• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.819-824
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• 2005

This paper describes the measurement result of leakage current flowing arresters connected in feeder lines to propose an optimal management method. Twenty seven arresters set in seven areas were analyzed on a regular basis for 4 months. The results showed that the RMS and the peak value of the total leakage currents for soundness arresters were a range of $200uA{\sim}00uA$. respectively. During the period of measurement, the magnitude of the leakage current didn't show conspicious changes and there were impossible places to analyze arrester's status due to including high THD rate in a feeder line, From the study, leakage current measurement has to be performed at a condition without running an electric train in the line, and the allowable RMS value of soundness arrester is bellow 600uA.

• 산업경영시스템학회지
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• 제23권59호
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• pp.1-10
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• 2000

The traveling salesman problem is a representative NP-Complete problem. It needs lots of time to get a solution as the number of city increase. So, we need an efficient heuristic algorithm that gets good solution in a short time. Almost edges that participate in optimal path have somewhat low value cost. This paper discusses the property of nearest neighbor and 3-opt. This paper uses nearest neighbor's property to select candidate edge. Candidate edge is a set of edge that has high probability to improve cycle path. We insert edge that is one of candidate edge into intial cycle path. As two cities are connected. It does not satisfy hamiltonian cycle's rule that every city must be visited and departed only one time. This paper uses 3-opt's method to sustain hamiltonian cycle while inserting edge into cycle path. This paper presents a highly efficient heuristic algorithm verified by numerous experiments.

• 수산해양기술연구
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• 제28권1호
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• pp.27-38
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• 1992

The paper presents a digital speed control approach of induction motor systems by using a digital redesign method and adopting a well known 2nd order model as the system model equation. The basic concept using the modeling equation is induced from the control theory stand point such that we can describe usually the motor system connected by inverter, generator and load etc. just as a mechanical system to be controlled. The concept does not demand us the complicated vector-based modeling equation adopted in the traditional methods for the speed control of induction motor. The effectiveness of the servo control system composed by the above mentioned design concept is illustrated by the experimental results in the presence of step reference change and generator load variation. It is observed from the experimental results that the steady state error of the experimental set up becomes zero after some regulation time and the induction motor system is robust in spite of reference signal change and load variation of generator.

• 대한수학회보
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• 제40권1호
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• pp.17-28
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• 2003

Let X be a closed, oriented, Riemannian 4-manifold with ${{b_2}^+}(x)\;>\;1$ and of simple type. Suppose that ${\sigma}\;:\;X\;{\rightarrow}\;X$ is an involution preserving orientation with an oriented, connected, compact 2-dimensional submanifold $\Sigma$ as a fixed point set with ${\Sigma\cdot\Sigma}\;{\geq}\;0\;and\;[\Sigma]\;{\neq}\;0\;{\in}\;H_2(X;\mathbb{Z})$. We show that if _X(\Sigma)\;+\;{\Sigma\cdots\Sigma}\;{\neq}\;0$ then the $Spin^{C}$ bundle $\={P}$ is not $\mathbb{Z}_2-equivariant$, where det $\={P}\;=\;L$ is a basic class with $c_1(L)[\Sigma]\;=\;0$.

• 대한수학회지
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• 제49권1호
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• pp.17-30
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• 2012

Let D be an arbitrary domain in $\mathbb{C}^n$, n > 1, and $M{\subset}{\partial}D$ be an open piece of the boundary. Suppose that M is connected and ${\partial}D$ is smooth real-analytic of finite type (in the sense of D'Angelo) in a neighborhood of $\bar{M}$. Let f : $D{\rightarrow}\mathbb{C}^n$ be a holomorphic correspondence such that the cluster set $cl_f$(M) is contained in a smooth closed real-algebraic hypersurface M' in $\mathbb{C}^n$ of finite type. It is shown that if f extends continuously to some open peace of M, then f extends as a holomorphic correspondence across M. As an application, we prove that any proper holomorphic correspondence from a bounded domain D in $\mathbb{C}^n$ with smooth real-analytic boundary onto a bounded domain D' in $\mathbb{C}^n$ with smooth real-algebraic boundary extends as a holomorphic correspondence to a neighborhood of $\bar{D}$.

