• Honam Mathematical Journal
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• v.24 no.1
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• pp.35-41
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• 2002

The solutions of a homogeneous system in state space form $\dot{x}=Ax$ are to the form $x=e^{At}x_0$ and the solutions of an inhomogeneous system $\dot{x}=Ax(t)+f(t)$ are to the form $x=e^{At}x_0+{{\int}_0^t}\;e^{A(t-{\tau})}f({\tau})d{\tau}$. In this note we show that the solution of descriptor systems under some conditions exists, and is unique, moreover it is interesting to know the solutions of descriptor system are schematically like the solutions as in the state space form. Also we will give some algorithms to compute these solutions.

• The Pure and Applied Mathematics
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• v.21 no.1
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• pp.39-50
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• 2014

In this paper, we study screen quasi-conformal irrotational half lightlike submanifolds M of a semi-Riemannian space form $\tilde{M}(c)$ admitting a semi-symmetric non-metric connection, whose structure vector field ${\zeta}$ is tangent to M. The main result is a classification theorem for such Einstein half lightlike submanifolds of a Lorentzian space form admitting a semi-symmetric non-metric connection.

• Communications of the Korean Mathematical Society
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• v.17 no.3
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• pp.519-529
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• 2002

In this paper. We Study (n + 1)-dimensional Contact CR-submanifolds of (n - 1) contact CR-dimension immersed in a Sasakian space form M$\^$2m+1/(c) (2m=n+p, p>0), and especially determine such submanifolds under additional condition concerning with shape operator.

• Journal of the Chungcheong Mathematical Society
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• v.24 no.4
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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.

• Korean Institute of Interior Design Journal
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• no.16
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• pp.106-115
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• 1998

Latest modernism shows general idea of phenomenal space through nature of place motility and experience sinceded from standard form and it has general idea of space. therefore this study presents the tension and the relaxation as a method looking for spatal change and value that in spatial experience. For the analysis of work the Conference Pavillon of Tadoa Ando in the furniture company in Vitra Fire Station of Zaha Hidid is analyzed in spatial experence. As the result the result the systematic straight mixture that has a superrimotion with long retangle which the space acts independently and is shown in the drawing of absolutism is formed and collapses theregularity of construction form by decomposition annexation mixing collision and ambivalence. The spatial experiance in this unstable form changes the grade of rank of space by opposite phenomenon by the change of spatial flowing the disorted and vague space that is occurred by superrimotion which has no direction and change of lirht and place and consolidates dynamic strain makes possible to construct against the gravity. And it also creates experienced space thatis reaxed with maintenance of organization of unity harmony, and stsbility.

• Korean Institute of Interior Design Journal
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• no.17
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• pp.52-59
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• 1998

In the modern ages when the surroundings of a city has become firm and monotonous this study designed to suggest an direction towards creative approaches to space planning by analyzing the images of interior space with the introduction of natural expressions as an alternative to create original space in order to give vitality to the previous standardized space and to satisfy human beings psychological desire. The results of the analysis as a way of expressing direct indirect and eclectic images using nature a source of arts read that most of the natural expressions show perceptive images strongly that natural elements can become the elements of design in any form and that nature's images are expressed by not only natural and artificial materials. In conclusion natural expression in interior space does not have any fixed form of expression but gives a great deal of vocabulary to the image formation of interior space by stimulating being's sentiment with the spatial restructure of nature's own particular order of form.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.468-471
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• 1995

In this paper, we propose a new strategy for a space robot to control its attitude. A space robot is an example of a class of non-holonomic systems, a system of which cannot be stabilized into its equilibria with continuous static state feedbacks even in the case that the system is, in some sense, controllable. Thus, we cannot design stabilizing controllers for space robots using conventional control theories. The strategy presented here transforms the non-holonomic system into a time-state control form, and allows us to make the state of the original system any desired one. In the stabilization, any conventional control theory can be applied. For simplicity, a space robot with a two-link manipulator is considered, and a simulated motion of the controlled system is shown.

• Journal of Astronomy and Space Sciences
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• v.30 no.4
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• pp.299-305
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• 2013

Ganui-Dae, built in the reign of King Sejong, Joseon Dynasty, is a comprehensive observatory. It has various instruments for observation and time signal such as Ganui, Gyupyo(Gnomon), water-hammering type Honui and Honsang, and so on. Studying on Ganui-Dae has been focused on its location, history, criterion, etc, so far. However, studying on its external form and construction method has been conducted insufficiently. This study suggests the model for restoration of Ganui-Dae. The model is based on the analysis about external form of Ganui-Dae in various antique maps, and its construction method in those days.

• Journal of the Korean Mathematical Society
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• v.45 no.2
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• pp.393-404
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• 2008

Biharmonic Legendre curves in a Sasakian space form are studied. A non-existence result in a 7-dimensional 3-Sasakian manifold is obtained. Explicit formulas for some biharmonic Legendre curves in the 7-sphere are given.

• The Pure and Applied Mathematics
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• v.16 no.3
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• pp.271-276
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• 2009

We study the geometry of screen conformal light like hypersurfaces M of a semi- Riemannian manifold M. The main result is a characterization theorem for screen conformal lightlike hypersurfaces of a semi-Riemannian space form.