• Ocean Systems Engineering
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• v.2 no.1
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• pp.17-31
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• 2012

This study investigated the behavior of a non-isothermal $CO_2$ bubble formed through a leak process from a high-pressure source in a deep sea. Isenthalpic interpretation was employed to predict the state of the bubble just after the leak. Three modes of mass loss from the rising bubble were demonstrated: dissolution induced by mass transfer, condensation by heat transfer and phase separation by pressure decrease. A graphical interpretation of the last mode was provided in the pressure-enthalpy diagram. A threshold pressure (17.12 bar) was identified below which the last mode was no longer present. The second mode was as effective as the first for a bubble formed in deep water, leading to faster mass loss. To the contrary, only the first mode was active for a bubble formed in a shallow region. The third mode was insignificant for all cases.

• Journal of KIISE:Software and Applications
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• v.30 no.3_4
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• pp.202-211
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• 2003

Abstract Formal definitions of syntax and semantics for the static and dynamic models in Object Oriented methods are already defined. But the behavior of interacting objects is not formalized. In this paper, we defined the common behavior of interacting objects in terms of process algebra using sequence diagram in UML and regularized properties of interacting objects. Based on the results, we can develop a formal specification by. using of the object interaction instead of the existence dependency suggested by M. Snoeck and G. Dedene[9].

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.196-199
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• 1999

The coexistence of the superconductivity and magnetism in the Ho1-xDyxNi2B2C is studied by using Ginzburg-Landau theory. This material violates the standard do Gennes scaling showing the coexistence and complex interplay of superconducting and magnetic order yielding an anomalous phase diagram. We propose a phenomenological model which includes two magnetic and two superconducting order parameters accounting for the multi-band structure of this material. We describe the magnetic fluctuations and order and demonstrate that they lead to anomalous behavior of the upper critical field. The doping dependence of Tc in Ho1-xDyxNi2B2C showing a reentrance behavior are analyzed yielding a very good agreement with experimental data.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.6
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• pp.724-730
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• 2006

Fracture behavior of brittle solids is closely related to microcracking. A meso-scale analysis method using the natural element method is proposed for the analysis of brittle microcracking solids. The microcracking is assumed to occur along Voronoi edges in the Voronoi diagram generated using the nodal points as the generators. The mechanical effect of microcracks is considered by controlling the material constants in the neighborhood of the microcracks. The meso-analysis method is applied to the simulation of the microcracking behaviors of brittle solids subjected to tensile macrostress. The method is also applied to the analysis of the propagation of a macrocrack accompanied by the coalescence with microcracks formed near the macrocrack-tip.

• ETRI Journal
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• v.11 no.4
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• pp.75-83
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• 1989

The diffusion mechanism of Si in GaAs was investigated using different diffusion sources based on the Si-Ga-As ternary phase equilibria. The Si profiles are measured with secondary ion mass spectrometry and differ significantly for sources taken from the different phase fields in the ternary phase diagram. Neutral As vacancy diffusion is proposed for acceptor Si diffusion anneals using a Ga - Si - GaAs source. Donor Si diffusion using As - rich sources and a Si -GaAs tie line source shows concentration dependent diffusion behavior. Concentration dependent diffusion coefficients of donor Si for As - rich source diffusion were found to be related to net ionized donor concentration and showed three regimes of different behavior: saturation regime, intermediate regime,and intrinsic regime. Ga vacancies are proposed to be responsible for donor Si diffusionin GaAs: $Si_Ga^+V_Ga^-$ (donor Si -acceptor Gavacancy) complex for the extrinsic regime and neutral $V_G$a, for the intrinsic regime.The Si - GaAs tie line source resulted in two branch profiles, intermediate between the As - rich and the Ga - rich source diffusion cases.

