• Journal of Electrical Engineering and Technology
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• v.4 no.2
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• pp.159-167
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• 2009

This paper presents the Improved Pre-prepared Power Demand (IPPD) table and Muller's method as a means of solving the Profit Based Unit Commitment (PBUC) problem. In a deregulated environment, generation companies (GENCOs) schedule their generators to maximize profits rather than to satisfy power demand. The PBUC problem is solved by the proposed approach in two stages. Initially, information concerning committed units is obtained by the IPPD table and then the subprob-lem of Economic Dispatch (ED) is solved using Muller's method. The proposed approach has been tested on a power system with 3 and 10 generating units. Simulation results of the proposed approach have been compared with existing methods and also with traditional unit commitment. It is observed from the simulation results that the proposed algorithm provides maximum profit with less computational time compared to existing methods.

• The Korean Journal of Applied Statistics
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• v.23 no.5
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• pp.813-822
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• 2010

We investigate a possible achievement in dimension reduction of time series via partially quantified principal component. Partial quantification technique allows us in modeling to accommodate artificial variable(s) of practical importance which is defined subjectively by the data analyst. Suggested procedures are described and in turn illustrated in detail by analyzing monthly unemployment rates in Korea.

• Journal of the Korean Home Economics Association
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• v.43 no.8 s.210
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• pp.25-35
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• 2005

The purpose of the study was to investigate the relationship between parenting stress and, parenting efficacy and on parenting behaviors in mothers with young children. Ed. Note: confirm wording. A total of 222 mothers, each having children aged three to five, participated in the study. The data were analyzed through frequency, percentile, mean, standard deviation, Pearson's correlation, and multiple regression analysis. Results of this study indicate that parenting efficacy and stress were significantly related to parenting behaviors. The relationship between the mother's parenting stress and parenting behaviors was mediated by the mother's parenting efficacy. In conclusion, the mother's parenting efficacy and a perception of parenting stress turn out to be important factors in predicting parenting behaviors.

• Journal of the Korean Ceramic Society
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• v.37 no.12
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• pp.1212-1220
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• 2000

Bi-2223 초전도체계에서 석출물을 flux-pinning center로 이용할 수 있는지 가능성을 타진하기 위하여 $Bi_{1.8}$P $b_{0.4}$S $r_{2}$C $a_{2.2}$C $u_3$ $O_{8}$ 조성을 가진 Bi-2223/Ag 선재를 반응온도, 산소분압, 시간 등을 변화시키면서 열처리를 행하였다. 열처리 후 석출물들은 XRD, SEM, TEM, EDS로 분석하였다. Bi-2223 모상내의 (Ca, Sr)$_2$(Pb,Bi) $O_4$, B $i_{0.5}$ P $b_3$S $r_2$C $a_2$Cu $O_{12+}$$\delta$/ (3221)와 같은 2차상들의 크기와 분포는 2223 입자들의 연결성을 파괴하지 않고 열처리 조건에 의해서 조절할 수 있었다. 서냉 열처리가 된 시편은 임계전류밀도( $J_{c}$)값이 증가하였는데, 이는 2223 입자내 나노미터 크기로 형성된 석출물들이 flux-pinning sites로 작용한 것으로 추정된다.다.

• Archives of Pharmacal Research
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• v.23 no.2
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• pp.151-154
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• 2000

Two sesquiterpene endoperoxides, 1S, 4R, 6R-1, 4-endoperoxy-bisabola-2, 10-diene (1), 1R, 4S, 6R-1, 4-endoperoxy-bisabola-2, 10-diene (II), and a sesquiterpene hydroperoxide, 1$\beta$-hydroperoxygermacra-4 (15), 5, 10 (14)-triene (III) were isolated from the aerial parts of Artemisia stolonifera (Compositae). Their chemical structures were assigned by spectral evidences. Compounds I and II exhibited cytotoxicity against five human tumor cell lines with their $\ED_50 values ranging from 0.20 to 5.43 ${\mu}g/m\ell$ and from <0.1 to 0.87 ${\mu}g/m\ell$, respectively.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.990-994
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• 2007

