• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.647-651
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• 2002

This study dealt with the free vibration of two identical rectangular plates coupled with fluid. In order to investigate the vibration characteristics of fluid-coupled rectangular plates, an analytical method based on the finite Fourier series expansion and Rayleigh-Ritz method was suggested. A commercial computer code, ANSYS was used to perform finite element analysis and we investigated the vibration characteristics with mode shapes and natural frequencies. As a result, the transverse vibration modes, in-phase and out-of-phase, were observed alternately in the fluid-coupled system. The effect of fluid bounding and plate boundary condition on the fluid-coupled natural frequency were investigated. It was shown that the mode numbers increased, the normalized natural frequencies monotonically increased.

• Water Engineering Research
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• v.4 no.2
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• pp.69-85
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• 2003

Previously developed empirical equations used to calculate the parameters of the transient storage model are analyzed in depth in order to evaluate their behavior in representing solute transport in the natural streams with storage zone. A comparative analysis of the existing theoretical and experimental equations used to predict parameters of the transient storage (TS) model is reported. New simplified equations for predicting 4 key parameters of the TS model using hydraulic data sets that are easily obtained in the natural streams are also developed. The weighted one-step Huber method, which is one of the nonlinear multi-regression methods, is applied to derive new parameters equation. These equations are proven to be superior in explaining mixing characteristics of natural streams with the transient storage zone more precisely than the other existing equations.

• The Korean Journal of Food And Nutrition
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• v.11 no.1
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• pp.68-71
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• 1998

In order make natural food color from gardenia(Gardenia jasminoides), we investigated optimal conditions of color extraction, in case of water extraction, optimal conditions for color extraction were 7$0^{\circ}C$, 48hrs, pH 7.0 and substrate 10%, respectively. And extracted crude color was purified by activated white clay, were isolated glycoside peak (238nm) and yellow color peak(40nm) from extracted crude color. The pruified color was increased by 27-fold and the yield was 96%.

• Kyungpook Mathematical Journal
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• v.48 no.3
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• pp.487-493
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• 2008

A. Di Nola & S.Sessa [8] showed that two compact spaces X and Y are homeomorphic iff the MV -algebras C(X, I) and C(Y, I) of continuous functions defined on X and Y respectively are isomorphic. And they proved that A is a semisimple MV -algebra iff A is a subalgebra of C(X) for some compact Hausdorff space X. In this paper, firstly by use of functorial argument, we show these characterization theorems. Furthermore we obtain some other functorial results between topological spaces and MV -algebras. Secondly as a classical problem, we find a necessary and sufficient condition on a given residuated l-monoid that it is segmenently embedded into an l-group with order unit.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.3
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• pp.96-102
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• 2007

An Optimal shape design of the boom system in high ladder vehicles is performed using 3-D finite element method (FEM). Results of structural analyses providing displacements, stresses are implemented for the optimum shape design. Lanzcos algorithm is used for the modal analysis in order to find natural frequencies. The optimal shape including cross sectional thickness and length of the boom system is controlled by the subproblem method besed on displacement and Von Mises stress. It is found that a plenty of materials can be saved by using shape design optimization in high ladder vehicles. It is also found that the natural frequency is increased until 6th mode and maintained similarly or decreased after 6th mode.

• Fashion & Textile Research Journal
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• v.6 no.2
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• pp.239-244
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• 2004

On the whole the various medium colors were developed by repeat dyeing with different colorants after dyeing with one colorant in case of natural dyeing. In this study, in order to obtain various colors on wool fabrics with Gardenia and Sappan wood colorants, pre-mordanting and combination dyeing were carried out. Gardenia and Sappan wood used as natural colorants for combination dyeing showed good miscibility in dye bath, Metal compounds containing alum, copper and iron were used for pre-mordants. The various medium colors such as yellow-red were obtained according to various metal compounds for pre-mordants and various mixing portion of these natural colorants. The surface reflactance spectra and color characteristics of wool fabrics by mordanting and combination dyeing were investigated.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2004.05a
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• pp.131-135
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• 2004

The purpose of this research is to improve exhibition effectiveness by implementing hands-on exhibition technique that best provides adults with cultural resting place and children with outdoor education which simply supports school curriculum. By completing this research, the museum of natural history will become defined innovatively as a place that enables people actively develop creativity. Seodaemun museum of natural history was selected for this research and itinerary tracking method of Robinson and Melton was adopted to find out adults' and children's particular movements in the museum. At the same time, observation method was used to get information on each room's visiting and viewing rate. In order to understand adults' and children's movements, their behavior was encoded.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.4
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• pp.8-15
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• 2011

In this paper, the influence of a crack on the natural frequency of cracked cantilever L-shaped beam with coupled bending and torsional vibrations by analytically and experimentally is analyzed. The L-shaped beam with a crack is modeled by Hamilton's principle with consideration of bending and torsional energy. The two coupled governing differential equations are reduced to one sixth-order ordinary differential equation in terms of the flexural displacement. The crack is assumed to be in the first, second and third mode of fracture and to be always opened during the vibrations. The theoretical results are validated by a comparison with experimental measurements. The maximal difference between the theoretical results and experimental measurements of the natural frequency is less than 7.5% in the second vibration mode.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.388-392
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• 1995

The Electronic Speckle Pattern Interferometry(ESPI) has been applied to many technical problems such as deformation and displacement measurement, strain visualization and surface roughness monitoring. Composite materials have various complicated characteristics depending on the ply materials,ply orientations,ply stacking sequences and boundary conditions. Therefore, it is difficult to analyze composite material. For efficient use of composit materials in engineering applications, the dynamic behavior such as, natural frequencies and modal patterns should be identified. This studying presents FEM results for the free vibration of symmetrically laminated composite as [30/-30/90] $_{s}$. The natural frequencies of laminated composite rectangular plates having the boundary condition(:2-edge clamped) are experimentally obtained. In order to demonstrate the validity of the experiment,FEM analysis using ANSYS was performed and natural frequencies experimentally obtained is compared with calculated by FEM analysis. The results obtained from both experiment and FEM analysis show a good agreement.t.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.1054-1059
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• 2002

A linearly tapered beam immersed partially in other material is considered and is modelled as a linearly tapered Bernoulli-Euler beam fixed at the bottom with a concentrated mass at the top. Its governing equations is derived and its free vibration analysis is performed for various boundary conditions. And the rotatory inertia of the eccentric lumped tip mass is considered. The problem of determining the natural frequencies leads to an eighth order determinant. The solutions of the frequency equations are obtained numerically. The non-dimensional frequency parameters are given in tabular form and the influence of non-dimensional parameters on natural frequency is discussed for various conditions.