are harassed late-type spirals.