• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2009년도 춘계학술대회
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• pp.249-252
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• 2009

본 연구는 화면전환 및 필기 등의 프레젠테이션을 편리하게 제어 할 수 있는 시스템을 구현하고자 한다. 카메라를 이용한 컴퓨터 비전 분야에서 주변의 조명 환경의 영향을 적게 받는 적외선을 이용한 연구가 활발하게 진행되고 있다. 제안하는 방법에서는 USB(Universal Serial Bus) 타입의 카메라를 적외선 환경에 맞게 개조하고, 이를 이용하여 적외선 LED(Light Emitting Diode)를 이용한 전자 분필 영상을 취득하여, 실시간으로 전자 분필의 위치를 검출한다. 검출된 영역은 사전에 사용자가 설정한 '필기 가능 영역'과 변형 함수에 기반하여, 실제 모니터 좌표로 사상되어 화면에 표시되게 된다. 제안하는 시스템은 저렴한 가격의 웹 캠과 적외선 조명 이외에는 별도의 장비가 필요하지 않으면서도, 대형 스크린을 터치 방식으로 활용할 수 있다는 장점을 가진다. 실험 결과, 계산된 모니터 좌표와 사용자가 의도한 위치간의 평균 RMS(Root Mean Square) 오차는 약 15픽셀로 나타나서, 글씨를 필기하고 화면의 특정 부분을 강조하기 위한 활용이 가능함을 확인할 수 있었다.

• 한국전기전자재료학회논문지
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• 제25권10호
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• pp.844-848
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• 2012

Encapsulant curing in terms of convection oven leads to thermal induced stress due to nonuniform thermal conductivity in LED package. We have adopted infrared (IR) light for silicone curing in order to release the stress. The light uniformity irradiated on an encapsulant surface is confirmed to be uniform by optical simulation. Shear strength of die paste using IR compared to convection oven is increased 19.2% at the same curing time, which indicates curing time can be shortened. The indentation depth difference between center and edge of silicone encapsulant in terms of convection oven and IR are 14.8% and 3.4%, respectively. Curing by IR also shows 2.3% better radiant flux persistency rate of LED at $85^{\circ}C$ after 1,000 h reliability test compared to convection curing.

• 대한치과보철학회지
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• 제47권4호
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• pp.416-423
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• 2009

연구목적: 이번 연구의 목적은 PLV 수복물의 접착 시 사용되는 광중합형 레진 시멘트의 중합도를 Fronrier transform infrared spectroscope로 측정하여 도재의 두께, 광원 및 광조사 시간에 따른 중합도의 차이를 비교하기 위함이다. 연구재료 및 방법: 대조군으로는 1.0 mm의 투명한 slide glass를 사용하였고, 도재 시편은 IPS Empress Esthetic shade ETC1을 선택하여 0.5, 1.0, 1.5 mm의 두께로 제작하였다. 레진 시멘트는 광중합형 레진 시멘트인 Rely $X^{TM}$ Veneer Shade A3를 사용하였다. 광원으로는 Quartz Tungsten Halogen (QTH), Light Emitting Diode (LED), Plasma arc curing (PAC) 광중합기를 사용하였다. 레진 시멘트의 중합도는 FT-IR과 OMNIC 프로그램을 이용하여 측정하였다. 통계분석은 one-way ANOVA와 Tukey HSD를 이용하였다 ($\alpha$=0.05). 결과: 대조군에서 QTH와 LED로 광중합을 시행하였을 때 PAC로 광조사를 시행한 경우보다 중합도가 높았다. QTH와 LED로 광조사를 시행한 경우, 대조군과 0.5 mm, 1.0 mm, 1.5 mm의 도재 두께에서 유의차를 보이지 않았다. 반면, PAC로 광조사를 시행한 결과, 도재의 두께가 1.5 mm인 실험군의 중합도가 대조군과 0.5 mm에서 보다 통계적으로 유의하게 낮은 결과를 보인다 (P<.05). 두께가 1.0 mm의 도재와 LED 광중합기로 광조사하여 중합도를 비교한 결과, 20초간 광조사를 시행하였을 때와 비교하여 80초와 160초간 광조사를 시행한 경우 통계적으로 유의하게 중합도의 평균값이 높았다 (P<.05). 결론: 이번 연구의 한계 내에서, 도재의 두께가 0.5-1.5 mm 이내의 PLV 접착 시, PAC 중합기의 사용은 고려되지 않으며, QTH나 LED로 40초 이상 중합한다면 광중합형 레진 시멘트를 사용할 수 있다. 또한, 광중합형 레진 시멘트를 LED로 중합시킬 경우, 광조사 시간의 증가가 중합도의 증가와 비례하지 않으며, 일정시간 이상의 광조사가 중합도에 큰 영향을 끼치지 않는다.

