• Title/Summary/Keyword: S.S. Chern

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INVARIANT MEASURE AND THE EULER CHARACTERISTIC OF PROJECTIVELY ELAT MANIFOLDS

  • Jo, Kyeong-Hee;Kim, Hyuk
    • Journal of the Korean Mathematical Society
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    • v.40 no.1
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    • pp.109-128
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    • 2003
  • In this paper, we show that the Euler characteristic of an even dimensional closed projectively flat manifold is equal to the total measure which is induced from a probability Borel measure on RP$^{n}$ invariant under the holonomy action, and then discuss its consequences and applications. As an application, we show that the Chen's conjecture is true for a closed affinely flat manifold whose holonomy group action permits an invariant probability Borel measure on RP$^{n}$ ; that is, such a closed affinly flat manifold has a vanishing Euler characteristic.

A Web Service Discovery based Approach to Adaptive Software (적응형 소프트웨어에 대한 웹 서비스 발견 기반 기법)

  • Kim Jin-Han;Lee Chang-Ho;Lee Kwang-Woo;Lee Byung-Jeong;Kim Hee-Chern
    • Proceedings of the Korean Information Science Society Conference
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    • 2006.06c
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    • pp.175-177
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    • 2006
  • 소프트웨어는 많은 상황을 염두에 두고 만들어진다. 하지만 모든 문제를 해결하도록 만들 수는 없기 때문에 문제가 발생했을 때 그 문제를 해결할 수 있도록 적응성을 두어야 한다. 본 논문에서 제시하는 아키텍처는 WSAS, 컴포넌트 변환, 적응성을 위한 부분으로 구성된다. WSAS는 기존의 UDDI를 변경하지 않고 확장된 검색을 지원하는 서비스이다. 그리고 컴포넌트 서비스를 위한 컴포넌트 저장소를 제공한다. 변환 아키텍처는 검색된 서비스를 통해 컴포넌트를 변환하고 변환된 컴포넌트는 적응형 아키텍처에서 재구성을 통해 문제를 해결한다. 본 논문에서는 컴포넌트 기반의 아키텍처에 적응성을 위해 개선된 웹 서비스 발견 기법을 제안한다.

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Absence of an Essential Thiol in Human Glutaminyl Cyclase: Implications for Mechanism

  • Temple, Jeffrey S.;Song, In-Seok;Burns, Kathleen H.;Bateman, Robert C.
    • Animal cells and systems
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    • v.2 no.2
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    • pp.243-248
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    • 1998
  • We have partially sequenced glutaminyl cyclases from several mammalian and one avian species and found that the two cysteine residues of the human glutaminyl cyclase are completely conserved. The mammalian glutaminyl cyclase has been reported to possess reactive thiols (Busby, Jr, et aI., 1987, J BioI Chern 262, 8532-8536). Mutagenesis of these cysteine residues, however, resulted in only a slight decrease in enzyme activity. Likewise, the recombinant human enzyme was completely resistant to attempted chemical modification of the putative reactive thiols. Although the human glutaminyl cyclase did not appear to have reactive thiols, it was sensitive to diethylpyrocarbonate and acetylimidazole, indicating the presence of functionally important histidine and tyrosine residues which could act as acid/base catalysts. Almost identical deuterium solvent isotope effect (1.2 vs 1.3) upon the reaction by the human and papaya enzymes, respectively, provides an evidence both animal and plant glutaminyl cyclases catalyze pyroglutamyl-peptide formation by intramolecular cyclization.

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SIX DIMENSIONAL ALMOST COMPLEX TORUS MANIFOLDS WITH EULER NUMBER SIX

  • Donghoon Jang;Jiyun Park
    • Bulletin of the Korean Mathematical Society
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    • v.61 no.2
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    • pp.557-584
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    • 2024
  • An almost complex torus manifold is a 2n-dimensional compact connected almost complex manifold equipped with an effective action of a real n-dimensional torus Tn ≃ (S1)n that has fixed points. For an almost complex torus manifold, there is a labeled directed graph which contains information on weights at the fixed points and isotropy spheres. Let M be a 6-dimensional almost complex torus manifold with Euler number 6. We show that two types of graphs occur for M, and for each type of graph we construct such a manifold M, proving the existence. Using the graphs, we determine the Chern numbers and the Hirzebruch χy-genus of M.

