• Journal of Advanced Navigation Technology
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• v.23 no.1
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• pp.61-68
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• 2019

Underwater wireless light communication system is quite necessary to retrieve recorded data from underwater devices or the black box without taking back it body. In this paper, a research on the light sensor technology in underwater wireless light communication under turbid sea was studied. A noise source under turbid sea for light communication was analysed, and a sensor system for light sensing using the reference light signal to remove the noises and to improve the output swing power wasstudied. Also, an underwater communication system was manufactured to validate the good performance of the development system, and using the system, the good performance of the developed system was validated through the light communication test in the tank containing the turbid sea water was presented.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.181-186
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• 2019

The floating photovoltaic system is a new concept in the renewable energy technology. That is similar to land based photovoltaic technology except floating system. So the system needs buoyant objects, mooring, ect, besides modules and supports, and that is able to withstand in water level changes and wind strength. Therefore the floating photovoltaic system is much different from land photovoltaic system. Unlike land-based photovoltaics developed on the rooftop and in the mountains of buildings, The floating photovoltaic power generation is a new concept in power generation technology in which photovoltaic modules are installed using buoyancy on the surfaces of dams and reservoirs. It is abundant enough to construct a power plant with a power generation potential of about 5% and a power generation capacity of 4,170MW, so that the land can be efficiently used without destroying the environment. In this paper, the technical standard for evaluating safety in addition to the water-state photovoltaic power generation system is not established yet, and the items to be considered for standardization of the water-state photovoltaic power generation system are summarized in this paper.

• Korean Journal of Construction Engineering and Management
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• v.18 no.5
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• pp.11-19
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• 2017

The purpose of this study is to analyze the efficiency of PV according to installation condition in the complex type buildings. For this purpose, annual performance of solar power generation in a certain area was investigated and various methods were conducted including post operation evaluation. In addition, we tried to find out influencing factors that affect the efficiency and sought to identify their relative impact of degree through the data analysis and site visits together. In the middle of this process we can draw up major considerations for the efficient photovoltaic power generation installation. In the mean while, previous studies are making something new related with method for efficiency enhancement and individual influential factors based on experimental environment rather than the empirical data site based. As a result of the study, it was confirmed that even if installed in the same area, the power generation efficiency is 1.5 times as high as the installation condition. Furthermore, statistical analyses were performed on azimuth, tilted angle and shade, which are variables affecting conversion efficiency, and it was statistically confirmed that all variables are meaningful factors that affect the conversion efficiency which is a dependent variable. The most influential factor is the azimuth, followed by the tilted angle and the shade factor. From this result, we expect to be able to provide installation guidelines for the solar power generation equipments on the rooftop zone.

• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.180-187
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• 2022

In order to select suitable light in a plant factory, electric energy use efficiency and light use efficiency should be considered simultaneously to consider operating costs as well as quantitative and functional aspects. The growth characteristics, electric energy use efficiency, light use efficiency by light intensity, LED ratio, and photoperiod conditions were compared together. Light intensity is 60, 130, 230, and 320 µmol·m^-2·s^-1 treatments, and light quality is the mixing ratio of red light and blue light 8:2, 6:4, 4:6, and 2:8 treatments. Photoperiod is 9, 12, 15, and 18 hours treatments based on the daytime. In the light intensity experiment, the growth rate increased as the light intensity increased, but there was no significant difference in the light use efficiency. When comparing the leaf fresh weight per power consumption, only the 320 µmol·m^-2·s^-1 treatment group showed significantly low efficiency, and there was no significant difference in the other treatments, so 230 µmol·m^-2·s^-1, which produced the most, was the most efficient. In the light quality experiment, the ratio of red light and blue light was measured to be high at the same time as the growth rate and light use efficiency in RB 8:2, and there was no significant difference in color difference and flavonoids content, so a Red:Blue ratio of 8:2 was the most suitable condition. In the photoperiod experiment, the longer the photoperiod, the higher the growth rate. However, there was no significant difference in the growth rate over 12 hours of daytime, so 12 hours considering the light consumption efficiency was a suitable condition. Based on the above results, LED light environmental conditions for perilla growth in plant factories were light intensity, light quality, and day length of 230 µmol·m^-2·s^-1 or more, 8:2, and 12 hours or more, respectively.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1406-1407
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• 2011

태양광발전은 태양의 복사에너지를 직접 전기에너지로 변환하는 시스템으로 가동부분이나 열기관이 없어 수명이 길고 운전과 유지보수가 용이하며 모듈로 구성되기 때문에 수요나 지형에 맞게 설계할 수 있다. 이러한 특성으로 인해 태양광 발전은 차세대 성장 에너지원으로 각광 받고 있으며, 최근 문제되고 있는 지구환경문제 해결에도 부합할 수 있는 잠재력을 갖고 있다. 또한 계통 연계형 태양광 발전시스템의 확대 보급시 태양광 발전시스템의 출력특성에 의한 기존 전력계통의 피크전력을 감소시키는 효과도 기대할 수 있다. 국내 태양광발전은 정부 지원정책에 힘입어 지속적으로 보급이 확대되고 있으며, 2009년도 기준으로 약 400 MWp 이상의 설비가 전력시장에 진입하여 상업 운전중에 있다. 태양광발전시스템은 육상에 설치하는 것이 주류를 이루고 있었으나 태양광 입지조건에 적합한 부지를 확보하는 것이 쉽지않기 때문에 최근에는 건물옥상이나 벽에 설치하는 사례가 증가되고 있다. 본 논문에서는 한전전력연구원(대전시 유성구 문지동)의 건물옥상에 설치되어 운전하고 있는 9.52kW급 BIPV 형식의 태양광발전시스템을 대상으로 2010년도 1년간의 운전특성에 대하여 분석 평가하고 이를 통해 BIPV시스템의 운전에 대한 기초자료를 제시하고자 한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.7
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• pp.799-804
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• 2014

