• Parasites, Hosts and Diseases
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• v.55 no.5
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• pp.565-568
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• 2017

An oval-shaped mass with a smooth surface was found in the ear canal of a 22-month-old male infant. Although the mass appeared to be almost entirely blocking the ear canal, it was successfully removed under a surgical microscope without general anesthesia at the outpatient department. Under an optical microscope with hematoxylin and eosin staining, the specimen was observed to have a cuticle with a serrated surface and a pore canal, as well as parts of the capitulum, salivary glands, muscles, midgut, and the legs. The specimen was identified as a hard tick of the family Ixodidae, based on gross and histological findings. This paper is the first report in Korea on the diagnosis and treatment of a tick bite in the ear canal.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.248-250
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• 2006

The study on a surface transformation hardening of a rod-shaped SM45C carbon steel is carried out by using CW Nd:YAG laser. Conventionally, $CO_2$ laser has been usually used as a laser source for a transformation hardening. however, it is needed to an additional absorbent coating like a colloidal graphite owing to a lower absorbtion rate. On the other hand, no cost and post-removal process of coating is required to Nd:YAG laser, due to a higher absorbtion rate relatively. Moreover, there is a merit which is capable of building up the more flexible processing system resulted from a beam delivery through a optical fiber. In this study, we were going to recognize characteristics of a transformation hardening using a optic head with a gaussian beam distribution.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.687-688
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• 2008

Air flow of inside automobile HVAC module has been visualized using a high-resolution PIV technique with varying the temperature operation mode. The PIV system consists of a 2-head Nd:YAG laser(125 mJ), a high-resolution CCD camera(2K x 2K), optics and a synchronizer. A real automobile HVAC module was used directly with slight modification for clear optical windows. Some parts of the HVAC module casing were replaced with transparent windows for capturing flow images with laser light sheet beam illumination. Time-averaged velocity field were measured in three temperature control modes. Flow characteristics of the air-conditioned air flow in the automobile HVAC system were evaluated.

• Journal of Biosystems Engineering
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• v.22 no.2
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• pp.227-236
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• 1997

Manual grading and sorting of red-ginsengs are inherently unreliable due to its subjective nature. A computerized technique based on optical and geometrical characteristics was studied for the objective quality evalution. Spectral reflectance of three categories of red-ginsengs - "Chunsam", "Chisam", "Yangsam" - were measured and analyzed. Variation of reflectance among parts of a single ginseng was more significant than variation among the quality categories of ginsengs. A PC-based image processing algorithm was developed to extract geometrical features such as length and thickness of body, length and number of roots, position of head and branch point, etc. The algorithm consisted of image segmentation, calculation of Euclidean distance, skeletonization and feature extraction. Performance of the algorithm was evaluated using sample ginseng images and found to be mostly sussessful.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.452-452
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• 2008

Abstract Head-mounted displays(HMD) are being developed and marketed in growing numbers for a variety of applications. Though most commonly associated with entertainment applications other applications are also being developed. The field vision on the display screens is expanded by the optical system producing an imaginary screen that appears to be positioned several meters in front of the viewer. In this study, the mold core for the prism lens of HMD was processed by fly-cutting method, and the form accuracy of the mold core was measured.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.12-12
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• 2002

We present the new jaw tracking system that utilizes five degrees of freedom of head and lower jaw. The proposed method does not disturb the physiology because the system does not need to fix magnetic field sensors or clutch on the patient's body or mouth. The impact of this result goes beyond the conventional optical and magnetic tracking system of jaw movement [1][2]. Position accuracy within 1mm and reasonable cost is necessary for practical use of the jaw tracking system. (omitted)

• Journal of Biomedical Engineering Research
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• v.14 no.3
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• pp.243-250
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• 1993

An endoscope is a medical device which observes the inner surface of an organ inside a body. Recently, a new type of endoscope using a CCD image sensor has been developed and turned out to have many strong points over the conventional optical fiber endoscope system. A swallowable insertion tube is an insertion tube having so small a diameter that the head of the insertion tube can reach the end of stomach only by mechanical movement of the esphagus and stomach or the patient's external movement. This paper presents some of the results that the Institute of Biomedical Engineering at Seoul National University has obtained while developing an electronic endoscope having a swallowable insertion tube. After some of the features of the developed system are presented, some of the image processing techniaues are addressed.

• Electrical & Electronic Materials
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• v.8 no.5
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• pp.633-639
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• 1995

Dropouts in magnetic media are a primary quality deficiency which is detrimental to magnetic signal quality and thus the major impediment to error-free recording, especially in high density digital recorders. The specific form of defects and causes found to be responsible for signal dropouts occurring in magnetic tape were studied. Dropout occurred when the RF signal falls to low level due to the various types of surface defects. However, the fall in the level of the RF signal in gravure roll coated tapes was most often caused by foreign particles adhering to the magnetic tape. It was also shown from the present study that scattered particles trapped under the tape surface or put on the top can lift it as it crosses the head, creating a spherical tent shaped defect and causing a temporary signal drop. Dropout producing substances were identified through optical and microchemical analyses. The results were correlated with measured electrical signal losses combined with analytical microscopy to clarify source identification of defects.

• Journal of the Korean Vacuum Society
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• v.8 no.3A
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• pp.249-255
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• 1999

Deposition characteristics of Cu thin films using Ar carrier gas and $H_2$ processing gas at various working pressures and substrate temperatures were investigated. Also, effects of $H_2$ pretreatment using plasma at $200^{\circ}C$ of substrate temperature and 0.6 Torr of chamber pressure were stdied. Cu thin films were deposited on TiN/Si substrate at working pressure of 0.5~1.5 Torr, substrate temperatures of 140~$240^{\circ}C$ with (hface)Cu(tmvs). Substrates were pretreated by $H_2$ plasma, and Cu films deposited in situ using twofold shower head. The purity, electrical resistivity, thickness, surface morphology, optical properties of the deposited Cu films were measured b the AES, four point probe, stylus profiler, SEM,. and the uv-visible spectrophotometer. This study suggests that $H_2$ plasma is an effective method for enhancing deposition rate and for producing high quality copper thin films.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.6
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• pp.995-1001
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• 1997

In this paper, a new positioning method with incoherence of white light is described and practically implemented to attach VCR heads on a drum very accurately. This method utilizes the Michelson Interferometer which uses white light with short coherence length as the light source to generate interference fringes only in case the optical path difference is shorter than about 2.mu.m. The course position of VCR heads and the fine are determined by appearance and visibility of interference fringes, respectively. The appearance are detected by an image processing technique using FFT(Fast Fourier Transform).