• Journal of the Korean Society for Precision Engineering
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• v.33 no.6
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• pp.491-497
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• 2016

This study aims to develop a vision inspection system for screw threads. To inspect external defects in screw threads, the vision inspection system was developed using front light illumination from which bright images can be obtained. The front light system, however, requires multiple side images for inspection of the entire thread surface, which can be performed by omnidirectional optics. In this study, an omnidirectional optical system was designed to obtain annular images of screw threads using an image sensor and two reflection mirrors; one large concave mirror and one small convex mirror. Optical simulations using backward and forward ray tracing were performed to determine the dimensional parameters of the proposed optical system, so that an annular image of the screw threads could be obtained with high quality and resolution. Microscale surface defects on the screw threads could be successfully detected using the developed annular inspection system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.9
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• pp.667-670
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• 2010

In this paper, a high voltage current sensing circuit for boost converter is designed and verified by Cadence SPECTRE simulations. The current mirror pair, power and sensing metal-oxide semiconductor field effect transistors (MOSFETs) with size ratio of K, is used in our on-chip current sensing circuit. Very low drain voltages of the current mirror pair should be matched to give accurate current sensing, so a folded-cascode opamp with a PMOS input pair is used in our design. A high voltage high side lateral-diffused MOS transistor (LDMOST) switch is used between the current sensing circuit and power MOSFET to protect the current sensing circuit from the high output voltage. Simulation results using 0.35 ${\mu}m$ BCD process show that current sensing is accurate and the pulse frequency modulation (PFM) boost converter using the proposed current sensing circuit satisfies with the specifications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.14-14
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• 2010

A high voltage current sensing circuit for LED driver IC is designed and verfied by Cadence SPECTRE simulations. The current mirror pair, power and sensing MOSFETs with size ratio of K, is used in our on-chip current sensing circuit. Very low drain voltages of the current mirror pair should be matched to give accurate current sensing, so a folded-cascode opamp with a PMOS input pair is used in our design. A high voltage high side LDMOST switch is used between the current sensing circuit and power MOSFET to protect the current sensing circuit from the high output voltage. Simulation results using 0.35um BCD process show that current sensing is accurate with properly frequency compensated opamp.

• KIEAE Journal
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• v.6 no.4
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• pp.11-16
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• 2006

This work has carried out some preliminary studies for the utilization of a solar mini-dish system capable of concentrating solar rays to higher densities. A typical mini-dish system considered employs an array of solar mini-dishes where major components are light and compact. It consists of small mini-dishes, optical fiber bundles and diffusers at the end. Each mini-dish (typically has a 20 to 30 cm in diameter) is designed with a simple parabolic profile, concentrating sunlight (after the glass glazing cover to avoid dust deposition on the reflector and facilitate cleaning) onto a centrally-located small mirror which is placed on the bottom side of the transparent glass cover. The focused sunlight is reflected by the mirror surface onto a focal point where the receiving aperture of a homogenizer is located. Optical fibers are used to carry high-density solar rays to the other end where diffusers are mounted for indoor illumination. The proposed high density mini-dish system could make an efficient daylighting system as it excludes large moving parts and expandable if necessary. Each component of the system could be made from the off-the-shelf technology and thus, make the generic unit inexpensive to manufacture. Depending on spatial demand or characteristics, the amount of introducing daylight could be controlled. Preliminary tests have been carried out for a trial system to check any functional problems when in operation. Suggestions are also made to improve the design enhancing its performance and applicability.

• Korean Journal of Veterinary Research
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• v.37 no.1
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• pp.203-212
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• 1997

Antibacterial efficacy and safety of copper sulfate pentahydrate (5% solution) was evaluated in laboratory and field studies for disinfection of some fish bacterial pathogens in cultured fish, flounder(Paralichthys olivaceus), mirror carp(Cyprinus carpio), gold fish(Carrassius auratus) and eel(Anguilla japonica). Dipping of fishes for acute toxicity was performed for a period of 48h, and the TLm value(median tolerance limit) were 4.0ppm in mirror carp and flounder, 4.4ppm in rainbow trout, and 10.0ppm in gold fish. After exposure below than TLm value for 1 month, no side effects and histopathological changes were observed. The test drug were shown high antibacterial activities against most bacterial pathogens by exposure in the laboratory and field trials. However, Aeromonas salmonicida showed a resistance to the dosage. We can prevent outbreaks of bacterial diseases of fish by the dosage of 1ppm for 6hr and the test drug is thought to be used effectively and widely as a disinfectant against most bacterial fish pathogens.

• Journal of Korean Philosophical Society
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• v.123
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• pp.135-164
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• 2012

This paper aims to clarify Heidegger's concept of 'play(Spiel)'. Through Heidegger's ideas of play, we are going to present that the concept of play, as frequently argued, not only stay with playful side associated with human mental activity but also like with further perspectives. In other words, we will show the ontological meaning of the Heidegger' concept of play. First, in Heidegger's early thinking, the play appears in 'play of life' or 'play of transcendence'. In contrast, in his later thinking, the play appears in 'play-space', 'Time-play-space', 'mirror-play', 'play of silent', etc. Thus, we have tried to clarify the Heidegger's concept of play that divided as the starting point of his turn(Kehre).

