• Journal of Ecology and Environment
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• v.38 no.3
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• pp.319-326
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• 2015

This study investigates the behavioral characteristics and forms of phosphorus in the sediment according to the oxygen condition (aerobic/anaerobic). In the behavioral characteristics analysis, Al-P and Fe-P concentrations were the highest among the forms of inorganic phosphorus, and therefore had the strongest impact on sorption and release corresponding to environmental condition changes. In the experimental investigation of the inorganic forms of phosphorus in the sediment according to the oxygen condition, we determined that the forms of inorganic phosphorus did not greatly affect the sorption or release reaction because the distribution ratios of the inorganic forms remained constant corresponding to changes of dissolved oxygen (DO) conditions. In contrast, the forms of organic phosphorus in the sediments affected both sorption and release. Furthermore, labile-P and moderately labile-P forms were the major mechanisms of sorption in sediment. Moderately labile-P was the greatest contributor to phosphorus release action in sediment. As environmental changes are important for the behavioral characteristics of phosphorus in sediment, the forms of phosphorus should be considered to have a greater effect, especially in the organic phosphorus case. Therefore, based on the present study results, sediment evaluation aimed at controlling internal pollutants in reservoirs should include an examination of the forms of phosphorus present, as well as the release characteristics of environmental changes, which are influential factors of phosphorus control. Further research in this field is required.

• Bulletin of the Korean Mathematical Society
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• v.55 no.6
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• pp.1811-1822
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• 2018

In this paper, we exhibit the explicit forms of continued fraction expansions of a family of algebraic power series over a finite field and we study their asymptotic distribution of approximation exponents.

• Communications for Statistical Applications and Methods
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• v.5 no.3
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• pp.591-597
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• 1998

We prove (at least empirically) that some forms of the scaled residuals calculated from i.i.d. multivariate normal random vectors are ancillary. We further show that, if the scaled residuals are ancillary, then they have the same distribution whatever form of rotation is rosed to remove sample correlations.

• Journal of Ocean Engineering and Technology
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• v.27 no.2
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• pp.1-7
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• 2013

This paper aims at contributing to the field of ship design by introducing new systematic variation methods for ship hull forms. Hull form design is generally carried out in two stages. The first is the global variation considering the sectional area curve. Because the geometric properties of a sectional area curve have a decisive effect on the global hydrodynamic properties of ships, the design of a sectional area curve that satisfies various global design conditions, e.g., the displacement, longitudinal center of buoyancy, etc., is important in the initial hull form design stage. The second stage involves the local design of section forms. Section forms affect the local hydrodynamic properties, e.g., the local pressure in the fore- and aftbody. This paper deals with a new method for the systematic variation of sectional area curves. The longitudinal volume distribution of a ship depends on the sectional area curve, which can geometrically be controlled using parametric variation and a variation that uses the modification function. Based on these methods, we suggest a more generalized method in connection with the derivation of the lines for a new design compared to those for similar ships. This is the so-called the volumetric balanced variation (VOB) method for ship forms using a B-spline modification function and an optimization technique. In this paper the global geometric properties of hull forms are totally controlled by the form parameters. We describe the new method and some application examples in detail.

• Journal of the Korean Mathematical Society
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• v.46 no.6
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• pp.1267-1276
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• 2009

This paper presents a method for approximation of the standard normal distribution by using hyperbolic tangent based functions. The presented approximate formula for the cumulative distribution depends on one numerical coefficient only, and its accuracy is admissible. Furthermore, in some particular cases, closed forms of inverse formulas are derived. Numerical results of the present method are compared with those of an existing method.

• Journal of Labour Economics
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• v.29 no.2
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• pp.67-116
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• 2006

This study directly analyzes the wage distributions rather than indirectly looking at a few of their moments. It also investigates wage distributions using various descriptive and semi-parametric methods. The wage distributions of Korean manufacturing industries can in general be represented by three distinct forms, underdeveloped, advanced and the medium of the two. The discrepancies in these distribution forms are explained by differences in the labor-type distributions and their weights in the composition of wage distribution forms, and further clarified through various descriptive statistics based on them. However, the descriptive statistical analysis has a limit in that it shows mixed outcomes of different categoric variables. Then, this problem is resolved by applying a semi-parametric estimation of hazard function and the marginal effect evaluations of variable changes on estimated distributions not on the function. As a result of this marginal analysis, the common features and differences of categoric variables and their intensities of effects on distributions are revealed.

• Journal of Distribution Science
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• v.16 no.7
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• pp.35-45
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• 2018

Purpose - The study investigates the impact of consignment on the economic performance in the supply chain with three stages. Through the analysis on distinct forms of consignment application, this study intends to answer to the question of how the consignment should be used in the multi-stage supply chain. Research design, data, and methodology - The proposed mathematical model represents the supply chain system with a manufacturer, a wholesaler, and a retailer. Three different forms of consignment application are considered depending on which stages adapt the consignment, and their system profits are compared with the traditional non-consignment system in numerical examples. Results - The numerical examples show that the serial consignment application performs better than any other forms of consignment as well as the non-consignment system. The additional analysis indicates that the system profit is significantly sensitive to the consignment rate. Conclusions - The outcome of this study implies the potential of consignment to improve the system performance even in the multi-stage supply chain system. Meanwhile, each supply chain member's preference to the specific form of consignment application could be different depending on which stage he has. All the supply chain members should jointly determine the appropriate consignment rates to obtain the best system performance.

• Bulletin of the Korean Mathematical Society
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• v.44 no.1
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• pp.195-202
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• 2007

We prove that a real hypersurface M in a complex space form Mn(c), $c{\neq}0$, whose Ricci operator and structure tensor commute each other on the holomorphic distribution and the Ricci operator is ${\eta}-parallel$, is a Hopf hypersurface. We also give a characterization of this hypersurface.

• Communications of the Korean Mathematical Society
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• v.25 no.2
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• pp.225-234
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• 2010

In this paper, we study the geometry of lightlike hypersurfaces of a semi-Riemannian manifold. We prove a classification theorem for Einstein lightlike hypersurfaces M of a Lorentzian space form subject such that the second fundamental forms of M and its screen distribution S(TM) are conformally related by some non-vanishing smooth function.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.4
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• pp.487-497
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• 2000

The purpose of this study was performed 1) to study the differences in advertisement expression and brand preference according to the lifestyle groups of high school girl students(Sports Uninterest Group, Friend Preference/Fashion Uninterest Group, Sports Preference/Horne Oriented Group. fashion Interest Group, and Confidence Group) and 2) to investigate the effects on the brand preference of adolescents of lifestyle, brand and advertisement image and advertisement expression forms. The subjects selected for the final analysis were high school girl students living in Pusan, Seoul and Taejeon, Korea. The statistics used for data analysis were factor analysis, one-way ANOVA, Duncan's multiple range test, stepwise multiple regression, frequency distribution and percentage by the SPSS program. The results of this study were as follows: 1. The preferences of advertising expression forms were significantly different among lifestyle groups: the Friend Preference/Fashion Uninterest Group preferred to sex appealing advertising expression form less than other groups. 2. The brand preferences were significantly different among lifestyle groups: the Confidence Group preferred brand less than other groups in general. 3. The brand preferences were affected by life style, brand and advertising image and preferences of advertising expression forms. And brand image influenced most significantly on the brand preferences.