• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.11 no.6
• /
• pp.73-80
• /
• 2008

This research investigated appropriate indoor light sources and light intensities for Hedera rhombea and Saxifraga stolonifera, which are shade-tolerant and cold-resistant indoor plants. Plants were grown in wood flames of 1 m in width${\times}$1 m in length${\times}$1 m in height. Light sources were fluorescent lamp, three wave fluorescent lamp and halogen lamp that are being used in most of the subway stations in Korea, and light intensities were 200 Lux, 700 Lux and 1,000 Lux. Results are as following. 1. Hedera rhombea Hedera rhombea heights did not show differences statistically as responses to light sources and light intensities. It, however, tended to be greater with an order of 1,000 Lux, 700 Lux and 200 Lux and halogen lamp, fluorescent lamp, and three wave fluorescent lamp. Number of branch increased under fluorescent lamp than under halogen lamp or three wave fluorescent lamp, and increased under higher light intensities. Number of leaf was higher with an order of three wave fluorescent lamp 1,000 Lux, fluorescent lamp 1,000 Lux and halogen lamp 1,000 Lux. Leaf shape became wider under low light intensities regardless of light sources. Chlorophyl contents in leaf were not significantly different under three wave fluorescent lamp and halogen lamp. However, the contents increased with an order of 200 Lux, 700 Lux and 1,000 Lux under fluorescent lamp. 2. Saxifraga stolonifera The plants were dead or declined under fluorescent lamp regardless of light intensities. When light intensities went under 200 Lux, Saxifraga stolonifera showed poor growth for all the light sources. Plant height, number of shoot, number of leaf, leaf width and leaf length have increased with an order of halogen lamp 1,000 Lux, three wave fluorescent lamp 1,000 Lux and three wave fluorescent lamp 700 Lux. Chlorophyl content was greater with an order of three wave fluorescent lamp 700 Lux, three wave fluorescent lamp 1,000 Lux and halogen lamp 1,000 Lux.

• Korean Journal of Environmental Agriculture
• /
• v.41 no.4
• /
• pp.245-251
• /
• 2022

BACKGROUND: Selection an suitable light source is essential in the year-round production of horticultural crops in closed production systems such as plant factory with controlled environments. This study was investigated to confirm the effects of artificial light sources on growth of cherry tomato'CF Jelly'(Lycopersicon esculentum var.) under high-pressure sodium lamps (HPS), metal-halide lamps (MH), and LEDs. METHODS AND RESULTS: Light intensity of the light sources was controlled at 220±30 µmol/m²/s with 12 hrs of photoperiod for a day. Flower development was significantly faster in HPS and MH treatments compared to the LEDs. There was no significant difference between the leaf number and leaf shape under the HPS and MH treatments. Reproductive growth of cherry tomato was significantly promoted by the LEDs treatment of blue plus red lights. Fruit yield per plant also increased under the LEDs compared to the others. CONCLUSION(S): Growth, flowering, and fruit setting of the cherry tomato were accomplished by the artificial lights under plant factory conditions. The HPS treatment showed negative effect on fruit quality in terms of blossom-end rot incidence compared to the LEDs or MH treatment. Effect of the LEDs on promotion of fruit weight and yield was also proved. Additional research should be carried out for improving sugar metabolism or decreasing disease in the fruits under plant factory system using only artificial lights.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.2
• /
• pp.32-42
• /
• 2011

In this paper to compare the economical efficiency of light sources for a tunnel lighting, we define a model tunnel and design tunnel lighting. And to examine economical efficiency of various tunnel lightings we compare the lighting expenses of tunnels. The results shows high pressure sodium lamps are more economical than fluorescent lamps.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.31 no.3
• /
• pp.421-430
• /
• 2004

The purpose of this study was to measure and compare the amount of unreacted TEGDMA from pit and fissure sealants cured with three different light sources; conventional halogen light curing unit, plasma arc light curing unit and argon laser. The specimens were eluted in distilled water for different time intervals. The time-related release of TEGDMA were analyzed by reverse-phase high performance liquid chromatography(HPLC). The result of present study can be summarized as follows: 1. The time-related release of TEGDMA decreased with increasing curing time in conventional halogen light, however, that not statistically significant difference(p>0.05). 2. The elution from the specimens cured for 6 and 9 seconds with plasma arc light was similar results corresponding with the time-related TEGBMA release, and was significantly lower than that cured for 3 seconds(p<0.05). 3. The elution of TEGDMA from the specimens cured with argon laser was significantly higher than that cured with halogen and plasma arc light(p<0.05). 4. The elution of TEGDMA from under recommended time of three different light sources were showed to be no statistically significant difference(p>0.05). 5. In time-related release of TEGDMA from recommended time of each light sources, the results correspond to 40 seconds of halogen light and 6 seconds of plasma arc light were similar(p>0.05). 6. The elution of TEGDMA, from over recommended time of three different light sources were showed to be no statistically significant difference(p>0.05). In this study, I suggest that curing time of plasma arc light is 6 and/or 9 seconds in the field of clinical pediatric dentistry claiming its effectiveness in optimal polymerization and reduced chair time.

