• Journal of the Korean Mathematical Society
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• v.33 no.4
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• pp.1047-1067
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• 1996

In this paper, we are interested in left invariant flat affine structures on Lie groups. These structures has been studied by many authors in different contexts. One of the fundamental questions is the existence of complete affine structures for solvable Lie groups G, raised by Minor [15]. But recently Benoist answered negatively even for the nilpotent case [1]. Also moduli space of such structures for lower dimensional cases has been studied by several authors, sometimes with compatible metrics [5,10,4,12].

• Journal of the Korean Mathematical Society
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• v.51 no.3
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• pp.527-543
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• 2014

The theory of random variable structures was first studied by Ben Yaacov in [2]. Ben Yaacov's axiomatization of the theory of random variable structures used an early result on the completeness theorem for Lukasiewicz's [0, 1]-valued propositional logic. In this paper, we give an elementary approach to axiomatizing the theory of random variable structures. Only well-known results from probability theory are required here.

• Bulletin of the Korean Mathematical Society
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• v.38 no.3
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• pp.551-564
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• 2001

We view Weyl structures as generalizations of Riemannian metrics and study the critical points of geometric functional which involve scalar curvature, defined on the space of Weyl structures on a closed 4-manifold. The main goal here is to provide a framework to analyze critical Weyl structures by defining functionals, discussing function spaces and writing down basic formulas for the equations of critical points.

• East Asian mathematical journal
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• v.16 no.2
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• pp.339-354
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• 2000

• Journal of the Korean Mathematical Society
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• v.24 no.1
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• pp.99-104
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• 1987

• Journal of the Korean Mathematical Society
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• v.12 no.2
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• pp.113-133
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• 1975

• Smart Structures and Systems
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• v.8 no.3
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• pp.275-302
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• 2011

This is a review paper on mathematical modeling of actively controlled piezo smart structures. Paper has four sections to discuss the techniques to: (i) write the equations of motion (ii) implement sensor-actuator design (iii) model real life environmental effects and, (iv) control structural vibrations. In section (i), methods of writing equations of motion using equilibrium relations, Hamilton's principle, finite element technique and modal testing are discussed. In section (ii), self-sensing actuators, extension-bending actuators, shear actuators and modal sensors/actuators are discussed. In section (iii), modeling of thermal, hygro and other non-linear effects is discussed. Finally in section (iv), various vibration control techniques and useful software are mentioned. This review has two objectives: (i) practicing engineers can pick the most suitable philosophy for their end application and, (ii) researchers can come to know how the field has evolved, how it can be extended to real life structures and what the potential gaps in the literature are.

• Journal of the Korean Mathematical Society
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• v.33 no.4
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• pp.879-889
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• 1996

In order to describe the nearness between fuzzy sets various structures like the fuzzy neighorhood structure ([7])), the Artico-Moresco fuzzy proximity ([2]) and the Lowen fuzzy uniformity ([8]) have been introduced.

• Honam Mathematical Journal
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• v.31 no.2
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• pp.239-245
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• 2009

In this paper, we introduce the notions of m-semiopen sets and M-semicontinuous functions on spaces with minimal structures and study some properties of such notions. In particular, we investigate characterizations for the M-semicontinuous function and the relationship between M-continuity and M-semicontinuity.

• Communications of the Korean Mathematical Society
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• v.10 no.2
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• pp.275-284
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• 1995

In this paper various G-module structures on M and all possible extensions of M by G will be studied, whence equivalence classes of extensions of M by G and those of extensions which are compatible with the given G-module structures of M will be determined explicitly. Further the difference between extensions and compatible extensions will be pointed out.