• International Journal of Control, Automation, and Systems
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• v.6 no.4
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• pp.559-570
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• 2008

This paper proposes an improved particle swarm optimization named PSO with Controllable Random Exploration Velocity (PSO-CREV) behaving an additional exploration behavior. Different from other improvements on PSO, the updating principle of PSO-CREV is constructed in terms of stochastic approximation diagram. Hence a stochastic velocity independent on cognitive and social components of PSO can be added to the updating principle, so that particles have strong exploration ability than those of conventional PSO. The conditions and main behaviors of PSO-CREV are described. Two properties in terms of "divergence before convergence" and "controllable exploration behavior" are presented, which promote the performance of PSO-CREV. An experimental method based on a complex test function is proposed by which the proper parameters of PSO-CREV used in practice are figured out, which guarantees the high exploration ability, as well as the convergence rate is concerned. The benchmarks and applications on FCRNN training verify the improvements brought by PSO-CREV.

• Geomechanics and Engineering
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• v.9 no.2
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• pp.169-193
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• 2015

This paper is the second part of the study for determining the seismic behavior of soil systems. The aim of this part is to present solution approaches for determining seismic site amplification. For this purpose, two solution techniques are used. The first technique is equivalent linear analysis which is mostly used in literature. The other technique is real time parameter updating approach and this approach uses the possibilities of Simulink effectively. A graphical user interfaced (GUI) program called DTASSA standing for Discrete-Time Analysis of Seismic Site Amplification is developed. In DTASSA, automatic block diagram producing system is developed and seismic site amplification for multiple soil layers may easily be investigated in real time. Numerical applications have been carried out to check the reliability of developed algorithm. The results of DTASSA are compared with SUA, EERA and NERA programs for the particular example problems.

• Geomechanics and Engineering
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• v.9 no.2
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• pp.145-167
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• 2015

Digital simulation has recently become the preferred method for designing complex and dynamic systems. Simulation packages provide interactive, block-diagram environment for modeling and simulating dynamic models. The block diagrams in simulation models are flowcharts which describe the components of dynamic systems and their interaction. This paper is the first part of the study for determining the seismic behavior of soil systems. The aim of this part is to present the constructed block diagrams for discrete-time analysis of seismic site amplification in layered media for vertically propagating shear waves. Detailed block diagrams are constructed for single and multiple soil layers by considering wave propagation with and without damping, respectively. The block diagrams for recursive filter to model attenuation in discrete-time form are also constructed. Finite difference method is used for strain calculation. The block diagrams are developed by utilizing Simulink which is a software add-on to Matlab.

• Proceedings of the Korea Concrete Institute Conference
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• 1992.04a
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• pp.143-147
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• 1992

Description of the behavior of the R.C structural members fixed on massive concrete is not normally generalization of recognized configuration for regular R.C. design guidanes. This can be due to the complexity of evaluation of internal resistancy and deflection changes of the members subjected to the various external forces. On the base of axially loaded member fixed on footing, however, the estimation of deflection changes due to flexural force shear force and rotational force is to be carried out in ways of specifying the bond characteristics of axial bars embedded in massive concrete. This work is to quantify adhesion of steel-concrete, initial concrete cracking stress near bar rib, maximum bond stress and residual stress in concrete respectively. In addition to quantification of them for particulate behavior, the suggestions of multi-linear bond stress-slip diagram made in carrying out finite element analyses for adhesion failure, examining concrete cracking status and reviewing existing experimental data lead to alternatively constructed relationship between bond stress and slip for a axial bars embedded massive concrete.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.762-766
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• 1995

The coercive field $H_{c}$ of amorphous Y-Fe alloys in the spin-glass state has been investigated. Foramorphous $Y_{10}Fe_{90}$ alloy, the thermal variations of $H_{c}$ in the maximum external field $H_{max}=300,\;600$ and 1 k Oe exhibit a maximum. Since spin-glass behavior is strongly affected by external magnetic fields, the maximum point moves to lower temperature with increasing $H_{max}$. The appearance of the maximum in $H_{c}$ has been discussed in terms of the change of the spin-glass state in the external magnetic field. When the value of $H_{max}$ is 55 kOe, the temperature dependence of $H_{c}$ has no maximum and shows an exponential decrease with increasing temperature. Similar trends have been observed over a wide concentration range. The concentration dependence of $H_{c}$ is associated with the magnetic phase diagram.