• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.333-342
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• 2010

For the energy-saving production of fresh vegetables in poor environment such as the Antarctic, a container-type plant factory was designed and developed. To maximize space usage of the 20 feet container ($L5.9m{\times}W2.4m{\times}H2.4m$), a three-level hydroponic cultivation system was installed and the nutrient solution was supplied by bottom watering. Using this system, 3 lettuce cultivars were grown under different the light source (light intensity). After 2 weeks from the transplanting, fluorescent lamp ($145\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) showed the best fresh weight of top part and leaf area. However, After 4 weeks, fluorescent lamp plus metal halide lamp ($150\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) led to the optimum growth of the each lettuce cultivar. The cultivar, 'Cheongchima', showed the best fresh weight of top part and leaf area, followed by 'Jeokchukmyeon' and 'Lollo rosa'. The chlorophyll concentrations (SPAD) showed no significant difference among the sources of lights. However, 'Cheongchima' showed relatively high chlorophyll concentration. With the above results, we found that the growth of lettuce is depend on light intensity and even at same intensity, the growth is different among the cultivars. Therefore, the selection of optimum cultivar should be considered in the plant factory system that has only weak light density.

• Korean Journal of Optics and Photonics
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• v.22 no.1
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• pp.46-52
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• 2011

A confocal microscope was developed utilizing a scanning sample stage based on a home-built double-compound flexure guide. A scanning sample stage with nano-scale resolution consisted of a double leaf spring based flexure, a displacement amplifying lever, a Piezo-electric Transducer(PZT) actuator and capacitance sensors. The performance of the two-axis stage was analyzed using a commercial finite element method program prior to the implementation. A single line laser was employed as the light source along with the Photo Multiplier Tube(PMT) that served as the detector. The performance of the developed confocal microscope was evaluated with a mouse ear skin imaging test. The designed scanning stage enabled us to build the confocal microscope without the two optical scanning mirror modules that are essential in the conventional laser scanning confocal microscope. The elimination of the scanning mirror modules makes the optical design of the confocal microscope simpler and more compact than the conventional system.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.189-199
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• 2021

In order to increase the self-reliance rate of new and renewable energy in order to respond to the mandatory domestic zero-energy buildings, the taller the building, the more limited the site area, and installing PV modules on the roof is not enough. Therefore, BIPV (Building integrated photovoltaic, hereinafter BIPV) is the industry receiving the most attention as a core energy source that can realize zero-energy buildings. Therefore, this study conducted a survey on the problems of the BIPV industry in a self-discussing method for experts with more than 10 years of experience of designers, builders, product manufacturers, and maintainers in order to suggest the right direction and revitalize the BIPV industry. Industrial problems of BIPV adjustment are drawn extention range of standard and certification for products, range improvement for current small condition of various kind productions, need to revise standards for capable of accomodating roof-type, color-module and louver-module, necessary of barrier in flow of foreign modules into korea through domestic certification mandatory, difficulty in obtaining BIPV information, request to prevent confusion among participants by exact guidelime about architectural application part of BIPV, and lack of the BIPV definition clearness, support policy, etc. Based on the improvements needed for the elements, giving change and competitiveness impacts aims to present and propose counter measures and direction.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.10a
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• pp.70-74
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• 1999

