• Phonetics and Speech Sciences
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• v.2 no.2
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• pp.51-60
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• 2010

This study is to examine how Korean speakers realize English stress on the homographic words. Experiments were performed by Korean speakers three times, before stress instruction, immediately after instruction, and six weeks after instruction. First, duration, fundamental frequency, and intensity of the vowel in a stressed syllable of three homographic words produced by Korean speakers were compared with those of native speakers of English. The result shows that when the words were used as nouns, before instruction Korean speakers had shorter duration and lower fundamental frequency in the stressed vowel than the native speakers, which indicates that Korean speakers did not assign the primary stress on the first syllable of the nouns. After instruction, the values of duration and fundamental frequency were increased and the differences between two groups were decreased. Next, the values of these stress features measured three times were analyzed in order to find out how they changed through instruction. The analysis shows that after instruction the values of three features were increased compared to the ones before instruction, and that the biggest change was in duration of the vowel and the next was fundamental frequency. Six weeks after instruction, the values of duration and intensity were decreased than those immediately after instruction. This means that instruction is helpful for Korean speakers to assign the stress for the English homographic words, and that instruction and practice are needed repeatedly.

• Communications of the Korean Mathematical Society
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• v.11 no.2
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• pp.391-405
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• 1996

In this article, we calculate the cohomology groups of flat vector bundles on some manifolds.

• Speech Sciences
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• v.15 no.4
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• pp.147-157
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• 2008

Habitual speaking fundamental frequency (sF0) plays an important role in determining the voice classification, which can be presented differently depending on the vocal fold length and language habits. The purpose of this study, therefore, was to compare the differences in sF0 for voice classification and closed quotient between speaking and singing. Seventeen singers (7 sopranos, 5 tenors, 5 baritones, mean age 25.1 years) with no evidence of vocal folds pathology were participated. sF0 and closed quotient (CQ) both in speaking and in singing (A3-A5 with soprano, A2-A4 with tenor and baritone) were measured using SPEAD program and electroglottography. No significant differences were observed for sF0 between tenor and baritone groups (p> 0.05). However, CQ in singing was significantly different among three groups (p< 0.05), but CQ in speaking was not (p> 0.05). Furthermore, CQ was significantly different with both soprano (p< 0.01) and tenor groups ((P= 0.02) whereas baritone group revealed there is no difference when compared between speaking and singing. No significant differences in sF0 between tenor and baritone participants may result from decision-making for voice classification by experience and should measure sF0 before determining the voice classification.

• Journal of applied mathematics & informatics
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• v.39 no.5_6
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• pp.769-783
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• 2021

Demirci ((1999) Vague groups. J. Math. Anal. Appl. 230, 142-156) introduced the concept of vague groups as one of uncertain reasoning structures where indistinguishable operators separate points. In this paper, we consider vague groups in which an indistinguishable operator does not need to separate points because it seems more appropriate to handle ambiguous situations. For our purposes we generalize or redefine some notions such as: vague closed subset, vague subgroup, vague kernel and vague injectiveness. Consequently we generalize most of the known results and obtain some new additional fundamental properties of vague groups, some of which are similar to ones of ordinary groups.

• Journal of the Korean Mathematical Society
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• v.33 no.4
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• pp.1047-1067
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• 1996

In this paper, we are interested in left invariant flat affine structures on Lie groups. These structures has been studied by many authors in different contexts. One of the fundamental questions is the existence of complete affine structures for solvable Lie groups G, raised by Minor [15]. But recently Benoist answered negatively even for the nilpotent case [1]. Also moduli space of such structures for lower dimensional cases has been studied by several authors, sometimes with compatible metrics [5,10,4,12].

• Bulletin of the Korean Mathematical Society
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• v.26 no.1
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• pp.1-9
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• 1989

In 1980 and 1983, it was proved that P $D^{2}$-groups are surface groups ([2], [3]). Since then, topologists have been positively studying about P $D^{n}$ -groups (or $D^{n}$ -groups). For example, let a topological space X have a right .pi.-action, where .pi. is a multiplicative group. If each x.memX has an open neighborhood U such that for each u.mem..pi., u.neq.1, U.cap. $U_{u}$ =.phi., this right .pi.-action is said to be proper. In this case, if X/.pi. is compact then (1) .pi.$_{1}$(X/.pi).iden..pi.(X:connected, .pi.$_{1}$: fundamental group) ([4]), (2) if X is a differentiable orientable manifold with demension n and .rho.X (the boundary of X)=.phi. then $H^{k}$ (X;Z).iden. $H_{n-k}$(X;Z), ([6]), where Z is the set of all integers.s.

