• Journal of Technologic Dentistry
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• v.38 no.3
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• pp.217-224
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• 2016

Purpose: This study aimed to generate 3-D occlusal curvatures and evaluate the relationship between the occlusal curvatures and mandibular occlusal morphology factors. Methods: Mandibular dental casts from 25 young adult Korean were scanned as a virtual dental models with a 3-D scanner(Scanner S600, Zirkonzahn, Italy). The curve of Spee, curve of Wilson, and Monson's sphere were generated by fitting a circle/sphere to the cusp tips using a least-squares method. The mandibular mesiodistal cusp inclination, buccolingual cusp inclination, and tooth wear parameters were measured on the prepared virtual models using RapidForm2004(INUS technology INC, Seoul, Korea). Wilcoxon signed-rank test was performed to test side difference, and Spearman's rank correlation coefficients were investigated to verify the correlation between occlusal curvatures and correlated factors (a=0.05). Results: The mean radii of curve of Spee were $83.09{\pm}33.94$ in the left side and $79.00{\pm}28.12mm$ in the right side. The mean radii of curve of Wilson were $66.82{\pm}15.87mm$ in the mesial side and $47.87{\pm}9.40mm$ in the distal side with significantly difference between mesiodistal sides(p<0.001). The mean radius of Monson's sphere was $121.85{\pm}47.11mm$. Most of the cusp inclination parameters showed negative correlation for the radius of Monson' sphere(p<0.05). Especially, the buccolingual cusp inclinations in mesial side of molar showed high correlation coefficients among the factors(p<0.05). Conclusion: The radius of Monson's sphere was greater than the classical 4-inch values, and the buccolingual cusp inclinations in mesial side of molar can be considered as one of the main factors correlating with the radius of Monson's sphere.

• Communications for Statistical Applications and Methods
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• v.8 no.1
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• pp.185-192
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• 2001

Using the Lorenz curve that is proved to be a powerful tool to measure the income inequality within a population of income receivers, we propose the normalized sample Lorenz curve for the goodness-of-fit test that is very important test in statistical analysis. For two hodgkin's disease data sets, we compare the Q-Q plot and the proposed normalized sample Lorenz curve.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.1097-1103
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• 1988

This paper deals with surface crack behavior and the fatigue life prediction of notched specimens using the relation between surface crack length, a, and the cycle ratio, $N/N_{f}$. From the $a-N\;/\;N_{f}$ curves, UC(the upper limit curve), LC(the lower limit curve) and MC(the middle limit curve) were assumed and utilized to predict the fatigue life and crack growth rate. The data computed from the three assumed curves were compared with the experimental data. It has been found that in the stable crack growth region ($N/N_{f}=0.3-0.8$) fatigue life can be predicted within 20% errors. Using the characteristics of $a-N\;/\;N_{f}$ curve, it is possible to predict the $da/dN-K_{max}$ curve, the $da/dN-{\Delta}K_{{\varepsilon}_t}$ curve, and the $S-N_{f}$ curve.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.33-41
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• 2004

This paper proposes a color matching 3D look-up table simplifying the complex color matching procedure between a monitor and a mobile display device. In other to perform color matching, it is necessary to process color of image in the device independent color space like CIEXYZ or CIELAB. To obtain the data of the device independent color space from that of the device dependent RGB color space, we must perform display characterizations. LCD characterization error using S-curve model is larger than tolerance error since LCD is more nonlinear than CRT. This paper improves the S-curve model to have smaller characterization error than tolerance error using the electro-optical transfer functions of X, Y, and Z value. We obtained images having higher color fidelity on mobile display devices through color matching experiments between monitor and mobile display devices. As a result of this experiments, we concluded that the color matching look-up table with 64(4${\times}$4${\times}$4) is the smallest size allowing characterization error to be acceptable.