발전소 시뮬레이션 시스템 기술은 종합적인 지식을 바탕으로 자료수집 및 분석, 소프트웨어 개발 환경, 수학적 모델, 전산기 구성, 각종 계기류 설계 및 구매 장착 등의 노하우를 알아야만 제작할 수 있는 종합적인 기술이다. 또 지시기반의 기술이며 부가가치가 높은 기술이기 때문에 선진 각국에서는 계측제어 시스템의 기술개발 및 시장 확대를 위하여 힘을 쓰는 동시에 타국으로의 기술정보 유출을 경계하는데 신경을 곤두세우고 있다. 현재 복잡화되어 가고 있는 산업 사회의 전력 수요에 대한 대폭적인 증가 추세에 따라 발전소에서는 보다 효율적이며 합리적이고 경제적인 전력 공급을 위해서 전력 생산에 대한 신뢰성 향상 및 안정성 확보는 물론, 효율성 높은 운전이 절실히 요구되고 있다. 한편, 국내의 시뮬레이션 시스템 분야 기술은 아직도 완벽한 수준에는 미치지 못하며, 이 분야의 기술력 확보 및 신기술 개발은 향후 미래의 모든 시스템산업의 성쇄를 판가름하는 아주 중요한 척도가 될 것이다. 이 중에서 접지 분야는 고전압 혼촉에 의한 저압측 선로의 전압상승 방지, 모선(Bus)이나 전력 기기의 절연보호 및 회로전압의 안정등으로 시스템 성능을 한층 증가 시켜줄 뿐아니라 기기의 오동작이나 낙뇌등으로 인명피해 발생을 없애주는 아주 중요한 분야임에도 불구하고 이 분야의 국내 관련법규등이 미비한 사항이다. 그래서 발전소 분산제어 시스템분야의 장기간 신뢰성 및 안정성을 가지고 있고, 국내에서 많이 사용하는 미국 Bailey의 infi-90 및 독일 ABB의 Procontrol-P를 비교 분석하여 발전소 시뮬레이션 시스템의 접지에 응용 하고져 한다.상호 발생기를 이용한 다양한 시스템 검증 및 분석에 이용할 수 있을 것이다. 본 논문은 가상호 발생기의 구조와 최대 용량 시험 방법을 소개하고, 더 나아가 호 Traffic에 대한 최대 용량 시험뿐 아니라 QoS를 향상시키기 위한 교환 시스템의 제반 성능 시험 및 분석에 이를 이용하기 위해 개선이 필요함을 서술하고자 한다.textrm{m}$~3.4$\mu\textrm{m}$ 범위에서의 투과 및 흡수 스펙트럼을 측정하였다. 결정 성장 결과 B3+, Er3+, Cr3+ 이온은 Ti4+ 이온과 이온의 크기 차이가 심하여 결정의 정상적인 성장을 방해하는 물성을 나타냈고, V5+, Cr3+ 이온은 흑색의 결정, Fe3+ 이온은 적갈색의 결정으로 성장되었다. Al3+, Zr4+, Al3+의 순서로 투과도가 높아지는 것이 관찰되었다. 불순이온의 농도에 따른 영향으로서 Al3+ 이온의 경우 주입농도가 높아질수록 low angle boundary와 oxygen deficiency가 감소하였고, 투과율은 조금 감소하거나 큰 차이가 없는 것으로 나타났다. 반면에 Cr3+ 이온을 주입한 경우 0.003 atomic%에서 최적의 물성을 보였으며, 주입농도가 높아질수록 결정성장이 어려워지고 광의 투과도가 급격히 저하되었다.은 1.3을 나타내었다.로 보인다.하면 수평축과 수직축의 분산 장벽의 비에 따라 cluster의 두께비가 달라지는 성장을 볼 수 있었고, 한 축 방향으로의 팔 넓이는 fcc(100) 표면의 경우 동일한 Ed+Ep값에 대응하는 팔 넓이와 거의 동일한 결과가 나타나는 것을 볼 수 있다. 따라서 이러한 비대칭적인

• Korean Journal of Optics and Photonics
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• v.33 no.6
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• pp.267-274
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• 2022

