• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.2
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• pp.212-223
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• 2017

This research investigated the screen printing method for natural indigo dye on cotton fabric. We examined four types of thickening agents (arabic gum, guar gum, indalca, and CMC) based on their ability to retard the oxidation of natural indigo print paste while the paste remained on the screen frame. The results indicated that the retardation of arabic gum towards oxidation was the greatest among the four types of thickening agents. The highest K/S value of the printed cotton was observed with a dye concentration of 50g/L fermented indigo powder. The best printing results were obtained when the duration of dye efficiency was tested for the 10 minutes of the dye paste remaining on the screen with a thickening agent concentration of 26.56% that represented 530 cps viscosity. The test of colorfastness to washing and rubbing of the printed cotton resulted in grade 5, and the colorfastness to sunlight resulted in grade 4. Chinese traditional Naminwhapo printing was reproduced on cotton fabric using the natural indigo printing method derived from this study.

• Design & Manufacturing
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• v.12 no.1
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• pp.36-40
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• 2018

The car requires an inside mirror installed between the driver's seat and the passenger's seat to ensure the driver's rear and side view of the driver. Inside mirrors must always be attached to the vehicle to ensure the driver's visibility. Inside mirrors attached to the windshield of a vehicle are always exposed to direct sunlight and should be semi-permanently usable in hot and humid summer weather in Korea. Therefore, the mirror mount, which is the junction of the inside mirror, is particularly important in corrosion resistance and wear resistance suitable for humidity. Mirror mounts are currently difficult to manufacture due to their reliance on powder molding technology in advanced countries such as Japan and Germany. This paper focuses on the fabrication of high corrosion resistant stainless mirror mounts by vacuum sintering technique and focuses on the selection of materials suitable for the production of mirror mounts through experiments of 300 series stainless steel and 400 series stainless steel manufactured by vacuum sintering.

• KIEAE Journal
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• v.8 no.1
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• pp.45-52
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• 2008

Daylighting systems can improve the luminous quality of indoor environment and reduce the building's electric lighting energy consumption. For designing good daylighting, place the light where it is desired and avoid excessive contrasts, glare and high light levels. Sun scoop, light scoop and sun catcher systems have been used for alternative systems compared to other natural lighting systems. This study aims to evaluate daylighting performance of sun scoop, light scoop and sun catcher systems using scale model experiments. For the purpose, the 1/10 scale models of the systems were made as the same areas of glazing(10 percent of floor area) on the top of the center roof. Totally 15 measuring points of illuminance on the horizontal work plane were monitored from 09:30 to 12:30 on October 29, 2007. Agilent data logger and photometric sensors Li-cor were used. As the results, the topside lighting systems can improve the illumination uniformity than side lighting and top lighting. However, the appropriated shading system should be integrated to prevent the direct sunlight.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1595-1600
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• 2011

We analyzed the noise effect from artificial light and sunlight on the signal performance in visible light communication systems based on Intensity Modulation/Direct Detection(IM/DD). System performance was experimentally demonstrated by transmitting 50ksysmbol/s QPSK signals at 2MHz sub-carrier. And received signals were analyzed using EVM and RF spectrum. Finally, the system performance was improved by utilizing a visor and we confirm that the outdoor visible light communication was possible using IM/DD method.

• Journal of Power Electronics
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• v.9 no.4
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• pp.631-642
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• 2009

The sun is a useful reference direction because of its brightness relative to other astronomical objects and its relatively small apparent radius as viewed by spacecrafts near the Earth. Most satellites use solar power as a source of energy, and so need to make sure that solar panels are oriented correctly with respect to the sun. Also, some satellites have sensitive instruments that must not be exposed to direct sunlight. For all these reasons, sun sensors are important components in spacecraft attitude determination and control systems. To minimize components and structural mass, some components have multiple purposes. The solar cells will provide power and also be used as coarse sun sensors. A coarse Sun sensor is a low-cost attitude determination sensor suitable for a wide range of space missions. The sensor measures the sun angle in two orthogonal axes. The Sun sensor measures the sun angle in both azimuth and elevation. This paper presents the development of a model to determine the attitude of a small cube-shaped satellite in space relative to the sun's direction. This sensor helps small cube-shaped Pico satellites to perform accurate attitude determination without requiring additional hardware.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.155-160
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• 2009

