• Proceedings of the KSME Conference
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• 2004.11a
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• pp.607-612
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• 2004

Spectral resolution enhancement method of Acousto-Optic Tunable Filter (AOTF) using incident light angle variation is described. AOTF is a small, mechanically rigid, high speed and spectral resolution light tunable filter. The basic theory of AOTF and its experimental verification is described. AOTF can generate two opposite polarized light simultaneously which wavelength can be changed by incident angle variation. We focused on the common region of two filtered light at the specific incident angle. This region can be used to enhance the spectral resolution of AOTF.

• Journal of Sensor Science and Technology
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• v.19 no.1
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• pp.62-66
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• 2010

We have proposed and demonstrated a rotation angle sensor based on the stress -optic effect of a fused fiber coupler whose transmission spectrum is altered by the torsional stress. The peak of transmission spectrum was shifted to longer wavelength region with rotation of the coupler. The rotation angle sensor revealed reproducibility and symmetric behavior with respect to the rotation direction. The sensitivity of the sensor was 0.367 [nm/degee].

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.342-345
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• 2005

To detect external acoustic signal, fiber optic sensor array using Fabry-Perot interferometer which had benefit of minimize and light-weight was used. The sensor head has 1cm in length, total length of fiber is 9.5cm, and the sensor supported at both ends, simply. External sound applied in lateral direction and detected two signals were compared each other. It was confirmed that the Fabry-Perot interferometric sensor array detected acoustic signal, effectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1862-1865
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• 2005

We have a plan to design a controller for electron beam manufacturing system. At first, we designed a controller for SEM. The controller consists of five parts (power source, beam controller, scanning controller, optic controller and main controller). Beam controller supplies pulse wave for generating high voltage and can monitor the status of high voltage instrument through emission current. Optic controller controls focus, spot size and image shift. Main controller transmits variables from operating program to each part and monitors the status of peripheral device.

• Journal of Korean Neurosurgical Society
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• v.61 no.3
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• pp.352-362
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• 2018

Gliomas are the most common pediatric tumors of the central nervous system. In this review, we discuss the clinical features, treatment paradigms, and evolving concepts related to two types of pediatric gliomas affecting two main locations: the optic pathway and thalamus. In particular, we discuss recently revised pathologic classification, which adopting molecular parameter. We believe that our review contribute to the readers' better understanding of pediatric glioma because pediatric glioma differs in many ways from adult glioma according to the newest advances in molecular characterization of this tumor. A better understanding of current and evolving issues in pediatric glioma is needed to ensure effective management decision.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.28-33
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• 2004

We developed a fiber-optic CT for large current monitoring in power systems. We used a FRG fiber sensor coil to suppress CT output degradation caused by linear birefringence, and different optical sources were used to compare their noise characteristics. From the experiments, we obtained output variation less than $\pm$0.4(%) when the sensor coil suffered mechanical perturbations, and the ASE source showed -23(㏈) less noise in the output than singlemode laser diode.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.25-32
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• 2010

Compared to general lighting method, the lighting system that uses optic fiber can provide only the visible light of good quality to subject by eliminating ultraviolet ray and infrared ray. Thanks to this merit, it is possible to prevent the hard phenomenon of subject caused by ultraviolet ray and infrared ray and to provide the agreeable light environment. This study developed indoors illumination system of high color rendering on the basis of plastic optic fiber with excellent optical property and processing to substitute halogen lamp which has been used for excellent color rendering in spite of low efficiency and short life. Producing pilot product of the designed illumination system and evaluating the property of electric and optical property, ultraviolet ray radiation quantity and temperature property, this study verified the excellence of suggested lighting system of plastic optic fiber.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.72-76
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• 2003

We developed a polarimetric fiber-optic current sensor using a length of twisted fiber and a Faraday rotator mirror which was used to suppress the linear birefringence effect. A gold coated mirror was also used as the sensor coil reflector, and the results were compared with the case of FRM. From the experimental results, it is clear that the FRM greatly enhances the stability of the fiber optic current sensor output..

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.4
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• pp.30-36
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• 2004

The development of LD(Laser Diode) tester and its control system based on the graphical programming language(LabVIEW) is addressed. The ill tester is used to check the optic power and the optic spectrum of the LD Chip. The emitter size of LD chip and the diameter of the Detector(optic fiber and photo diode) are very small, therefore the test device needs high accuracy. But each motion part of the test device could not accomplish high accuracy due to the limit of the mechanical performance. So, an image processing with machine vision is proposed to compensate for the error. By adopting our method we can reduce the error of position within $\pm$5$\mu\textrm{m}$.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.617-621
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• 1998

Optical sensing techniques have been associated with high sensitivity and precise measurements and attracted considerable attention in recent years. In this paper, two channels TDM(Time Division Multiplexing) fiber-optic hydrophone array for the underwater applications was fabricated and their acoustic characteristics were investigated by using the acoustic water tank. A fiber length of the order of 100m is wounded at the hollow cylinder type aluminum mandrel. An unbalanced interferometer (discrete Mach-Zehnder type) was used. Sound detection performance is tested in the underwater tank with 2kHz continuous sound source. Finally, it is shown that two channels TDM(Time Division Multiplexing) fiber-optic hydrophone array can detect 2kHz sound stably.