• Journal of Bio-Environment Control
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• v.7 no.1
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• pp.9-14
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• 1998

Air current speeds were controlled of 0.3, 0.5, 0.7 and 0.9 m.s$^{-1}$ to investigate the effects of air current speeds on the growth of eggplant plug seedlings (Solanum melongena L.) in a wind tunnel under artificial lighting. Growth of plug seedlings was influenced by the magnitude of air current speed and the traveling distance of regulated air flow. Stem length. ratio of length to diameter in stem, plant height .and number of leaves of plug seedlings decreased with the increasing air current speed and were significantly different at 5% level. Net photosynthetic rates of plug stand increased with the increasing air current speed and took a maximum value at the air current speed of 0.7~09 m.s$^{-1}$ . Stem diameter decreased and leaf area increased with the traveling distance of regulated air flow. Fresh weight and T/R ratio of dried weight were not influenced by the air current speed. Optimum control for microclimates inside the plug stand is needed to produce the uniform growth and high quality of plug seedlings in a semi-closed plant Production system under artificial lighting.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1148_1149
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• 2009

반사형 전동 블라인드는 BEMS(Building Energy Management System)에 이용되는 조명 에너지 절감 장치로서, 블라인드 날개를 반사형 재질로 제작하여, 외부 채광이 블라인드 날개에 반사되어 천장에 반사되고 반사된 빛은 천장에서 확산되어 실내 깊숙이 부드럽고 균일한 조도를 공급해 준다. 이를 이용하면, 실내 거주자의 불편함 없이 실내 인공조명 사용량을 줄일 수 있다. 이를 구현하기 위해서는 태양광선의 고도의 변화에 따라 블라인드의 제어 각도를 계산하여 블라인드 제어 전동 모터를 구동해야 한다. 따라서 본 논문에서는 외부 채광을 실내 천장 면에 균일하게 반사할 수 있는 블라인드 날개의 제어 각도의 최적 조건을 제시하고, 컴퓨터 시뮬레이션을 통해 제시한 블라인드 날개 각도의 최적성을 검증하였다.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.301-305
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• 2008

강원도 지역은 대부분의 지형이 산지로 이루어져 있고, 최근 심각해지고 있는 기후 변화로 인해 집중호우가 잦아지면서 이로 인한 산사태 피해 또한 증가하고 있는 상황이다. 하지만 기존에 이루어져왔던 직접 측량 방식은 많은 시간과 인력이 소모되고, 접근성의 제약으로 인해 곳곳에서 발생하는 모든 산사태를 체계적으로 감지하기에는 무리가 따른다. 따라서 효율적인 산사태 감지와 신속한 대처를 위해 최근 인공위성을 이용한 원격 탐측이 주목을 받고 있으며, 특히 고해상도 영상 레이더(Synthetic Aperture Radar, SAR)는 태양광의 유무나 대기 조건에 상관없이 상시 관측이 가능하다는 장점으로 인해 그 수요가 점점 늘어나고 있는 추세이다. 본 연구에서는 산사태가 집중되는 지역인 강원도 강릉 부근(N $37^{\circ}.30'{\sim}38{\circ}.10'$, E $128^{\circ}.05'{\sim}129^{\circ}.00'$)을 대상으로 SAR 영상 처리 기법 중 하나인 간섭기법(Interferometric SAR, InSAR)를 통해 생성되는 coherence 영상을 분석하여 93년 7월 27일과 동년 9월 9일 사이에 발생한 산사태 피해 지역을 추정하였다.

• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.110-115
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• 2022

Accurate current-voltage modeling of solar cell systems plays an important role in power prediction. Solar cells have nonlinear characteristics that are sensitive to environmental conditions such as temperature and irradiance. In this paper, the output characteristics of photovoltaic module are accurately predicted by combining the artificial neural network and physical model. In order to estimate the performance of PV module under varying environments, the artificial neural network model is trained with randomly generated temperature and irradiance data. With the use of proposed model, the current-voltage and power-voltage characteristics under real environments can be predicted with high accuracy.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.232-239
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• 2016

The objective of this study was to examine the effect of photoperiod and light intensity of RBW LED (red:blue:white = 2:1:1) on the growth of Taraxacum coreanum Nakai in a fully artificial light type plant factory. 3 photoperiods and 4 light intensity were used respectively in a fully artificial light type plant production system. Plants were cultured with three photoperiods and four light intensity regimes (conditions) for 270 and 120 days, respectively, using nutrient film technique (NFT) or aeroponics culture methods. For each photoperiod, the total leaves per plant harvested 8 times in all cultivation period was 224 in the 16/8(day/light) photoperiod that had no significant difference from 220 in the 12/12 photoperiod and the lowest number of leaves was 151 occurred in the 8/16 photoperiod, which means that the longer photoperiod, the more leaves harvest. Total fresh weight of above ground was the high in order of in 16/8 photoperiod as 125g, 12/12 photoperiod as 91g, 8/16 photoperiod as 56g. For each light intensity, the total leaves per plant harvested 4 times in all cultivation period was the great in order of $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ as 123, $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ as 107, $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ as 95, $50{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ as 56 which was the smallest number of total leaves harvest. Total fresh weight of above ground per plant was the high in order of $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ as 43.6g, $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ as 34.6g, $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ as 32.2g, $50{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ as 18.2g. From these results, it was concluded that photoperiod of 16/8 and light intensity at $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ can be used as the light condition of RBW LED (red:blue:white = 2:1:1) for optimal growth of Taraxacum coreanum Nakai in a fully artificial light type plant factory.

