• Journal of Sensor Science and Technology
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• v.29 no.2
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• pp.75-81
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• 2020

We introduce a new visible light communication (VLC) method in which three-level return-to-zero (RZ) modulation is used for flicker-free transmission. In the VLC transmitter, the three-level RZ modulation ensures that the average optical power is constant; thus, a flicker-free light-emitting diode (LED) light is achieved. In the VLC receiver, a resistor-capacitor high-pass filter is used for generating spike signals, which are used for data recovery while eliminating the 120 Hz optical noise from adjacent lighting lamps. In transmission experiments, we applied this method for wireless transmission of an air quality sensor message using the visible light of an LED array. This configuration is useful for the construction of indoor wireless sensor networks for air pollution monitoring using LED lights.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.1
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• pp.33-36
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• 2018

The purpose of this study is to improve the efficiency of anti-pollution film for PV module. The anti-pollution coating process was performed on a glass substrate, which is the same material as the glass substrate for the PV module. We coated the anti-pollution film on the glass substrate by spray coating. After coating process, annealing process was performed during 1 hour at $200^{\circ}C$, $300^{\circ}C$, and $400^{\circ}C$. And then we analyzed the surface characteristics according to the annealing temperature of the film. Annealing process can also improve the durability of the coated film. And then we analyzed the anti-pollution characteristics, particle size of anti-pollution film, light transmittance. The particle size of anti-pollution film was analyzed with FE-SEM. The light transmittance was analyzed with UV-Visible spectroscopy including integrating sphere.

• Korean Journal of Environment and Ecology
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• v.28 no.4
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• pp.484-489
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• 2014

In this paper, we examined factors that influenced light pollution in Korean national parks during peak and off-peak tourist seasons. Cloud-and moonlight-free nighttime satellite images that were collected during October 2012(for peak season) and January 2013(for off-peak season) by the Day and Night Band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor were used to estimate the levels of light pollution in 19 national parks (excluding the Bukhansan and Mudeungsan National Parks). Bootstrapping regression analyses were conducted to examine the effects of socioeconomic and policy factors on light pollution in the study national parks for peak and off-peak tourist seasons, separately. The characteristics of light pollution in the national parks varied by season. During the peak tourist season, light pollution in the national parks were affected more by night lights nearby the parks than those within in the parks, while in the off-peak season, light sources in the parks were more important. Scattering of light emitted from hotels and other recreational facilities outside the parks that led to the sky glow effect can be attributed to the greater impact of night lights nearby the parks during the peak season. This result suggests that regulating light pollution nearby the park areas is needed to mitigate light pollution in the national parks, especially in a peak tourist season.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.469-470
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• 2010

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.467-468
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• 2010

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2009.10a
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• pp.426-427
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• 2009

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2009.10a
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• pp.428-429
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• 2009

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.5
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• pp.87-92
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• 2000

The purpose of this study is to investigate Ozone which we have to contact in our daily lives. Recently Ozone becomes a serious pollutant in the inside and outside. To select th indicator plants or the purifier plants for air pollution caused by ozone, this stud has been conducted with interior landscape plant of 10 species. The results are as follows; 1) The visible demage by Ozone was firstly observed on Viburnum awabuki among 10 species, and it occurred after the lapse of 10, 8 and 4 hours on 0.5, 1.0 and 2.0 ppm ozone treatment, respectively. The first symptom of visible demage appeared on chlorosis or blotting of leaves, then progressed on necrosis of leaves. 2) On the other hand, Litsea japonica and Ardisia japonica were so resistant against Ozone fumigation that they were not demage independently of Ozone concentration till the lapse of 60 hours. 3) Chlorophyll contents were decreased by the increased Ozone concentration. At this time, grana destruction was observed. The most sensitive plant to ozone was Viburnum awabuki, and we suggest that Viburnum awabuki would be possible one to use for the indicator plant. The most resistance plant to Ozone was Litsea japonic and Ardisia japonica, we suggest that Litsea japonica and Ardisia japonica would be possible to use for the purifier plant for Ozone pollution.

• Biomedical Science Letters
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• v.26 no.3
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• pp.157-163
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• 2020

Long-term exposure to environmental pollutants can impair the human skin's barrier function and promote skin aging mechanisms. The visible consequences of these effects are dryness, wrinkles, black spots and worsening skin sensitivity. As awareness of the effects of environmental stressors on the skin has recently increased, consumers' demand for cosmetics that can provide anti-pollution effects is increasing. In this study, the possibility of anti-pollution cosmetic material was investigated by measuring the inhibitory effect of free radicals using a mixture of Nypa fruticans Wurmb (NF), Saussurea neoserrata (SN), Codium fragile (CF) and Enteromorpha compressa (EC), which has anti-inflammatory and antioxidant effects against irritation caused by dust. Combining the experimental results of a mixture of NF, SN, CF and EC by induction of fine dust stimulation, inhibition of inflammatory factors (PGE₂) and intracellular free radicals (ROS) by inhibiting effects were significant, indicating the possibility of use as anti-pollution cosmetics. The most plants used as sources of anti-pollution cosmetic ingredients contain antioxidants as active substances. In our highly industrialized and chemically polluted world, it is not surprising that most plants used as sources of anti-pollution cosmetic ingredients contain antioxidants as active substances. Considering our results, it can be suggested that this anti-pollutant consisting of NF, SN, CF and EC may be a good ingredient for skincare products for the cosmetic industry due to their antioxidant properties, which may especially alter skin aging.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.1
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• pp.78-80
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• 1993

Of the forma of Hibiscus Syriacus, national flower, a dozens of them have been recommended for landscape treess. To find out the highly resistant forma, 13 forma of Shrub al thea were fumigatedqr with $SO_2$ in phytotron and their visible injury was observed. Visible injury of Shrub al thea forma was spread on the vein in the shape of spot and diffused to whole leaf with wilting. The injury colors of forma were generally dull bluish green, dark grayish green. The tolerant forma to $SO_2$ were Sanchunyeo, Saeachim, Sulag and the highly sensitive forma were Lusi, Youngkwang. Therefore, Sanchunyeo, Saeachim and Sulag were recommeneded to plant in polluted areas.