• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.3
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• pp.273-281
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• 2010

In this paper, a method to predict the fatigue life of an axle drive shaft by the calibrated accelerated life test (CALT) method is proposed. The CALT method is very effective for predicting lifetimes, significantly reducing test time, and quantifying reliability. The fatigue test is performed by considering two high stress and one low stress levels, and the lifetime at the normal stress level is predicted by extrapolation. In addition, in this study, the major reliability parameters such as the lifetime, accelerated power index, shape parameter, and scale parameter are determined by conducting various experiments. The lifetime prediction of the axle drive shaft is verified by comparing the experimental results with load spectrum data. The results confirm that the CALT method is effective for lifetime prediction and requires a short test time.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.1
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• pp.77-81
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• 2016

Purpose: This study was performed to investigate the difference of meridional visual acuity and the loss of corrected visual acuity (VA) in order to emphasis the importance of astigmatic correction. Methods: 64 subjects (122 eyes) aged $22.75{\pm}2.36years$ participated in this study. After full correction of astigmatic refractive error, VA was measured in which the direction of the slit filter was matched with astigmatic axis and $90^{\circ}$ to the astigmatic axis. Results: 52 eyes showed no difference in VA between the two direction. However 70 eyes had difference VA between them. 14 out of 52 eyes and 24 out of 70 eyes had under 1.0 in monocular VA. The astigmatic degree was higher in the existence of VA difference between the two direction than non-existence. The difference is higher with under 1.0 monocular VA. Monocular VA is closely related to the focal line having better VA in the principal focal line. Glasses replacement period was analyzed as 6~12 months for the preservation of better VA. Conclusions: The final glasses prescription has to be given with full correction because continued under-correction for astigmatism causes meridional VA difference.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.820-823
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• 2010

There are still some controversies in treatment strategy for the very low-birth-weight baby with esophageal atresia even though the result of primary repair has been improving. We report a successful end to end anastomosis with staged approach in one of twin weighing 1,270 g at birth.

• Journal of Sensor Science and Technology
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• v.11 no.2
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• pp.111-117
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• 2002

In this paper, we proposed calibration techniques to improve measurement accuracy in the characteristic analysis system for semiconductor devices. Systematic errors can be reduced using proposed calibration techniques. Also, error current reduction procedures including leakage current and offset current are proposed to measure low-level current in pA level. Calibration parameters are calculated and stored by microprocessor using least-square fitting with measured sample data. During measurement time microprocessor corrects measured data using stored calibration parameters. Experimental results show that current measurement error above nA level is less than 0.02%. And they also show that current measurement in pA level can be performed with about 0.2% accuracy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.6
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• pp.572-580
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• 2015

RF skin tracking of instrumentation RADAR cannot acquire stable track data, because of effect of multipath interference especially elevation direction. In this paper, low altitude target tracking method using laser tracking system is suggested to overcome this restriction. The effect of multipath can be reduced by increasing angle resolution with laser characteristics of very short pulse and narrow beamwidth. RF skin track, beacon track and laser track data for the integrated calibration target on the ground and target ship on the sea are gathered. And they are compared and analyzed to confirm the performance of laser tracking system. As a result, it shows that the suggested laser track method has better performance than RF skin track under multipath conditions.

• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.79-83
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• 2018

In this paper, we measured and analyzed the dose correction factor, absorbed dose linearity, peak voltage X-ray response, angular dependence. Exposure dose correction factor, absorbed dose linearity, and peak voltage linearity using the medical X-ray generator were all in accordance with IEC-62387-1 (2007). The reference to the dosimetry direction at 0, 30, and 60 degrees relative to baseline radiation exposure was -29% (${\pm}30^{\circ}$) and + 67% (${\pm}60^{\circ}$). The values measured at $30^{\circ}$ were -8% lower than the standard and -18% lower than the standard at $60^{\circ}$. Therefore, the effect of direction should be corrected when using OSL dot dosimeter.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.357-360
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• 2013

A 1.8V 2-Gb/s scalable low voltage signaling (SLVS) transmitter (TX) is designed for mobile applications requiring high speed and low power consumption. It consists of 4-lane TX for data transmission, 1-lane TX for a source synchronous clocking, and a 8-phase clock generator. The proposed SLVS TX has the scaling voltage swing from 50 mV to 650 mV and supports a high speed (HS) mode and a low power (LP) mode. An output impedance calibration scheme for the SVLS TX is proposed to improve the signal integrity. The proposed SLVS TX is implemented by using a $0.18-{\mu}m$ 1-poly 6-metal CMOS with a 1.8V supply. The simulated data jitter of the implemented SLVS TX is about 8.04 ps at the data rate of 2-Gbps. The area and power consumption of the 1-lane of the proposed SLVS TX are $422{\times}474{\mu}m^2$ and 5.35 mW/Gb/s, respectively.