• Journal of Korean Society of Rural Planning
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• v.16 no.2
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• pp.57-64
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• 2010

This study aims to understand the degree of inequality of surveyed amenity resources and identify which resource and region have the highest concentration by estimating Lorenz Curve and the Gini's Coefficient. The Lorenz Curve and Gini's Coefficient derived from economics are introduced as tools for investigating and quantifying regional variability of amenity resources concentration. This study describes the concepts underlying the application of the Gini's coefficient to measure the concentration of amenity resources in 11 regions, Chungbuk Province, Korea. The Lorenz Curve presents a graphical view of the cumulative distribution of amenity resources and the Gini's Coefficient provides a single-parameter measure of the distributional concentration of amenity resources. Also the Gini's Coefficient is compared to the number of amenity resource for understanding distributional difference between concentration and quantitative distribution of amenity resources. The results demonstrate significantly different regional variation according to the amenity variables: almost intact nature, interaction between nature and man, man-made.

• Journal of Korean Society for Quality Management
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• v.31 no.2
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• pp.165-182
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• 2003

The fatigue has been considered to the most important failure mode where optimal design or reliability prediction of the machinery in aircraft, atomic reactors, and structure systems, etc., is required. When the statistical analysis of fatigue life data is performed, some difficulties are present because of the following facts : nonlinear relationship, heteroscedastic data, large scatter in the data, censored data (runouts), and existence of fatigue limit. To find the S-N curve models that characterize fatigue strength better, this research compares existing fatigue curve models developed recently in terms of the residual mean square and the estimate of fatigue limit, etc. for various fatigue data sets.

• Structural Engineering and Mechanics
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• v.24 no.5
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• pp.585-599
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• 2006

This paper describes a series of laboratory tests carried out to evaluate the influence of bed joint orientation on interlocking grouted stabilised mud-flyash brick masonry under uniaxial cyclic compressive loading. Five cases of loading at $0^{\circ}$, $22.5^{\circ}$, $45^{\circ}$, $67.5^{\circ}$ and $90^{\circ}$ with the bed joints were considered. The brick units and masonry system developed by Prof. S.N. Sinha were used in present investigation. Eighteen specimens of size $500mm{\times}100mm{\times}700mm$ and twenty seven specimens of size $500mm{\times}100mm{\times}500mm$ were tested. The envelope stress-strain curve, common point curve and stability point curve were established for all five cases of loading with respect to bed joints. A general analytical expression is proposed for these curves which fit reasonably well with the experimental data. Also, the stability point curve has been used to define the permissible stress level in the brick masonry.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.93-96
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• 2005

Since the columns with flexure-shear failure have lower ductility than those with flexural failure, shear capacity curve models shall be applied as well as flexural capacity curve in order to determine ultimate displacement for seismic design or performance evaluation. In this paper, a modified shear capacity curve model is proposed and compared with the other models such as the CALTRANS model, Aschheim et al.'s model, and Priestley et al.'s model. Four shear capacity curve models are applied to the 4 full scale circular bridge column test results and the accuracy of each model is discussed. It may not be fully adequate to drive a final decision from the application to the limited number of test results, however the proposed model provides the better prediction of failure mode and ultimate displacement than the other models for the selected column test results.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.186-189
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• 2006

Since the columns with flexure-shear failure have lower ductility than those with flexural failure, shear capacity curve models shall be applied as well as flexural capacity curve in order to determine ultimate displacement for seismic design or performance evaluation. In this paper, a proposed modified shear capacity curve model is compared with the other models such as the CALTRANS model, Aschheim et al.'s model, and Priestley et al.'s model. Four shear capacity curve models are applied to the 4 full scale and 7 small scale circular bridge column test results and the accuracy of each model is discussed. It may not be fully adequate to drive a final decision from the application to the limited number of test results, however the proposed model provides the better prediction of failure mode and ultimate displacement than the other models for the selected column test results.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.143-148
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• 2001

In this study, to investigate the effect of the generalized performance curve on the performance prediction and to find the optimal ones, a systematic study is performed. For this purpose, we compared the influence of the stage performance curves with experimental data in multi-stage axial compressors. As a result, it is discovered that the optimal generalized performance curves vary according to the number of the stages in compressors. And we found that for a low-stage compressors, Muir's pressure coefficient curve gives the best prediction results at design rotational frequency regardless of the efficiency curve. On the other hand, for high-stage compressors, Stone's pressure coefficient curve gives the optimistic results about the performance prediction at design rotational frequency.