• Explosives and Blasting
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• v.17 no.2
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• pp.19-35
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• 1999

Rock fragmentation with plasma blasting technique has advantageous properties in contrast to the conventional blasting method controlling of flying rocks and ground vibrations, when residents are complaining or surrounding structures stay in protection from blasting operations. The experiences show in urban construction works that the plasma blasting is the most possible method to prevent damages and minimize adverse environmental impacts. The fragmentation energy level is evaluated by numerical simulation using PFC for various drill hole patterns and tested accordingly to get the feasibility. The energy output of plasma blasting system has been improved to a level of 1 MJ, which can break a 2-3 ㎥ granite boulder or 1.5m height bench face. Measurements are carried out to get the ground vibration level and propagation equation, so that control of the blasting operations can be performed more precisely and safely.

• Tunnel and Underground Space
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• v.7 no.4
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• pp.267-273
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• 1997

Rock fragmentation with plasma blasting technique has advantageous properties in contrast to the conventional blasting method in controlling of flying rocks and ground vibrations, when residents are complaining or surrounding structures stay in protection from blasting operations. The experiences show in urban construction works that the plasma blasting is the most possible method to prevent damages and minimize adverse environmnetal impacts. The fragmentation energy level is evaluated by numerical simulation using PFC-2D for various drill hole pattern and tested accordingly to get the feasibility. The energy output of plasma blasting system has been improved to a level of 1 MJ, which can break a 2~3 ㎥ granite boulder or 1.5 m height bench face. Measurements are carried out to get the ground vibration level and propagation equation, so that the control of the blasting operations can be performed more precisely and safely.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1642-1647
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• 2007

The aim of this research is to implement a design framework based on reliability analysis and make it possibly used for a reliable and robust design under uncertainties. Different types of reliability methods and algorithms are programmed to explore their characteristics. In our work, RIA and the PMA are employed for formulating the reliability analysis problems. A number of reliability methods are introduced in this program such as FORM, AMV/AMV+ and MCS. Reliability analysis can be easily performed with this tool box only if a drive file is ready to run. Users need to select random design variables and define their distributions and correlation.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.70-70
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• 2004

Lower thermospheric winds are forced primarily by non-uniform solar heating, atmospheric tides and other waves coming from below, and energy and momentum forcing associated with high-latitude magnetosphere-ionosphere coupling, particularly ion drag and Joule heating. To understand the physical processes that control the thermospheric dynamics, we quantify the momentum forces that are mainly responsible for maintaining the high-latitude lower thermospheric wind system and examine the resulting momentum balance with the aid of the Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM) developed by the National Center for Atmospheric Research. (omitted)

• Journal of the Korean Mathematical Society
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• v.52 no.5
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• pp.955-964
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• 2015

Let K be a number field and let S be a finite set of primes of K containing all the infinite ones. Let ${\alpha}_0{\in}{\mathbb{A}}^1(K){\subset}{\mathbb{P}}^1(K)$ and let ${\Gamma}_0$ be the set of the images of ${\alpha}_0$ under especially all Chebyshev morphisms. Then for any ${\alpha}{\in}{\mathbb{A}}^1(K)$, we show that there are only a finite number of elements in ${\Gamma}_0$ which are S-integral on ${\mathbb{P}}^1$ relative to (${\alpha}$). In the light of a theorem of Silverman we also propose a conjecture on the finiteness of integral points on an arbitrary dynamical system on ${\mathbb{P}}^1$, which generalizes the above finiteness result for Chebyshev morphisms.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1112-1117
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• 2003

Polarized Fourier transform infrared (IR) absorption is used to probe molecular conformation in a ferroelectric liquid crystal (FLC) during the reorientation induced by the external field. Spectra of planar aligned cells of FLC W314 are measured as functions of IR polarizer orientation and electric field applied to the FLC. The time evolution of the dichroism of the absorbance due to biphenyl core and alkyl tail molecular vibration modes, is observed. Static IR dichroism experiments show a W314 dichroism structure in which the principal axis of dielectric tensor from molecular core vibration are tilted further from the smectic layer normal than those of the tail. This structure indicates the effective binding site in which the molecules are confined in the Sm-C phase has, on average, "zig-zag" shape and this zig-zag binding site structure is rigidly maintained while the molecular axis rotates about the layer normal during field-induced switching.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.5
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• pp.127-136
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• 1989

A Symbolic cover Minimization Algorithm and State CHDL Description for Finite State Machine Synthesizer are Presented. State CHDL are used for design of PLA based finite state machine, also the symbolic cover minimization algorithms are based upon single cube containment and distance 1 merging algorithms. The procedure for state machine synthesizer has been applied to practical example, including traffic light controller by using Boulder Optimal Logic Design System.

• Journal of Industrial Technology
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• v.33 no.A
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• pp.73-80
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• 2013

This paper is results of numerical analysis on the behavior of colluvium slope with combinations of soil nails and earth anchors during excavation. In order to maintain the stability of the colluvium cut, being composed of gravel and boulder and thus local in stability being expected during slope cut, temporary reinforcing method of soil nailing with shotcrete might be used. Subsequent method of cast-in-place facing with earth anchors can be used to maintain cut slope stable permanently. For the cut slope where these methods had been applied, the numerical techniques were applied to their behaviors and investigate the stability of the slope. Limit equilibrium methods were used to confirm to maintain the slope stability during and after excavation and application of those reinforcing methods. Another numerical technique of FEM was also used to find the stress and strain as well as deformation distribution in reinforcing materials and slope ground during excavation.

• Computers and Concrete
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• v.5 no.3
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• pp.175-194
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• 2008

Increasingly numerical (finite element) modeling of concrete hinges on our ability to develop a representative volume element with all its heterogeneity properly discretized. Yet, despite all the sophistication of the ensuing numerical models, the initial discretization has been for the most part simplistic. Whenever the heterogeneity of the concrete is to be accounted for, a mesh is often manually crafted through the arbitrary inclusion of the particles (aggregates and/or voids) in an ad-hoc manner. This paper develops a mathematical strategy to precisely address this limitation. Algorithms for the random generation and placement of elliptical (2D) or ellipsoid (3D) inclusions, with possibly radiating cracks, in a virtual concrete model are presented. Collision detection algorithms are extensively used.

• Bulletin of the Korean Mathematical Society
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• v.47 no.5
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• pp.1053-1066
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• 2010

In this paper, several properties of endomorphism rings of modules are investigated. A multiplication module M over a commutative ring R induces a commutative ring $M^*$ of endomorphisms of M and hence the relation between the prime (maximal) submodules of M and the prime (maximal) ideals of $M^*$ can be found. In particular, two classes of ideals of $M^*$ are discussed in this paper: one is of the form $G_{M^*}\;(M,\;N)\;=\;\{f\;{\in}\;M^*\;|\;f(M)\;{\subseteq}\;N\}$ and the other is of the form $G_{M^*}\;(N,\;0)\;=\;\{f\;{\in}\;M^*\;|\;f(N)\;=\;0\}$ for a submodule N of M.