In this paper, we report the design and fabrication of binary diffractive optical elements (DOEs) for random-dot-pattern projection for Schlieren imaging. We selected the binary phase level and a pitch of 10 ㎛ for the DOE, based on cost effectiveness and ease of manufacture. We designed the binary DOE using an iterative Fourier-transform algorithm with binary phase optimization. During initial optimization, we applied a computer-generated pseudorandom dot pattern of uniform intensity as a target pattern, and found significant intensity nonuniformity across the field. Based on the evaluation of the initial optimization, we weighted the target random dot pattern with Gaussian profiles to improve the intensity uniformity, resulting in the improvement of uniformity from 52.7% to 90.8%. We verified the design performance by fabricating the designed binary DOE and a beam projector, to which the same was applied. The verification confirmed that the projector produced over 10,000 random dot patterns over 430 mm × 430 mm at a distance of 5 meters, as designed, but had a slightly less uniformity of 84.5%. The fabrication errors of the DOE, mainly edge blurring and spacing errors, were strong possibilities for the difference.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.551-560
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• 2011

In this paper, a cooling system that includes a heat spreader and a natural convective heat sink is proposed for the cooling of a concentrating photovoltaic (CPV) module. The heat spreader and the natural convective heat sink are designed on the basis of previous analytical investigations. In order to evaluate the proposed cooling system, we conducted experimental investigations varying the heat rate and the inclined angle of the cooling system. From the experimental results, it is found that the proposed cooling system satisfies the design constraints for good operation of the CPV module. Finally, a correlation is suggested for estimating the effects of the heat rate and the inclined angle on the thermal performance of the natural convective heat sink is suggested.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.264-272
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• 2016

In previous research, we analyzed traffic accident characteristics in the Chungcheong region through factor analysis, cluster analysis, and a questionnaire using traffic accident analysis system data to enhance Korea's traffic safety. Based on the analysis results, we investigated the design and application of traffic safety technology in non-urban areas in this study. Three technologies are proposed to improve traffic safety facilities for the region: a recognition light at pedestrian crossing works, a recognition light on the road for the underprivileged in traffic works, and a safety LED sign for operation of agricultural machine works. Each technology complements the light pollution problem about snow removal and road safety when applied to existing facilities in the non-urban areas. Solar-based indigenous technology is expected to contribute to road safety in rural areas.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.161-165
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• 2012

It is one of the most important to protect the battery over charging for stable use and to extend the life of battery which occurs with repeated charging and discharging. Various research have been studied to know the state of health, and in this paper the terminal voltage of battery is measured to calculate the state of charge simply. The circuit used comparator is designed and built not to fall under the specific voltage of battery. The designed circuit board is attached to the automatic water sanitizer device with a solar power system. The system is located in the water tank where there is not water and electric service, and confirmed that the state of working is good.

• Journal of Digital Convergence
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• v.12 no.3
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• pp.211-218
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• 2014

Recently, wind energy is expanding to combination of computing to forecast of wind power generation as well as intelligent of wind powerturbine. Wind power is rise and fall depending on weather conditions and difficult to predict the output for efficient power production. Wind power is need to reliably linked technology in order to efficient power generation. In this paper, distributed power generation forecasts to enhance the predicted and actual power generation in order to minimize the difference between the power of distributed power short-term prediction model is designed. The proposed model for prediction of short-term combining the physical models and statistical models were produced in a physical model of the predicted value predicted by the lattice points within the branch prediction to extract the value of a physical model by applying the estimated value of a statistical model for estimating power generation final gas phase produces a predicted value. Also, the proposed model in real-time National Weather Service forecast for medium-term and real-time observations used as input data to perform the short-term prediction models.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.465-470
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• 2020

Complex materials are widely used in aviation industries where lightweighting is essential because they have lighter properties than metals. However, composite materials can cause defects such as internal void formation, poor adhesive mixing, and non-adhesive parts during the production process, and there is a risk of micro-cracking and interlayer separation due to low energy impact. Therefore, a structural damage test is essential. As a result, structural integrity monitoring using FBG is drawing attention. Compared to conventional electrical sensors, FBG has the advantage of being more corrosion-resistant and multiplexed without being affected by electrical noise. However, interloggers measuring FBG are expensive and have a large disadvantage because they are made on the premise of measuring large structures. In this paper, low-cost interloggers were designed for use in unmanned or small aircraft using optical switche, WDM filter, and LTFs, and compared to conventional high-priced interrogator.