• 한국전산구조공학회논문집
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• 제21권2호
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• pp.199-208
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• 2008

본 논문에서는 초기값을 갖는 비동질 반무한 평면문제를 비례경계유한요소법으로 해석하기 위하여 무한요소를 이 해석법에 도입하였다. 초기값을 갖는 반무한 평면의 자유면은 비례경계좌표계의 원주방향의 좌표를 이용하여 모델링하였고 무한요소는 이 자유면이 나타내는 무한한 영역을 모사하기 위해 사용되었다. 반무한 평면의 물성치(탄성계수)에 대한 초기값은 비례중심의 위치와 비례경계좌표계에서의 반지름 멱함수를 이용하여 나타내었다. 사상형 무한요소를 사용하여 일관된 정식화가 가능하였고, 제안된 해석법에 대한 적용성과 성능을 두 수치예제를 통하여 보였다.

• 대한수학회보
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• 제29권2호
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• pp.245-256
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• 1992

In this article, we study the behavior of half integral weight thetaseries under theta operators. Theta operators are very important in the study of theta-series in connection with Hecke operators. Andrianov[A1] proved that the space of integral weight theta-series is invariant under the action of theta operators. We prove that his statement can be extened for half integral weight theta-series with a slight modification. By using this result one can prove that the space of theta-series is invariant under the action of Hecke operators as Andrianov did for intrgral weight theta-series [A1].

• 충청수학회지
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• 제24권4호
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• pp.769-781
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• 2011

We study the geometry of half lightlike sbmanifolds M of a semi-Riemannian space form $\tilde{M}(c)$ admitting a semi-symmetric metric connection subject to the conditions: (1) The screen distribution S(TM) is totally umbilical (geodesic) and (2) the co-screen distribution $S(TM^{\bot})$ of M is a conformal Killing one.

• Animal cells and systems
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• 제4권3호
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• pp.239-243
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• 2000

Most space-related life science programs are expensive and time-consuming, requiring international cooperation and resources with trans-disciplinary expertise. A comprehensive future program in "life sciences in space" needs, therefore, well-defined research goals and strategies as well as a sound ground-based program. The first half of this review will describe four key aspects such as the environment in space, previous accomplishments in space (primarily focusing on amphibian embryogenesis), available resources, and recent advances in bioinformatics and biotechnology, whose clear understanding is imperative for defining future directions. The second half of this review will focus on a broad range of interdisciplinary research opportunities currently supported by the National Aeronautics and Space Administration (NASA), National Institute of Health (NIH), and National Science Foundation (NSF). By listing numerous research topics such as alterations in a diffusion-limited metabolic process, bone loss and skeletal) muscle weakness of astronauts, behavioral and cognitive ability in space, life in extreme environment, etc., we will attempt to suggest future opportunities.

• 대한수학회논문집
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• 제32권1호
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• pp.119-133
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• 2017

In this paper, we study half lightlike submanifolds of an indefinite Kaehler manifold with a semi-symmetric non-metric connection. First, we characterize the geometry of two types of half lightlike submanifolds of such an indefinite Kaehler manifold. Next, we investigate the geometry of half lightlike submanifolds of an indefinite complex space form with a semi-symmetric non-metric connection.

• 대한수학회보
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• 제51권4호
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• pp.979-994
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• 2014

We study half lightlike submanifold M of an indefinite trans-Sasakian manifold such that its structure vector field is tangent to M. First we study the general theory for such half lightlike submanifolds. Next we prove some characterization theorems for half lightlike submanifolds of an indefinite generalized Sasakian space form.

• 한국정밀공학회지
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• 제19권5호
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• pp.81-88
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• 2002

An interface crack of a piezoelectric medium bonded between an elastic layer and a half-space is analyzed using the theory of linear piezoelectricity. Both out-of-plane mechanical and in-plane electrical loads are applied to the piezoelectric laminate. By the use of courier transforms, the mixed boundary value problem is reduced to a singular integral equation which is solved numerically to determine the stress intensity factors. Numerical analyses for various material combinations are performed and the results are discussed.

• Earthquakes and Structures
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• 제9권4호
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• pp.753-766
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• 2015

An investigation has been carried out for the propagation of torsional surface waves in an inhomogeneous prestressed layer over an inhomogeneous half space when the upper boundary plane is assumed to be rigid. The inhomogeneity in density, initial stress (tensile and compressional) and rigidity are taken as an arbitrary function of depth, where as for the elastic half space, the inhomogeneity in density and rigidity is hyperbolic function of depth. In the absence of heterogeneities of medium, the results obtained are in agreement with the same results obtained by other relevant researchers. Numerically, it is observed that the velocity of torsional wave changes remarkably with the presence of inhomogeneity parameter of the layer. Curves are compared with the corresponding curve of standard classical elastic case. The results may be useful to understand the nature of seismic wave propagation in geophysical applications.

• Structural Engineering and Mechanics
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• 제9권2호
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• pp.127-139
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• 2000

The isoparametric element method is used for a plate on non-homogenous foundation. The surface displacement due to a point force acting on the non-homogeneous foundation is the fundamental solution. Based on this analysis, the interaction between the foundation and plate can be determined and the reaction of the foundation can be treated as the external force to the plate. Therefore, only the plate needs to be divided into some elements. The method presented in this paper can be used in cases such as thin or thick plate, different plate shapes, various loading, homogenous and non-homogenous foundations. The examples in this paper show that this method is versatile, efficient and highly accurate.

• Steel and Composite Structures
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• 제20권5호
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• pp.1103-1117
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• 2016

The present investigation is to study the plane problem in initially stressed thermoelastic half-space with voids due to thermal source. Lord-Shulman (Lord and Shulman 1967) theory of thermoelasticity with one relaxation time has been used to investigate the problem. A particular type of thermal source has been taken as an application of the approach. Finite element technique has been used to solve the problem. The components of displacement, stress, temperature change and volume fraction field are computed numerically. The resulting quantities are depicted graphically for different values of initial stress parameter. The relaxation time and the initial stress parameter have a significant effect on all distributions.