• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.603-606
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• 2000

This dissertation is concerned with ultra-precision profile measurement of aspheric surfaces using contact probing technique. A contact probe has been designed as a sensing device to obtain measuring resolutions in nanometer regime utilizing a leaf spring mechanism and a capacitive-type sensor. The contact probe is attached on the z-axis during measurement while aspheric objects are supported on an precision xy-stage whose lateral motions are monitored by a set of two orthogonal plane mirror type laser interferometers. Experimental results show that the contact probing technique developed in this investigation is capable of providing a repeatability of 50 nanometers with a $\pm$3$\sigma$ uncertainty of 300 nanometers. Thermal disturbance is found the most significant factor that should be precisely controlled for accurate measurement.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.391-395
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• 2002

This paper described about the ultra-precision profile measurement of aspheric surfaces using contact probing technique. A contact probe has been designed as a sensing device to obtain measuring resolutions in nanometer regime utilizing a leaf spring mechanism and a capacitive-type sensor. The contact probe is attached on the z-axis during measurement while aspheric objects are supported on the single point diamond turning machine(SPDTM). The machine xz-axis motions are monitored by a set of two orthogonal plane mirror type laser interferometers. Experimental results show that the contact probing technique developed of On-machine Measurement System in this investigation is capable of providing a repeatability of 20 nanometers with a $\pm$20 uncertainty of 300 nanometers.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.67.3-68
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• 2020

A prime focus telescope, e.g., Schmidt telescope, has advantages especially for a wide field of view survey in astronomy. In this optical configuration, the camera is placed in front of the primary mirror. Since the installation of a typical filter wheel to the prime focus telescope causes serious obscuration of the incoming light, a customized filter device is required for high sensitivity images. In this poster, we present a new filter exchange mechanism, which can host four filters moving along quadrant directions. We plan to install this on the Celestron 36 cm Rowe-Ackermann Schmidt Astrograph (RASA 36) located at El Sause Observatory in Chile.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1225-1230
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• 2017

3D printers have been growing mainly in industrial use, but the recent growth of the personal 3D printer market advanced through economic effects and cost reduction due to technological development. However, current 3D personal printers are very low in customer satisfaction on the limitations of molding speed, size, and precision. In this paper, we propose SLA 3D printer using LSU to overcome the technical limitation of personal 3D printer. In order to verify the operation of the scanning mechanism which is responsible for core functions, the movement of molding board using stepping motor and laser output test was conducted. These tests ensure that the laser was operating and control well was confirmed that a certain point is output to the X-axis by means of a laser module and a polygon mirror. 3D printers which are proposed to improve the accuracy and manufacturing speed is expected to replace the traditional low-budget 3D printer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5469-5476
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• 2011

The purpose of this study was to analyze relating with Faucult's disciplinary power which factors influence a dancer's self-management (weight control)Total 10 ballet major undergraduate students of two respective universities in Seoul and Daijon were selected for the research and the chosen method was an interview with them. After the researchers analyzed the interview result, they found out the following several significant results. The first reason that major ballet dancers control their weight is to show their beautiful figures on the stage and to make their appearances look slender in the mirror. Dancers adapt various methods for effective weight management (diet control) such as dietary control, 1 food intake (potatoes, bananas, grapes, etc), physical force to advise or ingest (injection, taking medicines, reflexology, vomiting, etc.) Then, what is the hidden vision that makes such a practice of weight control maintain? The study presents a "mirror" as a tool of control playing a significant role, in terms that the power of discipline functions automatically in a dancer's body. In addition, another constant factor of dancers' weight management is monitoring each other's performance continuously, which is called "synopticon" Symptoms. Lastly, the fact that a question about placing a ruler could function in the continuous practice was also revealed.

• Journal of Conservation Science
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• v.37 no.4
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• pp.362-369
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• 2021

In museums, exhibition content focuses mostly on cultural heritage's historical values and functions, but doing so tends to limit visitors' interest and immersion. To counter this limitation, the study developed an experiential media art exhibition fusing bronze mirrors' traditional production technology and modern conservation science. First, for the exhibition system, scientific cultural heritage contents were projected on the three-dimensional (3D) printed bronze mirror through interactions between motion recognition digital information display (DID) and the projector. Then, a scenario of 17 missions in four stages (production process, corrosion mechanism, scientific analysis and diagnosis, and conservation treatment and restoration) was prepared according to the temporal spectrum. Additionally, various media art effects and interaction technologies were developed, so visitors could understand and become immersed in bronze mirrors' scientific content. A user test was evaluated through the living lab, reflecting generally high levels of satisfaction (90.2 points). Qualitative evaluation was generally positive, with comments such as "easy to understand and useful as the esoteric science exhibition was combined with media art" (16.7%), "wonderful and interesting" (11.7%), and "firsthand experience was good" (9.2%). By combining an esoteric science exhibition centered on principles and theories with visual media art and by developing an immersive directing method to provide high-level exhibition technology, the exhibition induced visitors' active participation. This exhibition's content can become an important platform for expanding universal museum exhibitions on archaeology, history, and art into conservation science.

