• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.1
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• pp.57-63
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• 2007

The systematic method to construct equivalent static load from a given dynamic load is proposed in the present study. Previously reported works to construct equivalent static load were based on ad hoc methods. Due to improper selection of loading position, they may results in unreliable structural design. The present study proposes the employment of primary degrees of freedom for imposing the equivalent static loads. The degrees of freedom are selected by two-level condensation scheme with reliability and efficiency. In several numerical examples, the efficiency and reliability of the proposed scheme is verified by comparison displacement for equivalent static loading and dynamic loading at the critical time.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.897-902
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• 2012

The purpose of this study is to determine the possibility of using Crataegi fructus as natural health food source. The research was conducted to determine the biofunctional activities of Crataegi fructus extract. Methanolic extract from Crataegi fructus was partitioned by using organic solvents, including n-hexane, ethyl acetate, n-butanol, and water. Ethyl acetate soluble fraction was shown to have the strongest antioxidant activity ($RC_{50}=4.39{\mu}g/m{\ell}$) among the fractions. In the antimicrobial activity assays, ethyl acetate soluble fraction was effective in bacterial inhibition, against the cases of Escherichia coli and Klebsiella pneumonia, with minimum inhibitory concentrations in $125{\mu}g/m{\ell}$. In the anticomplementary activity assays, water soluble fraction was the most effective exhibiting 18.4% inhibitory activity.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.1
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• pp.16-23
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• 2002

In this paper, we propose the growing and pruning algorithm to design the optimal structure of modular wavelet neural network(MWNN) with F-projection and geometric growing criterion. Geometric growing criterion consists of estimated error criterion considering local error and angle criterion which attempts to assign wavelet function that is nearly orthogonal to all other existing wavelet functions. These criteria provide a methodology which a network designer can construct MWNN according to one's intention. The proposed growing algorithm increases in number of module or the size of modules of MWNN. Also, the pruning algorithm eliminates unnecessary node of module or module from constructed MWNN to overcome the problem due to localized characteristic of wavelet neural network which is used to modules of MWNN. We apply the proposed constructing algorithm of the optimal structure of MWNN to approximation problems of 1-D function and 2-D function, and evaluate the effectiveness of the proposed algorithm.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.12
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• pp.1686-1692
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• 2012

The antioxidative activity of Kalopanax pictus shoots extracted using five different methods, stirrer extraction (SE), ultrasonification extraction (USE), vacuum extraction (VE), reflux extraction (RE), and reflux extraction after ultrasonification extraction (RUE), was evaluated to determine the most effective extraction method. RUE showed the highest yield of extract, and total polyphenol and flavonoid content. Additionally, the RUE extract showed higher antioxidative activity than that of the other extracts based on DPPH and ABTS free radical scavenging (90.85%, 99.83%), reducing power activity (OD 0.95, 700 nm), nitrite scavenging activity (55.46%), and ferrous ion chelating effect (45.12%).

• Journal of Forest and Environmental Science
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• v.22 no.1
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• pp.13-17
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• 2006

Approximately each 5 kg dried Paulownia coreana leaves, seeds, outer barks, inner barks and wood were ground, extracted with acetone-$H_2O$ (7:3. v/v). concentrated under reduced pressure and successively fractionated using n-hexane. $CH_2Cl_2$, EtOAc and $H_2O$ on a separation funnel. Each fraction was then freeze dried and weighed. The extraction yield of each sample was investigated and the yield of inner barks was the highest, while the wood was the lowest. Antioxidative activities of crude extracts, precipitates and partitioned fractions were evaluated by DPPH radical scavenging method. The results indicated that all EtOAc soluble fractions, including some of $H_2O$ soluble fractions, showed significantly high antioxidative potential compared with ${\alpha}$-tocopherol and BHT used as controls.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.1
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• pp.1-8
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• 2005

