• Management Science and Financial Engineering
• /
• 제21권1호
• /
• pp.11-17
• /
• 2015

Min-max stochastic optimization is an approach to address the distribution ambiguity of the underlying random variable. We present a unified approach to the problem which utilizes the theory of convex order on the random variables. First, we consider a general framework for the problem and give a condition under which the convex order can be utilized to transform the min-max optimization problem into a simple minimization problem. Then extremal distributions are presented for some interesting classes of distributions. Finally, applications to the single-period inventory control problems are given.

• 한국인쇄학회지
• /
• 제29권3호
• /
• pp.133-142
• /
• 2011

We produce a photosensitive convex plate to research a Nickel metal relief printing plate using galvanic process. A Method for preparing DLC convex plate that is metalized on Nickel metal relief printing plate using CVD(Chemical Vapor Deposition) process and $N_2DLC$-convex plate that is DLC metalized thin film layer of $N_2$ plasma surface treatment are comprised. DLC thin film layers on Nickel surface are fragile. The results of the research indicate that the coefficient of friction on DLC metalized thin film layer is relatively low than Nickel surface and the durability of Nickel surface coated DLC metalized thin film layer is superior to Nickel surface. A relative evaluation of three form plate wetting properties using varnish liquid-drop plate indicates superior printing aptitudes for $N_2DLC$, DLC, Nichel plate order as above.

• 대한수학회보
• /
• 제56권1호
• /
• pp.265-276
• /
• 2019

For a simple implementation, a linear convex splitting scheme was coupled with the Fourier spectral method for the Cahn-Hilliard equation with a logarithmic free energy. However, an inappropriate value of the splitting parameter of the linear scheme may lead to incorrect morphologies in the phase separation process. In order to overcome this problem, we present a nonlinear convex splitting Fourier spectral scheme for the Cahn-Hilliard equation with a logarithmic free energy, which is an appropriate extension of Eyre's idea of convex-concave decomposition of the energy functional. Using the nonlinear scheme, we derive a useful formula for the relation between the gradient energy coefficient and the thickness of the interfacial layer. And we present numerical simulations showing the different evolution of the solution using the linear and nonlinear schemes. The numerical results demonstrate that the nonlinear scheme is more accurate than the linear one.

• 호남수학학술지
• /
• 제23권1호
• /
• pp.41-50
• /
• 2001

This paper concerns with the subclass of normalized analytic function f in D = {z : |z| < 1}, namely a ${\delta}$-convex function in a sector. This subclass is denoted by ${\Delta}({\delta})$, where ${\delta}$ is a real positive. Given $0<{\beta}{\leq}1$ then for $z{\in}D$, the exact ${\alpha}({\beta},\;{\delta})$ is found such that $f{\in}{\Delta}({\delta})$ implies $f{\in}S^*({\beta})$, where $S^*({\beta})$ is starlike of order ${\beta}$ in a sector. This work is a more general version of the result of Nunokawa and Thomas [11].

• 대한수학회보
• /
• 제38권2호
• /
• pp.357-367
• /
• 2001

Let $Q(\beta)$ be the class of normalized strongly quasiconvex functions of order $\beta$ in the open unit disk. Sharp Fekete-Szego inequalities are obtained for functions belonging to the class $Q(\beta)$. We also consider the integral preserving properties in a sector.

• 대한수학회보
• /
• 제37권2호
• /
• pp.291-301
• /
• 2000

We give sufficient coefficient conditions for a class of meromorphic univalent harmonic functions that are starlike of some order. Furthermore, it is shown that these conditions are also necessary when the coefficients of the analytic part of the function are positive and the coefficients of the co-analytic part of the function are negative. Extreme points, convolution and convex combination conditions for these classes are also determined. Fianlly, comparable results are given for the convex analogue.

• Kyungpook Mathematical Journal
• /
• 제59권3호
• /
• pp.481-491
• /
• 2019

In the present paper, we investigate the upper bounds on third order Hankel determinants for certain class of close-to-convex functions in the unit disk. Furthermore, we obtain estimates of the Zalcman coefficient functional for this class.

• Korean Journal of Mathematics
• /
• 제27권2호
• /
• pp.357-374
• /
• 2019

In this paper, first we obtain some inequalities of Hadamard type for (h - m)-convex functions via Caputo k-fractional derivatives. Secondly, two integral identities including the (n + 1) and (n+ 2) order derivatives of a given function via Caputo k-fractional derivatives have been established. Using these identities estimations of Hadamard type integral inequalities for the Caputo k-fractional derivatives have been proved.

• Nonlinear Functional Analysis and Applications
• /
• 제27권3호
• /
• pp.621-640
• /
• 2022

The aim of this study is to establish some mean convergence theorems for double array of fuzzy random variables in metric space endowed with a convex combination operation under various assumptions.

• 호남수학학술지
• /
• 제18권1호
• /
• pp.59-77
• /
• 1996

In this paper, we study how the second coefficient in the power series expansion of functions in $P_n$(a; b, M), $F_n$(a; b, M) and $G_n$(a; b, M) influences certain properties like distortion, ${\gamma}-spiral$ radius and radius of starlikeness of these classes.