• Journal of the Architectural Institute of Korea Structure & Construction
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• v.36 no.3
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• pp.159-167
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• 2020

For modern people who spend most of their time indoors, the indoor environment is very important. The efficiency of work depends on the amenity level of the occupants who use the office space. Therefore, the experiment was conducted to derive the proper illuminance according to the amenity level of the occupants. The experiment was conducted in an office in Chilgok County for 6 days. The illuminance of the indoor was changed every day, the feeling brightness of the occupants was measured every 10 minutes, the eye fatigue was measured every 30 minutes, and the overall illuminance and the work surface illuminance were measured every hour. Experimental results show that the feeling brightness is different depending on the position of the occupants. Also, it was found that the brightness survey preferred by the occupants required more proper illuminance than the brightness. In addition, it is considered that there is a correlation with indoor temperature and humidity as the eye fatigue of occupants. Brightness preference by time of day was analysis from feeling brightness of occupants and preference brightness of occupants, and then it was analyzed like eye fatigue to derive proper illuminance per hour. Based on these results, it can be utilized for improvement of eye amenity existing office space.

• Electrical & Electronic Materials
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• v.10 no.3
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• pp.262-267
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• 1997

In order to improve the brightness and chromaticity of green emitting low voltage phosphor for FED, we examine PL, PLE and CL emission characteristics of ZnGa$_{2}$O$_{4}$:Mn,O prepared in Ar and vacuum. ZnGa$_{2}$O$_{4}$:Mn,O sintered in vacuum shows about 16 times as bright as the one fabricated in Ar and excellent chromaticity. In PL emission spectra of ZnGa$_{2}$O$_{4}$:Mn,O at low temperature of 9 K, two peaks are observed at 504 nm and 513 nm. At room temperature, the two peaks are superimposed due to the lattice thermal vibrational energy, and only one peak is observed at 509 nm. From PLE measurements, it is believed that the energy levels of the host lattice and Mn ions are coexisted. The energy transfer from the host lattice to the emission center of Mn$^{2+}$ ions occurs.s.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1337-1340
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• 2008

Since 2006, the Industrial Technology Research Institute and the University of Cincinnati have been jointly exploring approaches for high brightness flexible electrowetting displays (EWDs). Recently, ITRI demonstrated for the $1^{st}$ time a 6" AM-EWD reflective display panel. To create flexible AM-EWDs, Cincinnati has developed low-temperature processing and improved pixel structures.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.1
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• pp.8-14
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• 2014

Brightness temperature spectra acquired from FTIR(Fourier Transform Infrared)-SCADS (Standoff Chemical Agent Detection System) could be available for detection and identification of the chemical agents and pollutants from different background. IR spectrum range of 770 to 1350 $cm^{-1}$ is corresponding to "atmospheric window". A 2-dimensional(2D) brightness temperature spectrum was drawn from combining each data point through automatic continuous scanning of FTIR along with altitude and azimuth. At higher altitude, temperature of background was decreased but scattering effect of atmospheric gases was increased. Increase in temperature difference between background and blackbody in SCADS at higher temperature causes to increases in peak intensity of $SF_6$. This approach shows us a possibility that 2D visual information is acquired from scanning data with a single FTIR-SCADS.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.5
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• pp.333-338
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• 2022

The single jet of decane/methylcyclohexane mixed fuel that is surrogate for kerosene was injected into supercritical environment and visualized using shadowgraph technique. The injection pressure drop of the fuel jet of T_r = 0.484 was kept constant at 0.5 MPa and the experiment was conducted above the critical point of the mixed fuel, and the reduced temperatures of the chamber was changed from 1.00 to 1.23, and the reduced pressures was 1.00 and 1.38. As an index for reducing the density of jets sprayed into the supercritical environment, the brightness intensity of the post-processed jet image was observed with the internal temperature and pressure of the chamber. It was confirmed that the decrease in the brightness intensity of the jet when the temperature inside the chamber increased, and when the pressure inside the chamber was higher at the same temperature, the decrease in the brightness intensity of the jet was delayed. When the pressure inside the chamber is high, it is thought that the change in brightness intensity is delayed due to the increase in the pseudo-critical temperature of the fuel and the increase in the temperature required to reduce the density of the fuel jet.

