• Bulletin of the Korean Mathematical Society
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• v.40 no.3
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• pp.411-423
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• 2003

Some B.-Y. Chen inequalities for different kind of submanifolds of generalized complex space forms are established.

• Bulletin of the Korean Mathematical Society
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• v.42 no.1
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• pp.189-201
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• 2005

In this article, we establish relations between the sectional curvature function K and the shape operator, and also relationship between the k-Ricci curvature and the shape operator for slant submanifolds in generalized complex space forms with arbitrary codimension.

• Honam Mathematical Journal
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• v.44 no.2
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• pp.179-194
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• 2022

In the present study, we investigate generic lightlike submanifolds of indefinite nearly Kaehler manifolds. After proving the existence of generic lightlike submanifolds in an indefinite generalized complex space form, a non-trivial example of this class of submanifolds is discussed. Then, we find a characterization theorem enabling the induced connection on a generic lightlike submanifold to be a metric connection. We also derive some conditions for the integrability of distributions defined on generic lightlike submanifolds. Further, we discuss the non-existence of mixed geodesic generic lightlike submanifolds in a generalized complex space form. Finally, we investigate totally umbilical generic lightlike submanifolds and minimal generic lightlike submanifolds of an indefinite nearly Kaehler manifold.

• Journal of the Korean Mathematical Society
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• v.46 no.5
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• pp.979-995
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• 2009

As warped product manifolds provide an excellent setting to model space time near black holes or bodies with large gravitational field, the study of these manifolds assumes significance in general. B. Y. Chen [4] initiated the study of CR-warped product submanifolds in a Kaehler manifold. He obtained a characterization for a CR-submanifold to be locally a CR-warped product and an estimate for the squared norm of the second fundamental form of CR-warped products in a complex space form (cf [6]). In the present paper, we have obtained a necessary and sufficient conditions in terms of the canonical structures P and F on a CR-submanifold of a nearly Kaehler manifold under which the submanifold reduces to a locally CR-warped product submanifold. Moreover, an estimate for the second fundamental form of the submanifold in a generalized complex space is obtained and thus extend the results of Chen to a more general setting.

• Communications of the Korean Mathematical Society
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• v.11 no.3
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• pp.707-723
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• 1996

We first define the concept of the generalized analytic Fourier-Feynman transforms of a class of functionals on function space induced by a generalized Brownian motion process and study of functionals which plays on important role in physical problem of the form $ F(x) = {\int^{T}_{0} f(t, x(t))dt} $ where f is a complex-valued function on $[0, T] \times R$. We next show that the generalized analytic Fourier-Feynman transform of the convolution product is a product of generalized analytic Fourier-Feynman transform of functionals on functin space.

• Bulletin of the Korean Mathematical Society
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• v.26 no.1
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• pp.75-82
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• 1989

It is recently proved by Aiyama and the authors [2] that a complete space-like complex submanifold of a complex space form $M^{n+p}$$_{p}$ (c') (c'.geq.0) is to totally geodesic. This is a complex version of the Bernstein-type theorem in the Minkowski space due to Calabi [4] and Cheng and Yau [5], which is generalized by Nishikawa[7] in the Lorentz manifold satisfying the strong energy condition. The purpose of this paper is to consider his result in the complex Lorentz manifold and is to prove the following.e following.

• Kyungpook Mathematical Journal
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• v.58 no.1
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• pp.149-165
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• 2018

A. Bejancu [2] was the first who instigated the new concept in differential geometry, i.e., CR-submanifolds. On the other hand, CR-submanifolds were generalized by B. Y. Chen [7] as slant submanifolds. Further, he gave the notion of a Kaehlerian slant submanifold as a proper slant submanifold. This article has two objectives. For the first objective, we derive Simons' type formula for a minimal Kaehlerian slant submanifold in a complex space form. Then, by applying this formula, we give a complete classification of a minimal Kaehlerian slant submanifold in a complex space form and also obtain its some immediate consequences. The second objective is to prove some results about semi-parallel submanifolds.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5C
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• pp.415-422
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• 2010

In this paper, we derive exact closed-form formulas, in terms of Meijer's G-function, for the ergodic capacity of space-time block codes (STBCs) from generalized linear complex orthogonal designs (GLCODs) and generalized coordinate interleaved orthogonal designs (GCIODs) in quasi-static frequency-nonselective i.i.d. Nakagami-m fading channels. The derived analytical results show an excellent agreement with Monte-Carlo simulation results. Thus, a useful means for analyzing and predicting the ergodic capacity performance of STBCs from GLCODs or GCIODs can be provided in various antenna configurations and different channel conditions without extensive Monte-Carlo simulations. We present some numerical results to verify the accuracy of the derived formulas.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.2
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• pp.9-17
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• 2008

When the stagnation temperature of the combustion chamber or ambient air increases, the specific heats and their ratio do not remain constant any more, and start to vary with this temperature. The gas remains perfect, except, it will be calorically imperfect and thermally perfect. A new generalized form of the Prandtl Meyer function is developed, by adding the effect of variation of this temperature, lower than the threshold of dissociation. The new relation is presented in the form of integral of a complex analytical function, having an infinite derivative at the critical temperature. A robust numerical integration quadrature is presented in this context. The classical form of the Prandtl Meyer function of a perfect gas becomes a particular case of the developed form. The comparison is made with the perfect gas model for aim to present a limit of its application. The application is for air.

• Proceedings of the KIPE Conference
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• 1998.11a
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• pp.5-8
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• 1998

The adaptation to vector control theory is so generalized that it is widely used for implementing the high-performance of AC machine. Nowadays, One-Chip microprocessors or DSP chips are being well-used to implement Vector Control algorithm. DSP Chip have less flexibility for memory decoding and I/O rather than One-Chip microprocessor so that is requires more additional circuit and high cost. And the past One-Chip micro processors have difficult of implementation the complex algorithm because of small memory capacity and low arithmetic performance. Therefore we implemented the vector control algorithm of PMSM(Permanent Magnetic Synchronous Motors) using 80296SA form intel , which have many features as 6M memory space, 500MHz clock frequency, including memory decoding circuit and general I/O, Special I/O(EPA, Interrupt controller, Timer/Count, PWM generator) which is proper controller for the complex algorithm or operation program requiring so much memory capacity, So in this paper we fully digitized the vector control of PMSM included SVPWM Voltage controller using the intel 80296SA