• Genomics & Informatics
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• v.5 no.2
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• pp.68-76
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• 2007

Due to the increasing interest in SNPs and mutational hot spots for disease traits, it is becoming more important to define and understand the relationship between SNPs and their flanking sequences. To study the effects of flanking sequences on SNPs, statistical approaches are necessary to assess bias in SNP data. In this study we mainly applied Markov chains for SNP sequences, particularly those located in intronic regions, and for analysis of in-del data. All of the pertaining sequences showed a significant tendency to generate particular SNP types. Most sequences flanking SNPs had lower complexities than average sequences, and some of them were associated with microsatellites. Moreover, many Alu repeats were found in the flanking sequences. We observed an elevated frequency of single-base-pair repeat-like sequences, mirror repeats, and palindromes in the SNP flanking sequence data. Alu repeats are hypothesized to be associated with C-to-T transition mutations or A-to-I RNA editing. In particular, the in-del data revealed an association between particular changes such as palindromes or mirror repeats. Results indicate that the mechanism of induction of in-del transitions is probably very different from that which is responsible for other SNPs. From a statistical perspective, frequent DNA lesions in some regions probably have effects on the occurrence of SNPs.

• Journal of Aerospace System Engineering
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• v.12 no.3
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• pp.9-17
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• 2018

For Earth observation, a small satellite camera has relatively weak structural stability compared to medium-sized satellite, resulting in misalignment of optical components due to severe launching and space environments. These alignment errors can deteriorate the optical performance of satellite cameras. In this study, we proposed a 3-axis focus mechanism to compensate misalignment in a small satellite camera. This mechanism consists of three piezo-electric actuators to perform x-axis and y-axis tilt with de-space compensation. Design requirements for the focus mechanism were derived from the design of the Schmidt-Cassegrain target optical system. To compensate the misalignment of the secondary mirror (M2), the focus mechanism was installed just behind the M2 to control the 3-axis movement of M2. In this case, flexure design with Box-Behnken test plan was used to minimize optical degradation due to wave front error. The wave front error was analyzed using ANSYS. The fabricated focus mechanism demonstrated excellent servo performance in experiments with PID servo control.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.8
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• pp.1298-1310
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• 1997

In recent years, grinding techniques for precision machining of brittle materials used in electric, optical and magnetic parts have been improved by using superabrasive wheel and precision grinding machine. The completion of optimum dressing of superabrasive wheel makes possible the effective precision grinding of brittle materials. However, the present dressing system cannot have control of optimum dressing of the superabrasive wheel. In this study, a new system and the grinding mechanism of optimum in-process electrolytic dressing were proposed. This system can carry out optimum in-process dressing of superabrasive wheel, and give very effective control according to unstable current and gap increase. Therefore, the optimum in-process electrolytic dressing is a good method to obtain the efficiency and mirror-like grinding of brittle materials.

• Korean Journal of Cognitive Science
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• v.16 no.1
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• pp.17-27
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• 2005

After prolonged viewing of a moving pattern, a stationary pattern can appear to move in the opposite direction, a phenomenon known as motion aftereffect (MAE). Unlike the classical explanation MAE was not confined to an adapted region; instead it can spread to an adjacent region, which was not adapted previously. In order to examine the relative locus of the mechanism responsible for MAE spreading, a rotating harmonic spiral pattern was presented as an adapting stimulus within an annulus window, and then the duration of MAE was measured in both the adapted annulus region and the non-adapted inner region. Two different kinds of test patterns were used: the same and mirror images of the original adapting pattern. An interesting characteristic of a harmonic spiral is that the orientation of a contour at a given location is different from thar of its mirror image by 90 degrees, and consequently the adapting effect of local motion detector is not expected to occur in the mirror image. The results showed that MAE duration in an adapted region was longer in the same image condition than in its mirror image condition, while MAE duration in an non-adapted region was not found to be different between those two different image conditions. These results suggest that MAE spreading might be produced by the adaptation of global motion detectors, not by local motion detectors.