• International Journal of Naval Architecture and Ocean Engineering
• /
• v.7 no.4
• /
• pp.770-783
• /
• 2015

Lately, high production rate welding processes for Al alloys, which are used as LNG FPSO cargo containment system material, have been developed to overcome the limit of installation and high rework rates. In particular, plasma-metal inert gas (MIG) hybrid (PMH) welding can be used to obtain a higher deposition rate and lower porosity, while facilitating a cleaning effect by preheating and post heating the wire and the base metal. However, an asymmetric undercut and a black-colored deposit are created on the surface of PMH weld in Al alloys. For controlling the surface defect formation, the wire feeding speed and nozzle diameter in the PMH weld was investigated through arc phenomena with high-speed imaging and metallurgical analysis.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.1514-1522
• /
• 2006

This study has described the case that has been experienced personally by centering on discords created in railway construction projects while performing practical duties at the construction field. Accordingly, as seen from the experience of performing one method called discord reconciliation conference, it seems that there are many parts to be improved on for the particular details because the conference was progressed by the position of a non professional in its content or procedure. But as seen from the word origin called "discord", looking at the state of finding one solution after another from vagueness of solving difficult and entangled problems, we could sense that the sincere communication and honesty was more progressive method in the phase of looking for one solution after another. Although this essay was centered on a typical case of railway construction project, I hope for it to spread throughout the whole society and especially hope that many discords created in public work sites such as public works would become settled smoothly between the parties concerned.

• Industrial Engineering and Management Systems
• /
• v.14 no.2
• /
• pp.196-209
• /
• 2015

Retail sales forecast is a special area of forecasting. Its unique characteristics call for unique data models and treatment, and unique forecasting processes. In this paper, we will address lessons learned and challenges encountered in retail sales forecast from a practical and technical perspective. In particular, starting with the data models of retail sales data, we proceed to address issues existing in estimating and processing each component in the data model. We will discuss how to estimate the multi-seasonal cycles in retail sales data, and the limitations of the existing methodologies. In addition, we will talk about the distinction between business events and forecast events, the methodologies used in event detection and event effect estimation, and the difficulties in compound event detection and effect estimation. For each of the issues and challenges, we will present our solution strategy. Some of the solution strategies can be generalized and could be helpful in solving similar forecast problems in different areas.

• IE interfaces
• /
• v.23 no.1
• /
• pp.1-11
• /
• 2010

There are various ways to manage the patient flow of the hospital outpatient system. However, it is difficult to apply many implementation solutions to the real outpatient system at once. Because first, the expected effects of each different solution are very much depend on the real situation of the system and applied other solutions, and second, owing to the limited resources, each solution should be implemented according to the priority. In order to overcome these difficulties, this paper focuses on proposing the comprehensive subset of implementation solutions, which is one of the most effective among various kinds of subsets, and verifying the effects of it. The comprehensive subset of solutions is derived from conducting design of experiments and simulation which determine the optimum set of different solutions and analyze the particular interactions and priority order among them. This implementation strategy can solve the difficulties of applying different kinds of various solutions to the hospital outpatient system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.11a
• /
• pp.621-624
• /
• 1999

Metalization technology of the fine patterns by electroless plating is required in place of electrodeposition as high-density printed boards(PCR) become indispensable with the miniaturization of electronic components. Electroless nickel plating is a suitable diffusion barrier between conductor meta1s, such as Al and Cu and solder is essetional in electronic packaging in order to sustain a long period of service. Moreover, Electroless nickel has particular characteristics including non-magnetic property, amorphous structure. wear resistance, corrosion protection and thermal stability In this study fundamental aspects of electroless nickel deposition were studied with effort of complexeing agents of different kinds. Then the property of electroless deposit are controlled by the composition of the deposition solution the deposition condition such as temperature and pH value and so on. the characteristics of the deposits has been carried out.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.07a
• /
• pp.865-868
• /
• 2000

It was examined that the relationship between microstructures, electrical properties and crystal structure of (1-x)CaMnO$_3$-xCaTiO$_3$solid solution system which was made by mixing a semiconducting material CaMnO$_3$of low resistance and a dielectric material CaTiO$_3$of high resistance with variable ratios (x=0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0). As the CaTiO$_3$increased, the resistance, B constant and lattice constant were increased, but the grain size was decreased. On particular, above 50wt% of CaTiO$_3$, the resistance at 2 5$^{\circ}C$ was rapidly increased due to the correlation in connectivity of the lattices between the conductive Mn$^{+4}$ octahedron and the insulative Ti$^{+4}$ octahedron.ron.

• Structural Engineering and Mechanics
• /
• v.7 no.3
• /
• pp.259-276
• /
• 1999

An analytical solution for the shape functions of a beam segment supported on a generalized two-parameter elastic foundation is derived. The solution is general, and is not restricted to a particular range of magnitudes of the foundation parameters. The exact shape functions can be utilized to derive exact analytic expressions for the coefficients of the element stiffness matrix, work equivalent nodal forces for arbitrary transverse loads and coefficients of the consistent mass and geometrical stiffness matrices. As illustration, each distinct coefficient of the element stiffness matrix is compared with its conventional counterpart for a beam segment supported by no foundation at all for the entire range of foundation parameters.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.8 no.11
• /
• pp.69-77
• /
• 1985

The queue theory is based on the assumption that most system are normally assigned to stay under steady state. Therefore, the initial problem can be represented by a symbolic model but such a representation does not permit analysis of all the interesting alternatives. When the solution to the problem is thus restricted to a particular subclass of available alternatives, the symbolic model can be solved by mathematics to deduce which alternative is optimal. However, when be consider slightly more complicated alternatives, the analytic procedures become interactable. The purpose of this study is to show how a simulation model enable us to handle the more complicated system after examining the characteristics of the complications that negate more complicated system. Then construct a simulation model and compare the solution of simulation models with analytic methods.

• Bulletin of the Korean Mathematical Society
• /
• v.56 no.1
• /
• pp.245-251
• /
• 2019

Assume that ${\Omega}$ is a bounded domain in ${\mathbb{R}}^n$ with $n{\geq}2$. We study positive solutions to the problem, ${\Delta}u=u^p$ in ${\Omega}$, $u(x){\rightarrow}{\infty}$ as $x{\rightarrow}{\partial}{\Omega}$, where p > 1. Such solutions are called boundary blow-up solutions of ${\Delta}u=u^p$. We show that a boundary blow-up solution exists in any bounded domain if 1 < p < ${\frac{n}{n-2}}$. In particular, when n = 2, there exists a boundary blow-up solution to ${\Delta}u=u^p$ for all $p{\in}(1,{\infty})$. We also prove the uniqueness under the additional assumption that the domain satisfies the condition ${\partial}{\Omega}={\partial}{\bar{\Omega}}$.

• Coupled systems mechanics
• /
• v.10 no.1
• /
• pp.79-102
• /
• 2021

In this paper we deal with instability problems of structures under nonconservative loading. It is shown that such class of problems should be analyzed in dynamics framework. Next to analytic solutions, provided for several simple problems, we show how to obtain the numerical solutions to more complex problems in efficient manner by using the finite element method. In particular, the numerical solution is obtained by using a modified Euler-Bernoulli beam finite element that includes the von Karman (virtual) strain in order to capture linearized instabilities (or Euler buckling). We next generalize the numerical solution to instability problems that include shear deformation by using the Timoshenko beam finite element. The proposed numerical beam models are validated against the corresponding analytic solutions.