• Journal of Korean Institute of Industrial Engineers
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• v.31 no.1
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• pp.10-19
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• 2005

The minimum spanning tree (MST) problem is one of the traditional optimization problems. Unlike the MST, the degree constrained minimum spanning tree (DCMST) of a graph cannot, in general, be found using a polynomial time algorithm. So, finding the DCMST of a graph is a well-known NP-hard problem of importance in communications network design, road network design and other network-related problems. So, it seems to be natural to use evolutionary algorithms for solving DCMST. Especially, when applying an evolutionary algorithm to spanning tree problems, a representation and search operators should be considered simultaneously. This paper introduces a new tree representation scheme and a genetic operator for solving combinatorial tree problem using evolutionary algorithms. We performed empirical comparisons with other tree representations on several test instances and could confirm that the proposed method is superior to other tree representations. Even it is superior to edge set representation which is known as the best algorithm.

• Korean Journal of Mathematics
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• v.23 no.4
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• pp.665-732
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• 2015

Existence results for multiple positive solutions of two classes of boundary value problems for bilateral difference systems are established by using a fixed point theorem under convenient assumptions. It is the purpose of this paper to show that the approach to get positive solutions of boundary value problems of finite difference equations by using multi-fixed-point theorems can be extended to treat the bilateral difference systems with one-dimensional Laplacians. As an application, the sufficient conditions are established for finding multiple positive homoclinic solutions of a bilateral difference system. The methods used in this paper may be useful for numerical simulation. An example is presented to illustrate the main theorems. Further studies are proposed at the end of the paper.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1441-1452
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• 2015

This paper proposes a new Hybrid Particle Swarm Optimization (HPSO) method that integrates the Evolutionary Programming (EP) and Particle Swarm Optimization (PSO) techniques. The proposed method is applied to solve Economic Dispatch(ED) problems considering prohibited operating zones, ramp rate limits, capacity limits and power balance constraints. In the proposed HPSO method, the best features of both EP and PSO are exploited, and it is capable of finding the most optimal solution for the non-linear optimization problems. For validating the proposed method, it has been tested on the standard three, six, fifteen and twenty unit test systems. The numerical results show that the proposed HPSO method is well suitable for solving non-linear economic dispatch problems, and it outperforms the EP, PSO and other modern metaheuristic optimization methods reported in the recent literatures.

• Journal of the Korea Furniture Society
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• v.27 no.4
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• pp.362-374
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• 2016

The ability of 'creative thinking' is one of the most important fact for designers to complete their design process. It is not only the overall concept of the process but also all details related to each steps of the process such as planning product strategies, research, finding ways to solve problems image development, broadening ideas, etc. It is, however, not easy to creative as designers by natural learning through experiences unless they have geniuses for creative designing. Many experienced designers in the field are even in dilemmas being not be able to differentiate from copying other designs. This study is focused on the researches on the works of famous designers, architects and artists who have shown great creativities throw their works or processes. It is aimed to define their ways of thinking which could be fundamental motives for the creativeness, various behavioral methods to solve problems in creative ways, technical approaches to improve creativities, and overall intuition in the design working processes.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.169.5-169
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• 2001

This study proposes a neural network for solving optimization problems such as the TSP (Travelling Salesman Problem), scheduling, and line balancing. The Hopfield network has been used for solving such problems, but it frequently gives abnormal solutions or non-optimal ones. Moreover, the Hopfield network takes much time especially in solving large size problems. To overcome such disadvantages, this study adopts nodes whose outputs changes with a fixed value at every evolution. The proposed network is applied to solving a TSP, finding the shortest path for visiting all the cities, each of which is visted only once. Here, the travelling path is reflected to the energy function of the network. The proposed network evolves to globally minimize the energy function, and a ...

• Honam Mathematical Journal
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• v.14 no.1
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• pp.107-121
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• 1992

In this paper, we consider an iterative algorithm for solving a new class of quasi complementarity problems of finding $u{\epsilon}R^{n}$ such that $g(u){\in}K(u)$, $Tu+A(u){\in}K^{*}(u)$, and < g(u), Tu + A(u) >=0, where T, A and g are continuous mappings from $R^{n}$ into itself and $K^{*}(u)$ is the polar cone of the convex cone K(u) in $R^{n}$. The algorithms considered in this paper are general and unifying ones, which include many existing algorithms as special cases for solving the complementarity problems. We also study the convergence criteria of the general algorithms.

• Journal of the military operations research society of Korea
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• v.24 no.2
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• pp.17-29
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• 1998

This paper is to aimed to design a model of Korea defense information resource management structure from the viewpoint of system's approach, especially focusing on planning/programming procedures, organizational structure and business process re-engineering. The author analyzed current projects and plans on the field of Korea defense information systems, for finding what kinds of problems and why the problems occurred. The author concluded that many problems came from wrong approach of previous information resource management. Highlights of the proposed model are as follows: 1) Planning and programming structure must be considered as a major information resources and it must be managed as a key role through the whole system life cycle; 2) Organizational structure should be properly set up for managing and implementing information system projects; 3) Business process should also be analyzed thoroughly for re-engineering and innovating current inefficient organizational structure. These three additional viewpoints added to previous model for improving Korea defense information resource management.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.80-84
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• 2008

This research has been carried out in order to provide countermeasure plans, fire prevention, improving institutional plans through analyzing accidental causes and investigating the situation of damage from the fire incident of the cold storage at Icheon. By the analysis of the incident, which is organized the process; for incidence, firstly a field investigation, next the overview of related laws, finally the analysis of problems and deducting suggestions, it was possible to find out the causes of casualties. We also suggested improving plans through finding out several problems such as safety management system and safety regulations, the permit on the completion of the cold storage and the completion examination of fire facilities as institutional problems and fireproof construction and the selection of finishing materials.

• Journal of Information Technology Applications and Management
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• v.24 no.4
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• pp.71-92
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• 2017

Finding a root cause is an essential step to solving a complex problem. Some previous studies have used the Delphi method for gathering opinions about root causes from geographically dispersed experts. However, we assert that complicated problems such as an industry ecosystem would make a general type of the Delphi method less practical because of too much psychological burden on study participants. In this study we present a preliminary list-based Delphi study method for identifying a root cause. This method was used to identify a root cause and draw a causal map for the information industry ecosystem problems.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.4
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• pp.235-243
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• 2012

The Voronoi diagram of spheres and power diagram have been known as powerful tools to analyze spatial characteristics of weighted points, and these structures have variety range of applications including molecular spatial structure analysis, location based optimization, architectural design, etc. Due to the fact that both diagrams are based on different distance metrics, one has better usability than another depending on application problems. In this paper, we compare these diagrams in various situations from the user's viewpoint, and show the Voronoi diagram of spheres is more effective in the problems based on the Euclidean distance metric such as nearest neighbor search, path bottleneck locating, and internal void finding.