• 대한수학회지
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• 제34권3호
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• pp.599-608
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• 1997

In this paper we give a generalization of the well-known Borsuk-Ulam theorem and its extensions to countably many products of spheres.

• 대한수학회지
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• 제35권4호
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• pp.891-901
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• 1998

We give a definition of the vector-valued index for Z-actions extending the numerical index in [9] and prove the extension theorem for Z-actions for showing basic properties of the vector-valued index.

• Journal of Hydrospace Technology
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• 제1권1호
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• pp.111-124
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• 1995

An improved analysis model for material nonlinearity induced by elasto-plastic deformation and damage including a large strain response was proposed. The elasto-plastic-damage constitutive model based on the continuum damage mechanics approach was adopted to overcome limitations of the conventional plastic analysis theory. It can manage the anisotropic tonsorial damage evolved during the time-independent plastic deformation process of materials. Updated Lagrangian finite element formulation for elasto-plastic damage coupling problems including large deformation, large rotation and large strain problems was completed to develop a numerical model which can predict all kinds of structural nonlinearities and damage rationally. Finally a finite element analysis code for two-dimensional plane problems was developed and the applicability and validity of the numerical model was investigated through some numerical examples. Calculations showed reasonable results in both geometrical nonlinear problems due to large deformation and material nonlinearity including the damage effect.

• Journal of Information Technology Applications and Management
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• 제17권3호
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• pp.163-189
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• 2010

The purpose of this research is to develop a decision-making model for the calculation of the National Disaster Management System's standard prevention workforce quota. The final purpose of such model is to support in arranging a rationally sized prevention workforce for local authorities by providing information about its calculation in order to support an effective and efficient disaster management administration. In other words, it is to establish and develop a model that calculates the standard disaster prevention workforce quota for basic local governments in order to arrange realistically required prevention workforce. In calculating Korea's prevention workforce, it was found that the prevention investment expenses, number of prevention facilities, frequency of flood damage, number of disaster victims, prevention density, and national disaster recovery costs have positive influence on the dependent variable when the standard prevention workforce was set as the dependent variable. The model based on the regression analysis-which consists of dependent and independent variables-was classified into inland mountainous region, East coast region, Southwest coastal plain region to reflect regional characteristics for the calculation of the prevention workforce. We anticipate that the decision-making model for the standard prevention workforce quota will aid in arranging an objective and essential prevention workforce for Korea's basic local authorities.

• 대한조선학회논문집
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• 제45권5호
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• pp.469-476
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• 2008

In this paper, it is shown that an input-output (I/O) feedback linearized controller can be designed rationally by utilizing the time-scale properties of heave and pitch for an underwater vehicle. It is assumed that the dynamics of the vehicle is restricted to the vertical plane. An output-feedback control is designed, which stabilizes steady cruising paths. It is shown that the vehicle dynamics with acceleration as output becomes minimum phase. The dynamics can be transformed into a reduced system through a kind of partial linearization and singular perturbation technique. The reduced system is not only minimum phase but also exactly I/O linearizable via feedback. The I/O dynamic characteristics of the heave and pitch modes can be made linear and decoupled. Furthermore it becomes independent of cruising condition such as vehicle velocity. This study may help for designing autopilot systems for underwater vehicles.

• 대한조선학회논문집
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• 제30권1호
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• pp.145-156
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• 1993

대변형, 대회전, 대변형도 문제를 고려한 탄소성-손상 유한요소 정식화 과정을 연구함으로써 구조물의 모든 비선형 거동 및 손상을 합리적으로 예측할 수 있는 수치모형을 개발하였다. 재료의 소성 변형과정에서 발생되는 손상을 합리적으로 고려하기 위하여 연속체 손상역학의 접근방법을 이용하여 구성방정식을 정식화하였으며 Updated Lagrangian 정식화방법, 호장증분법 등의 비선형 강성방정식 해법을 적용하여 2차원 평면문제를 대상으로 하는 탄소성-손상 유한요소해석 프로그램을 구성하였다. 여러가지 예제 계산을 통하여 이 수치모형의 적용성 및 타당성을 검토한 결과 대변형 문제, 손상을 포함하는 재료 비선형문제 공히 합리적인 해석결과를 제시하고 있슴을 확인할 수 있었다.

• 수산경영론집
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• 제36권3호
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• pp.37-63
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• 2005

According to the Fisheries Cooperative Law, the Fisheries Cooperative has made a substantial contribution to the development of Korea's fisheries industry amid the nation's rapid economic growth and drastic social changes since its establishment in April 1st 1962, It is, however, generally believed that the cooperative has made a poor performance in improving its business constitution. Therefore, the reform of its board of director system is one of the ways to strengthen the constitution. For the purpose of making the board of director system to operate rationally, this dissertation is divided into five chapters. Chapter I provides an overview of this study, such as research background and objectives. Chapter II focuses on the Fisheries Cooperative's board of director: its function, composition, and election. Chapter III analyzes the responses of the Fisheries cooperatives to questionnaires about the board of director system, and subsequently presents the causes and the meaning of the analysis results. Chapter IV deals with the various ways to improve the Fisheries Cooperative's board of director system, including director and cooperative governance. Finally, Chapter V draws a conclusion of this study. The independent function of the Cooperative's board of director and responsible directorship is one of the most important factors which can prevent the Cooperative from insolvency. Unlike the past, not only it has become difficult to keep the Cooperative's business under the government's support, but also the Cooperative itself is now facing a situation where the support from the government cannot be expected. This ist he reason why the Cooperative should manage itself autonomously, workout its organization, and respond to the current situation with a renovativemanagement and business strategy. Therefore, a rational operation of the board of director is urgently needed.