• Ecology and Resilient Infrastructure
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• v.4 no.3
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• pp.142-148
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• 2017

Nitrogen and phosphorus are key factors in causing eutrophication of water body. In this study, ceramics media was selected to increase the removal efficiency of nitrogen and phosphorus. We designed vertical, horizontal flow constructed wetlands to create aerobic and anaerobic flow conditions by using the media, then proceeded to performance evaluations after acrylic reactors were produced. In the case of vertical and horizontal flow constructed wetlands, we measured oxygen concentrations to evaluate aerobic and anaerobic conditions. we got the result of 2.7 mg/L in the aerobic condition, N.D in the anaerobic condition respectively, which suited our purpose. The result of the combined vertical and horizontal flow condition showed that the removal efficiency of SS was 94%, 91%, 61% at 140 min, 80 min, 60 min of running times, respectively, and the removal efficiency of T-P was 84%, 71%, 63% during each running time. In case of T-N, the removal efficiency was 63%, 49%, 42% during each running time. We found that the reactor exerted better removal efficiency when in the short time compared to 12 - 24 hr residence time of existing wetlands. In this study, we conducted experiments to explore functional effects after applying combined vertical and horizontal flow methods in the field. Further study will be carried out to identify its mechanism and administrative perspective.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.10
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• pp.1017-1026
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• 2009

The solar cell system operates by facing the sun-light. Minor cracks, static discharge, and thermal shock that can happen during production/testing phase can lead to degradation in performance during operation, since solar cells are exposed to extreme thermal/mechanical environment in space. In order to detect small cracks and internal damages in the solar cells due to thermal shocks, which are the core units of a solar cell system, expensive equipment, complicated test process, and much time are required. Therefore, a qualitative method for easily and quickly testing the 'health' of solar cell functionality is required. This dissertation describes a theoretical and technical grounds for quickly and easily evaluating the health of solar cells using electroluminescence effect of Gallium-Arsenide solar cells that are most widely used by spacecrafts in recent years. Also described in the dissertation is the technical issues and constraining factors for applying the proposed method to actual space-rated solar cell systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7990-8000
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• 2015

Plant factories are plant cultivation systems which produce farm products uniformly under the controlled environmental condition regardless of seasons and places. Thermal flow in the plant factory is an important parameter in cultivating plants. In this research, we study thermal flow characteristics for a hybrid plant factory with multi-layer cultivation shelves using computer simulation techniques. In order to obtain numerical solutions for thermal flow characteristics, a finite volume method was applied. We consider a low-Reynolds-number ${\kappa}-{\epsilon}$ turbulence model, incompressible viscous flows, and pressure boundary conditions for numerical simulation. Commercial software Solid Works Flow Simulation is then used to investigate characteristics of thermal flows in the plant factory applying several different inflow air velocities and arrangements of cultivation shelves. From numerical analysis results, we found that temperatures in cultivation shelves were uniformly distributed for Case 3 when the inflow air velocity was 1.6 m/s by using a blower in the plant factory. However in Case 1 lower temperature distributions were observed in test beds, TB2 and TB3, which indicated that additional temperature control efforts would be required. Average shelf temperature increased by $3^{\circ}C$ using artificial light source (DYLED47) with 50% blue and 50% red LED ratios. Korea Academia-Industrial cooperation Society.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.359-367
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• 2015

Physiological plasticity of insects can be closely related with their epigenetic change. This hypothesis was tested using a polyphagous lepidopteran insect, Spodoptera exigua, by assessing the effects of different diets on development and DNA methylation. Three different diets (Welsh onion (WO), Chinese cabbage (CC), artificial diet (AD)) were assessed by feeding a cohort of larvae from neonate to last instar. There were significant differences in larval developmental rate, pupal weight and adult emergence according to diet treatments. AD-fed larvae exhibited the fastest developmental rate along with the highest pupal weight and adult emergence. Among natural hosts, WO was more favorable for development of S. exigua than CC. Total hemolymph proteins and sugars in the last instar larvae were varied among different diets. Gene expression of an insulin-like peptide (SeILP1) presumably associated with development was also varied among diets. Cytosine methylation of genomic DNA was assessed using a monoclonal antibody. Genomic DNA of S. exigua larvae was methylated. DNA methylation was apparently varied among different diet-fed larvae. The facts that a cohort of S. exigua was differentiated in developmental rate and cytosine methylation by different diets suggest that epigenetic factor(s) may play a crucial role in the physiological plasticity.

• Korean Journal of Plant Tissue Culture
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• v.26 no.1
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• pp.59-63
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• 1999

Efficient plant regeneration via shoot organogenesis from in vitro cultured leaf segments of chrysanthemum (Dendranthema grandiflora Tzvelev cv. Namjeon) was achieved. Adventitious shoot formation from leaf explants was greatly influenced by plant growth regulator, leaf age, light condition, explant number per culture vessel, and explant orientation. Leaf segments, obtained from fully expanded young 1-2nd leaves and inoculated 8 explants per petri-dish with adaxial surface contact with MS medium supplemented with 0.5 mg/L BA and 2.0 mg/L NAA, produced 100% regeneration frequency and 13.7 shoots per explant. Regenerated adventitious shoots were successfully rooted in MS medium with 0.1 mg/L NAA. The plantlets were acclimatized in artificial soil mixtures (Vermiculite:Perlite=1:1), and transferred to greenhouse for flowering. The regenerated plants showed normal phenotypes.