• Geomechanics and Engineering
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• v.32 no.1
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• pp.35-47
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• 2023

Deformability of road pavements in the form of ruts represent a safety risk for road users. In the procedures for dimensioning the pavement structure, the requirement that such deformations do not occur is imperatively included, which results in the appropriate selection of elements (material, geometry) of the pavement structure. Deformability and functionality, will depend of the correct design of pavement structure during exploitation period. Nevertheless, there are many examples where deformations are observed on the pavement structure, in the form of rutting at parts of the road with relatively short length, realised in the same climatic and the same geoenvironmental conditions. The performed analysis of deformability led to the conclusion that the level of deformation is a function of the speed of traffic. This effect is observed on city roads, but also outside of urban areas at roads with speed limits are significant, due to the traffic management, traffic jams (intersections, etc.). Still, the lower speed cause greater deformations. The authors tried to describe the deformability of flexible pavement structures, from the aspects of geotechnical problems, as a function of driving speed. Outcome of the analysis is a traffic load correction coefficient, in terms of using the existing methods of flexible pavement structures design.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.4
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• pp.40-48
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• 2012

This paper models the hue shift phenomenon and proposes a hue correction method to give perceptual matching between projector with and without additional white channel. To quantify the hue shift phenomenon for whole hue angle, 24 color patches with the same lightness are frist created along equally-spaced hue angle, and these are displayed one by one both displays with different luminance levels. Next, each hue value of the patches appeared on the projector with additional white channel is adjusted by observers until the hue values of patches on both displays appear the same visually. After obtaining the hue shift values from the color matching experiment, these values are piecewise fit into six polynomial functions, which approximately determine shifted hue amounts for an arbitrary hue values of each pixel in projector with additional white channel and are utilized to correct them. Actually, an input RGB image is converted to CIELAB LCH color space to get hue values of each pixel and this hue value is shifted as much as the amount calculated by the functions of hue shift model for correction. Finally, corrected image is inversely converted to an output RGB image. For an evaluation, the matching experiment with several test images and the z-score comparisons were performed.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.557-559
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• 2004

The aminolyses of anilinothioethers $(C_6H_5N(CH_3)CH_2SC_6H_4Z)$ in acetonitrile with benzylamines $(XC_6H_4CH_2NH_2)$ have been investigated. The rates are much lower in acetonitrile than in methanol (with aniline). The Bronsted ${\beta}_X$ values are similar but ${\beta}_Z$ values are smaller compared to those for the reactions in MeOH with anilines. The large negative ${\rho}_{XZ}({\cong}-0.8$, after correction for fall-off) value is interpreted to indicate a frontside attack $S_N2$ mechanism, in which the two oppositely changed reaction centers in the TS, $-N^{{\delta}+}{\cdots}S^{{\delta}-}-$, are in close vicinity increasing the interaction between nucleophile and leaving group. The inverse secondary kinetic isotope effects ($k_H/k_D$ < 1.0) are observed with deuterated benzylamines $(XC_6H_4CH_2ND_2)$.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.40.1-40.1
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• 2015

Off-axis reflective optical systems have attractive advantages relative to their on-axis or refractive counterparts, for example, zero chromatic aberration, no obstruction, and a wide field of view. For the efficient operation of off-axis reflective system, the surface accuracy of freeform mirrors should be higher than the order of wavelengths at which the reflective optical systems operate. Especially for applications in shorter wavelength regions, such as visible and ultraviolet, higher surface accuracy of freeform mirrors is required to minimize the light scattering. In this work, we propose the error compensation algorithm (ECA) for the correction of wavefront errors on freeform mirrors. The ECA converts a form error pattern into polynomial expression by fitting a least square method. The error pattern is measured by using an ultra-high accurate 3-D profilometer (UA3P, Panasonic Corp.). The measured data are fitted by two fitting models: Sag (Delta Z) data model and form (Z) data model. To evaluate fitting accuracy of these models, we compared the fitted error patterns with the measured error pattern.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.2
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• pp.145-152
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• 1999

JPL(Jet Propulsion Laboratory) has been routinely produced the precise GPS ephemeris and clock's correction parameter using data collected from globally distributed permanent GPS tracking stations, and has been offering the automated GPS data analysis(Precise Point Positioning： PPP) service by using them. In this study, after investigating the potential capacity of JPL's PPP service, the coordinates computation of the GPS base station by this service were investigated. For this, the dual frequency P codes data of 24 hours were observed from continuously operating four reference stations in USA. sent to the JPL's main computer through E-mail and/or ftp, and then were processed by Gipsy/Oasis-II (GOA-II) software with the precise GPS transmitter parameters. Centimeter-level positioning results were available to obtain in X, Y, Z geocentric rectangular coordinate system.