To combine to the power transmission, photovoltaic inverter is demanded, because the photovoltaic system is generated direct current power. However, photovoltaic inverter is sensitive to high temperature. In the temperature rising such as at noon and on summer, efficiency of machine is decreased due to the loss increment. Because this problem causes national energy loss according to the expanding the photovoltaic industry, countermeasure is demanded. There, in this paper, we installed a cooling system using a thermoelement regardless of the temperature. Also, we analyze the cooling effect according to the position of two fans which improve the effect maximize.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.708-709
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• 2011

본 논문에서는 환경오염이 거의 없고, 무한한 에너지 원인 태양광을 이용하여 발전하는 태양광발전장치를 이용하여, 2차전지 및 IT기술을 기반으로 태양광발전장치를 이용한 전원공급장치를 제작하였다. 이 장치를 한국기술대학교의 몽골 해외봉사단에서 직접 설치, 운용하여, 상용전원이 제한적인 개발도상국가 및 후진국에 도입하여 생활의 질을 한층 높일 수 있도록 하였다. 이 태양광발전 전원공급장치는 발전된 전기 에너지를 충전 컨트롤러를 통해 2차전지 및 독립형인버터로 전달되어 상용전원으로 사용할 수 있게 된다. 독립형 태양광발전장치는 대상 부하의 크기를 고려하여 각각의 장비를 선정하였고, 2차전지를 이용하여 주간에 저장된 전기에너지를 발전을 하지 않는 저녁에 사용하므로 단속적인 태양광에너지의 단점을 보완하였으며, 태양광 발전장치에서 실시간으로 출력되는 데이터 값을 IT기술을 통하여 감시 및 제어할 수 있게 구성하였다. 이는 상용전원 공급이 제한적인 개발도상국이나 독립적인 전원이 필요한 외진 곳의 수용가에게 전기 수요를 만족시킬 수 있을 것이라고 예상된다.

• Journal of IKEEE
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• v.21 no.3
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• pp.211-218
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• 2017

This paper proposes the self-powered solar tracker system without CPU. Conventional solar tracker system occurs the problem of cost and durability because of using CPU. In addition, this system has effects from installation site and environment. The proposed solar tracker system without CPU is possible to achieve the high efficiency because it tracks the maximum of the light source. The validity of proposed solar tracking system is verified with experiment results.

• The KIPS Transactions:PartC
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• v.13C no.4 s.107
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• pp.441-446
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• 2006

In recent years, WDM networks have received much attention as the Internet backbone networks because of the explosive growth of the Internet IP-based traffic. The Optical Burst Switching (OBS) has been proposed as an effective optical switching technology in the WDM networks. The OBS has the advantages in 1) the high usage rate of the bandwidth, and 2) no necessity of optical buffer. However, the OBS has the burst-contention problem in the networks. The deflection routing is proposed as one of means to solve this problem. In this paper, we propose a new routing method to minimize burst loss in the deflection routing based networks. In addition, we propose a QoS control method using a new routing algorithm. Finally, we show the variety of the proposed methods by computer simulations.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.224-224
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• 2003

광통신을 위한 구성 요소는 빛을 발생시키는 발광소자, 빛을 검출하는 수광소자 그리고 광신호를 처리하는 광신호처리 소자로 구성된다. 이때 각 소자간 광전송과 광소자에 의한 광 신호 처리 과정에서 광전송 손실이 심각하게 일어나 광정보를 상실하게 되므로 각 요소별로 광신호 증폭이 반드시 필요하다. 뿐만 아니라 완전 광화에 의한 초고속/대용량 광통신망의 구축에는 저가이며, 광집적화가 가능한 광도파로형 광증폭기가 요구되고 있다. 짧은 거리에 높은 증폭 효율을 얻기 위한 광도파로형 광증폭기를 구현하기 위해서는 광통신 파장대인 1.55$\mu\textrm{m}$ 대역의 증폭이 가능한 Er 이온을 고농도로 도핑 할 필요가 있다. 그러나 Er 이온을 단순히 고농도로 첨가하면 Er-Er 간 뭉침 현상에 의해 더 이상의 증폭이 어렵게 된다. 본 연구에서는 이러한 문제를 해결하면서 스핀 코팅이 가능하여 저가 공정이 가능한 유/무기 졸-겔 재료 내에 Er 이온을 제어된 방법으로 첨가하고 그 결합 환경을 FT-IR 및 $^{17}$ O-NMR로 분석하였다. 유/무기 졸겔 재료 제조를 위하여 먼저 MPTS(MethAcryoxyPropylTrimethoxySilane)를 부분 가수분해한 후 ZrOCl$_2$.8$_2$O (Zirconyl Chloride Octahydrate) 와 ErCl$_3$. 6$H_2O$ (Erbium(III) Chloride Hexahydrate)를 순차적으로 결합시키고, Zr/MPTS 및 Zr/Er의 첨가비에 따른 발광 특성을 PL(photoluminescence) 스팩트럼으로 분석하여 Er 이온의 주위 결합 환경이 PL에 미치는 영향을 조사하였다. 또한 Si 기판에 코팅한 Er이 도핑된 유/무기 하이브리드 졸-겔 코팅막의 굴절율 등 광도파로 재료로서의 특성도 프리즘 커플러 등을 이용하여 조사하였다.