Dear colleagues and researchers,
The Journal of the Korean Society for Industrial and Applied Mathematics (J-KSIAM) Volume24 Number1 (March 2020 issue) has been posed on https://www.ksiam.org/archive or other information on the journal is available on the KSIAM website http://www.ksiam.org or https://www.ksiam.org/journal.
The journal is one of Korea Citation Indexed (KCI) journals since 2007 and is indexed in Emerging Sources Citation Index (ESCI) since 2017.
Readers interested in the following articles may download each of articles free of charge from our website and authors are encouraged to submit a paper via the online submission site.
Hi Jun Choe, Editor-in-Chief
Zhiming Chen, Hyeong-Ohk Bae, Tao Tang, Associate Editors-In-Chief
Jae Hoon Jung, Jaemyung Ahn, Wanho Lee, Managing Editors
LEAST-SQUARE SWITCHING PROCESS FOR ACCURATE AND EFFICIENT GRADIENT ESTIMATION ON UNSTRUCTURED GRID
SEUNGPYO SEO, CHANGSOO LEE, EUNSA KIM, KYEOL YUNE, AND CHONGAM KIM
An accurate and efficient gradient estimation method on unstructured grid is presented by proposing a switching process between two Least-Square methods. Diverse test cases show that the gradient estimation by Least-Square methods exhibit better characteristics compared to Green-Gauss approach. Based on the investigation, switching between the two Least-Square methods, whose merit complements each other, is pursued. The condition number of the Least-Square matrix is adopted as the switching criterion, because it shows clear correlation with the gradient error, and it can be easily calculated from the geometric information of the grid. To illustrate switching process on general grid, condition number is analyzed using stencil vectors and trigonometric relations. Then, the threshold of switching criterion is established. Finally, the capability of Switching Weighted Least-Square method is demonstrated through various two- and three-dimensional applications.
CURVATURE-WEIGHTED SURFACE SIMPLIFICATION ALGORITHM USING VERTEX-BASED GEOMETRIC FEATURES
HAN-SOO CHOI, DALHYEON GWON, HEEJAE HAN, AND MYUNGJOO KANG
The quadratic error metric (QEM) algorithm has been frequently used for simplification of triangular surface models that utilize the vertex-pair algorithm. Simplified models obtained using such algorithms present the advantage of smaller storage capacity requirement compared to the original models. However, a number of cases exist where significant features are lost geometrically, and these features can generally be preserved by utilizing the advantages of the curvature-weighted algorithm. Based on the vertex-based geometric features, a method capable of preserving the geometric features better than the previous algorithms is proposed in this work. To validate the effectiveness of the proposed method, a simplification experiment is conducted using several models. The results of the experiment indicate that the geometrically important features are preserved well when a local feature is present and that the error is similar to those of the previous algorithms when no local features are present.
OPTIMAL ERROR ESTIMATE OF A DECOUPLED CONSERVATIVE LOCAL DISCONTINUOUS GALERKIN METHOD FOR THE KLEIN-GORDON-SCHRO¨ DINGER EQUATIONS
In this paper, we propose a decoupled local discontinuous Galerkin method for solving the Klein-Gordon-Schr¨odinger (KGS) equations. The KGS equations is a model of the Yukawa interaction of complex scalar nucleons and real scalar mesons. The advantage of our scheme is that the computation of the nucleon and meson field is fully decoupled, so that it is especially suitable for parallel computing. We present the conservation property of our fully discrete scheme, including the energy and Hamiltonian conservation, and establish the optimal error estimate.
FAST ANDROID IMPLIMENTATION OF MONTE CARLO SIMULATION FOR PRICING EQUITY-LINKED SECURITIES
HANBYEOL JANG, HYUNDONG KIM, SUBEOM JO, HANRIM KIM, SERI LEE, JUWON LEE,
AND JUNSEOK KIM
In this article, we implement a recently developed fast Monte Carlo simulation (MCS) for pricing equity-linked securities (ELS), which is most commonly issued autocallable structured financial derivative in South Korea, on the mobile platform. The fast MCS is based on Brownian bridge technique. Although mobile platform devices are easy to carry around, mobile platform devices are slow in computation compared to desktop computers. Therefore, it is essential to use a fast algorithm for pricing ELS on the mobile platform. The computational results demonstrate the practicability of Android application implementation for pricing ELS.
TRIDIAGONALITY OF J-NORMAL AND J-CONJUGATE NORMAL HESSENBERG MATRICES
M. GHASEMI KAMALVAND AND K. NIAZIASIL
STEADY-STATE TEMPERATURE ANALYSIS TO 2D ELASTICITY AND THERMO-ELASTICITY PROBLEMS FOR INHOMOGENEOUS SOLIDS IN HALF-PLANE
KIRTIWANT P. GHADLE AND ABHIJEET B. ADHE
The concept of temperature distribution in inhomogeneous semi-infinite solids is examined by making use of direct integration method. The analysis is done on the solution of the in-plane steady state heat conduction problem under certain boundary conditions. The method of direct integration has been employed, which is then reduced to Volterra integral equation of second kind, produces the explicit form analytical solution. Using resolvent- kernel algorithm, the governing equation is solved to get present solution. The temperature distribution obtained and calculated numerically and the relation with distribution of heat flux generated by internal heat source is shown graphically.
HALL EFFECTS ON HYDROMAGNETIC NATURAL CONVECTION FLOW IN A VERTICAL MICRO–POROUS–CHANNEL WITH INJECTION/SUCTION
P. BHASKAR AND M. VENKATESWARLU
In this work, the hydromagnetic and thermal characteristics of natural convection flow in a vertical parallel plate micro–porous–channel with suction/injection is analytically studied in the presence of Hall current by taking the temperature jump and the velocity slip at the wall into account. The governing equations, exhibiting the physics of the flow formation are displayed and the exact analytical solutions have been obtained for momentum and energy equations under relevant boundary conditions. The impact of distinct admissible parameters such as Hartmann number, Hall current parameter, permeability parameter, suction/injection parameter, fluid wall interaction parameter, Knudsen number and wall-ambient temperature ratio on the flow formation is discussed with the aid of line graphs. In particular, as rarefaction parameter on the micro–porous–channel surfaces increases, the fluid velocity increases and the volume flow rate decreases for injection/suction.