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.4
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• pp.92-102
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• 2012

The process of the wind noise analysis around an OSRVM is developed and is verified by simulating unsteady flow field past a generic OSRVM mounted on the flat plate at the Reynolds number of $Re_D=5.2{\times}10^5$ based on the mirror diameter. The transient flow field past a generic OSRVM is simulated with various turbulence models, namely DES-SA, LES Constant SGS, and LES Dynamic SGS. The sound radiation is predicted using the Ffowcs- Williams and Hawkings analogy. For the present simulation, the 6.35million cells are generated. Time averaged pressure coefficients at 34 locations on the surface of the generic OSRVM are compared with the available experimental data. Also, 12 Sound Pressure Levels located on the surrounding mirror are compared with the available experimental data. Both of them show good agreements with experimental data.

• Archives of Plastic Surgery
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• v.36 no.5
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• pp.642-648
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• 2009

Purpose: Hexadactyly without thumb is a rare congenital anomaly of the hand where six triphalangeal digits are symmetrically distributed without thumb. Contrary to mirror hands, triphalangeal six digits are symmetrically distributed on each side at the midline with well - differentiated carpal bones, extensor tendons, one ulnar and one radius. The authors developed a new surgical technique based on a three - dimensional concept to correct the hexadactyly and applied to 2 cases of hexadactyly with good functional and aesthetic results. Here we document the surgical technique and its result. Methods: A 16 month old male patient visited our clinic with chief complaints of bilateral hexadactyly deformity. On physical examination most radial first and second digits showed no opposition and adduction motion on both side hands. Radiography showed 6 triphalangeal digits with normal development of carpal, radial and ulnar bone. Right side abnormality was corrected by removal of most radial side extra - digit, rotation and migration of 2nd ray to thumb position and creation of 1st web by transposing a mid - palm based rectangular palmar flap as in Snow & Littler procedure which has been being applied for correction of 1st web syndactyly in cleft hand deformity. Seven months later, left side abnormality was also corrected with the same procedure. Results: Postoperative appearances of the both hands were satisfactory. Flexion, extension, opposition and grasping were possible with the pollicized 2nd ray. Pinching power was 3.0 kg 15 months after surgery and 2.5 kg 22 months after in right hand respectively. Conclusion: In correction of hexadactyly deformity, satisfactory aesthetic and relevant functional results can be expected with authors' newly developed technique: removal of most radial digit, rotation and migration of 2nd digit to thumb position as well as creation of the 1st web space by transposition of mid - palm based rectangular flap.

• Journal of Yeungnam Medical Science
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• v.20 no.2
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• pp.117-128
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• 2003

Thallium-201 scintigraphy is used to discriminate the malignant bone tumor from the benign by qualitatively and quantitatively, and to predict the response of preoperative chemotherapy in osteosarcoma, by comparing the changes of thallium uptake ratio after chemotherapy to the tumor necrosis ratio. Thallium-201 scintigraphy scan should be done prior to surgical biopsy. PICKER Prism 2000 gamma camera with high resolution parallel hole collimator is usually used for scanning. The patient is injected with 2-3mCi of Tl-201 and the early phase is checked in 30 minutes and delayed phase in 3 hours. The scan images are visually evaluated by a blinded nuclear medicine physician. We could evaluate true positive, true negative, false positive and false negative by the comparison of results with those of biopsy, and calculate positive and negative predictive value(%), sensitivity(%), specificity(%) and diagnostic accuracy(%). For the quantitative analysis of thallium uptake, we drew the region of interest on the tumor side and contralateral normal side as mirror image, and calculated the uptake ratio with dividing the amount of gamma count in tumor side by normal side. We could calculate the percent changes of thallium uptake ratio in early and delayed phase, and compare them to the ratio of tumor necrosis. Thallium-201 scintigraphy proved as useful imaging study to discriminate malignant bone tumor from benign, but had exception in giant cell tumor and low grade malignant bone tumors. We can use T1-201 scan to differentiate the benign from the malignant tumor, and to evaluate the response of preoperative chemotherapy or radiotherapy, and to determine the residual tumor or local recurrence. For the better result, we need to have a more detail information about false positive cases and a more objective and quantitative reading technique.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.7
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• pp.765-773
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• 2016

The vehicle interior noise caused by exterior fluid flow field is one of critical issues for product developers in a design stage. Especially, turbulence and vortex flow around A-pillar and side mirror affect vehicle interior noise through a side window. The reliable numerical prediction of the noise in a vehicle cabin due to exterior flow requires distinguishing between the aerodynamic (incompressible) and the acoustic (compressible) surface pressures as well as accurate computation of surface pressure due to this flow, since the transmission characteristics of incompressible and compressible pressure waves are quite different from each other. In this paper, effective signal processing technique is proposed to separate them. First, the exterior flow field is computed by applying computational aeroacoustics techniques based on the Lattice Boltzmann method. Then, the wavenumber-frequency analysis is performed for the time-space pressure signals in order to characterize pressure fluctuations on the surface of a vehicle side window. The wavenumber-frequency diagrams of the power spectral density shows clearly two distinct regions corresponding to the hydrodynamic and the acoustic components of the surface pressure fluctuations. Lastly, decomposition of surface pressure fluctuation into incompressible and compressible ones is successfully accomplished by taking the inverse Fourier transform on the wavenumber-frequency diagrams.