• The korean journal of orthodontics
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• v.28 no.2 s.67
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• pp.219-229
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• 1998

The purpose of this study is to define the characteristics of the skeleton and soft tissues of severe adult class III malocclusion. The materials selected for this study were lateral cephalograms of 112 adult class III malocclusion patients with ANB difference below -2 degrees. and the mean age was 22.9 years old. The normal control sampler consisted of lateral cephalograms of 50 adults in normal occlusion and the mean age was 22.1 years old. The Horizontal reference line was FH line and the vertical reference line was nasion perpendicular to FH line. The skeletal and soft tissue characteristics of Class III malocclusion are as follows : 1. In the skeletal profile evaluated by vertical reference line (Nasion perpendicular to FH), the forehead and maxilla was similar to normal, but the mandible was protruded significantly. 2. The soft tissue profile is concave. The thickness of soft tissue covering forehead area and nose is within normal range. but the upper lip is thicker and the nasolabial angle is smaller than normal. The lower lip and inferior labial sulcus is thinner than normal. The degree of eversion of lower lip is lesser than normal. 3. The cranial base of class III malocclusion is shorter and saddle angle is smaller than normal. 4. The location of midface evaluated in relations to cranial base is within normal range but, the length of midface is shorter than normal when compared from the deep portion of the facial skeleton. 5. The location of maxilla in reference to cranial base is within normal range but the length of maxilla was shorter in class III malocclusion. 6. The mandible was protruded, ramus height and body length, gonial angle were greater than normal, and the chin angle was smaller. 7. Upper incisor was proclined, lower incisor was retroclined.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.91-95
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• 2009

The use of stainless steel crowns are indicated for restoration of primary or permanent molars with proximal dental caries, extensive dental caries, or previous pulp treatment with increased danger of tooth fracture. Stainless steel crowns were introduced by Humphrey in 1950. For their improved durability, longevity, and success rate, they have been strongly considered for restoring extensive and multi-surfaced dental caries of molars in pediatric dentistry. However, they also have shortcomings, such as possibility of pulpal exposure or damaging proximal surface of adjacent teeth. In addition, when oversized stainless steel crowns are used, eruption of the adjacent permanent teeth may be disturbed by their prominent margin. As a means to compensate the shortcomings of stainless steel crowns, use of orthodontics bands may be considered. It is an alternative restoration method, where an orthodontic band is placed on a tooth first and cavity is restored with filling material, such as composite resin, glass ionomer, or amalgam. The use of an orthodontic band is indicated for molar restoration with cervical dental caries, extensive dental caries, enamel hypoplasia, or previous pulp treatment. Because it requires shorter chair time compared to stainless steel crown, its application is very useful for children with poor behavior. However, restoration using an orthodontic band requires good oral hygiene after its application. This case report illustrates the conservative restoration of primary molars and permanent molars with extensive dental caries using orthodontic bands.

• Korean Journal of Optics and Photonics
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• v.19 no.6
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• pp.439-447
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• 2008

There is a need for a finite schematic presbyopic eye that models vision and image quality under various conditions such as cataract or refractive surgery, as well as near vision corrections with an ophthalmic lens or contact lens. Using recently measured biometric data of presbyopic eyes, new model eyes were designed that are optically and anatomically close to real eyes. The parameters changing significantly with age were incorporated into models for four different age groups. The new model eyes have alpha angle, decentered pupil, aspheric GRIN lens and aspheric retinal surface. It is likely that the new finite presbyopic model eyes will be useful for designing visual instruments such as low vision aids, PALs, IOL and contact lenses, and for the clinical prediction of the retinal image quality of a presbyopic patient.