• 센서학회지
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• 제9권6호
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• pp.448-454
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• 2000

This paper describes the implementation of a multi-subject, multi-channel optical telemetry system for the short range measurement of electrocardiograms (EKGs) a system which receives command signals and transmits physiological signals to the external system using LED (Light Emitting Diode) and PD (Photodiode). This system decreases the dependency of power supply voltage to the CMOS IC chips and a new enforced synchronization technique using infrared bi-directional communication has also been proposed. The telemetry IC with the size of $5.1{\times}5.1mm^2$ has the following functions: receiving of command signal, initialization of internal state of all functional blocks, decoding of subject selection signal, time division multiplexing of 4-channel modulated physiological signals, transmission of modulated signals to external system, and auto power down control.

• ETRI Journal
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• 제34권4호
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• pp.542-552
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• 2012

In this paper, a gaze estimation method is proposed for use with a large-sized display at a distance. Our research has the following four novelties: this is the first study on gaze-tracking for large-sized displays and large Z (viewing) distances; our gaze-tracking accuracy is not affected by head movements since the proposed method tracks the head by using a near infrared camera and an infrared light-emitting diode; the threshold for local binarization of the pupil area is adaptively determined by using a p-tile method based on circular edge detection irrespective of the eyelid or eyelash shadows; and accurate gaze position is calculated by using two support vector regressions without complicated calibrations for the camera, display, and user's eyes, in which the gaze positions and head movements are used as feature values. The root mean square error of gaze detection is calculated as $0.79^{\circ}$ for a 30-inch screen.

• Restorative Dentistry and Endodontics
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• 제39권3호
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• pp.155-163
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• 2014

Objectives: Light-curing of resin-based materials (RBMs) increases the pulp chamber temperature, with detrimental effects on the vital pulp. This in vitro study compared the temperature rise under demineralized human tooth dentin during light-curing and the degrees of conversion (DCs) of three different RBMs using quartz tungsten halogen (QTH) and light-emitting diode (LED) units (LCUs). Materials and Methods: Demineralized and non-demineralized dentin disks were prepared from 120 extracted human mandibular molars. The temperature rise under the dentin disks (n = 12) during the light-curing of three RBMs, i.e. an Ormocer-based composite resin (Ceram. X, Dentsply DeTrey), a low-shrinkage silorane-based composite (Filtek P90, 3M ESPE), and a giomer (Beautifil II, Shofu GmbH), was measured with a K-type thermocouple wire. The DCs of the materials were investigated using Fourier transform infrared spectroscopy. Results: The temperature rise under the demineralized dentin disks was higher than that under the non-demineralized dentin disks during the polymerization of all restorative materials (p < 0.05). Filtek P90 induced higher temperature rise during polymerization than Ceram.X and Beautifil II under demineralized dentin (p < 0.05). The temperature rise under demineralized dentin during Filtek P90 polymerization exceeded the threshold value ($5.5^{\circ}C$), with no significant differences between the DCs of the test materials (p > 0.05). Conclusions: Although there were no significant differences in the DCs, the temperature rise under demineralized dentin disks for the silorane-based composite was higher than that for dimethacrylate-based restorative materials, particularly with QTH LCU.

• 생물환경조절학회지
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• 제27권2호
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• pp.158-165
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• 2018

