• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.2
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• pp.180-185
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• 1995

TMJ ankylosis is classified with true and false type. A true ankylosis is defined as any condition that produces fibrous or bony adhesions between the articular surfaces of the temporomandibular joint. The main causes of true ankylosis are trauma or infection. A false ankylosis results from pathologic conditions outside the joint that limit mobility of the mandible such as myogenic disorders, coronoid impingement or rare direct bony fusion between maxilla and mandible. The treatment of choice of TMJ ankylosis is surgical intervention. We experienced the male patient with complete mouth opening limitation since 45 years before. This patient has true TMJ ankylosis and rare bony synostosis between maxilla and mandible in the right posterior region. We performed surgical intervention and had a favorable result.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.10 s.253
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• pp.1219-1226
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• 2006

The ASTM test standard recommends the use of the compact tension specimen for creep crack growth rates measurement. In the creep crack growth rate test, the displacement rate due to creep is obtained by subtracting the contribution of elastic and plastic components from the total load line displacement rate based on displacement partitioning method fur determining $C^*-integral$, which involves Ramberg-Osgood (R-O) fitting procedures. This paper investigates the effect of the R-O fitting procedures on plastic displacement rate estimates in creep crack growth testing, via detailed two-dimensional and three-dimensional finite element analyses of the standard compact tension specimen. Four different R-O fitting procedures are considered; (i) fitting the entire true stress-strain data up to the ultimate tensile strength, (ii) fitting the true stress-strain data from 0.1% strain to 0.8 of the true ultimate strain, (iii) fitting the true stress-strain data only up to 5% strain, and (iv) fitting the engineering stress-strain data. It is found that the last two procedures provide reasonably accurate plastic displacement rates and thus should be recommended in creep crack growth testing. Moreover, several advantages of fitting the engineering stress-strain data over fitting the true stress-strain data only up to 5% strain are discussed.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.2
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• pp.171-177
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• 2011

Tensile tests were conducted at low temperatures for the steel materials which are used for outer shell of the vessels making transit through the polar regions. The selected steel materials were GL-DH32, GL-DH36 and GL-EH36. In comparison with the results at room temperature, the yield stress increases approximately by 10 to 13 percent at $-30^{\circ}C$ and by 13 to 19 percent at $-50^{\circ}C$ while the tensile strength increases about by 9 percent at $-30^{\circ}C$ and 11 to 14 percent at $-50^{\circ}C$. To obtain true stress-true strain, i.e. correct plastic hardening characteristics, Bridgman's(1952) necking correction formula was introduced taking triaxial state of stresses after onset of diffuse necking into consideration. Photographs of fractured surfaces were taken by using Scanning Electron Microscope immedately after tensile tests completed and one for GL-EH36 has been presented in this paper.

• Research in Community and Public Health Nursing
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• v.18 no.4
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• pp.543-551
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• 2007

Purpose: The purpose of this study was to compare obesity-related quality of life according to obesity classification by BMI (body mass index) and self-assessment. Methods: The participants were 286 female college students in J City. Data were obtained by measuring height. weight and BMI, and using a questionnaire for self-assessment of obesity, weight control, and quality of life. The quality of life was measured using 14 items of the Korean version of obesity-related quality of life (KOQOL). Results: Thirty five percent of the students assessed themselves as overweight and obese despite their BMI <$23m^2/kg$(false overweight). True overweight students with BMI $\geq23m^2/kg$ who perceived themselves as overweight and obese were 23%. The total KOQOL score between true and false overweight students showed no significant difference. True overweight students had a lower total KOQOL score including psychosocial, physical, daily living, sex related. and food-related domains than true normal weight students. Conclusions: The quality of life was not different between true and false overweight students. These results indicate that self-assessment about obesity affects the quality of life like as actual BMI in female college students. Therefore, it is necessary to care students who distort themselves as obese.

• Journal of Radiation Protection and Research
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• v.43 no.4
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• pp.137-142
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• 2018

Background: Gamma-ray detectors having a thin window of a material with low atomic number can increase the true coincidence summing effects for radionuclides emitting X-rays or gamma-rays. This effect can make efficiency calibration or spectrum analysis more complicated. In this study, a Cu shield was tested as an X-ray filter to neglect the true coincidence summing effect by X-rays and gamma-rays in gamma-ray spectrometry, in order to simplify gamma-ray energy spectrum analysis. Materials and Methods: A Cu shield was designed and applied to an n-type high-purity germanium detector having an $X-{\gamma}$ summing effect during efficiency calibration. This was tested using a commercial, certified mixed gamma-ray source. The feasibility of a Cu shield was evaluated by comparing efficiency calibration results with and without the shield. Results and Discussion: In this study, the thickness of a Cu shield needed to avoid true coincidence summing effects due to $X-{\gamma}$ was tested and determined to be 1 mm, considering the detection efficiency desired for higher energy. As a result, the accuracy of the detection efficiency calibration was improved by more than 13% by reducing $X-{\gamma}$ summing. Conclusion: The $X-{\gamma}$ summing effect should be considered, along with ${\gamma}-{\gamma}$ summing, when a detection efficiency calibration is implemented and appropriate shielding material can be useful for simplifying analysis of the gamma-ray energy spectra.

• Communications for Statistical Applications and Methods
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• v.6 no.2
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• pp.383-395
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• 1999

This study is concerned with the evaluation of predictive ability of classification models with ordered multiple categories. If categories can be ordered or ranked the spread of misclassification should be considered to evaluate the performance of the classification models using loss rate since the apparent error rate can not measure the spread of misclassification. Since loss rate is known to underestimate the true loss rate the bootstrap method were used to estimate the true loss rate. thus this study suggests the method to evaluate the predictive power of the classification models using loss rate and the bootstrap estimate of the true loss rate.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.139-142
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• 2008

Developing from stereoscopic to autostereoscopic, researchers on display technology are trying to provide more depth cues to viewer, leading to the advent of true 3D display. Volumetric 3D displays seem to be practical technology at present. Ultimate display will function like human vision system, with characteristics of providing all depth cues and free interaction.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.225-226
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• 2010

The problem in orthoimage generation is to recover occlusion areas. In this study, occlusion areas - double mapping regions of the building roofs - were mutually corrected by using multiple images. The proposed method could be efficient for generating true orthoimages in urban areas.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.793-798
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• 2000

As we review the mechanism regarding digital font generation and birth of TrueType font, we realizes that the process is composed of sequential steps such as contour fonts from glyph table. This fact implies that we propose classification of TrueType font in terms of segment width and the number of occurrence from the glyph data.

• Journal of information and communication convergence engineering
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• v.10 no.3
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• pp.253-257
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• 2012

This paper presents an efficient filtering system for a metastable state-based true random number generator. To output a result with high randomness, we use loop-storage for storing the value of metastability. During the metastable state, the output value is accumulated to the storage. When the non-metastable state arises, the stored metastable value will be used for output instead of the result of the non-metastable state. As a result, we can maintain high entropy together with the original throughput.