ON A GENERALIZATION OF HIRZEBRUCH'S THEOREM TO BOTT TOWERS

  • Kim, Jin Hong
    • Journal of the Korean Mathematical Society
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    • v.53 no.2
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    • pp.331-346
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    • 2016
  • The primary aim of this paper is to generalize a theorem of Hirzebruch for the complex 2-dimensional Bott manifolds, usually called Hirzebruch surfaces, to more general Bott towers of height n. To do so, we first show that all complex vector bundles of rank 2 over a Bott manifold are classified by their total Chern classes. As a consequence, in this paper we show that two Bott manifolds $B_n({\alpha}_1,{\ldots},{\alpha}_{n-1},{\alpha}_n)$ and $B_n({\alpha}_1,{\ldots},{\alpha}_{n-1},{\alpha}_n^{\prime})$ are isomorphic to each other, as Bott towers if and only if both ${\alpha}_n{\equiv}{\alpha}_n^{\prime}$ mod 2 and ${\alpha}_n^2=({\alpha}_n^{\prime})^2$ hold in the cohomology ring of $B_{n-1}({\alpha}_1,{\ldots},{\alpha}_{n-1})$ over integer coefficients. This result will complete a circle of ideas initiated in [11] by Ishida. We also give some partial affirmative remarks toward the assertion that under certain condition our main result still holds to be true for two Bott manifolds just diffeomorphic, but not necessarily isomorphic, to each other.

Antimicrobial activity of eight root canal sealers before and after setting (8종 root canal sealers의 경화 전, 후의 항균효과에 관한 연구)

  • Fang, Denny Y.;Lee, Woo-Cheol;Lai, Chern H.
    • Restorative Dentistry and Endodontics
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    • v.27 no.2
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    • pp.207-211
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    • 2002
  • 항균 활성도는 Root canal sealer가 갖추어야 할 필수요소 중 하나이다. 본 연구는 최근 임상술식에 사용되고 있는 8종의 root canal sealer의 근관내 혐기성 세균에 대한 항균효과를 알아보기 위해 시행되었다. 또한 본 연구에서는 혼합직후의 경화되지 않은 sealer와 경화 7일 후 sealer의 항균효과도 비교하였다. 항균효과 측정을 위해 사용된 균주는 최근 실패한 근관치료 증례에서 배양되어 보고된 바 있는 Enterococcus faecalis와 근관내 주요 감염균인 그램음성 혐기성세균인 Staphylococcus aureus를 대상으로 하였고, Agar diffusion test 방법을 사용하였다. 실험방법으로는 2개의 paper disk에 신선하게 혼합한 각각의 sealer를 도포하여 한개의 disk는 즉시 실험에 사용하고 다른 한개의 disk는 일주일간 혐기성 배양기에서 경화시킨 다음 사용한다 각각의 균주를 Brucellar blood agar plate에 접종한 다음, sealer가 도포된 paper disk를 plate상에 올려놓는다. 대조군으로는 식염수에 침윤시킨 disc를 같은 방법으로 각 실험단계에 사용한다. 각 plate를 혐기성 배양기에서 48시간동안 배양한 뒤 실험에 사용한 sealer의 항균효과를 6mm paper-disk를 둘러싼 inhibition zone을 측정하여 평가한다. Fisher's PLSD분석방법 결과 E. faecalis에 대하여 경화 전과 후의 AH26모두 경화 전과 후의 Roth 801, Dentalis, Apexit, AH Plus, RSA그리고 경화 후의 MCS보다 유의성 있게 강한 항균효과를 나타내는 것으로 보고되었으며. 경화 후의 AH26은 경화 전의 AH 26, 경화 전의 Ketac Endo, 경화 전의 MCS보다 통계학적으로 유의성이 있는 항균작용을 하는 것이 관찰되었다 (p<0.05). 경화 후 Roth 801, 경화전과 후의 Dentalis, AH plus, Apexit, RSA는 E. faecalis에 대한 항균효과를 나타내지 못하였다. S. aureus에 대하여 경화후의 AH26이 경화 전과 후의 Roth 801, Apexit, AH Plus, RSA보다 유의성있는 항균효과를 보이는 것을 발견 할 수 있었고, 경화 전의 AH 26이 경화 후의 AH plus보다 나은 항균효과를 나타냄을 알 수 있었다. 또, 경화 전과 후의 Apexit, 경화 후의 AH Plus, 경화 전과 후의 RSA에서는 S. aureus에 대한 항균작용이 발견되지 않았다. 본 실험의 결과 AH26이 가장 강한 항균 작용을 갖는 것을 알 수 있었으며, 각 sealer의 경화 전과 후의 항균효과는 AH26이 경화 전보다 경화 후에서 더 강한 항균효과를 나타내는 것 이외에는 효과의 차이가 없었다.