In this paper, peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) with respect to the subchannel coding schemes for interchannel interference (ICI) self-cancellation is analyzed. It is shown theoretically and experimentally that a shaping component is generated in the transmitted sequence in the conventional correlative coding where a pair of antipodal signals is assigned in adjacent subchannels. Due to the shaping component, the signal powers in the mid and edges of a symbol are scaled by different weighting coefficients, resulting in increased PAPR. To overcome this problem a simple adjacent subchannel coding scheme is presented in this paper. In the new scheme, the shaping component caused by partial repetition of signals is eliminated by assigning a pair of signals in which phase difference varies signal-to-signal. As results, the new scheme has 2-3 dB smaller PAPR than the conventional ICI self-cancellation OFDM while maintaining much higher carrier-to-interference ratio than a normal OFDM system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.1
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• pp.9-13
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• 2009

Flos Sophora japonica L. (Leguminosae), commonly called scholar tree, is a well-known traditional medicine used for the treatment of bleeding and as an antihemorrhagic agent. This research was conducted to determine biofunctional activities of Flos Sophora japonica extract. Methanolic extract from Flos Sophora japonica was partitioned by using organic solvents, including n-hexane, ethyl acetate, n-butanol, and water. Ethyl acetate soluble fraction showed the strongest antioxidant activity ($RC_{50}=3.13{\mu}g/mL$) among the fractions. In antimicrobial activity assays, ethyl acetate soluble fraction was effective to bacterial inhibition, such as Escherichia coli and Klebsiella pneumonia, with minimum inhibitory concentrations in $125{\mu}g/mL$. In anticomplementary activity assays, water soluble fraction was the most effective exhibiting 21% inhibitory activity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.3
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• pp.185-192
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• 1993

A numerical model has been used for the prediction of wave agitations in a harbor which are induced by the intrusion and transformation of incident waves. Based on linear wave theory a mild-slope equation has been used. A partial absorbing boundary condition has been used on solid boundary. Functional has been derived following Chen and Mei(l974)'s technique based on Hybrid Element Method which uses finite discretisation in the inner region and analytical solution of Helmholtz equation in the outer region. Final simultaneous equation has been solved using the Gaussian Elimination Method. Helmholtz natural period and second peak period of seiche in Donghae Harbor coincide very well with the results from numerical calculation. Computed amplification factors show good agreement, especially when the reflection coefficient on solid boundary is 0.99, with those of measurements.

• Journal of the Korean Wood Science and Technology
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• v.34 no.1
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• pp.79-85
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• 2006

Paulownia coreana Uyeki fruits were collected, extracted with acetone-$H_2O$ (7:3, v /v), fractionated with n-hexane, methylene chloride, and ethyl acetate, then freeze dried to give some dark brown powder. The ethyl acetate soluble mixture was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluents. Spectrometric analysis such as NMR and MS including TLC were performed to establish the structures of the isolated compounds. From the ethyl acetate fraction, one phenolic acid (I) and five flavonoids (II~VI) and were isolated and elucidated. The antioxidative activities were tested on the isolated compounds, crude and fractionated extractives by DPPH radical scavenging method. The result showed that caffeic acid, kaempferol, luteolin, quercetin and the EtOAc soluble fraction exhibited higher activities than those of ${\alpha}$-tocopherol and BHT.

• The Korean Journal of Food And Nutrition
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• v.23 no.3
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• pp.299-305
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• 2010

The purpose of this study was to investigate antimicrobial, antioxidant, DPPH radical scavenging and SOD-like activity effect of Jubak(AFC) extract using hot water and ethanol solvent. All extracts from Jubak(AFC) had antimicrobial activities in the Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. Antioxidant activities of the Jubak(AFC) using soybean oil emulsion was confirmed to be higher in the extract using ethanol and hot water than control and the antioxidant was practically effective when concentration of the Jubak was 200 ppm. Scavenging effect of DPPH radical of Jubak extracts showed inhibition effect was above 80%. SOD-like activity were higher in hot water extracts than in ethanol extracts. If keeping up Jubak's study, it could have potential as a cosmetic raw material. Additionally, Jubak could be expected as functional material in food by different extract method.