• KCI Concrete Journal
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• v.11 no.3
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• pp.99-107
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• 1999

In designing the Prestressed concrete box-girder bridge. dead load, prestressing force, creep and shrinkage of concrete are the main factors which influence the camber and deflection of segmental concrete structure under construction. Among these factors the creep and shrinkage are the functions of the time-dependent property which. therefore, must be considered with time. The prediction model for estimating creep and shrinkage of concrete has been suggested by ACI, CEB/FIP, JSCE and KSCE design code and EMM, AEMM, RCM, IDM and SSM has been suggested for analytical method in consideration of time-dependent characteristics. In this study the creep test was carried out for four different curing ages of concrete which were applied to the Prestressed concrete structure at the construction site, and the results of test were compared with the values of creep prediction proposed by the design code. Also the creep test was performed with step-wise incremental stresses and the results were compared to the analytical values.

• Structural Engineering and Mechanics
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• v.18 no.2
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• pp.195-209
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• 2004

By means of the two-dimensional basic equations of transversely isotropic magneto-electro-elastic media and the strict differential operator theorem, the general solution in the case of distinct eigenvalues is derived, in which all mechanical, electric and magnetic quantities are expressed in four harmonic displacement functions. Based on this general solution in the case of distinct eigenvalues, a series of problems is solved by the trial-and-error method, including magneto-electro-elastic rectangular beam under uniform tension, electric displacement and magnetic induction, pure shearing and pure bending, cantilever beam with point force, point charge or point current at free end, and cantilever beam subjected to uniformly distributed loads. Analytical solutions to various problems are obtained.

• Wind and Structures
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• v.36 no.3
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• pp.161-174
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• 2023

The analytical model of tornado vortices plays an essential role in tornado wind description and tornado-resistant design of civil structures. However, there is still a lack of guidance for the selection and application of tornado analytical models since they are different from each other. For single-cell tornado vortices, this study conducts a comparative study on the velocity characteristics of the analytical models based on numerically simulated tornado-like vortices (TLV). The single-cell stage TLV is first generated by Large-eddy simulations (LES). The spatial distribution of the three-dimensional mean velocity of the typical analytical tornado models is then investigated by comparison to the TLV with different swirl ratios. Finally, key parameters are given as functions of swirl ratio for the direct application of analytical tornado models to generate full-scale tornado wind field. Results show that the height of the maximum radial mean velocity is more appropriate to be defined as the boundary layer thickness of the TLV than the height of the maximum tangential mean velocity. The TLV velocity within the boundary layer can be well estimated by the analytical model. Simple fitted results show that the full-scale maximum radial and tangential mean velocity increase linearly with the swirl ratio, while the radius and height corresponding to the position of these two velocities decrease non-linearly with the swirl ratio.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.521-525
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• 1996

An attempt is made to characterize and synthesize engineered surfaces. The proposed method is not only an analytical tool to characterize but alsoto generate/synthesize three-dimensional surfaces. The developed method expresses important engineered surface characteristics such as the autocorrelation or pwoer spectrum density functions in terms of the two-dimensional autoregressive coefficients.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.114-119
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• 2008

A refined three-dimensional finite element interaction model between the high-speed train and railway bride deck has been developed in the present study. Analytical predictions of vertical deflections for a railway bridge are compared with in-situ test results and a good agreement is achieved. Then, input variables employed in the analytical comparisons are selected as random variables for the limit state functions. followed by risk assessment. For this purpose, a linear adaptive weighted response surface method has been developed and applied. A typical railway bridge has been selected and the limit state functions are employed from UIC and Korean specifications in the comparative studies. The results reveal that Korean specifications give significantly risky reliability indices in comparison with UIC specifications. It is thus encouraged from the above that the present linear adaptive weighted response surface method can be an alternative for the fast estimation of nonlinear structural systems.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.1
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• pp.43-54
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• 1997

This paper presents an approximate analytical solution to a two-region one-dimensional model for the charging process of stratified thermal storage tanks with variable inlet temperature in the presence of momentum-induced mixing. Based on the superposition principle, an arbitrary-varying inlet temperature is decomposed into inherent discontinuous steps and continuous intervals approximated as a finite number of piecewise linear functions. This approximation allows the temperature of the upper perfectly-mixed layer to be expressed in terms of constant, linear and exponential functions with respect to time. Applying the Laplace transform technique to the model equation for the lower thermocline layer subject to each of three representative interfacial conditions yields compact-form solutions, a linear combination of which constitutes the final temperature profile. A systematic method for deriving solutions to the plug-flow problem having polynomial-type boundary conditions is also established. The effect of adiabatic exit boundary on solution behaviors proves to be negligible under the actual working conditions, which justifies the assumption of semi-infinite domain introduced in the solution procedure. Finally, the approximate solution is validated by comparing it with an exact solution obtained for a specific variation of inlet temperature. Excellent agreements between them suffice to show the necessity and utility of this work.