• Journal of Ecology and Environment
• /
• v.32 no.2
• /
• pp.83-86
• /
• 2009

We conducted a landscape analysis to investigate the possibility of adverse effects of anthropogenic light sources, such as roads and residential buildings, on Lethocerus deyrollei on Jeju Island, Wetlands inhabited by L. deyrollei had fewer anthropogenic structures within a 3 km radius that had the potential to produce artificial light at night than wetlands not inhabited by L. deyrollei, In particular, the presence of artificial lights within a 1 km radius appears to reduce the probability of inhabitation by L. deyrollei, Our results suggest that artificial light sources may be critical determinants of L. deyrollei inhabitation patterns in a landscape, and that habitats that have a buffer area of at least 600$\sim$700 m radius free from residential buildings are the most appropriate habitats for L. deyrollei.

• Journal of Korean Ophthalmic Optics Society
• /
• v.3 no.1
• /
• pp.201-207
• /
• 1998

It was theoretically calculated the image position and size using matrix to obtain the reflection pattern for eye's cornea and crystalline, and made system to measure the reflection pattern by three light sources and a reflex camera. Hyperopia and myopia were measured by reflect pattern using single light source at retina, and cornea and curvature of crystalline were measured by the reflection pattern using double light sources.

• Journal of the Korean Professional Engineers Association
• /
• v.42 no.5
• /
• pp.41-45
• /
• 2009

The last century of lighting has been dominated by incandescent, fluorescent and high-intensity discharge(HID)light sources. In the late 1970's, after green LEDs were invented, Dr. Ching Tang at Eastman Kodak discovered that sending an electrical impulse through carbon compound caused such material glow. Present day LED commercial packages have reached 100 lm/W, comparable to the efficacies of fluorescent and certain HID lamps. LED products available today are market as "Green-Industry" but actually low light output compared to typical light sources. The combination of high price and low light output make them a poor replacement for current technology. It is very important to compare new LED products to the most efficient conventional technology that could be used for any specific application. As LED technology advances, costs decrease, and efficiency improves, LEDs will build market share in the general illumination market.

• Current Optics and Photonics
• /
• v.6 no.3
• /
• pp.332-336
• /
• 2022

Given a cubic space, it is easy to uniformly illuminate the floor with light sources placed on top. However, little has been reported about uniform illumination on walls with the same configuration of light sources. Here we present a luminaire consisting of nine light-emitting diodes (LEDs) with perfect Lambertian distribution, placed on the top as a 3 × 3 rectangular LED array. The distances between LEDs and tilt angles of each individual LED are adjustable and optimized by an annealing algorithm. After optimization, the array produces a rectangular illumination pattern on one wall with a uniformity of about 89%. Analysis shows that the tilt angles of individual LEDs are key parameters for uniform side illumination. In a scenario that is more practical, the tilt angles of all the LEDs are set to be the same, only decreasing the uniformity to 83%.

• Journal of the Korean Society of Industry Convergence
• /
• v.26 no.5
• /
• pp.785-792
• /
• 2023

Because hyperspectral imaging provides detailed spectral information across a broad range of wavelengths, it can be utilized in numerous applications, including environmental monitoring, food quality inspection, medical diagnosis, material identification, art authentication, and crime scene analysis. However, hyperspectral images often contain various types of distortions due to the environmental conditions during image acquisition, which necessitates the proper removal of these distortions through a data preprocessing process. In this study, a preprocessing method was investigated to effectively correct the distortion caused by artificial light sources used in indoor hyperspectral imaging. For this purpose, a halogen-tungsten artificial light source was installed indoors, and hyperspectral images were acquired. The acquired images were then corrected for distortion using a preprocessing that does not require complex auxiliary equipment. After the corrections were made, the results were analyzed. According to the analysis, a statistical transformation technique using mean and standard deviation with reference to a reference signal was found to be the most effective in correcting distortions caused by artificial light sources.

• Journal of Mushroom
• /
• v.16 no.4
• /
• pp.331-333
• /
• 2018

The incorporation of Shiitake culture into sawdust is a widely utilized technique that can assist in reducing the cost and time consumption associated with oak cultivation. In sawdust cultivation, browning of the surface mycelia is an important stage with respect to the utility and longevity of the sawdust media. Surface browning forms a protective coating on the substrate, which can inhibit the invasion of pathogens and suppress water evaporation. Several different light sources (red LED, white LED, blue LED, and fluorescent light) were used and the intensity of illumination was carefully controlled (1.5, 10.5, $20.5{\mu}mol/m^2s$ for LEDs and 10, 100, 300 lux for the fluorescent light) to induce browning. The light sources were regulated via a 1 h on/off cycle in a controlled room environment at a temperature of $20^{\circ}C$, 60% humidity, and 1200 ppm $CO_2$ concentration for 60days. The browning effect varied depending on the source and the intensity of illumination. This effect was most effectively induced at $1.5{\mu}mol/m^2s$ for the red and blue LEDs. All light sources induced less browning at the highest intensity of illumination. This indicates that intensity values higher than $20.5{\mu}mol/m^2s$ in the case of the LEDs and 300 lux for the fluorescent light are not effective. After harvesting of the fruit bodies, we measured the weight, length, and width of the pileus and stipe in addition to their chromaticity and hardness. Treatment with $1.5{\mu}mol/m^2s$ blue LED produced the best harvest with the highest average chromaticity, weight (21.2 g), stipe length (30.8 mm), and hardness (377.9 g), with a fine length and width of the pileus.