• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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• pp.75-82
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• 2001

A dynamic interaction analysis of an adjacent surface fecundation on a layered half-space is performed in the frequency domain. A semi-analytical approach is employed to reduce the integration range of the wavenumber in the surface fundamental solution for a layered half-space in boundary element (BE) formulations. The present study then adopts a combined boundary and finite element method to analyze the dynamic behavior of a system of flexible surface foundations on an elastic homogeneous and layered half-space. Numerical examples are presented to demonstrate the accuracy of the developed method. The examples show the feasibility of an extended application fur the complicated dynamic interaction of foundations on layered media.

• Structural Engineering and Mechanics
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• 제10권2호
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• pp.111-123
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• 2000

An asymptotic solution for snap-through buckling of single-layer squarely-reticulated shallow spherical shells continuously supported on springs is developed in this paper. Based on the fundamental governing equations and boundary conditions, a nondimensional analytical expression associated with the external load, stiffness of spring and central transverse displacement (deflection) is derived with the aid of asymptotic iteration method. The effects of stiffness of spring and characteristic geometrical parameter on buckling of the structures are given by the analyses of numerical examples. In a special case, for reticulated circular plates, the influence of stiffness of spring on the characteristic relation between load and deflection is also demonstrated.

• Selected Papers of The Society of Naval Architects of Korea
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• 제2권1호
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• pp.63-78
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• 1994

This paper deals with the treatment of the open boundary in two-dimensional free-surface wave problems. Two numerical schemes are investigated for the implementation of the open boundary condition. One is to add the artificial damping term to the dynamic free-surface boundary condition, in which the determination of suitable damping coefficient and the damping zone is the most important. The other is a modified Orlanski's method, which is known to be very useful for the uni-directional waves. Using these two schemes, numerical tests have been conducted for a few typical free-surface wave problems. To obtain the numerical solution of the free-surface boundary value problem, the fundamental source-distribution method is used and the fully nonlinear free-surface boundary conditions are applied. The computed results are presented in comparison with those of others for the proof of practicality of these two schemes.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 봄 학술발표회 논문집
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• pp.121-128
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• 1997

The Boundary Element Method(BEM) has many advantages. Nevertheless the applicability of BEM to structural analysis is seemed to be behind the other methods. This study presents the application of the BEM for analysis of assembled plate structures which is light weight and has a great loading capacity. Firstly, we formulate the boundary integral equation of the single plate, using the biharmonic fundamental solution for plate bending and internal force problems. Nextly, each plates are assembled on 3-dimensional space. In this process, the boundary conditions on assemble line are used. To verify the objectivity and universal validity of analysis by BEM, the results of BEM was compared to that of SAP90 by using FEM.

• Nuclear Engineering and Technology
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• 제4권1호
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• pp.11-22
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• 1972

최대치(또는 최소치) 원리의 기본개념을 써서 제어함수 u(t)를 찾는데는 2점간 경계치 문제의 해결이 요구된다. 그런데 최근에는 2점간 문제를 푸는 방법으로 초기 costate vector를 찾아 문제를 해결하는 여러가지 편법이 개발되고 있다. 여기에서는 최적제어 함수를 찾는 새로운 방법의 하나로써 고안된 Newton's sequential방법을 써서 여러가지 공학적 문제를 풀어 봄으로써 이 방법이 매우 유효하다는 것을 알아냈다.

• 전기학회논문지
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• 제60권7호
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• pp.1404-1409
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• 2011

The fundamental research for the mobile robot navigation using the numerical optimization method is presented. We define the mobile robot navigation problem as an unconstrained optimization problem to minimize the cost function with the pose error between the goal position and the position of a mobile robot. Using the nonlinear least squares optimization method, the optimal speeds of the left and right wheels can be found as the solution of the optimization problem. Especially, the rotational speed of wheels of a mobile robot can be directly related to the overall speed of a mobile robot using the Jacobian derived from the kinematic model. It will be very useful for applying to the mobile robot navigation. The performance was evaluated using the simulation.

• 설비공학논문집
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• 제8권4호
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• pp.451-462
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• 1996

In this study, which focuses on ice storage, a fundamental study in cooling and solidification was performed, including the interesting phenomena of density inversion, supercooling and dendritic ice. A numerical study was performed for natural convection and ice formation considering existence of subcooling and dendritic ice were analyzed numerically by using finite difference method and boundary fixing method. In the mesh, the solid fraction was introduced with adding as a term to the energy conservation equation. A flow in the dendrite was modelled as a flow in a porous medium, and the momentum conservation equation was modified to incorporate resistance forces involved in flows through porous media. A numerical solution of the time dependencies of dendrite area and dense ice front was successfully obtained, and the numerical results were good agreement with experimental results. Based on this methodology, a discussion was made of phenomena and characteristics of cooling and freezing processes under various conditions.

• 한국진공학회지
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• 제1권1호
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• pp.16-23
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• 1992

Conductance calculation is essential in designing a vacuum system. Since mathematical solution is nearly impossible except for a few simple cases, it has been so usual to calculate the conductance for a series connection of components using an approximate formula by Oatley. However, Oatley's formula has a fundamental flaw of totally neglecting the effect of gas beaming. In this study, a new technique is suggested for calculating the conductance with the same accuracy as the Monte Carlo method but with much less computing time, and applied to a system of tube connections in series. The effects of gas beaming in the calculation of conductance is analyzed quantitatively by comparing the conductance calculated by this method with those from Oatley's formula.

• Nuclear Engineering and Technology
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• 제1권2호
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• pp.79-85
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• 1969

최대치 (또는 최소치)원리의 기본개념을 써서 제어함수 u(t)를 찾는데는 2점간 경계치 문제의 해결이 요구된다. 그런데 최근에는 2점간 문제를 푸는 방법으로 초기 costate vector를 찾아 문제를 해결하는 여러 가지 편법이 개발되고 있다. 여기에서는 최적제어함수를 찾는 새로운 방법의 하나로써 Newton's Sequential 방법을 적용하였다. 그리고 일차적으로 주어진 문제의 수학적인 전개를 시도하였다. 앞으로 이 방법의 물리적인 의의와 공학적인 가치는 Computer에 의해서 여러 가지 응용문제를 해결함으로써 밝혀질 것이다.

• 지역사회간호학회지
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• 제15권4호
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• pp.517-527
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• 2004

Purpose: This research is to find a solution for educational work on high blood pressure control in public health centers by analyzing their current status. Method: It analyzed data from 133 public health centers that had been doing educational work on high blood pressure, through a questionnaire. Also, it developed recommendations by converging opinions from an expert group made of 25 people with nominal group technique. Result: The educational methods of public health centers did not make any approach to get to the goal of the work. The mass media education and campaign activities for the general public had just temporary and passive propensities. In education for patients, it did not use appropriate methods to present management techniques for diagnosis process of patients, medication management, self monitoring BP, and risk factors. Pocket book for monitoring high blood pressure was not focused on self-recording for self-management. The expert group recommended that educational materials for adults should be developed focusing on treatments and observance of risk factors through daily living, and those for children should be focused on basic understanding about diseases, and life style. Conclusion: Presenting direction and strategy of fundamental education work is needed for public health centers by giving them standard educational guidelines of managing high blood pressure nationally, and it is desirable that fundamental frameworks of educational materials should be developed and distributed by professional groups nationally.