• 한국인터넷방송통신학회논문지
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• 제13권3호
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• pp.1-7
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• 2013

다양한 간섭환경에서 MIMO 기반 가시광 무선 통신 시스템의 성능 분석을 위해서 LED 패널을 고정하고, PD를 가진 단말기를 움직여 모의실험을 수행하으며 MIMO 기술을 기반으로 하여 외부광에 의한 간섭이 통신 채널 품질 변화에 미치는 영향을 분석하였다. 또한 채널에서의 전송시간 지연에 의한 왜곡은 등화기를 사용하여 보상해 주어야 하며, 특히 데이터 전송 속도가 고속이 될수록 등화기의 사용이 절대적으로 필요하게 된다. 따라서 본 논문에서는 VLC 시스템의 변조방식에 따라 채널 등화를 이용한 BER성능을 분석하였다.

• Bulletin of the Korean Chemical Society
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• 제31권1호
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• pp.133-139
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• 2010

Photoelectrocatalytic decolorization of methlene blue (MB) in the presence of two types of carbon nanotube/titania and yttrium-treated carbon nanotube/titania electrodes in aqueous solutions were studied under visible light. The prepared composite electrodes were characterized by X-ray diffraction, transmission and scanning electron microscopy, energy dispersive X-ray analysis, and photoelectrocatalytic activity. The photoelectrocatalytic performances of the supported catalysts were evaluated for the decolorization of MB solution under visible light irradiation. The results showed that yttrium incorporation enhanced the decolorization rate of MB. It was found that the photoelectrocatalytic degradation of a MB solution could be attributed to the combined effects caused by the photo-degradation of titania, the electron assistance of carbon nanotube network, the enhancement of yttrium and a function of the applied potential. The repeatability of photocatalytic activity was also tested. The presence of yttrium enhanced the hydrophillicity of yttrium-carbon nanotubes/titania electrode because more OH groups can be adsorbed on the surface.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.483-486
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• 2014

가시광통신(VLC: Visual Light Communication) 시스템은 조명에 통신을 융합하는 개념으로, 조명기능의 깜박임을 최소화(Flickerless)하고 통신기능의 데이터 송수신 거리를 최대화하는 것이 핵심 설계목표가 된다. 본 논문에서는 VLC 통신시스템의 수신된 신호에 포함된 노이즈를 감쇠시킴으로써 송신측에서 보낸 신호를 정확히 검출할 수 있는 방법을 제안하고 그 구현 결과를 제시하였다. 본 연구의 1,2차 구현을 통하여, 수신측에 설계한 특정주파수 대역의 LPF와 HPF를 단계별로 삽입함으로써 송신 데이터의 인식률이 높아졌고, 이러한 인식률 증대를 통하여 광도가 미약한 보다 먼 거리에서 데이터 수신이 가능함을 확인할 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.303.1-303.1
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• 2016

Polymer-like amorphous carbon films were deposited on polyethylene naphthalate (PEN) substrate by plasma-enhanced chemical vapor deposition (PECVD) and their water vapor transmission rates (WVTR) were tested. propane was used as precursors. To make a polymer-like amorphous carbon film the deposition rate, surface roughness, light transmittance, and WVTR of the films were characterized as a function of the precursor feed ratio and plasma power. The water vapor transmission rates of bare PEN film and single layer PAC on PEN substrate were 6.95 g/m2/day and 0.3 g/m2/day, respectively. The superior property the water vapor permeability of thin layers of PAC was attributed to uniform coverage and good adhesion between PAC film and PEN substrate.

• 한국위성정보통신학회논문지
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• 제9권3호
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• pp.47-52
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• 2014

본 논문은 이미지 처리 기술을 이용한 광 카메라 통신(OCC: Optical Camera Communications) 기술을 제안한다. OCC 시스템의 구조 및 동작을 제안한다. 상용 30fps 카메라의 샘플링 동작에 의해 제한되는 데이터율을 증가시키기 위해 칼라 이미지 처리기술을 이용한 멀티칼러 전송기법을 제안한다. 멀티칼라 부호화 및 이미지 처리기반의 복호화 기법을 제안한다.

• 전기학회논문지
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• 제57권10호
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• pp.1790-1795
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• 2008

Energy scavenging is a technique that converts ambient energy, for example, vibration and light, to electrical energy in order to supply power to low power electronic devices such as ubiquitous sensors. In this paper, we propose an optimal operation condition of power delivery circuit and design strategy for energy scavenging system in which the generated power is order of microwatt and, consequently, efficient handling of power is critical. We also propose that high data transmission rate is more realistic optimal design objective rather than high energy efficiency. It is shown that disconnection of load from the storage capacitor right after data transmission reduces energy wasting and that optimal value of storage capacitor can be determined at this condition. The feasibility of our propose is proved by experiments and we believe that the proposed design strategy will promote the application of piezoelectric micropower generator to the ubiquitous sensor networks.

• 한국전자파학회논문지
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• 제21권3호
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• pp.285-291
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• 2010

본 논문에서는 조명용 LED와 솔라 셀을 사용하여 실내 무선광 통신이 가능함을 보인다. 조명용 LED를 광원으로 사용하면 조명과 신호의 송신을 겸할 수 있으며, 솔라 셀을 수광 소자로 이용하면 조명광을 수신하여 에너지를 축적하는 동시에 신호를 검출할 수 있기 때문에 별도의 통신 시설을 설치하지 않고 전송이 가능하여 매우 편리하다. 실험에서는 조명용 LED와 솔라 셀을 사용하여 9.6 kbps 속도로 무선광 데이터 전송을 실시하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1779-1783
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• 2006

The hybrid thin-film (HTF) passivation layer composed of the UV curable acrylate layer and MS-31 (MgO:SiO2=3:1wt%) layer was adopted in organic light emitting diode (OLED) to protect organic light emitting materials from penetrations of oxygen and water vapors. The moisture resistance of the deposited HTF layer was measured by the water vapor transmission rate (WVTR). The results showed that the HTF layer possessed a very low WVTR value of lower than $0.007g/m^2$ per day at $37.8^{\circ}C$ and 100% RH. Therefore, the HTF on the OLED was found to be very effective in protect what from the penetrations of oxygen and moisture.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1993년도 춘계학술대회
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• pp.116-119
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• 1993

In this paper, we implemented a pulse wave type oximeter system that continuously measure the of oxyhemoglobin saturation of the arterial blood(SaO2) and pulse rate with non-invasively. We use the transmission type and reflection type transducer for comparison the percentage of hemoglobin oxgen saturation. The light Iron the two kind of LEDs is transmitted through the tissue, then received by a single photodiode with alternatively. By the phase sensitive detection circuit, the output of the photodiode is separated in to red and near infrared signal. We calculated a ratio of light transmittance between two kind of LEDs, and then, it is applied to the oxgen saturation coefficent calculation formular.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.659-662
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• 2007

The characteristics of a $SiN_x$ passivation layer grown by a specially designed catalyzer enhanced chemical vapor deposition (CECVD) system and electrical and optical properties of OLEDs passivated with the $SiN_x$ layer are described. Despite the low substrate temperature, the single $SiN_x$ passivation layer, grown on the PC substrate, exhibited a low water vapor transmission rate of $2{\sim}6{\times}10^{-2}\;g/m^2/day$ and a high transmittance of 87 %. In addition, current-voltage-luminescence results of an OLED passivated with a 150 nm-thick $SiN_x$ film compared to nonpassivated sample were identical indicating that the performance of an OLED is not critically affected by radiation from tungsten catalyzer during the $SiN_x$ deposition.