• Honam Mathematical Journal
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• v.36 no.3
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• pp.695-706
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• 2014

Various properties of digital covering spaces have been substantially used in studying digital homotopic properties of digital images. In particular, these are so related to the study of a digital fundamental group, a classification of digital images, an automorphism group of a digital covering space and so forth. The goal of the present paper, as a survey article, to speak out utility of digital covering theory. Besides, the present paper recalls that the papers [1, 4, 30] took their own approaches into the study of a digital fundamental group. For instance, they consider the digital fundamental group of the special digital image (X, 4), where X := $SC^{2,8}_4$ which is a simple closed 4-curve with eight elements in $Z^2$, as a group which is isomorphic to an infinite cyclic group such as (Z, +). In spite of this approach, they could not propose any digital topological tools to get the result. Namely, the papers [4, 30] consider a simple closed 4 or 8-curve to be a kind of simple closed curve from the viewpoint of a Hausdorff topological structure, i.e. a continuous analogue induced by an algebraic topological approach. However, in digital topology we need to develop a digital topological tool to calculate a digital fundamental group of a given digital space. Finally, the paper [9] firstly developed the notion of a digital covering space and further, the advanced and simplified version was proposed in [21]. Thus the present paper refers the history and the process of calculating a digital fundamental group by using various tools and some utilities of digital covering spaces. Furthermore, we deal with some parts of the preprint [11] which were not published in a journal (see Theorems 4.3 and 4.4). Finally, the paper suggests an efficient process of the calculation of digital fundamental groups of digital images.

• Journal of Microbiology and Biotechnology
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• v.31 no.4
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• pp.510-519
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• 2021

The pathological impact of haze upon the phyllosphere microbiota awaits investigation. A moderate degree of haze environment and a clean control were selected in Chengdu, China. Artemisia argyi, a ubiquitously distributed and extensively applied Chinese herb, was also chosen for experiment. Total genome DNA was extracted from leaf samples, and for metagenome sequencing, an Illumina HiSeq 2500 platform was applied. The results showed that the gene numbers of phyllosphere microbiota derived from haze leaves were lower than those of the clean control. The phyllosphere microbiota derived from both haze and clean groups shared the same top ten phyla; the abundances of Proteobacteria, Actinomycetes and Anorthococcuso of the haze group were substantially increased, while Ascomycetes and Basidiomycetes decreased. At the genus level, the abundances of Nocardia, Paracoccus, Marmoricola and Knoelia from haze leaves were markedly increased, while the yeasts were statistically decreased. KEGG retrieval demonstrated that the functional genes were most annotated to metabolism. An interesting find of this work is that the phyllosphere microbiota responsible for the synthesis of primary and secondary metabolites in A. argyi were significantly increased under a haze environment. Relatively enriched genes annotated by eggNOG belong to replication, recombination and repair, and genes classified into the glycoside hydrolase and glycosyltransferase enzymes were significantly increased. In summary, we found that both structure and function of phyllosphere microbiota are globally impacted by haze, while primary and secondary metabolites responsible for haze tolerance were considerably increased. These results suggest an adaptive strategy of plants for tolerating and confronting haze damage.

• Journal of the Korean Mathematical Society
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• v.32 no.3
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• pp.563-571
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• 1995

The recent work of Hopkins, Kuhn and Ravenel [H-K-R] indicates the Morava K-theory, $K(n)^*(-)$, occupy an important and fundamental place in homology theory. In particular $K(n)^*(BG)$ for classifying spaces of finite groups are studied by many authors [H-K-R], [R], [T-Y 1, 2] and [Hu].

• Korean Journal of Mathematics
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• v.29 no.3
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• pp.603-612
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• 2021

We generalize 3-manifolds supporting non-positively curved metric to construct manifolds which have the following properties : (1) They are not locally CAT(0). (2) Their fundamental groups are residually finite. (3) They have subgroup separability for some abelian subgroups.