• Journal of the Korea Fashion and Costume Design Association
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• v.21 no.4
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• pp.165-179
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• 2019

This study used 3D body scan data to classify body shapes according to the torso shape of adult males aged 20-75 years. This data will be provided so that the apparel industry can make apparel products corresponding to body characteristics by age. The study used 1,796 adult males between the ages of 20 and 75 and the 3D body shape data of the '5th Research on National Standard Anthropometry'. For data analysis, the program SPSSWIN Ver. 17.0 was used to calculate the mean and frequency allowing for a factor analysis, cluster analysis, analysis of variance, and Duncan test. To classify body shape according to the torso shape of adult males, this study considered nine factors: 'horizontal size of torso,' 'vertical size of body,' 'curve of torso and waist-abdomen flatness ratio,' 'length of torso,' 'shape of neck area,' 'degree of lateral curve,' 'difference between front and back interscye length,' 'shoulder armscye shape,' and 'chest flatness ratio.' Based on the results of the factor analysis, the torso shapes of adult males were classified into five types. Type 1 is "upright body with flat, curvy shape", Type 2 is "curve sway back body type", Type 3 is "flat, abdominally obese body", Type 4 is "obese, crooked body" and Type 5 is "thick sway front body type." named.

• Journal of the Korean Data and Information Science Society
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• v.19 no.4
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• pp.1441-1448
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• 2008

We propose the modified quantile-quantile (Q-Q) plot using the approximate maximum likelihood estimators and the modified normalized sample Lorenz curve (NSLC) plot for the extreme value distribution based on multiply Type-II censored samples. Using two example data sets, we picture the modified Q-Q plot and the modified NSLC plot.

• Bulletin of the Korean Mathematical Society
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• v.53 no.2
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• pp.519-530
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• 2016

In this paper, we study surfaces of revolution in the three dimensional pseudo-Galilean space. We classify surfaces of revolution generated by a non-isotropic curve in terms of the Gauss map and the Laplacian of the surface. Furthermore, we give the classification of surfaces of revolution generated by an isotropic curve satisfying pointwise 1-type Gauss map equation.

• Journal of Biosystems Engineering
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• v.40 no.4
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• pp.305-313
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• 2015

Purpose: This study was performed to predict the fatigue life of a crank-type rotavator operated in domestic soil conditions using Recurdyn$^{(R)}$, a dynamic analysis program. Methods: Torque on the PTO shaft was measured using experiments conducted on the uplands and paddy fields in Korea. On the basis of the experimental and analytical results, the fatigue life of the crank-type rotavator was predicted by constructing an S-N curve according to the GL (Germanischer Lloyd Wind Energie GmbH) guideline. Results: The torques experienced by the PTO shaft in the paddy soil and the uplands were in the range of 472~797 N m and 313~430 N m, respectively, for every condition. In case of load condition, the peak torques (846 N m, 770 N m) were applied for severe conditions, resulting in a maximum (von Mises) stress of 75 MPa at the crank arm. The fatigue life of the crank-type rotavator was predicted to be 1,167 h that satisfies the target value of 1,110 h, by substituting the analysis results into an S-N curve of crank arm. Conclusions: The fatigue life of the crank-type rotavator was within the target life for the studied soil conditions; however, further field experiments for various soil conditions would be required to verify the prediction results.

• Kyungpook Mathematical Journal
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• v.59 no.4
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• pp.821-834
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• 2019

The reductivity of a spherical curve is the minimal number of times a particular local transformation called an inverse-half-twisted splice is required to obtain a reducible spherical curve from the initial spherical curve. It is unknown if there exists a spherical curve whose reductivity is four. In this paper, an unavoidable set of configurations for a spherical curve with reductivity four is given by focusing on 5-gons. It has also been unknown if there exists a reduced spherical curve which has no 2-gons and 3-gons of type A, B and C. This paper gives the answer to this question by constructing such a spherical curve.

• Journal of the Korean Society of Safety
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• v.27 no.2
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• pp.117-126
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• 2012

Understanding driver's characteristic of visual activity is important process because driver depends on a visual signal more than 90% for getting outside information needed to drive, thus a series of driving, including perception, judgement, and activity, is completed. This study analyzes quantified driver's sight range in curved section where recognition of various information is critical due to biggest speed change among sections. Simulation is utilized for this study because of safety problem on field experiment and difficulties in using equipment. Building 6 roads that have different in curve radius by virtual driving map, experiment is carried out recruiting 30 people. Through analytical researches, it shows that drivers keep an eye on direction of driving, and driver's visual range is narrowed on left curve than right curve, and the more curve radius become small, the more drivers see in narrow angle.

• Journal of applied mathematics & informatics
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• v.32 no.1_2
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• pp.17-26
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• 2014

In this paper, we present an algorithm for computing the number of points on the Jacobian varieties of genus 3 hyperelliptic curves of type $y^2=x^7+ax$ over finite prime fields. The problem of determining the group order of the Jacobian varieties of algebraic curves defined over finite fields is important not only arithmetic geometry but also curve-based cryptosystems in order to find a secure curve. Based on this, we provide the explicit formula of the characteristic polynomial of the Frobenius endomorphism of the Jacobian variety of hyperelliptic curve $y^2=x^7+ax$ over a finite field $\mathbb{F}_p$ with $p{\equiv}1$ modulo 12. Moreover, we also introduce some implementation results by using our algorithm.

• Journal of ILASS-Korea
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• v.4 no.1
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• pp.55-61
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• 1999

The first maximum point in the stability curve of liquid jet, i.e., the critical point is associated with the critical Reynolds number. This critical Reynolds number should be predicted by simple means. In this work, the critical Reynolds number in the stability curve of liquid jet are predicted using the empirical correlations and the experimental data reported in the literatures. The critical Reynolds number was found to be a function of the Ohnesorge number, nozzle lengh-to-diameter ratio, ambient Weber number and nozzle inlet type. An empirical correlation for the critical Reynolds number as a function of the Ohnesorge number and nozzle length-to-diameter ratio is newly proposed here. Although an empirical correlation proposed in this work may not be universal because of excluding the effects of ambient pressure and nozzle inlet type, it has reasonably agrees with the measured critical Reynolds number.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.53.1-53.1
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• 2017

The YONSEI (YOnsei Nearby Supernova Evolution Investigation) project is to investigate the luminosity evolution of Type Ia supernovae (SNe Ia) by using their early-type host galaxies. As a part of this project, we have constructed our own SN catalogue. SALT2 and MLCS2k2 light-curve fitters implemented in SNANA package are employed to analyze the light-curve data. The catalogue provides a rest-frame peak magnitude in B-band or distance modulus, a light-curve shape parameter, and a color or an extinction value of each SN in the redshift range from 0.01 to 1.4. In this poster, we will present our progress in the detailed systematic tests for this catalogue.

• Communications for Statistical Applications and Methods
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• v.26 no.2
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• pp.191-203
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• 2019

The problem of examining how well an assumed distribution fits the data of a sample is of significant and must be examined prior to any inferential process. The observed failure time data of items are often not wholly available in reliability and life-testing studies. Lowering the expense and period associated with tests is important in statistical tests with censored data. Goodness-of-fit tests for perfect data can no longer be used when the observed failure time data are progressive Type II censored (PC) data. Therefore, we propose goodness-of-fit test statistics and a graphical method based on generalized Lorenz curve for PC data from a location-scale distribution. The power of the proposed tests is then assessed through Monte Carlo simulations. Finally, we analyzed two real data set for illustrative purposes.