• 한국지열·수열에너지학회논문집
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• 제14권3호
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• pp.15-20
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• 2018

To study the effects of solar energy in a greenhouse, outdoor air temperature and wind speed on inside air temperature, a simulation model for forecasting the greenhouse air temperature was conducted on the basis of the energy and mass balance theory. Application of solar energy to the greenhouse is major area in the renewable energy research and development in order to save energy. Recently, considering the safety and efficiency of the heating of greenhouse, clean energy such as geothermal and solar energy has received much attention. The analysed greenhouse has $50m^2$ of ground area which located in jocheon-ri of Jeju Province. Experiments were carried out to collect data to validate the model. The results showed that the simulated air temperature inside a plastic greenhouse agreed well with the measured data.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.745-748
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• 2008

The theory of Bartleson and Breneman that the perceived image contrast changes with surround luminance (the lighter surround provides higher contrast) was tested an over bright condition($8500d/m^2$). Contrarily to the Bartleson and Breneman's results, we observed the fact that perceived constrast was decreased when surround huminance increased from dark to over bright through two sets of psychophysical experiments based upon both uniform gray patches and complex color images.

• KIEAE Journal
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• 제2권2호
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• pp.39-44
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• 2002

Recently, underground spaces can be usually applied to the alternative of land use for parking. However, lack of window and natural light are among the most cited drawbacks associated with dark image of underground. If underground parking lots are designed to be positive and safe environment for people, openings for daylighting will play a significant role. The natural light and unobstructed view to outdoor are main elements to create optimal underground parking lots. This paper focuses on investigating the actual day lighting conditions and evaluating the day lighting performance of openings as potential lighting resources. For the study, the field measurements and Questionnaire surveys are conducted. And then, the day lighting performance of underground parking lots based on opening geometry and orientation are evaluated by scaled model experiments. As results, the feelings of safety and orientation of underground parking lots are improved by openings for day lighting regardless of the sizes. The required illuminances (daylight factor 0.5%) for underground parking lots can be satisfied in the skylight opening ratio of 4% or more.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.232-235
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• 2000

Design and experiments of a nondestructive system to inspect deterioration of ACSR-OC (ACSR Outdoor Cross-linked Polyethylene Insulated Wire usually used in HV overhead distribution lines presented in this paper. ACSR-OC conductor built to pollutants air for a long period would be easily progress to corrode so that it may lead to the reduction of the effective cross section area of conductors. A fault diagnosis system consisting of a solenoid sensor, a constant current source with RF frequency signal processing unit and a motor driver/controller designed and implemented. This instrument can dot the sensor output variation due to deterioration corrosion, continuously. As a result, it was shown such corrosion detector can readily be utilized estimating the diameter change due to deterioration overhead distribution lines and in giving an warning or inform before severe aged conductor lead to fail.

• 한국환경과학회지
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• 제11권5호
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• pp.445-454
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• 2002

Material exposure experiments were performed to evaluate the relationship between air pollution and material corrosion rates based on collaboration with researchers in China, Japan, and Korea. Qualitative and quantitative atmospheric corrosion was estimated from damage caused to bronze, copper, steel, marble, cedar, cypress, and lacquer plates exposed to outdoor and indoor conditions in certain East Asian cities. The effects of atmospheric and meteorological factors on the damage to the copper plates and marble pieces were estimated using a regression analysis. The results indicated that sulfur dioxide produced the most destruction of the materials, especially in South Korea and China. In Japan, the copper plates were damaged as a result of natural conditions and sea salt. Copper was also found to be damaged by the surface deposition of sulfur and chlorine. Meanwhile, marble was substantially degraded by gaseous sulfur dioxide, yet sulfate ions in rain had no effect. Accordingly, the analysis of air pollution from the perspective of material damage was determined to be very useful in evaluating and substantiating the intensity of air pollution in East Asia.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.28-31
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• 1997

Experiments and design efforts have been made to improve performance of the levitation magnet. One pole of the pair-magnet is manufactured as a solid core without stagger and its test result gives a 5 % increment of levitation force. One effort is to make molding coil to protect it from vibration and precifitation due to outdoor usage. In addition, a permeant magnet embedded type has been designed and analyzed by using FEM program.

• 한국대기환경학회지
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• 제15권3호
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• pp.223-233
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• 1999

The wind-flow characteristics over a two-dimensional triangular prism with a porous windbreak are numerically investigated. The geometry is a simplified model of large outdoor stack with a frontal wall-type windbreak which is used to prevent particle dispersion by reducing wind speed over stak surface. In the present numerical model, the RNG k-$\varepsilon$ model, the orthogonal grid system and the QUICK scheme are employed for the successful simulation of separated flow. The predicted results are compared and validated with the associated wind-tunnel experiments. In addition, the trajectories of dispersed particles and their sedimentation characteristics are quantitatively investingated using a Lagrangian turbulent-dispersion model.

• 한국군사과학기술학회지
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• 제9권1호
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• pp.109-116
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• 2006

This paper presents a real time distance measuring device using a W-band linear frequency modulated continuous wave(FMCW) radar and TMS320C6701 digital signal processor(DSP). We used FFT operation for measuring distance with the beat signals and the results of FFT could be converted to distance with ease. We presented how to implement a real time miniaturized hardware system including network protocols using a single DSP core. Also how to control the modulation signal of FMCW system to compensate the VCO nonlinearity using the Time Gating control of DSP is presented. We have shown that the proposed system has good performances for measuring distance in real time via outdoor environment experiments.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.852-855
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• 2002

Quality of the reflective LCD as a display is strongly influenced by the environment where the display is evaluated. Up to now, several methods for the evaluation of the reflective LCDs have been proposed. We have developed a new method in which the optical characteristics of the reflective LCDs from the spot light and the diffuse light can be obtained at the same time. The results obtained in our experiments by using the new method showed a good agreement with those evaluated at office and outdoor environments.

• 로봇학회논문지
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• 제4권3호
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• pp.218-224
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• 2009

We propose a formation-keeping and changing methods for outdoor multiple mobile robots in chained form. Our proposed method is designed to maintain the follower to its desired distance and orientation with respect to the pole using the concept of virtual force such as potential field. The client robots use a behavior-based control to perform kinematic control to keep formation under the centralized system in our software framework. The relationship of each poles that is expressed by set of distance and angle is the description of the formation type and the type converting is performed using this set. In addition, we also examine the stability and capability in the simulation and experiments with real robots.