• Korean Journal of Optics and Photonics
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• v.33 no.2
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• pp.74-83
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• 2022

The entire process, from the raw material to the final system qualification test, has been developed to fabricate a large-diameter, lightweight reflective-telescope system for a satellite observation. The telescope with 3 anastigmatic mirrors has an aperture of 700 mm and a total mass of 66 kg. We baked a silicon carbide substrate body from a carbon preform using a reaction sintering method, and tested the structural and chemical properties, surface conditions, and crystal structure of the body. We developed the polishing and coating methods considering the mechanical and chemical properties of the silicon carbide (SiC) body, and we utilized a chemical-vapor-deposition method to deposit a dense SiC thin film more than 170 ㎛ thick on the mirror's surface, to preserve a highly reflective surface with excellent optical performance. After we made the SiC mirrors, we measured the wave-front error for various optical fields by assembling and aligning three mirrors and support structures. We conducted major space-environment tests for the components and final assembly by temperature-cycling tests and vibration-shock tests, in accordance with the qualifications for the space and launch environment. We confirmed that the final telescope achieves all of the target performance criteria.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.5
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• pp.811-821
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• 2019

Image making for a person is a way to improve various factors that can express oneself, such as appearance, impression, and confidence. In general, people use mirror or camera as a traditional method to make their own image or perform presentation exercises. Recently, as smart mirrors are widely used in various fields, attempts to use smart mirrors as image making tools instead of mirrors have been frequently made. Smart Mirror is considered as a suitable tool to provide image making service because it can attach various devices such as a camera and a microphone in addition to the main advantage of a mirror that it is easily accessible. In this paper, we present BuddyMirror - a smart mirror software that provides image-making service to users, and a dedicated mobile app for flexibly running the mirror software. BuddyMirror provides functions for presentation, mock interview, and styling service at the request of users, interworking with the dedicated mobile app. We also describe the techniques developed for implementing and activating each of the new services as a module of MagicMirror, a widely used smart mirror development platform. The developed mobile app enables users to deliver presentations to BuddyMirror or to download the recorded video for image-making services.

• Transactions of Materials Processing
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• v.11 no.2
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• pp.103-107
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• 2002

With the great demand for WDM (Wavelength Division Multiplexing) optical communications, optical switches are expected to become one of the dominant components in future networks. Conventional mechanical switches suffer from poor reliability and large size; however, many micromachined optical switches with moving mirrors have been proposed for high scale OXC (Optical Crossconnect) or ADM (Add/Drop Multiplex) because of the low power consumption and high reliability of these switches. In this paper, we introduce the technological trends of optical switches using MEMS, related micromachining technologies and their characteristics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.649-652
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• 2005

Abrasive jet machining is a well-known process for patterning window glass and mirrors. The technics is now being developed for the production structure with high precision. This paper describes erosion profile modeling of micro abrasive jet machining and compares with other researcher's model.

• Archives of Pharmacal Research
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• v.27 no.11
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• pp.1099-1105
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• 2004

The peroxisome proliferator-activated receptors (PPARs) are a primary regulator of lipid metabolism. Potency for activation of PPAR$\gamma$, one of a subfamily of PPARs, particularly mirrors glucose lowering activity. We prepared thiazolidinediones featuring benzoxazole moiety for subtype selective PPAR$\gamma$ activators. 5-[4-[2-(Benzoxazol-2-yl-alkylamino)ethoxy]benzyl]thiazolidine-2,4-diones have been prepared by Mitsunobu reaction of benzoxazolylalkylaminoethanol 8 and hydroxybenzylthiazolidinedione 6 and their activities were evaluated. Most compounds tested were identified as potent PPAR$\gamma$ agonists.

• Electronics and Telecommunications Trends
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• v.33 no.4
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• pp.61-69
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• 2018

Driver-specific technology in the automotive field has been commercialized for vehicle accessories, driver memory sheets, and side mirrors. In recent years, the demand for customized technology has expanded to include the user interface of an infotainment system (Infotainment System) and advanced driver support system (Advanced Driver Assistance System), and customized technologies for drivers have been studied. Therefore, this article describes the driver-tailored technology trends being studied in these fields, and examines the major research issues related to future driver-tailored technologies in the automotive field.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.8
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• pp.1289-1293
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• 1990

In this paper, the oscillation condition for the linear phase-conjugate oscillator which consists of one photorefractive crystal, two conventional mirrors, and two pump waves applied externally has been analyzed. In the result, it has been shown that the oscillation condition of this oscillator can be easily controlled by adjusting the various parameters such as the intensity ratio, polarization states, and light path difference of two pump waves, etc.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.12
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• pp.104-109
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• 1996

A current-controlling transadmittance amplifier is proposed. It consists of a linear transadmittor and a current gain cell followed by three current mirrors. The proposed transadmittance amplifier is used to design a current-controlling frequency-dependent negative resistor (FDNR). Experimental results are presented to verify theoretical predictions. The results show close agreement between predicted behaviour and experimental performance.

• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.128-129
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• 2005

• International Journal of Internet, Broadcasting and Communication
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• v.4 no.2
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• pp.22-27
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• 2012

The design characteristics of circular vertical-cavity surface-emitting lasers are studied by using a newly developed equivalent network. Optical parameters, such as the stop-band or the reflectivity of periodic mirrors and the resonance wavelength, are explored for the design of these structures. To evaluate the differential quantum efficiency and the threshold current density, a transverse resonance condition of modal transmission-line theory is also utilized. This approach dramatically reduces the computational time as well as gives an explicit insight to explore the optical characteristics of circular vertical-cavity surface-emitting lasers (VCSELs).