FORMOSAT-2'S EFFECTIVENESS TO TAIWAN'S PUBLIC EDUCATION

  • Chern, Jeng-Shing;Wu, Lance;Liou, Yuei-An
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.959-962
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    • 2006
  • Public education is undoubtedly a very important aspect for a country to develop space program. People have the rights to understand how the tax they paid is being used. This paper addresses the effectiveness of FORMOSAT-2 on public education in Taiwan. As the first remote sensing satellite of the National Space Organization (NSPO) of Taiwan, FORMOSAT-2 is a small satellite of 746 kg mass for two remote sensing missions: Earth and upward lightning observations. The mission orbit is sun-synchronous of 888 km altitude for exactly 14 revolutions per day. For earth observation, the payload is an advanced high resolution remote sensing instrument (RSI) with ground sampling distance (GSD) 2 m in panchromatic (PAN) band and 8 m in four multi-spectral (MS) bands. For upward lightning observation, the payload is an imager of sprites and upper atmospheric lightning (ISUAL). After more than two years of Earth observation started in June 2004, the effectiveness of FORMOSAT-2 images on public education in Taiwan is very promised. Five domestic universities and one private company in Taiwan have signed contracts respectively with NSPO to take the roles of satellite image investigator and distributor. A private company has signed contract with NSPO to generate and provide URMAP (= your map) in its website for general public applications by using FORMOSAT-2 images. The Newtonkids Book Company used FORMOSAT-2 images to publish a kind of calendar for children education purpose. Besides, a science team in National Cheng Kung University (NCKU) is doing the research work on the 3820 (up to 30 June 2006) transient luminous events (TLEs) observed by FORMOSAT-2.

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The Effect of Nutrition Knowledge and Attitudes on fat Consumption Using 1989/1991 Continuing Survey of Food Intakes by Individuals/Diet and Health Knowledge Survey(CSFII/DHKS)

  • Park, sunmin;S, Chern-Wen
    • Journal of Nutrition and Health
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    • v.30 no.4
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    • pp.434-441
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    • 1997
  • Fat consumption has decreased since the 1950's in the United States, and coronary heart disease mortality rates have gradually declined as well. These changes might be associated with changes of attitudes due to increased information about the relationship between fat consumption and hear disease. The purpose of this study was to determine whether knowledge and attitudes concerning fat and foods high or low in fat had an impact on peoples' actual fat consumption. for this study, the data of fat consumption and knowledge/attitudes of people came from the 1989-1991 Continuing Survey of food Intakes by Individuals/Diet and Health Knowledge Survey (CSFII/DHKS), conducted by USDA. It was found that women 65 years ed older tried to avoid more fat and consume more vegetables than those aged 25-64 years ; in fact, the actual fit consumption of those over 65 years was lowest among all age categories. However, the elderly did not have as much nutrition knowledge as people aged 25-64 years. Attitudes concerning vegetables and health were a better predictor of fat consumption than those concerning fat itself. However, low-fat milk consumption was influenced by nutrition knowledge as well as attitudes about fat intake people with better knowledge and attitudes concerning fat intake consumed more low-fat milk. This could be resulted from the reason that low-fat milk is a good substitute for whole milk. The conclusion of this study is that there are two essential elements in healthy eating patterns: a) good attitudes towards fat and vegetable consumption, and b) correct nutritional knowledge concerning the fat-content of foods and the availability of alternatives.

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Eine Studie $\"{u}ber$ zweisprachige Verbvalenzlexika (이중언어 동사 결합가 사전에 관한 연구)

