• Journal of The Korean Astronomical Society
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• v.24 no.2
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• pp.173-190
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• 1991

Disk stellar luminosity function has been derived with stars in the Lowell Proper Motion Survey which contains about 9000 stars with ${\mu}\;{\geq}\;0".27$ of arc/yr, $8\;<\;m_{pg}\;<\;17$ and with bright stars in the Smithsonian Astrophysical Observatory (SAO) Star Catalogue, Luminosity function has been obtained with stars within 20 pc by Luyten's mean absolute magnitudes method using Reduced Proper Motion Diagram to select disk stars. Magnitudes and colors, in the SAO Star Catalogue as well as in the Lowell Proper Motion Survey have been transformed to the UBV system from the published UBV data. It has been found that stars which have higher proper motion than the original limit of the proper motion survey are missed, when the relation between the absolute magnitude and reduced proper motion is applied to sample stars without considering the dispersion in magnitude. Correction factors for missing stars have been estimated according to their limits of proper motion which are dependent on the absolute magnitude. Resulting luminosity function shows Wielen's dip at $M_B{\sim}10$, and systematic enhancement of stars on the average of about ${\Delta}\log\;{\Phi}\;(M_B){\sim}0.2$ compared with Luyten's luminosity function.

• Communications of the Korean Mathematical Society
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• v.26 no.2
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• pp.305-320
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• 2011

The relations among various types of continuity of fuzzy proper function on a fuzzy set and at fuzzy point belonging to the fuzzy set in the context of $\v{S}$ostak's I-fuzzy topological spaces are discussed. The projection maps are defined as fuzzy proper functions and their properties are proved.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.7
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• pp.535-540
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• 2019

The coupling between different models for MDO (Multi-disciplinary Optimization) greatly increases the complexity of the computational framework, while at the same time increasing CPU time and memory usage. To overcome these difficulties, POD (Proper Orthogonal Decomposition) and RBF (Radial Basis Function) are used to solve the optimization problem of determining the thickness of composites and sandwich cores when composite sandwich structures are used as aircraft wing skin materials. POD and RBF are used to construct surrogate models for the wing shape and the load data. Optimization is performed using the objective function and constraint function values which are obtained from the surrogate models.

• The korean journal of orthodontics
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• v.44 no.5
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• pp.263-267
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• 2014

Objective: To three-dimensionally elucidate the effects of occlusal hypofunction on the periodontal ligament and alveolar bone proper of rat molars by micro-computed tomography (micro-CT). Methods: Occlusal function in the molar area was restricted by attaching an anterior bite plate on the maxillary incisors and a metal cap on the mandibular incisors of 5-week-old male Wistar rats for 1 week. The periodontal ligament space and alveolar bone proper around roots of the mandibular first molar were assessed by histology and micro-CT. Results: The periodontal ligament space was narrower and the alveolar bone proper was sparser and less continuous in the hypofunction group than in the control group. Further, both the volume of the periodontal ligament and the volumetric ratio of the alveolar bone proper to the total tissue in the region of interest were significantly lower in the hypofunction group (p < 0.05). Conclusions: Occlusal hypofunction induces atrophic changes in the periodontal ligament and alveolar bone proper of rat molars.

• Journal of The Korean Astronomical Society
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• v.22 no.2
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• pp.101-111
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• 1989

We have analysed the proper motion data of LHS catalog, to derive the faint end of the luminosity function more precise than ever before, by mean absolute method, and by making use of the reudced proper motion diagram. It is found that the relations between the mean absolute magnitude and the reduced proper motion for main sequence stars, subdwarfs, and white dwarfs are so different that the proper application of an appropriate relation to each group is much more important. The derived luminosity function shows the broad maximum peak from $M_B{\sim}14$ to $M_B{\sim}17$ and declines after $M_B{\sim}17$ up to $M_B{\sim}22$.

• Bulletin of the Korean Mathematical Society
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• v.48 no.2
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• pp.325-334
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• 2011

In this paper we consider the discrete time delayed renewal risk model. We investigate what will happen when the distribution function of the discounted proper deficit is asymptotic in the initial surplus. In doing this we establish several lemmas regarding some related ruin quantities in the discrete time delayed renewal risk model, which are of significance on their own right.

• Honam Mathematical Journal
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• v.21 no.1
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• pp.105-113
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• 1999

Suppose that ${\Omega}$ is a bounded domain with $C^{\infty}$ smooth boundary in the plane whose associated Bergman kernel, exact Bergman kernel, or $Szeg{\ddot{o}}$ kernel function is an algebraic function. We shall prove that any proper holomorphic mapping of ${\Omega}$ onto the unit disc is algebraic.

• Journal of Korean Society on Water Environment
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• v.25 no.3
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• pp.432-440
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• 2009

The effect of selecting hydrologic item for calculating objective function on calibration of stream flow was evaluated by Hydrologic Simulation Porgram-Fortran (HSPF) linked with Model Independent Parameter Optimizer (PEST). Daily and monthly stream flow and flow duration were used to calculate objective function. Automated calibration focused on monthly stream was proper to analyze seasonal or yearly water budget but not proper to predict daily stream flow or percent chance flow exceeded. Calibration result focused on flow duration is proper to predict precent chance flow exceeded but not proper to analyze water budget or predict peak flow. These results indicate that hydrologic item calculated for objective function on calibration procedure could influence calibration results and watershed modeler should select carefully hydrologic item for the purpose of model application. Current, the criteria of stream flow of Korean TMDL is generated based on percent chance flow exceeded, so flow duration should be included to calculate objective function on calibration procedure for the estimation of criteria of stream flow using hydrologic model.

• Journal of computational fluids engineering
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• v.12 no.1
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• pp.35-42
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• 2007

This paper describes a recent development on the divergence free basis function based on a hermite stream function and verifies its validity by comparing results with those from a modified residual method known as one of stabilized finite element methods. It can be shown that a proper choice of degrees of freedom at a node with a proper arrangement of the hermite interpolation functions can yield solenoidal or divergent free interpolation functions for the velocities. The well-known cavity problem has been chosen for validity of the present algorithm. The comparisons from numerical results between the present and the modified residual showed the present method yields better results in both the velocity and the pressure within modest Reynolds numbers(Re = 1,000).

• Journal of the Korean Mathematical Society
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• v.46 no.3
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• pp.551-560
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• 2009

A theorem of Robert Blumenthal is used here in order to obtain a sufficient condition for a function between two Finsler manifolds to be a fibre bundle map. Our study is connected with two possible constructions: 1) a Finslerian generalization of usually Kaluza-Klein theories which use Riemannian metrics, the well-known particular case of Finsler metrics, 2) a Finslerian version of reduction process from geometric mechanics. Due to a condition in the Blumenthal's result the completeness of Euler-Lagrange vector fields of Finslerian type is discussed in detail and two situations yielding completeness are given: one concerning the energy and a second related to Finslerian fundamental function. The connection of our last framework, namely a regular Lagrangian having the energy as a proper (in topological sense) function, with the celebrated $Poincar{\acute{e}}$ Recurrence Theorem is pointed out.