• Structural Engineering and Mechanics
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• v.77 no.6
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• pp.765-777
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• 2021

Recently, the plate bending analysis has been interpreted in terms of the tensor's components of curvatures and bending moments by presenting the conceptual perspectives of the Hydrostatic Method of Analysis (HM) and theoretical formulations that combine the continuum mechanics with the graphical statics analysis, the theory of thin orthotropic and isotropic plates, and the elasticity theory. In pursuance of uncovering a genuine formulation of the plate's flexural differential equations, that possess the general-covariance and coordinates-independency. This study had then, tackled various natural and structural problems in both solid and fluid branches of the continuum mechanics in a description of such theoretical and conceptual attainment in uncovering the dimensional independent diffeomorphism covariant partial differential laws.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.119-124
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• 2001

A general procedure to implement the sensitivity analysis of PSC flexural members is proposed based on the analytical calculation of the gradients of stresses and strains with respect to the 21 design variables in a closed format. The formulation covers the long term losses including concrete creep, shrinkage, and PS steel relaxation as well as load effects. The derived formulation is applied to the rectangular section PSC beam with prestressing and nonprestressing steels for the sensitivity analysis. The analytically calculated sensitivity results are compared with those numerically calculated.

• Journal of Ginseng Research
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• v.46 no.2
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• pp.296-303
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• 2022

Background: Skin microbiota is important for maintenance of skin homeostasis; however, its disturbance may cause an increase in pathogenic microorganisms. Therefore, we aimed to develop a red ginseng formulation that can selectively promote beneficial bacteria. Methods: The effects of red ginseng formulation on microorganism growth were analyzed by comparing the growth rates of Staphylococcus aureus, S. epidermidis, and Cutibacterium acnes. Various preservatives mixed with red ginseng formulation were evaluated to determine the ideal composition for selective growth promotion of S. epidermidis. Red ginseng formulation with selected preservative was loaded into a biocompatible polymer mixture and applied to the faces of 20 female subjects in the clinical trial to observe changes in the skin microbiome. Results: Red ginseng formulation promoted the growth of S. aureus and S. epidermidis compared to fructooligosaccharide. When 1,2-hexanediol was applied with red ginseng formulation, only S. epidermidis showed selective growth. The analysis of the release rates of ginsenoside-Rg1 and -Re revealed that the exact content of Pluronic F-127 was around 11%. The application of hydrogel resulted in a decrease in C. acnes in all subjects. In subjects with low levels of S. epidermidis, the distribution of S. epidermidis was significantly increased with the application of hydrogel formulation and total microbial species of subjects decreased by 50% during the clinical trial. Conclusion: We confirmed that red ginseng formulation with 1,2-hexanediol can help maintain skin homeostasis through improvement of skin microbiome.

• Structural Engineering and Mechanics
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• v.68 no.2
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• pp.237-245
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• 2018

This study proposes an empirical formulation to predict the maximum deformation of offshore blast wall structure that is subjected to impact loading caused by hydrocarbon explosion. The blast wall model is assumed to be supported by a simply-supported boundary condition and corrugated panel is modelled. In total, 1,620 cases of LS-DYNA simulations were conducted to predict the maximum deformation of blast wall, and they were then used as input data for the development of the empirical formulation by regression analysis. Stainless steel was employed as materials and the strain rate effect was also taken into account. For the development of empirical formulation, a wide range of parametric studies were conducted by considering the main design parameters for corrugated panel, such as geometric properties (corrugation angle, breadth, height and thickness) and load profiles (peak pressure and time). In the case of the blast profile, idealised triangular shape is assumed. It is expected that the obtained empirical formulation will be useful for structural designers to predict maximum deformation of blast wall installed in offshore topside structures in the early design stage.

• Computational Structural Engineering
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• v.9 no.3
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• pp.179-186
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• 1996

A simple nonlinear programming(NLP) formulation for the optimal topology problem of structures is developed and examined. The NLP formulation is general, and can handle arbitrary objective functions and arbitrary stress, displacement constraints under multiple loading conditions. The formulation is based on simultaneous analysis and design approach to avoid stiffness matrix singularity resulting from zero sizing variables. By embedding the equilibrium equations as equality constraints in the nonlinear programming problem, we avoid constructing and factoring a system stiffness matrix, and hence avoid its singularity. The examples demonstrate that the formulation is effective for finding an optimal solution, and shown to be robust under a variety of constraints.