The increasingly high prices for oil, the exhaustion of fossil fuels as well as concern about global warming are driving rapid growth of alternative sources of energy in the world. The active solution for global environment and exhaustion of energy sources is to develop and popularize the technologies to use natural energy such as sunlight, wind, and water. PV(Photovoltaic) modules are efficient devices that has been considered a logical material for use in buildings. Recent advanced BIPV(Building Integrated PV) technology have rapidly made PVs suitable for direct integration into construction in the world. Recently, building has been higher and higher. Tall buildings have many advantages for BIPV such as wide facade area and no shading effect by the surrounding buildings. However. BIPV has not been applied for tall building facade yet. Therefore, the purpose of the research is to develop suitable BIPV for tall buildings and to put these technologies to practical use. Therefore, the purpose of the study is to investigate unification of BIPV to curtain wall to apply BIPV on tall building through research into advanced application of overseas BIPV cases.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.148-154
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• 2009

By the skyscraper building, increase of skin area and expansion of curtain wall system will be the important factors of acceleration in extending supply of BIPV system. In the future interior environmental evaluation is not a necessary to the residents but an essential term which will bring enormous influence. In the interior environmental evaluation, natural light will let the residents with direct contact with outside circumstances and make them feel opened. also only the daylight has radiant energy and color rendering that will have a great influence to residents' mental, operation efficiency and advancing productivity. This research compares and analyzes BIPC system in office spaces with two general sunlight's module. In addition to natural light's efficiency for BIPC system's comfort and confirmed economical efficiency will be applied to basic research data. Hence forth, ensuring indoor intensity of illumination and controlling light system to reducing energy research data will be demanded to increase the amount of supplying BIPC system. Also continuance research in the possibility of applying BIPC system in various buildings, room temperature affected by location of windows and its condensation, and economical evaluation will be required.

• Journal of Environmental Health Sciences
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• v.10 no.2
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• pp.99-111
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• 1984

The survey was made on the use and care of cooking oil during a period from March 1st to April 30th in 1984to attribute for the later studies on the betterment of dietary conditions. 849 housewives in Seoul were selected randomly for the survey. The results obtained are as followes : Among 849 respondents, age of thirties consisted of 52.5% and 32.6% of for the fourties. For the levels of education, 26.1% of housewives was the graduates of university and 35.1% was of highschool. 38.2% of the respondents earned more than 600, 000won monthly, but 46.8% were on less than 600, 000won. 1. 67.8% of 370 housewives purchased soybean oil once a month, and 17.0% did once every three month. 2. In the method of placing the oil, 41.0% of housewives kept it at a cool place where no direct sunlight reaches, and the rest 51.8% kept the oil under the sink. 3. For the kind of container to keep the oil, 30.3% of them used glass and 24.3% used the plastic. 4. For the period of keeping the cooking oil for the reuse, 58.5% of the housewives kept the used oil for one month whereas 13.2% kept for two months. 5. 39.9% of housewives reused the same cooking oil twice before discarding it but 27.9% reused three times. 6. 27.0% of them dump rancid oil in drains, and 37.0% dump in dustbins.

• Korean Institute of Interior Design Journal
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• v.18 no.6
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• pp.12-19
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• 2009

The characteristics of light in the paintings of Rembrandt van Rijn, Johaness Vermeer and Edward Hopper are very different. While Rembrandt and Vermeer lived in the 17th century, Hopper lived in the 20th century. Although this time gap, comparative study on their light-space relationship is important because there are spatial similarities as well as light differences. Most three painters' works depict interior spaces with one person inside. The interior space is filled with different light and shadow. In the Rembrandt's paintings, only part of the figure is lit in the ambiguous darkness. In the Vermeer's paintings, the soft indirect light is filled in the domestic space and the boundary between the figure and space is blurred. In the Hopper's paintings, the direct sunlight invades the interior and the figure confronts with strong daylight. These light differences were caused by the artists' intentions as well as the environmental situations. 4 case paintings of each artist were analyzed by phenomenological aspects and computerized light brightness test. Scale models were built to re-construct the three different light characteristics. The model experimentation will have potential to develop 2 dimensional art analysis into 3 dimensional space design by means of light. However it was very difficult to construct the three lights, the experimentation shows they have unique characteristics that can be applied to spatial design studies.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.1-9
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• 2009

A recent research trend on the Daylight Responsive Dimming Systems, using available daylight for energy savings, is to integrate automated roller shading systems and venetian blind systems which are vertically controlling daylight to indoor based on sun profile angle. Therefore, this paper suggests Grating Louver System into a pair glass as a new shading system, which can control daylight vertically and horizontally. The optimized spacing of louvers, which is to block direct sunlight into a space, was calculated. And then, the system was simulated for analysis and evaluation of characteristics of daylight by Desktop Radiance 2.0.