• East Asian mathematical journal
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• v.39 no.1
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• pp.65-73
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• 2023

In this paper, we present an optimal control strategy to prevent the EMT process by downregulating the level of overexpressed β-catenin in the cytoplasm. To do this, we propose a mathematical model that expresses relationship between the Wnt signaling pathway and TGF-β in cancer cells. We also define an optimal control problem considering the side effects that occur simultaneously with the method for controlling the concentration of β-catenin. Finally numerical simulations show that treatment effect is quantitatively changes depending on the concentration of core proteins of the Wnt signaling pathway.

• The Korean Journal of Mycology
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• v.20 no.1
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• pp.58-64
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• 1992

This research was focused on investigation of the general condition for protoplast formation of Trichoderma speues. for protoplast formation, the mycelia cultured in YM medium were collected from each growth phase and were treated with the Iytic enzymes. This procedure was carried out by all strains. The most optimal conditions of NOVOZYM 234 and DRISELASE were determined by T. saturnisporum IAM 12535 and T. longibruchiatum IBM 13107, respectively. The effect of osmotic stabilizers appeared ${KCI}>(NH_4)_2{SO_4}>NaCl>mannitol>{MgSO}_4$ and the optimal concentration of each osmotic stabilizer wns determined by 0.6-0.9 M. The optimal condition of DRISELASE for protoplast formation ; optimal pH 5.0, optimal concentration, 2%, optimal reaction time, 4 hours, and optimal temperature, $30^{\circ}C$. The optimal condition of NOVOZYM 234 for protoplast formation ; optimal pH 5.5, optimal concentration 1%, optimal reaction time 3 hours, and optimal temperature $30^{\circ}C$. The optimal culture period of mycelia for protoplast formation was between the initial and the middle exponential phase. Generally, DUSELASE was more effective than NOVOZYM 234 on protoplast formation except for T. longibruchiatum IAM 13107 and T. viride IAM 5141.

• Journal of Korean Society on Water Environment
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• v.21 no.3
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• pp.263-266
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• 2005

Comparison between photocatalysis (UV+$TiO_2$) and sonophotocatalysis (Sonication+UV+$TiO_2$) were performed in lab-scale experiments for the treatment of chloroform. The effect of operational parameters, i.e., initial chloroform concentration, $TiO_2$ concentration, UV light intensity and sonication time on the degradation rate of aqueous solution of chloroform has been examined. The optimal conditions for photocatalysis and sonophotocatalysis processes were determined: initial chloroform concentration was 25 mg/L, the concentration of $TiO_2$ was 200 mg/L and UV light intensity was $6.630 mW/cm^2$, respectively. The optimal sonication time on sonophotocatalysis process was 90 min. Under the optimal conditions, sonophotocatalysis was effective for inducing faster degradation of the chloroform.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.137-145
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• 2005

The present research deals with structural analysis and optimal design of the heating drum of a hot-rolling press for medium density fiberboard. Stress concentration in the journal of the heating drum is analyzed by the submodel technique of the finite element method. The fatigue life under operating conditions is analyzed and evaluated by the stress-life theory. Shape optimal design problems, to minimize the maximum stress occurring in the journal, are formulated and shape parameters of the corner fillets of the journal are defined as the design variables. The problems are solved by the numerical optimization method and optimal shapes are found. The optimal designs are shown to be reliable in terms of the maximum stress and the fatigue life.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.312-317
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• 2005

Electric Multiple Unit is one of the major mass public transportation systems and passengers are under the influence of indoor air quality such as air temperature, relative humidity and concentration of CO2 gas. Therefore ventilation system of Electric Multiple Unit should be designed for both healthy and comfortable environments. We survey the optimal ventilation rate and the permissible CO2 concentration in the saloon with the consideration of the cooling and heating capacity and fresh air induced from tunnel.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.13 no.1
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• pp.7-14
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• 1987

Production of shikonin derivatives through cell suspension culture of Lithospermum erythrorhizon was investigated. Optimal concentrations of IAA and kinetin on the growth of cell suspension were 0.2 and 0.1 ppm respectively. Pigment content was markedly increased when aluminum oxide was added to the production medium and its optimal concentration was 1.5g/70ml medium. The most effective concentration of IAA was 0.5 ppm and the production of pigment did not depend on the kinetin concentration.

