• New & Renewable Energy
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• v.2 no.4 s.8
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• pp.39-45
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• 2006

This paper introduces a preliminary work for the design of a mini-dish cluster system for power generation. Each mini-dish [typically has a 20 to 30 cm in diameter] is designed with a simple parabolic profile concentrating sun light [after the glass glazing cover to avoid dust deposition on the reflector and facilitate cleaning] onto a centrally located small plane[or concave] mirror which is placed on the bottom side of a transparent glass cover. The mirror with a mini-dish concentrator is designed to focus beam radiation onto a focal point before it enters a bundle of optical fibers connected to a remote receiver for power generation. Different options are considered in designing a mini-dish concentrator to maximize its effectiveness for the collection and use of solar energy.

• International Journal of Aerospace System Engineering
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• v.7 no.2
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• pp.1-5
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• 2020

When a rigid wedge is indented in to a semi-infinite block, the material is bulged up around the wedge that is generally called lip. The previous works in this filed considered the outer profile of the lip to be linear. But, present authors observed both experimentally and with the aid of finite element analysis that the profile of the lip is not always linear, and it depends on the angle of the wedge and friction parameters. So, in this work, attempts have been made to calculate hardness of indentation for different wedge angles and friction parameters. As hardness is intrinsic property of material, consideration of either linear or parabolic lip will not be affected much. A comparative study of hardness for linear and parabolic free surface profiles of the piled up material around the cone is analyzed in this work.

• Advances in Energy Research
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• v.8 no.3
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• pp.137-144
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• 2022

This study presents an experimental investigation of conventional and enhanced receiver tube performance for the application of a concentrated parabolic trough collector (CPC). The CPC system is fabricated and tested for the conventional and enhanced receiver tubes. The experiments were performed on both tubes for the change of flow rates. The temperature rise of the tube surface, as well as working fluid, were monitored for varying flow rates. The results were compared and discussed in view of enhanced CPC system performance. The results exhibited that the temperature rise of the working fluid passing through the tube was more in the case of the enhanced tube compared to the conventional receiver tube under the same flow rates.

• Transactions on Electrical and Electronic Materials
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• v.16 no.4
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• pp.201-205
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• 2015

This paper dealt with the condensing technology of an LED light source that uses a parabolic reflector to replace a searchlight equipped with a xenon lamp. A ray-tracing simulation was conducted to analyze the influence of the diameter of the reflector and the size of the light source on light condensing. The combination of a parabolic reflector with a diameter of 620 mm and a focal distance of 220 mm, and a 9 mm multi-chip package (MCP) with a luminous flux of 7,000 lm showed the narrowest beam angle. The luminous intensity at the center was measured at 7.7×10⁶ cd. The distance between the light source and the point where the illuminance was 1 lx was calculated to be 2.8 km. The power consumption of the system was 95 W, which is only 9.5% of that of the 1 kW xenon searchlight, and the beam angle was 1.03°. In a site experiment, it was confirmed that the light ray reflected from the LED searchlight proceeds forward without any diffusion because of the narrow beam angle.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.321-325
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• 2009

Sub-pel level motion estimation contributes to significant increase in R-D performance for H.264|MPEG 4 Part 10 AVC. However, several supplements, such as interpolation, block matching, and Hadamard transform which entails large computational complexity of encoding process, are essential to find best matching block in sub-pel level motion estimation and compensation. In this paper, a fast motion estimation scheme in sub-pel accuracy is proposed based on a parabolic model of SAD to avoid such computational complexity. In the proposed scheme, motion estimation (ME) is only performed in integer-pel levels and the following sub-pel level motion vectors are found from the parametric SAD model for which the model parameters are estimated from the SAD values obtained in the integer-pel levels. Fall-back check is performed to ensure the validity of the parabolic SAD model with the estimated parameters. The experiment result shows that the proposed scheme can reduce the motion estimation time up to about 30% of the total ME times in average with negligible amount of PSNR drops (0.14dB in maximum) and bit increments (2.54%in maximum).

• 한국기계연구소 소보
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• s.15
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• pp.105-115
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• 1985

For the application of factory automation, a 3-axis numerical control system with personal computer and KM3701 function generator LSI chip, which has liner, circular, parabolic, logarithmic, and exponential interpolations, is developed. The developed system also has 2 control function to stabilize tooling speed and 1/1000mm step sizes.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.411-420
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• 2016

Efforts have continued in recent years to research and develop new alternative energy sources to replace coal and oil. These days interest is exploding in new pollution-free renewable energy due to the rising prices of finite energy sources. In the field of solar energy, one of new renewable energy that has been actively researched and commercialized, research efforts have been focused on solar light energy, whose efficiency has, however, reached a saturation point already. Thus, this paper proposed a solar tracking-type parabolic heat collection device to utilize solar thermal energy rather than solar light energy. The proposed device was designed in a parabolic form to collect solar heat effectively. The investigator made its prototype by incorporating a five-axis censor-based solar tracking technology in it to sense changes to the location of the sun according to the seasons and periods. In addition, an administrator interface was designed and implemented for the efficient management of heat collection device.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.989-996
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• 2017

The proposed directional pencil beam antenna consists of a waveguide feeder with bended elliptical conductor plate feed and a parabolic curved reflector. Two rectangular apertures located at the broad wall near the end of the feed waveguide inserted from behind the reflector are located at the focus of the reflector and emit electromagnetic energy with bended elliptical conductor plate. This plate is designed to reflect electromagnetic energy primarily and to face the main reflector. The two rectangular apertures located at the waveguide end have inwardly protruding tabs for impedance matching of the antenna system, the shape of the tabs is a truncated oval. The proposed parabolic reflector antenna has a diameter of 400 mm and a focal length of 134.23 mm. The antenna gain is 33.68 dBi at the center frequency of 16.5 GHz, the beam width is $3.3^{\circ}$ and the reflection loss is -15 dB. Using the HFSS-IE, simulation results are performed to validate the proposed antennas.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.4
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• pp.448-454
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• 2015

In this paper, the band structural design that is typically in a line was arranged in a ring shape, so as to configure the high power LED lighting in such a way as to form a concentrated light distribution angle of less than 15 degrees. The parabolic aluminized reflector PAR38 that facilitates design using area and the area of the optical system to the same extent, applied a multiple light-source condenser lens optical system for the control of integration. The LED used here implemented a single linear light source using ans LED module with ans LED, flip-chip chip-scale package. The optical system was designed based on the energy star standard.

• Journal of the Korean Solar Energy Society
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• v.27 no.2
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• pp.61-69
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• 2007

The final energy consumption in the building sector in Korea represents almost 20% of the total energy consumption. Besides, Space heating and hot water generation in Korea are based on fossil fuels, with a serious environmental impact. Despite the popularity of simple solar domestic hot water systems, active solar space heating remains, for various reasons, marginal. And thus, the aim of this paper is to demonstrate potentialities of solar assisted space heating systems, both technically and economically. From this study found that the solar heating system with CPC solar collectors integrated the roof of a single-story residential building shares $50{\sim}55%$ of the annual heating load.