• Biomolecules & Therapeutics
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• v.15 no.2
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• pp.118-122
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• 2007

This study was performed to evaluate the bioequivalency between the Osmetone$^{TM}$ Tablet (Myeongmoon Pharm. Co., Ltd.) as a test formulation and the Relafen$^{TM}$ Tablet (Handok Pharm. Co., Ltd.) as a reference formulation. Twenty-four healthy male volunteers were administered the formulations by the randomized Latin square crossover design, and the plasma samples were determined by a high performance liquid chromatography (HPLC) with Ultra-Violet (UV) detector. AUC$_t$, C$_{max}$ and T$_{max}$ were obtained from the time-plasma concentration curves, and log-transformed AUC$_t$ and C$_{max}$ and log-untransformed T$_{max}$ values for two formulations were compared by statistical tests and analysis of variation. AUC$_t$ was determined to be 897.8${\pm}$431.1 ug.hr/ml for the reference formulation and 902.3${\pm}$408.4 ug.hr/ml for the test formulation. The mean values of C$_{max}$ for the reference and test formulations were 24.2${\pm}$8.9 and 24.0${\pm}$9.5 ug/ml, respectively. The AUC$_t$ and C$_{max}$ ratios of the reference Relafen$^{TM}$ Tablet to the test Osmetone$^{TM}$ Tablet were +5.01% and -0.83%, respectively, showing that the mean differences were satisfied the acceptance criteria within 20%. The results from analysis of variance for logtransformed AUC$_t$ and C$_{max}$ indicated that sequence effects between groups were not exerted and 90% confidence limits of the mean differences for AUC$_t$ and C$_{max}$ were located in ranges from log 0.80 to log 1.25, satisfying the acceptance criteria of the KFDA bioequivalence. The Osmetone$^{TM}$ Tablet as the test formulation was considered to be bioequivalant to the Relafen$^{TM}$ Tablet used as its reference formulation, based on AUC$_t$ and C$_{max}$ values.

• Biomolecules & Therapeutics
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• v.14 no.1
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• pp.50-55
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• 2006

The objective of the study was to evaluate the bioequivalency between the $Rozid^{TM}$ Tablet (Ilhwa Pharm. Co., Ltd.) as a test formulation and the $Rulid^{TM}$ Tablet (Handok Pharm. Co., Ltd) as a reference formulation. Twenty-four healthy male volunteers were administered the formulations by the randomized Latin square crossover design, and the plasma samples were determined by a high performance liquid chromatography (HPLC) with fluorescence detector. $AUC_t,\;C_{max}\;and\;T_{max}$ were obtained from the time-plasma concentration curves, and log-transformed $AUC_t\;and\;C_{max}$ and log-untransformed $T_{max}$ values for two formulations were compared by statistical tests and analysis of variation. $AUC_t$ was determined to be $63.30{\pm}25.57{\mu}g.hr/ml$ for the test formulation and $64.02{\pm}29.27mg.hr/ml$ for the reference formulation. The mean values of $C_{max}$ for the test and reference formulations were $5.07{\pm}2.14\;and\;5.53{\pm}2.60{\mu}g/ml$, respectively. The $AUC_t,\;and\;C_{max}$ ratios of the test $Rozid^{TM}$ Tablet to the reference $Rulid^{TM}$ Tablet were -1.12% and -8.32%, respectively, showing that the mean differences were satisfied the acceptance criteria within 20%. The results from analysis of variance for log-transformed $AUC_t,\;and\;C_{max}$ indicated that sequence effects between groups were not exerted and 90% confidence limits of the mean differences for $AUC_t,\;and\;C_{max}$ were located in ranges from log 0.80 and log 1.25, satisfying the acceptance criteria of the KFDA bioequivalence. The RozidTM Tablet as the test formulation was considered to be bioequivalent to the RulidTM Tablet used as its reference formulation, based on $AUC_t,\;and\;C_{max}$ values.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.2
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• pp.71-78
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• 2018

This paper presents the assembling of multiple patches based on the single patch isogeometric formulation for the shear deformable shell element given in the previous study. The geometrically exact shell formulation has been accomplished with the shell theory based formulation and the generalized curvilinear coordinate system directly derived from the given NURBS geometry. For the knot elements matching across adjacent surfaces, the zero-th and first parametric continuity conditions are considered and the corresponding coupling constraints are implemented by a master-slave formulation between adjacent patches. The constraints are then enforced by a substitution method for condensation of the slave variables, thereby reducing the model size. Through numerical investigations, the important features of the first parametric continuity condition are confirmed. The performance of the multi-patch shell models is also examined comparing the rate of convergence of response coefficients for the zero and first order continuity conditions and continuity in coupling boundary between two patches is confirmed.

• Composites Research
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• v.36 no.2
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• pp.117-125
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• 2023

This paper proposes a new finite element formulation based on enhanced first-order shear deformation theory including the transverse normal strain effect via the mixed formulation (EFSDTM-TN) for the effective thermo-mechanical analysis of laminated composite structures. The main objective of the EFSDTM-TN is to provide an accurate and efficient solution in describing the thermo-mechanical behavior of laminated composite structures by systematically establishing the relationship between two independent fields (displacement and transverse stress fields) via the mixed formulation. Another key feature is to consider the thermal strain effect without additional unknown variables by introducing a refined transverse displacement field. In the finite element formulation, an eight-node isoparametric plate element is newly developed to implement the advantage of the EFSDTM-TN. Numerical solutions for the thermo-mechanical behavior of laminated composite structures are compared with those available in the open literature to demonstrate the numerical performance of the proposed finite element model.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.213-218
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• 1993

F.E.M formulation is carried out in order to determine temperature distribution in the concrete structure. According to this formulation an F.E.M. code is developed, which is capable of silmulating time varying boundary conditions and nonlinear thermal properties.