• East Asian mathematical journal
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• v.29 no.3
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• pp.337-347
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• 2013

For an even integer m at least 4 and any positive integer $t$, it is shown that the complete equipartite graph $K_{km(2t)}$ can be decomposed into edge-disjoint gregarious m-cycles for any positive integer ${\kappa}$ under the condition satisfying ${\frac{{(m-1)}^2+3}{4m}}$ < ${\kappa}$. Here it will be called a gregarious cycle if the cycle has at most one vertex from each partite set.

• East Asian mathematical journal
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• v.33 no.1
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• pp.67-74
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• 2017

Let k, m and t be positive integers with $m{\geq}4$ and even. It is shown that $K_{km+1(2t)}$ has a decomposition into gregarious m-cycles. Also, it is shown that $K_{km(2t)}$ has a decomposition into gregarious m-cycles if ${\frac{(m-1)^2+3}{4m}}$ < k. In this article, we make a remark that the decompositions can be circulant in the sense that it is preserved by the cyclic permutation of the partite sets, and we will exhibit it by examples.

• East Asian mathematical journal
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• v.30 no.3
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• pp.311-319
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• 2014

It is shown that, for an even positive integer m with $m{\geq}4$ and arbitrary positive integer k and t, the complete multipartite graph $K_{km+1(2t)}$ can be decomposed into edge-disjoint gregarious m-cycles in such a way that the decomposition is circulant.

• Bulletin of the Korean Mathematical Society
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• v.44 no.4
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• pp.709-719
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• 2007

In [8], it is shown that the complete multipartite graph $K_{n(2t)}$ having n partite sets of size 2t, where $n{\geq}6\;and\;t{\geq}1$, has a decomposition into gregarious 6-cycles if $n{\equiv}0,1,3$ or 4 (mod 6). Here, a cycle is called gregarious if it has at most one vertex from any particular partite set. In this paper, when $n{\equiv}0$ or 3 (mod 6), another method using difference set is presented. Furthermore, when $n{\equiv}0$ (mod 6), the decomposition obtained in this paper is ${\infty}-circular$, in the sense that it is invariant under the mapping which keeps the partite set which is indexed by ${\infty}$ fixed and permutes the remaining partite sets cyclically.

• East Asian mathematical journal
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• v.26 no.5
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• pp.655-670
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• 2010

The complete multipartite graph $K_{n(m)}$ with n $ {\geq}$ 4 partite sets of size m is shown to have a decomposition into 4-cycles in such a way that vertices of each cycle belong to distinct partite sets of $K_{n(m)}$, if 4 divides the number of edges. Such cycles are called gregarious, and were introduced by Billington and Hoffman ([2]) and redefined in [3]. We independently came up with the result of [3] by using a difference set method, and improved the result so that the composition is circulant, in the sense that it is invariant under the cyclic permutation of partite sets. The composition is then used to construct gregarious 4-cycle decompositions when one partite set of the graph has different cardinality than that of others. Some results on joins of decomposable complete multipartite graphs are also presented.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.523-528
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• 2016

The migratory locust Locusta migratoria, one of the world's most notorious insect pests, has polyphenic (gregarious or solitarious) characteristics. Although this species is known to have several morphological variants, it is genetically divided into two different lineages using mitochondrial genome analysis: Southern (Africa, Southern Europe, Southern Asia, and Australia) and Northern (East Asia and the Eurasian continent). In 2014, a large number of orange black-colored gregarious L. migratoria nymphs suddenly appeared at Haenamgun, Jeollanamdo in the south of Korea. This is the first report of gregarious phase locusts occurring in Korea. In this study, mitochondrial COI sequences of one nymph and 11 adults of L. migratoria were analyzed to examine the genetic lineage of the gregarious nymphs of L. migratoria. Our results showed that all 12 individuals belong to the Northern linage and have low intraspecific genetic divergences (0.0% - 0.9%).

• Journal of the Korean Mathematical Society
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• v.45 no.6
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• pp.1623-1634
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• 2008

The complete multipartite graph $K_{n(2t)}$ having n partite sets of size 2t, with $n\;{\geq}\;6$ and $t\;{\geq}\;1$, is shown to have a decomposition into gregarious 6-cycles, that is, the cycles which have at most one vertex from any particular partite set. Complete sets of differences of numbers in ${\mathbb{Z}}_n$ are used to produce starter cycles and obtain other cycles by rotating the cycles around the n-gon of the partite sets.

• Journal of the Korean Society of Costume
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• v.14
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• pp.185-198
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• 1990

The purpose of this study is to identify and profile Korean women's fashion opinion leaders on demographic, psychological and communication channels dimensions. The questionnaire was administered to 1204 students from a purposively selected. women's universities in Seoul. The data was analyzed using $X^2$-test, t-test, multiple regression analysis and discriminant analysis, The significance level was set at. 05. The major findings derived from analysis are as follows: 1. Fashion opinion leaders are generally come from families with higher income, more education and higher occupational status than followers. 2. Fashion opinion leaders are more likely to be exhibitionistic, self-confident, individualistic, risk taking and gregarious than followers. 3. Fashion opinion leaders are more exposed to impersonal communication media, especially to fashion magazines than followers. These findings imply an obvious usefulness for both manufacturers in the apparel industry as well as retailers to help them in the identification of their target market for the introduction and acceptance of fashion items.

• Mycobiology
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• v.43 no.3
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• pp.366-370
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• 2015

Acanthopanax divaricatus, a member of the Araliaceae family, has been used as an invigorant in traditional Korean medicine. During disease monitoring, a stem with small, irregular, brown lesions was sampled at a farm in Cheonan in 2011. The symptoms seen were sunken cankers and reddish-brown needles on the infected twig. The isolated fungal colonies were whitish, having crenated edges and aerial mycelium on the surface, and with black gregarious fruiting bodies. The reverse plate was creamy white. Conidia were $17{\sim}22{\times}3.5{\sim}4.2{\mu}m$, fusiform, 4-septate, and straight to slightly curved. The nucleotide sequence of the partial translation elongation factor 1 alpha gene of the fungal isolate, shares 99% sequence identity with that of known Pestalotiopsis ellipsospora. Based on the results of the morphological and molecular analyses, the fungal isolate was identified as P. ellipsospora. In Korea, this is the first report of canker on A. divaricatus.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.1
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• pp.45-49
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• 2006

The present investigation was conducted to know the effects of host age on development and morphological characteristics of Nesolynx thymus, a gregarious ectopupal parasitoid of the uzi fly, Exorista bombycis, a serious en do-larval parasitoid of the silkworm, Bombyx mori L. For experimentation, 3 - 11 day-old pupae of E. bombycis were exposed to 2 day-old adults of N. thymus at $25{\pm}2^{\circ}C\;and\;60{\pm}10%$ RH. A highly significant negative correlation between host age and the following development and morphological characteristics of the parasitoid was observed: number of pupae parasitised, total adult recovery, sex ratio and recovery, longevity, body length, wing span, abdomen length, and abdomen width of females. The findings of the present study clearly demonstrate that various development and morphological parameters of N. thymus are influenced by the age of E. bombycis pupae.