종류가 다른 보광등과 난방등으로 보광을 해 주었을 때, 절화 장미의 수확량, 절화수명, 엽색에 미치는 영향을 비교 분석하였다. 이를 위하여 보광등으로 LED등(Light emitting diode lamp, LED), 메탈할라이드등(Metal halide lamp, MH), 고압나트륨등 (High-pressure sodium lamp, HPS)과 난방등으로 나노탄소섬유 적외선등 (Nano-carbon fiber infrared lamp, NCFI)을 절화장미를 재배하고 있는 농가의 수경재배 베드 위에 설치하였다. 절화 장미 수확량과 판매 가능한 절화수는 HPS 처리에 의해 봄과 가을에 크게 증가하였다. 품질의 주요기준이 되는 절화장은 봄철에는 전등처리에 의해 대조구보다 길어졌으나, 겨울에는 오히려 감소하였다. 겨울에는 전등처리로 인해 개화가 촉진되어 영양생장기간이 상대적으로 짧아졌기 때문으로 생각된다. 절화수명은 전등 처리시간이 짧은 가을에는 처리간 차이가 보이지 않았으나, 겨울에는 HPS에서만 대조구에 비해 3일 정도 길어졌다. 엽색은 가을철 보다는 겨울철에 전등처리의 영향을 크게 받았으며, 모든 보광등(LED, MH, HPS)처리에서 엽색이 짙어진 반면, 난방등으로 이용되고 있는 NCFI에서는 대조구와 비슷한 밝기였다. 결론적으로, HPS는 절화장과 절화수명을 길게하며, 수확량도 증가시키므로 매우 좋은 보광등이라고 판단되었다. NCFI는 발열양이 많기 때문에 난방등으로의 기능은 충분할지라도 판매 가능한 절화수가 감소하고 품질지수가 저하되기 때문에 보광등으로서의 역할은 미약할 것으로 판단되었다.

• 한국정밀공학회지
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• 제31권5호
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• pp.417-422
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• 2014

A guitar pickup is a transducer that converts string vibration to an electrical signal. The magnetic and piezo pickups are the most commonly used for the respective electric and electroacoustic guitars. The magnetic pickups are prone to magnetic interference between the steel strings and permanent magnets, while the piezo ones are not free from signal inference between the strings. Thus, this paper presents the development of an optical pickup for the electroacoustic guitar. The proposed optical pickup has the top-to-bottom structure. It uses two of Infrared (IR) Light Emitting Diode (LED) and one photodetector. The developed optical pickup is subjected to the evaluation with commonly used piezoelectric pickup. It becomes obvious that SNR with the optical pickup is increased by 45 percent in average, compared with the piezoelectric pickup. It can be concluded that the developed optical pickup has a potential to be applied to the acoustic guitar.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.423-423
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• 2009

Currently, lasers are one of the most popular light sources in use for medical treatment. Many studies on low power lasers are being done in cell culture or through animal tests and most report different findings, making it difficult to verify their true effects. There are shifts in trends of studies from laser and LED that are expensive and generate heat problem to LED that are economically effective and safe. Its near infrared rays can penetrate deep into skin or muscle, up to 23 cm, without causing thermal damage or impairing neighboring tissues. This study verified the performance and effectiveness of an LED irradiator that was designed to emit similar wavelengths to that of a laser and thus could be used instead of a low level laser therapy in experiments on animals. And then, each experiment was performed to irradiation group and non-irradiation group for NTacSam:SD tissue cells. MIT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590nm transmittance of ELISA reader. As a result, the cell increase of NTacSam:SD tissue cells was verified in irradiation group as compared to non-irradiation group. The fact that specific wavelength irradiation has an effect on cell vitality and proliferation is known through this study.

• Medical Lasers
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• 제10권3호
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• pp.123-131
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• 2021

Optical imaging modalities with properties of real-time, non-invasive, in vivo, and high resolution for image-guided surgery have been widely studied. In this review, we introduce two optical imaging systems, that could be the core of image-guided surgery and introduce the system configuration, implementation, and operation methods. First, we introduce the optical coherence tomography (OCT) system implemented by our research group. This system is implemented based on a swept-source, and the system has an axial resolution of 11 ㎛ and a lateral resolution of 22 ㎛. Second, we introduce a fluorescence imaging system. The fluorescence imaging system was implemented based on the absorption and fluorescence wavelength of indocyanine green (ICG), with a light-emitting diode (LED) light source. To confirm the performance of the two imaging systems, human malignant melanoma cells were injected into BALB/c nude mice to create a xenograft model and using this, OCT images of cancer and pathological slide images were compared. In addition, in a mouse model, an intravenous injection of indocyanine green was used with a fluorescence imaging system to detect real-time images moving along blood vessels and to detect sentinel lymph nodes, which could be very important for cancer staging. Finally, polarization-sensitive OCT to find the boundaries of cancer in real-time and real-time image-guided surgery using a developed contrast agent and fluorescence imaging system were introduced.