• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.1912-1914
• /
• 2004

As the characteristics of LED disposition, LED warning light must be designed differently from general incandescent lamp warning light whose light source is located in origin. In this paper, the globe's lens of LED warning light was designed considering the LED intensity distribution and the arrangement of the LED. And prove the appropriateness of that design by simulation in LightTools which is optical design program.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.6 no.5
• /
• pp.19-26
• /
• 1992

A computer program to calculate the illumination distributions of a room interior was made. The room has a light source with arbitrary intensity distribution. The program follows the paths of the particles from the light sources, and the illumination distribution is calculated by repeating this following to many particles. Monte Carlo method is applied to the decision of the direction of the particle from light source, and the new direction of the reflected particles. Making simulation program on this basis, illumination distributions were measured for various light sources and wall surfaces tocertify the calculated results. As a results, it is known that the calculated distribution would be correct if the size of the light source is sufficiently smaller than the size of the room.

• The Korean Journal of Ecology
• /
• v.21 no.3
• /
• pp.291-300
• /
• 1998

The forest vegetation of Mt. Odae based on the interspecific relationship was classified into 4 groups : Quercus mongolica, Pinus densiflora, Quercus variabilis and Patrinia saniculaefolia. Thirty-one species of Quercus mongolica group including Quercus mongolica and Acer mone, 12 species of Pinus densiflora group comprising Pinus densiflora and Spodiopogon sibiricus, 6 species of Quercus variabilis group and 4 species of Patrinia saniculaefolia were positively correlated. in the results of species ordination by principal component analysis, 7 clusters by the humidity and acidity of soil, 4 clusters by the humidity and light intensity and 7 clusters by the acidity and light intensity were formed. The plot ordination showed that the distribution of species based on the humidity, soil acidity and total organic matters was in the order of Pinus densiflora, Quercus variabilis and Quercus mongolica groups, and based on the light intensity was in the order of Quercus variabilis, Pinus densiflora and Quercus mongolica groups.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.22 no.4
• /
• pp.56-60
• /
• 1986

The purpose of this study is to find the light intensity which induced maximum gathering rate and to observe the variation of the gathering rate both in daytime and at night by using rock trout, He.'~agrammos otakii (Jordan et starks). An experimental tank (360L x SOW x 55H cm) was set up in a dark room. An illumination system was attached to the end of one side of the tank to control horizontal light intensity. Six artificial light sources were prepared by combination of two light bulbs (5 W, 150 W) and seven filters. During the experiment water depth was maintained 50 em level in the tank. The tank was marked into six longitudinal sections each being 60 em long to observe the distribution of fish. The fish were acclimatized in dark condition for 50 minutes prior to the main experiment. Upon turning on the light, the number of fish in each section was counted 40 times every 30 seconds. and the gathering rate was obtained from the average number of fish in each section. The light intensity inducing maximum gathering rate was O. 7 lux (0. 5~1. 1 lux) in the daytime and 5. 2/ux (3.2-7.7 lux) at night. The variation of the gathering rate of fish in illumination time was sma II and showed the decreasing trend.

• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.1746-1749
• /
• 1997

A distributed optical fiber temperature sensor can continually monitor the measurand at every point along of its fiber length. It is based on OTDR technics which used extreamlly weak backward scattered light called Raman scattering. When the Pulsed high intensity laser light injected into the optical fiber there are several kind of backscattered light such as Rayleigh, Stokes, and anti-Stokes, etc. caused by impurities molecular vibrations. The temperature distribution is derived form the intensity ratio Raman scatted light-Stokes versus anti-Stokes-and the time function between light injection and signal detection. It is shown that the priniciple of distributed sensing, the system desing, and the result of experiments.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.26 no.3
• /
• pp.328-336
• /
• 2017

The exit surface of a lens is designed using a three-dimensional free-form expression in order to easily modify a curved surface. This enables the design of numerical values and mathematical things using three-dimensional free-form expression, and enhances precision because it can be fine-tuned via numerical control. The standard of "Classification of Luminaire Light Distribution" for outdoor lighting fixtures by IESNA is adopted in order to examine the correlation between three-dimensional free-form surface expression and lighting performance. The variation of light distribution type and range is analyzed using the values of maximum light intensity and 50% light intensity. The actual tolerance occurs owing to parameters such as the thickness of the lens, the distance between LEDs, and the movement of the center of the incident surface; the effects of changes in these parameters on the performance are compared and analyzed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2008.05a
• /
• pp.205-208
• /
• 2008

In this paper, we have measured and compared the optical and electrical characteristics of LED(light emitting diode) and CNT(carbon nano-tube) lightings. Especially, the IES format files are used for each of the luminaire LlD(luminous intensity distribution) analysis and light level simulation for analyze the maximum, minimum, and average light level. In the future, when CNT and the LED based lighting technology standards are writing, this data will be used in judging.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.23 no.1
• /
• pp.64-68
• /
• 2014

This paper introduces the use of a crown-shaped (CR) lens to effectively diffuse the light from a light-emitting diode (LED) without any loss in the light intensity, in contrast to polymer-bulb-type diffusers. The diffusion lens was designed based on the Snell's law, which describes the physical path of a ray passing through the boundary between different media. CR lenses were fabricated by polydimethylsiloxane (PDMS) casting and UV-embossing processes, which used a pre-designed metal mold and UV-curable resin, respectively. Through experiments and optical evaluations, it was verified that the newly proposed CR lens not only decreased the vertical light strength and glare effect from an LED light source but also improved the diffusion characteristics while maintaining the quality of the LED's light intensity.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.2
• /
• pp.48.2-48.2
• /
• 2019

Light from universe is absorbed, scattered, and re-released by interstellar dust before it reaches us. Therefore, accurate correction of the observed light requires not only spatial distribution of interstellar dust, but also information on absorption and scattering for each wavelength. Far-ultraviolet (FUV) light is mainly produced by bright, young O-type and some B-type stars, but it is also observed in interstellar space without these stars. Called FUV Galactic light (DGL), these lights are mostly known as starlight scattered by interstellar dust. With the recent release of GAIA DR2, not only accurate distance information of stars in our Galaxy, but also accurate three-dimensional distribution maps of interstellar dust of our Galaxy were produced. Based on this, we performed 3-dimensional Monte Carlo dust scattering radiative transfer simulations for FUV light to obtain dust scattered FUV images and compared them with the observed FUV image obtained by FIMS and GALEX. From this, we find the scattering properties of interstellar dust in our Galaxy and suggest the intensity of extragalactic background light. These results are expected to aid in the study of chemical composition, size distribution, shape, and alignment of interstellar dust in our Galaxy.

• New Physics: Sae Mulli
• /
• v.68 no.11
• /
• pp.1268-1274
• /
• 2018

Aircraft-warning lights are lights that are used to inform pilots in flight about the presence of buildings or dangerous objects. Currently, the light sources of most aircraft-warning lights have been replaced by light-emitting diodes (LEDs). However, the aircraft-warning lights that are installed do not meet the optical performance standards and may cause airplane collisions. Therefore, the use of such light poses a risk to aviation safety. In order to solve this problem, we designed a Fresnel lens with the same luminous intensity distribution ovef $360^{\circ}$ direction; thus, we collimated the light beam from the LED light source with a narrow beam divergence angle in the form of an array of aspheric pieces. After that, we designed and simulated an aircraft-warning-light optical system with a center luminous intensity of 20,000 cd and a vertical divergence angle of $3^{\circ}$ or more by optimizing the lens' tilt and the distance between the LED and the Fresnel lens.