• Geomechanics and Engineering
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• v.22 no.1
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• pp.97-108
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• 2020

The time-consuming and less objectivity are the main problems of conventional micromechanical parameters calibration method of Particle Flow Code simulations. Thus this study aims to address these two limitation of the conventional "trial-and-error" method. A new calibration method for the linear parallel bond model (CM-LPBM) is proposed. First, numerical simulations are conducted based on the results of the uniaxial compression tests on limestone. The macroscopic response of the numerical model agrees well with the results of the uniaxial compression tests. To reduce the number of the independent micromechanical parameters, numerical simulations are then carried out. Based on the results of the orthogonal experiments and the multi-factor variance analysis, main micromechanical parameters affecting the macro parameters of rocks are proposed. The macro-micro parameter functions are ultimately established using multiple linear regression, and the iteration correction formulas of the micromechanical parameters are obtained. To further verify the validity of the proposed method, a case study is carried out. The error between the macro mechanical response and the numerical results is less than 5%. Hence the calibration method, i.e., the CM-LPBM, is reliable for obtaining the micromechanical parameters quickly and accurately, providing reference for the calibration of micromechanical parameters.

• Journal of Korean Dental Science
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• v.13 no.1
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• pp.28-34
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• 2020

Purpose: The purpose of this study was to investigate the influence of different implant computer software on the accuracy of image registration between radiographic and optical scan data. Materials and Methods: Cone-beam computed tomography and optical scan data of a partially edentulous jaw were collected and transferred to three different computer softwares: Blue Sky Plan (Blue Sky Bio), Implant Studio (3M Shape), and Geomagic DesignX (3D systems). In each software, the two image sets were aligned using a point-based automatic image registration algorithm. Image matching error was evaluated by measuring the linear discrepancies between the two images at the anterior and posterior area in the direction of the x-, y-, and z-axes. Kruskal-Wallis test and a post hoc Mann-Whitney U-test with Bonferroni correction were used for statistical analyses. The significance level was set at 0.05. Result: Overall discrepancy values ranged from 0.08 to 0.30 ㎛. The image registration accuracy among the software was significantly different in the x- and z-axes (P=0.009 and <0.001, respectively), but not different in the y-axis (P=0.064). Conclusion: The image registration accuracy performed by a point-based automatic image matching could be different depending on the computer software used.

• Wind and Structures
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• v.22 no.3
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• pp.291-305
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• 2016

In this paper, a refined shear deformation plate theory which eliminates the use of a shear correction factor was presented for FG sandwich plates composed of FG face sheets and an isotropic homogeneous core. The theory accounts for parabolic distribution of the transverse shear strains and satisfies the zero traction boundary conditions on the surfaces of the plate. The mechanical properties of the plate are assumed to vary continuously in the thickness direction by a simple power-law distribution in terms of the volume fractions of the constituents. Based on the present refined shear deformation plate theory, the governing equations of equilibrium are derived from the principle of virtual displacements. Numerical illustrations concern buckling behavior of FG sandwiches plates with Metal-Ceramic composition. Parametric studies are performed for varying ceramic volume fraction, volume fraction profiles, Boundary condition, and length to thickness ratios. The accuracy of the present solutions is verified by comparing the obtained results with the existing solutions.

• Archives of Plastic Surgery
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• v.33 no.2
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• pp.135-143
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• 2006

The characteristics of the cleft lip nasal deformity is defined in this article in three planes. The alar flaring is explained in X axis, the lower positioning of the alar free margin is imagined in Y axis and the short hemicolumella is in Z axis. Most cleft surgeons have focused on the malposition of the lateral crus of alar cartilage while the author defined it in X and Y axises and tried to correct that deformity of short hemicolumella in Z axis. For the last 13 years the author applied that method in 818 cases of secondary cleft lip nose deformity. Through the columellar splitting incision extended to free margin of the alar not beyond the nasal dorsum, the skin and soft tissue of the webbing deformed the nasal tip was excised in crescent fashion. The dissected short hemicolumella including the medial crus was thus elevated and advanced into the space of the deformed nasal tip after the crescent excision. This procedure should be followed by the correction of the deformities in X and Y axis. The medial crus elevation is more effective and critical way to have the constant and nice outcome than the lateral crus reposition in secondary cleft lip nasal deformity

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.1
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• pp.1-8
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• 2001

The aim of this study is to know the GPS absolute positioning accuracy after discontinuing of Selective Availability (SA). The GPS satellite clock errors and the observation station coordinates were calculated using GPS C/A code pseudorange and compared with the JPL precise ephemerides and the previous known coordinates. As the results, the correction or the GPS clock errors in SA-on is about $\pm$40m but in SA-off $\pm$2m. The 95% probable errors for the measurements in SA-on are about $\pm$65m but in SA-off $\pm$10m in X, Y and SA-off $\pm$15m in Z.