• Journal of the KSME
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• v.49 no.11
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• pp.28-33
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• 2009

이 글에서는 태양광 연구를 선도하고 있는 해외 선진업체의 개발 현황과 기술 수준을 소개하고, 국내 태양광 산업현황을 가치사슬별로 정리하였다. 또한 국내의 태양광 연구개발 및 산업화를 추진하기 위한 정부의 태양광 R&D 추진체계를 소개한다.

• The Optical Journal
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• s.172
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• pp.49-51
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• 2017

• Journal of the Korea Society of Computer and Information
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• v.18 no.9
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• pp.33-41
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• 2013

In this paper, a photovoltaic switch is suggested that is operated by solar module, a substitute for CdS(Cadmium Sulfide) of most existing automatic switches and thus is powered by its renewably charged battery, and its usability is investigated through various experiments. At first the characteristics of CdS and the operation principle of the existing automatic switch are investigated, and then the characteristics of solar module are examined. These preparatory research shows the possibility of substitution of solar module instead of CdS in light activated switch. Secondly the suggested photovoltaic switch's circuit is designed, implemented and then its experimental comparison data shows the possibility for the replacement of the existing switch to the suggested switch, and furthermore its superiorities.

• Journal of Bio-Environment Control
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• v.9 no.4
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• pp.223-229
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• 2000

This study was conducted to analyze the opto-electric characteristics of light-emitting diodes(LED) designed for growth and morphogenesis control of transplant and to quantify the photon flux emittig from LED using a quantum sensor spectroradiometer. Difference in photon flux for blue and red LED between measured by a quantum sensor and measured by a spectroradiometer and numerically integrated was not observed. This result implies a spectroradiometer can be applied to quantify the photon flux emitting from far-red LED, which can not be measured using a quantum sensor. Since photon flux increases in proportion to wavelength, photon flux of LED modules arranged for red and far-red increased in proportion to wavelength, photon flux of LED modules arranged for red and rar-red increased gradually as the number of LED stick emitting far-red in LEd modules increased. Illumination of LED modules arranged for red and far-red decreased as the number of LED stick emitting far-red in LED modules increased. There was no difference in irradiance between LED modules arranged for red and far-red.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.14-18
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• 2006

Optical interferometer is used for various optical measurement fields in optical metrology and biomedical measurements. In an optical interferometer, optical delay line has to change the optical path length of a reference arm to match with that of a sample in and it's speed was limited by reference arm movement speed. In this paper, we proposed an all-fibered RSODRapid Scanning-speed Optical Delay) without any mechanical movement, and we applied this system to optical interferometer. Experimental setup is consist of pulse laser source (center wavelength 1304nm, pulse width 30ps, repetition rate 10GHz), two phase modulators and dispersive shifted fiber. As experimental results, we obtain the maximum time delay of 11ps at 10MHz repetition rate, and it is easily tuneable the time delay by modulation frequency and modulation voltage.

• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.55-60
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• 2001

To investigate the effect of red light (R) and far-red light(FR) on controlling the growth of tomato transplants, height, length of 1st internode, and stem diameter of plant were measured every 12 days during 24 days of light treatment. At the end of experiment, fresh and dry weights of roots and shoots were measured. Generally, it was shown that the height of plant was suppressed by the treatment of FR. However, the effect of light-treatment time (10 or 20 min) on plant height was not significant. Stem diameter of the plant treated with R was greater than that of the plant treated with FR or the control. Dry weight ratio of shoot to root of the plant treated with R was smaller that of the plant treated with FR. R was more effective than the control, which was more effective than FR, in making the transplant compact.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.5
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• pp.518-525
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• 2012

In this study, the feasibility of hyperspectral reflectance imaging technique was investigated for the discrimination of viable and non-viable lettuce seeds. The spectral data of hyperspectral reflectance images with the spectral range between 750 nm and 1000 nm were used to develop PLS-DA model for the classification of viable and non-viable lettuce seeds. The discrimination accuracy of the calibration set was 81.6% and that of the test set was 81.2%. The image analysis method was developed to construct the discriminant images of non-viable seeds with the developed PLS-DA model. The discrimination accuracy obtained from the resultant image were 91%, which showed the feasibility of hyperspectral reflectance imaging technique for the mass discrimination of non-viable lettuce seeds from viable ones.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.54-54
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• 2023

하천유역조사는 관련 법률의 규정에 의해 물관리정책의 수립에 필요한 기초정보를 제공하는 것을 목적으로 기본현황, 이수, 치수 환경생태 등 유역관리에 필요한 주요 조사항목을 대상으로 수행되고 있다. 조사방법 중 원격탐사자료 활용한 조사는 드론 모니터링 영상 및 위성영상자료를 이용해 댐·제방과 같은 치수 시설물의 안전관리, 수질 모니터링, 하천지형조사, 하상변동조사 등에 활용되고 있다. 최근에는 일반 RGB 영상뿐만 아니라 수백개의 분광밴드를 포함한 초분광영상을 이용한 하천조사 연구가 이루어지고 있다. 초분광영상은 분광해상도가 높아 다항목 조사에 활용할 수 있다는 장점이 있지만, 많은 양의 분광정보를 포함하고 있기 때문에 초기 수집 자료의 용량이 너무 크고, 분석을 위한 전처리 과정이 까다롭다는 단점이 있다. 반면, 10개 이하 밴드의 분광정보를 수집하는 다분광영상은 2개 밴드를 이용해 정규식생지수(NDVI)를 즉각적으로 모니터링할 수 있고, 작물의 생육현황 등을 분석할 수 있어 농업 및 산림분야에서 널리 활용되고 있다. 초분광영상을 이용한 수심산정 연구는 최적 밴드비 탐색 기법(OBRA)을 활용해 측정수심과 상관관계가 높은 밴드비를 이용해 수심맵을 구축하는 방식이 활용되어왔다. 본 연구에서는 기존의 초분광영상을 활용한 수심산정기법을 다분광영상에 적용하여 분광밴드수가 축소된(경량화된) 자료를 활용한 수심산정 가능성을 확인하기 위해 동일한 현장에서 초분광과 다분광 두가지 영상을 촬영하였으며, 각각 수심맵을 구축해 하천분야에서 다분광영상의 활용도를 평가하였다. 또한, 기존의 OBRA의 한계를 개선하기 위해 가우시안 혼합 모델(GMM; Gaussian Mixture Model)을 활용해 영상을 군집화하여 수심산정 정확도를 개선하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.7 s.98
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• pp.746-752
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• 2005

In this paper, optical noise effect is reduced by using the loss characteristics of plastic fibers in an optical wireless system. The attenuation coefficient of a plastic fiber for the signal is different from that f3r the noise light, and the length difference between two fibers to the 2PD's behaves like a discriminative element. It is possible to eliminate the optical noise effect and detect only the signal without optical filters. The signal to noise ratio in a differential detector using fibers was 9.7 dB higher than in a single photodiode without optical fiber.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.1
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• pp.54-62
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• 1999

In this paper, we investigated the signal-to-noise ratio improvement in a differential detector, which is a function of the optical noise coupling ratio and the differential gain ratio. A differential detector consists of two photodiodes and a differential amplifier. The differential detector reduced the noise component and improved the signal-to-noise ratio by about 20 dB when the differential gain ratio equals to the optical noise coupling ratio. The differential detector is very effective in removing the environmental optical noise or interference from an adjacent optical channel. This method is also effective when the noise wavelength is similar to the signal.