• Journal of the Korean Mathematical Society
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• v.50 no.3
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• pp.479-491
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• 2013

Let M be a smooth real hypersurface in complex space of dimension $n$, $n{\geq}3$, and assume that the Levi-form at $z_0$ on M has at least $(q+1)$-positive eigenvalues, $1{\leq}q{\leq}n-2$. We estimate solutions of the local $\bar{\partial}$-closed extension problem near $z_0$ for $(p,q)$-forms in Sobolev spaces. Using this result, we estimate the local solution of tangential Cauchy-Riemann equation near $z_0$ in Sobolev spaces.

• Honam Mathematical Journal
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• v.23 no.1
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• pp.91-111
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• 2001

In this paper we prove the following : Let M be a semi-invariant submanifold with almost contact metric structure (${\phi}$, ${\xi}$, g) of codimension 3 in a complex hyperbolic space $H_{n+1}{\mathbb{C}}$. Suppose that the third fundamental form n satisfies $dn=2{\theta}{\omega}$ for a certain scalar ${\theta}({\leq}{\frac{c}{2}})$, where ${\omega}(X,\;Y)=g(X,\;{\phi}Y)$ for any vectors X and Y on M. Then M has constant eigenvalues correponding the shape operator A in the direction of the distinguished normal and the structure vector ${\xi}$ is an eigenvector of A if and only if M is locally congruent to one of the type $A_0$, $A_1$, $A_2$ or B in $H_n{\mathbb{C}}$.

• Proceedings of the KIEE Conference
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• 1979.08a
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• pp.164-165
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• 1979

Two dimensional kernels which reconstruct the tomographic image from the blurred one formed by simple back-projection are investigated and their performances are compared. These kernels are derived from tile point spread function of the tomographic system and have the form of a ramp filter modified by several window functions to suppress ringing in the reconstruction. Computer simulation using a computer generated phantom image data with different correction functions(kernels) has been carried out. In this simulation, filtering in frequency domain by 2-D FFT technique or in space domain by 2-D direct convolution is considered. It is found that the-computation time required for real space convolution technique is much larger than that of Fourier 2-D filtering technique in the pratical situation.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2006.11a
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• pp.54-57
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• 2006

The digital modeling process is visualization of designer's specific intension in digital virtual space by constructing computer and information system that fits the designer's intension and morphological characteristic of the space that to be modeled. Digital Modeling Process has been brought to attention for it's design efficiency and potentialities as new creative tool. The effect of DMP, in spacial design process has been grown from simply providing a ways to visualize designer's idea toward utilizing modeling data for real construction which includes architectural and constructional material. The purpose of this study is to find optimal methodological answers to spatial design process that is improved and specialized due to rapid improvement of digital media.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.6
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• pp.548-555
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• 2007

Typical helicopter simulation programs rely on differential equations of a closed form. However, since these equations are derived using various assumptions, their usefulness is limited to small flight regions and specific model types. This paper presents a component based rotorcraft simulation program. The program adopts methods of multi-body dynamics and is written in an object-oriented programming language. The program was validated using an AH-1G helicopter simulation. The trim results are well matched with flight test data. It is also shown that program is capable of running in real-time on a desktop computer.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.394-398
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• 1988

In this paper, the time-averaged behavior of the three-phase Inductor-Converter Bridge (ICB) circuit has been analyzed by using the state-space averaging method. The results are in closed form far from the results obtained by using the Fourier series. Therefore, the computational difficulties of the infinite Fourier series can be avoided and the results derived in this paper are available especially in real time control. Unlike the SFC, $S^{4}LCL$, DFC and other circuits which have time varying switching intervals for a constant time-averaged value of coil voltage, the ICB circuits operate with a clock-driven sequence of gate pulses which have constant switching intervals.

• Journal of Ocean Engineering and Technology
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• v.23 no.1
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• pp.152-157
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• 2009

In designing and manufacturing a submarine, an expensive real mock up is usually built as a reference because of the spatial constraints of a submarine. This paper presents an integrated and automated design process for a submarine that uses a digital mock up. Various equipment libraries are built for feature based design. Using the developed digital mock up, this paper shows various ways to verify the design, including a space analysis to check for any interference between pieces of equipment and the hull and an ergonomic analysis using lifelike dummies to examine the work space and operability. As a part of the integrated design system, a design automation system was also developed to generate surface point data for the outer hull, pressure hull, casing, and sail. The whole process was applied to the design of a submarine for verification.

• The Research Journal of the Costume Culture
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• v.7 no.5
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• pp.104-121
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• 1999

The purpose of this paper is to make sure of identity as a paradigm of new fsahion to introduce the concept of Sumulacres by J. Baudrillard, For converting to new aesthetic value. To do this, we started observing the general concept of Simulacres, and examined Cyberpunk within thinking of Simulacres and Cyberpunk fashion at virtual space, and then divided aesthetic consciousness appeared at Cyberpunk fashion centering on the concept of Simulacres into inwards sense and outwards sense. Cyberpunk is understood to be one of tendency in the cyber cultures controlled by computer and electronic technology. It is not yet defined clearly and therefore ambiguous and still being elaborated. However, the form started changing our sense sinking into overall cultures in the World, including even movie, literature, music and fashion, and giving complex, deep cultural and artistic possibilities. Also, as a subculture, Cyberpunk is building its own cultural territory in cyber space and is experiencing more real Simulacres than that of it in the ordinary life.

• Journal of the Korean Institute of Rural Architecture
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• v.14 no.1
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• pp.99-106
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• 2012

Transformation which is the major damage factor of living space in folk village is caused by improvement behaviors reflecting real requirements of residents who are the subjects of life. Such a process changes traditional space structure gradually and lowers preservative value of folk village. Therefore this study examines transformational conditions of living space centering around changes of spatial components and plane forms through literature and field research and analyzes characteristics of transformational phenomenon. This study examined changes of components and transformation of Seongeup folk village. While main room plane was diversified by residents' requirements, it was not harmonized with traditional image of Seongeup folk village. Transformation of living space at Seongeup Folk Village was positive from the side of residents' living requirements, but negative in that it damaged unique identity of folk village. Accordingly, it is thought that deliberation considering residents' living requirements as the field of their life with maintenance of original form for the purpose of preserving folk village and professionals' support and legal study for revision of approval system are continuously required.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.36.3-37
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• 2009

This is an attempt to improve a formula to predict variations of geomagnetic storm indices (Dst) from solar wind parameters. A formula which is most widely accepted was given by Burton et al. (1975) over 30 years ago. Their formula is: dDst*/dt = Q(t) - Dst*(t)/$\tau$, where Q(t) is the Dst injection rate given by the convolution of dawn-to-dusk electric field generated by southward solar wind magnetic field and some response function. However, they did not clearly specify the response function. As a result, misunderstanding seems to be prevailing that the injection rate is proportional to the dawn-to-dusk electric field. In this study we tried to determine the response function by examining 12 intense geomagnetic storms with minimum Dst < -200 nT for which solar wind data are available. The method is as follows. First we assume the form of response function that is specified by several time constants, so that we can calculate the injection rate Q1(t) from the solar wind data. On the other hand, Burton et al. expression provide the observed injection rate Q2(t) = dDst*/dt + Dst*(t)/$\tau$. Thus, it is possible to determine the time constants of response function by a least-squares method to minimize the difference between Q1(t) and Q2(t). We have found this simple method successful enough to reproduce the observed Dst variations from the corresponding solar wind data. The present result provides a scheme to predict the development of Dst 30 minutes to 1 hour in advance by using the real time solar wind data from the ACE spacecraft.