• Atmosphere
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• v.18 no.4
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• pp.267-277
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• 2008

The occurrence and strength of the Asian Dust over the Korea Peninsular have been increased by the expansion of the desert area. For the continuous monitoring of the Asian Dust event, the geostationary satellites provide useful information by detecting the outbreak of the event as well as the long-range transportation of dust. The Infrared Optical Depth Index (IODI) derived from the MTSAT-1R data, indicating a quantitative index of the dust intensity, has been produced in real-time at Korea Meteorological Administration (KMA) since spring of 2007 for the forecast of Asian dust. The data processing algorithm for IODI consists of mainly two steps. The first step is to detect dust area by using brightness temperature difference between two thermal window channels which are influenced with different extinction coefficients by dust. Here we use dynamic threshold values based on the change of surface temperature. In the second step, the IODI is calculated using the ratio between current IR1 brightness temperature and the maximum brightness temperature of the last 10 days which we assume the clear sky. Validation with AOD retrieved from MODIS shows a good agreement over the ocean. Comparison of IODI with the ground based PM10 observation network in Korea shows distinct characteristics depending on the altitude of dust layer estimated from the Lidar data. In the case that the altitude of dust layer is relatively high, the intensity of IODI is larger than that of PM10. On the other hand, when the altitude of dust layer is lower, IODI seems to be relatively small comparing with PM10 measurement.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.76-82
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• 1998

Increase of greenhouse gas due to $CO_2$ and CH$_4$ gases would cause the global warming in the atmosphere. According to the global circulation model, it is pointed out in the Okhotsk Sea that the large increase of atmospheric temperature might be occurredin this region by global warming due to the doubling of greenhouse effectgases. Therefore, it is very important to monitor the sea ice extents in the Okhotsk Sea. To improve the sea ice extents and concentration with more highly accuracy, the field experiments have begun to comparewith Airborne Microwave Radiometer (AMR) and video images installed on the aircraft (Beach-200). The sea ice concentration is generally proportional to the brightness temperature and accurate retrieval of sea ice concentration from the brightness temperature is important because of the sensitivity of multi-channel data with the amount of open water in the sea ice pack. During the field experiments of airborned AMR the multi-frequency data suggest that the sea ice concentration is slightly dependending on the sea ice types since the brightness temperature is different between the thin and small piece of sea ice floes, and a large ice flow with different surface signatures. On the basis of classification of two sea ice types, it is cleary distinguished between the thin ice and the large ice floe in the scatter plot of 36.5 and 89.0GHz, but it does not become to make clear of the scatter plot of 18.7 and 36.5GHz Two algorithms that have been used for deriving sea ice concentrations from airbomed multi-channel data are compared. One is the NASA Team Algorithm and the other is the Bootstrap Algorithm. Intrercomparison on both algorithms with the airborned data and sea ice concentration derived from video images bas shown that the Bootstrap Algorithm is more consistent with the binary maps of video images.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.2
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• pp.98-104
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• 2003

This paper proposes the design of a multi-color lamp using high brightness RGB LEDs for color variation. Appropriate number of RGB LEDs is so chosen according to the color mixing theory that the overall LEDs represent a color temperature of 6500K. Also, the chosen RGB LEDs are suitably arranged by using an optical design program. The lamp has an internal controller circuit, so it can be directly connected to the existing incandescent lamp socket. It's main body is comprised of two PCB layers. The upper layer contains 44 LEDs and the lower one has a simple microcontroller-based PWM control circuit. The lamp has functions of both ON/OFF control and PWM control, and enables color variation of over 100,000 colors and of more than 10 patterns.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1997.11a
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• pp.140-145
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• 1997

A stuey to investigate the perception characteristics of color and brightness was conducted in a combined PC and TV monitor, The objective of this study is to suggest user's favorite color temperature in PC mode and user's favorite contrast in TV mode. Investigated factors were monitor coating(coatiog vs. non-coation)and screen brightness (30fL vs. 35fL)in first experiment and monitor coating and pucture movement(static vs. dynamic) in second experiment. The first experiment was conducted in TV mode. Twenty-three subjects (male 12, female 11) perticipated in this experiment. In first experiment, average color temperatures were about 8000K in all experimental conditions. In addition, there was significant difference between coating and non-coating screen at 0.1 level. In second experiment, average contrasts were obtained in all esperimental conditions. There was significant difference between coating and ndn-coating screen at 0.05 level, In addition, there was significant difference between static picture and dynamic picture at 0.1 level

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.243-247
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• 2009

A Radioactive constraint of the nuclear fuel assembly irradiated by neutron during normal operation cycle of the nuclear power plant is typically on the order of about 3 kGy/h. In order to inspect nuclear fuel assembly using a VT (vision technology) system, the light such as halogen lamp is used. As the halogen lamp has lower color temperature than the sun light, the objects under halogen lamp illumination are seemed to be tinted with red. In this paper, high brightness LED is considered to be used as the light source of VT system. The high brightness LED, which is a key light source of the VT system, have been gamma irradiated at the dose rate of 4 kGy/h during two hours up to a total dose of 8 kGy. The radiation induced color-center in the LED housing cap made of plastics materials is observed.