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2005년도 춘계학술발표회 및 정기총회 2권1호(통권2호)
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• pp.215-226
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• 2005

To study the influence of an lower part on the seismic response of a spatial structure as the upper part of a structure, as a first step, authors subsititude the upper part and the lower part of a structure to single degree of freedom systems indivisually, and set up structural models connected by them. It is clarified that the mass ratio and the period ratio of an upper part to a lower part are important parameteres to find the amplification or reduction of the sesimic response of an upper part by considering of a lower part.

• Management Science and Financial Engineering
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• 제16권1호
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• pp.17-46
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• 2010

This paper studies six different AHP (Analytic Hierarchy Process) approaches and suggests that the features of the approaches are classified by application circumstances in order to contribute to the applicability and quality usage of the AHP. Our study investigates the hierarchical principles and characteristics of the AHP, and historical debates on the AHP evaluation in which the six approaches have been involved. One of six approaches is an ANP (Analytic Network Process) application that is directly connected to AHP usage. The application differences among the six approaches are validated with a plain example. Then, the four circumstances of AHP applications are classified by two dimensions: the first dimension is whether or not the importance (weights) of criteria is independent of restrictively setting alternatives, and the second dimension is whether or not preference (priorities) of alternatives is independent of adding alternative(s) to or removing alternative(s) from the considering set of alternatives. Then featuring way of weighting criteria is classified. We suggest the distinguishing manners and describe the implications of the AHP application. Finally, we discuss rank reversal and multiplicative AHP.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.884-889
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• 1994

In this work, rapid prototyping and three dimensional finite element analysis are simltaneously applied to design metal forming processes. Rapid prototyping is a new prototyping technology which producess three dimensional part models directly from CAD data and has been extensively applied to various manufacturing processes. There are many types of rapid prototyping systems due to their building principles and materials. In this work, Stereolithography Apparatus (SLA) which is the most widely-used rapid prototyping system is introduced to manufacture the die set. To prepare STL file generally, mesh data which are in describing the die surface in finite element analysis are translated so that rapid prototyping and finite element analysis are effectively connected. The die sets are manufactured using SLA prototypes, and matal forming experiments are carried out using them. Comparing experiments results with analyses, the processes can be predicted and designed successfully.

• 한국정밀공학회지
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• 제23권5호
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• pp.119-127
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• 2006

Design structure of a mobile phone has been changed to a converged style, which has so many functions. However, the converged mobile phone could not satisfy the users who want to use only specific functions, so with Axiomatic Design, we have studied for making a proposal to set up the new concept. The goal of this study is to derive a general solution with Axiomatic Design to verify the Independence. By enhancing the existing design model and differentiating the function of mobile phone, user will be able to choose desirable products, which have only specific functions and/or specific parts. First of all, we checked the Independence about the existing design model. Then, we developed the new design model with the idea that base mobile phone should have basic functions and additional functions can be separated, surely be connected when users want.

• Kyungpook Mathematical Journal
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• 제55권2호
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• pp.279-287
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• 2015

A subset S of V (G), where G is a graph without isolated vertices, is a double dominating set of G if for each $x{{\in}}V(G)$, ${\mid}N_G[x]{\cap}S{\mid}{\geq}2$. This paper, shows that any positive integers a, b and n with $2{\leq}a<b$, $b{\geq}2a$ and $n{\geq}b+2a-2$, can be realized as domination number, double domination number and order, respectively. It also characterize the double dominating sets in the Cartesian and tensor products of two graphs and determine sharp bounds for the double domination numbers of these graphs. In particular, it show that if G and H are any connected non-trivial graphs of orders n and m respectively, then ${\gamma}_{{\times}2}(G{\square}H){\leq}min\{m{\gamma}_2(G),n{\gamma}_2(H)\}$, where ${\gamma}_2$, is the 2-domination parameter.