Bioassay-guided fractionation of the MeOH extract from the sponge Discodermia calyx collected off the coast of Jeju Island, South Korea, led to the isolation of a polyketide, icadamide C (1), along with previously reported theopederin K (3). Structure elucidation was performed by a combination of high resolution mass and 2D-NMR (principally COSY, HMBC, HSQC, and NOESY) spectroscopy. Stereochemistry of compound 1 was determined as 2R*, 3R*, 6R*, 10S*, 11S*, 12R*, 13S*, 15R* and 2'S by NMR data and Marfey analysis. Isolated metabolites displayed potent cytotoxic activity against a small panel of five human solid tumor cell lines with ED50 values of less than 0.1 μg/mL.

• Archives of Pharmacal Research
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• v.24 no.4
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• pp.312-315
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• 2001

Repeated column chromatographic separation of the $CH_{2}Cl_{2}$ extract of Artemisia stolonofera (Asteraceae) led to the isolation of a triterpene (I), a sesquiterpene (II), two aromatic compounds (III and IV) and a benzoquinone (V). Their structures were determined by spectroscopic means to be simiarenol (I), (1S,7S)-1 $\beta$-hydroxygermacra-4(15),5, 10(14)-triene (II), 3'-methoxy-4'-hydroxy-trans-cinnamaldehyde (III), vanillin(IV) and 2,6-dimethoxy-1,4-benzoquinone (V), respectively. Among these products, compound V showed significant cytotoxicity against five human tumor cell lines in vitro, A549 (non small cell lung adenocarcinoma), SK-OV-3 (ovarian), SK-MEL-2 (skin melanoma), XF498 (CNS) and HCT15 (colon) with ED_{50}$ values ranging from 1.33~4.22${\mu}g/ml$.

• Journal of the Korean Society for information Management
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• v.5 no.2
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• pp.53-98
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• 1988

The purpose of this Study is to irwest~gate the Zipfian distribution in Har~gul literature. The result shows that the formulas derived from the liangul Ilterature are it1 accordance with the getlcra\ized Zipf's first law. The result also shows that the formulas derived from the Harlgul literature arc2 not in accordance with the Zlpf's second law and the penerali~ed Zipf's second law.

• Bulletin of the Korean Chemical Society
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• v.27 no.3
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• pp.377-380
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• 2006

The semiconductor PbS nanobelts (width 50-120 nm and length over 3 $\mu$m) were self-assembled in a simple reverse micelle solvent system containig the surfactant of polyoxyethylene (9) dodecy ether $(C_{12}E_9)$. The nanobelts synthesized were found to possess cube galena poly-crystal structure with high purity when analyzed by ED and X-ray diffraction. Significant “blue shift” from bulk material was observed on the PbS nanobelts using photoluminescence and UV-Vis spectroscopy. A mechanism involving the possible formation of nanobelts based on surfactant template was also proposed.

• Archives of Pharmacal Research
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• v.20 no.4
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• pp.368-371
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• 1997

In an effort to increase of the antitumor activity of 2(S)-$2^{I}$,$5^{I}$-trihydroxy-7, 8-dimethoxyflavanone isolated from Scutellaria indica, we synthesized its analogues, II, III and IV. They showed potent cytotoxicity in vitro against cancer cell lines, L1210, K562 and A549. On the basis of $ED_50$ values against the cancer cell lines, III exhibited about 2-7 times stronger activity than I against various cell lines. We tested the antitumor activity of the analogues against Sarcoma 180 cells in vivo and evaluated the structure-activity relationship. The antitumor activity appeared to be related to the hydrogen bond between carbonyl group at C-4 and hydroxyl group at C-5, in contrast to cytotoxic action.