  • Rhie Jum-Chool
    • Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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    • v.1
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    • pp.11-39
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    • 1999
  • Das Ziel dieses Aufsatzes liegt darin, $da\ss$ wir eine Unterlage $f\"{u}r$ die Erarbeitung des kunftigen vergleichenden deutsch-koreanischen Verbvalenzlexikons bereitstellen, indem wir zweisprachige Valenz-lexika vergleichen, bei denen die Muttersprache der Lemenden als Ausgangssprache und die deutsche Sparche als Zielsprache fungieren, und ein neues Valenzmodell mit dem Verb 'kaufen 팔다' aufzeigen. Als Ergebnis dieser Arbeit $k\"{o}nnen$ wir feststellen, $da\ss$ die Entwicklung der kontrastiven Valenzlexikographie vom register-ahnlichen Lexikon hin zum benutzerfreundlichen $W\"{o}rterbuch$ $verl\"{a}uft$. Und ferner ist die Tendenz ansteigend, zweisprachige Versionen aus den einsprachigen $W\"{o}rterb\"{u}chern$ des Deutschen zu entwickeln, denn die kontrastiven $W\"{o}rterb\"{u}cher$ kommen den praktischen $Bed\"{u}rfnissen$ des Fremdsprachenunterrichts $f\"{u}r\;Anf\"{a}nger$ mehr entgegen als die einsprachigen. Die Valenzlexika sollten $prim\"{a}r$ dem Deutsch Lernenden helfen, seinen Wortschatz zu erweitern und korrekte $S\"{a}tze$ zu bilden, sollten jedoch nicht unmittelbares Selbststudienmaterial, sondern Nachschlagewerke sein. Die neuere Entwicklung in der Valenzlexikographie $f\"{u}hrt$ hin zum didaktisch orientierten $W\"{o}rterbuch$, in dem die $Valenzeintr\"{a}ge$ neben anderen syntaktischen und semantischen Informationen stehen. $F\"{u}r$ Studenten im Grundstudium sind $W\"{o}rterb\"{u}cher$ in der Fremdsprache zu schwierig. Bei der zweisprachigen Version erleichtern die $Valenzeintr\"{a}ge$ In der Muttersprache den Studierenden den Umgang mit dem $Lernw\"{o}rterbuch$. In Zukunft $k\"{o}nnen\;Valenzw\"{o}rterb\"{u}cher$ als wichtige Hilfsmittel im Fremd­sprachenunterricht noch an Bedeutung gewinnen. Ein $Valenzw\"{o}rterbuch$ ist vor allem ein $Produktionsw\"{o}rterbuch,\;denn\;es\;enth\"{a}lt$ syntaktisch-semantische Informationen und $Beispiels\"{a}tze$, die bei der Produktion korrekter Strukturen helfen. Das $Valenzw\"{o}rterbuch$ soll ein Nachschlagewerk, ein $Lernw\"{o}rter-buch$ zur weiteren Erforschung der syntaktish-semantischen Eigenschaften der deutschen Verben sein. Diese Untersuchung $\"{u}ber$ zweisprachige Verbvalenzlexika $k\"{o}nnte\;zur\;k\"{u}nfigen$ Erarbeitung des deutsch-koreanischen kontrastiven Verbvalenzlexikons beitragen.

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Polarity affects the antioxidant and antimicrobial activities of jellyfish (Acromitus hardenbergi) extracts

  • Khong, Nicholas M.H.;Foo, Su Chern;Yau, Sook Kun;Chan, Kim Wei;Yusoff, Fatimah Md.
    • Fisheries and Aquatic Sciences
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    • v.25 no.4
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    • pp.189-201
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    • 2022
  • Jellyfish is an emerging aquaculture species, farmed for Oriental cuisines and nutraceutical ingredients. This study aimed to examine antioxidative and antimicrobial potentials of various fractions of the jellyfish, Acromitus hardenbergi. The bell and oral arms of the jellyfish were sequentially extracted with petroleum ether (PE), dichloromethane (DCM), chloroform (CHCl3), methanol (MeOH), and water (H2O) to extract its bioactive in an increasing polarity gradient. Test fractions were assayed for antiradical activities using electron spin resonance spectrometry, β-carotene-linoleate model and Folin-Ciocalteu assay; and antimicrobial activity against 2 Gram-negative bacteria, 4 Gram-positive bacteria and 2 fungal species using the disc diffusion assay. All fractions were also subjected to Fourier Transform Infrared (FTIR) analysis to identify types of functional groups present. It was found that the hydrophilic extracts (H2O fractions) possessed the most effective radical scavenging activity (p < 0.05) while the lipophilic extracts (PE fractions) the most active antimicrobial activity, especially against Gram-positive bacteria (p < 0.05). Total oxidation substrates content was found to be highest in the PE fractions of jellyfish bell and oral arms (p < 0.05). FTIR data showed that the H2O and MeOH fractions contains similar functional groups including -OH, -C=O, -N-H and -S=O groups, while the PE, DCM, and CHCl3 fractions, the -CH3, -COOH groups. This study showed that A. hardenbergi contains antioxidants and antimicrobials, thereby supporting the traditional claim of the jellyfish as an anti-aging and health-promoting functional food. Bioassay-guided fractionation approach serves as a critical milestone for the strategic screening, purification, and elucidation of therapeutically significant actives from jellyfish.