• Nuclear Engineering and Technology
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• v.41 no.6
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• pp.813-820
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• 2009

A rapid pneumatic transfer system (PTS) for an instrumental neutron activation analysis (INAA) is developed as an automatic irradiation facility involving the measurement of a short half-life nuclide and a delayed neutron counting system. Three new PTS designs with improved functions were constructed at the HANARO research reactor in 2006. The new system is composed of a manual system and an automatic system for both an INAA and a delayed neutron activation analysis (DNAA). The design and basic conception of a modified PTS are described, and the functions of system operation and control, radiation protection and emissions of radioactive gas are improved. In addition, a form of capsule transportation of these systems is tested. The experimental results pertaining to the irradiation characteristics with variation of the neutron flux and the temperature of the irradiation position with the irradiation time are presented, as is an analysis of the reference material for analytical quality control and uncertainty assessments.

• Advances in materials Research
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• v.12 no.2
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• pp.161-177
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• 2023

This paper proposes an analytical method to investigate the free vibration behaviour of new functionally graded (FG) carbon nanotubes reinforced composite beams based on a higher-order shear deformation theory. Cosine functions represent the material gradation and material properties via the thickness. The kinematic relations of the beam are proposed according to trigonometric functions. The equilibrium equations are obtained using the virtual work principle and solved using Navier's method. A comparative evaluation of results against predictions from literature demonstrates the accuracy of the proposed analytical model. Moreover, a detailed parametric analysis checks for the sensitivity of the vibration response of FG nanobeams to nonlocal length scale, strain gradient microstructure-scale, material distribution and geometry.

• Journal of the Korean Society for Advanced Composite Structures
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• v.1 no.3
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• pp.1-9
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• 2010

In this paper, we used various shear deformation functions for modelling isotropic, symmetric composite and sandwich plates discretized by a mixed finite element method based on the Lagrangian/Hermite interpolation functions. These shear deformation theories uses polynomial, trigonometric, hyperbolic and exponential functions through the thickness direction, allowing for zero transverse shear stresses at the top and bottom surfaces of the plate. All shear deformation functions are compared with other available analytical/3D elasticity solutions, are predicted the reasonable accuracy for investigated problems. Particularly, The present results show that the use of exponential shear deformation theory (Karama et al. 2003; Aydogu 2009) provides very good solutions for composite and sandwich plates.

• Biomolecules & Therapeutics
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• v.30 no.1
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• pp.98-116
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• 2022

The small GTPase RhoA has been studied extensively for its role in actin dynamics. In this study, multiple bioinformatics tools were applied cooperatively to the microarray dataset GSE64714 to explore previously unidentified functions of RhoA. Comparative gene expression analysis revealed 545 differentially expressed genes in RhoA-null cells versus controls. Gene set enrichment analysis (GSEA) was conducted with three gene set collections: (1) the hallmark, (2) the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and (3) the Gene Ontology Biological Process. GSEA results showed that RhoA is related strongly to diverse pathways: cell cycle/growth, DNA repair, metabolism, keratinization, response to fungus, and vesicular transport. These functions were verified by heatmap analysis, KEGG pathway diagramming, and direct acyclic graphing. The use of multiple gene set collections restricted the leakage of information extracted. However, gene sets from individual collections are heterogenous in gene element composition, number, and the contextual meaning embraced in names. Indeed, there was a limit to deriving functions with high accuracy and reliability simply from gene set names. The comparison of multiple gene set collections showed that although the gene sets had similar names, the gene elements were extremely heterogeneous. Thus, the type of collection chosen and the analytical context influence the interpretation of GSEA results. Nonetheless, the analyses of multiple collections made it possible to derive robust and consistent function identifications. This study confirmed several well-described roles of RhoA and revealed less explored functions, suggesting future research directions.