• Korean Journal of Medicinal Crop Science
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• v.24 no.4
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• pp.263-270
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• 2016

Background: In this study, microwave extraction was used, which is an effective method to extract useful bioactive substances as it requires low quantities of solvent and short time periods. The aim of this study was to determine the optimal extraction conditions for Agrimonia pilosa Ledeb. Methods and Results: The independent variables were ethanol concentration, microwave power, and extraction time, each of which had five levels. The dependent variables were total polyphenol and total flavonoid content, and DPPH radical scavenging activity. To determine the optimal extraction conditions for bioactive compounds, a response surface methodology was employed. Contour maps were generated from polynomial equations. The optimal conditions were then assumed by superimposing these contour maps. Based on the resulting graph, the optimal microwave extraction conditions for Agrimonia pilosa Ledeb were determined as 42 - 48% ethanol concentration, 240 - 280W microwave power, and 13 - 20 min of extraction time. Conclusions: Ethanol concentration had a significant effect on microwave extraction, in terms of total polyphenol and total flavonoid content, as well as DPPH radical scavenging activity. Microwave power and extraction time influenced the total polyphenol content, but not the total flavonoid content or the DPPH radical scavenging activity.

• Journal of Korean Society on Water Environment
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• v.22 no.4
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• pp.585-589
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• 2006

Comparison between photocatalysis and sonophotocatalysis were performed in lab-scale experiments for the treatment of benomyl. The effect of operational parameters, i.e., initial benomyl concentration, $TiO_2$ concentration, $H_2O_2$ concentration on the degradation rate of aqueous solution of benomyl has been examined. The optimal conditions for photocatalysis and sonophotocatalysis processes were determined: initial Benomyl concentration was 3 mg/L, the concentration of $TiO_2$ was 2 g/L and $H_2O_2$concentration was 1.5 mM. Under the optimal conditions, sonophotocatalysis was effective for inducing faster degradation of the benomyl.

• The Korean Journal of Mycology
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• v.29 no.1
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• pp.52-60
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• 2001

This study was carried out to obtain the basic data on artificial culture of Hohenbuehelia petaloides. The optimum medium are glucose peptone medium (GP), Hennerberg medium, Phellinus igniarius medium (PIM), Lentinus edodes medium (LEM), Czapek dox medium. The optimum condition for the mycelial growth was $30^{\circ}C$ and pH 6.0. The carbon sources such as dextrine, fructose and lactose were favorable to mycelial growth. The optimal concentrations of carbon sources are 10% dextrin and fructose. As nitrogen sources, tryptone, casamino acid and histidine appeared to be favorable. The optimal concentrations of nitrogen sources are 1% soy tone and 0.3% ammonium nitrate. The optimal concentration of yeast extract is 0.4%. The mineral nutrients of $KH_2PO_4$, $K_2HPO_4\;and\;MgSO_4{\cdot}7H_2O$ were effective and the optimal concentrations were 0.046, 0.1 and 0.05%, respectively.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.3
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• pp.707-715
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• 1994

This study presents thickness optimization for the pressure vessel domes subject to internal pressure and axial force simultaneously. The considered typical pressure vessel domes are ellipsoidal and tori-spherical domes with skirt and nozzle part. These pressure vessel domes under loading have higher stress concentration on geometric discontinuity parts. Therefore, thickness optimization of axi-symmetric pressure vessel domes is essentially concerned on minimizing this stress concentration. The objective function is minimization of weight of pressure vessel dome. The design variable is thickness of dome and cylinder. Considered constraint is Von Mises equivalent stress. In the optimization procedure, ANSYS code is used. The equivalent and hoop stress of original shape domes are compared with those of optimal shape domes. And optimal thicknesses for pressure vessel domes are presented.