• Bulletin of the Korean Mathematical Society
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• v.51 no.4
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• pp.943-948
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• 2014

Suppose that G is a finite group and H is a subgroup of G. H is said to be an ss-quasinormal subgroup of G if there is a subgroup B of G such that G = HB and H permutes with every Sylow subgroup of B; H is said to be semi-p-cover-avoiding in G if there is a chief series 1 = $G_0$ < $G_1$ < ${\cdots}$ < $G_t=G$ of G such that, for every i = 1, 2, ${\ldots}$, t, if $G_i/G_{i-1}$ is a p-chief factor, then H either covers or avoids $G_i/G_{i-1}$. We give the structure of a finite group G in which some subgroups of G with prime-power order are either semi-p-cover-avoiding or ss-quasinormal in G. Some known results are generalized.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.513-516
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• 2007

Because many scientific applications require large data processing, the importance of parallel I/O has been increasingly recognized. Collective I/O is one of the considerable features of parallel I/O and enables application programmers to easily handle their large data volume. In this paper we measure and analyze the performance of original collective I/Os and the subgroup method, the way of using collective I/O of MPI effectively. From the experimental results, we found that the two kinds of subgroup method showed different performance. In terms of collective write operation, the subgroup method caused the performance degradation. However, the subgroup method for collective read showed good performance with small data size.

• Journal of Life Science
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• v.31 no.1
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• pp.52-58
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• 2021

Pseudomonas syringae pv. actinidiae, which causes bacterial canker in kiwifruit, is divided into five biovars (1, 2, 3, 5, 6) on the basis of genetic characteristics and toxin productivity. Among them, biovar 3 is responsible for the current global outbreak, and has been isolated in Korea since 2011. Biovar 3 strains isolated from Korea are subdivided into six genetically different lineages (subgroup I, IV, V, VI, VII, and VIII) based on random amplified polymorphic DNA (RAPD) analysis. In this work, the subgroup-specific sequence characterized amplified region (SCAR) primers were developed from sequenced differential RAPD bands. Distribution of the subgroups of the biovar 3 strains collected in Korea from 2011-2017 were examined using these subgroup-specific primer sets. Among the 54 strains tested, 35 strains (64.8%) belonged to subgroup V, 9 strains (16.7%) belonged to subgroup IV, 4 strains (7.4%) belonged to subgroup VI, 3 strains (5.6%) belonged to subgroup VII, 2 strains (3.7%) belonged to subgroup VIII, and 1 (1.9%) strain belonged to subgroup I. Strains belonging to subgroups IV, V, and VI were shown to be related to strains isolated from China, New Zealand, and Chile, respectively. The study revealed that the biovar 3 strains in Korea are genetically diverse and are estimated to have been introduced through pollen sourced from foreign countries.

• The Plant Pathology Journal
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• v.27 no.4
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• pp.372-377
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• 2011

A virus causing mottle and stunt symptom on Zea mays was observed around Ulleng-do, Korea and identified as Cucumber mosaic virus (CMV-ZM) based upon biological, serological, and molecular characteristics. In host range studies, the CMV-ZM isolate produced local lesions on Datura stramonium, Vigna unguiculata, Cucurbita moschata, Chenopodium amaranticolor, Ch. quinoa, whereas this isolate produced systemic mosaic on Nicotiana tabacum cv. 'Xanthi-nc', Capsicum annuum, Solanum lycopersicum, Solanum melongena, Cucurbita pepo, and Z. mays. In addition, chlorotic local rings on inoculated leaves along with severe mosaic, malformation, and fern leaf symptoms on upper systemic leaves were shown in N. glutinosa plants. Complete nucleotide sequences of each genomic RNA segment was determined and compared to those of the other CMV strains. Comparison of the nucleotide sequence of 1a open reading frame (ORF) revealed approximately 89.2-92.4% sequence identity with each CMV subgroup IA and IB strain, while showing only 78% sequence identity with CMV subgroup II. Nucleotide sequence analysis of RNA2 ORFs revealed 85.3-97.6% sequence identity with subgroup I. In ORFs of RNA3, levels of nucleotide sequence identities were higher than 92-99.2% with CMV subgroup I and lower than 82% with CMV isolates of subgroup II. These results suggest that CMV-ZM isolate is more closely related to subgroup I than subgroup II and therefore, CMV-ZM isolate might be classified into as CMV subgroup I based on biological and molecular analysis.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.3
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• pp.274-282
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• 2019

The purpose of this study was to evaluate effect of saliva decontamination procedures on microtensile bond strength (MTBS) of 1-step self-etching adhesives to dentin of primary posterior teeth. 63 sound primary-posterior teeth were randomly divided into 3 groups according to different kinds of 1-step self-etching adhesives: $Scotchbond^{TM}$ Universal Adhesive (SBU), All-Bond $Universal^{(R)}$ (ABU), and $Tetric^{(R)}$ N Bond Universal (TBU). Each group was randomly categorized into 7 subgroups: (I) application of adhesive without saliva contamination (control); (II - IV) contamination by saliva before photopolymerization; (V - VII) contamination by saliva after photopolymerization; (II, V) decontamination by drying; (III, VI) decontamination by washing and drying; (IV, VII) decontamination by washing, drying, and reapplication of adhesive. All samples were cut into the blocks. At least 15 blocks were tested for each subgroup. For SBU and ABU, the MTBS values of subgroups (I, IV, VII) were significantly higher than those of subgroups (II, III, V, VI). For TBU, the MTBS values of subgroups (I, IV) was significantly higher than those of subgroup (II, III, V, VI). The MTBS of 3 adhesives was reduced by saliva contamination. The adhesive strength on dentin of primary posterior teeth was restored by reapplication of the adhesives after washing and drying.

• Journal of Korean Society of Forest Science
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• v.79 no.1
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• pp.42-55
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• 1990

The forest communities of this area were studied phytosociologically by the method of Z$\ddot{u}$rich-Montpellier school. 1) Forest vegetation in this area divided into mountain forest(Pinus densiflora-Alnus hirsuta community) and plateau(Basin) forest(Weigela subsessilis-Athyrium yokoscense community). 2) Mountain forest(I. Pinus densiflora-Alnus hirsuta community) divided into I-A. Carpinus laxiflora group, I-B. Acer mono group., I-A. Carpinus laxiflora group is further subdivided into I-A-1. Styrax obassia subgroup, I-A-2. Lindera erythrocarpa subgroup, I-A-3. Typical subgroup, I-A-4. Zanthoxylum schinifolium subgroup. 3) Plateau(Basin) forest(II. Weigela subsessilis-Athyrium yokoscense community.) divided into II-A. Carpinus laxiflora group, II-B. Carpinus cordata-Actinidia arguta group, II-C. Typical group. II-A. Carpinus laxiflora group is further subdivided into II-A-1. Symplocos chinensis for. pilosa subgroup, II-A-2. Typical subgroup. II-A-3. Acer mono subgroup. The flora of vasicula plants distributed in Mt. Kasan area was 105 families 350 genera, 515 species, 87 varieties, 2 subspecies and 12 formae in total 616 taxa (This amount to some 64.7% of the whole plant (952 kinds) in Mt. Palgong nature area.).

• The Plant Pathology Journal
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• v.20 no.2
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• pp.131-134
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• 2004

A strain of Cucumber mosaic virus (CMV) was isolated from a weed, water chickweed (Stellaria aquatica), growing in the pepper field in Chunchon, Korea. This isolate, CMV-Sa, was differentiated from other CMVs based on biological properties and nucleotide sequence analysis of the coat protein (CP) gene. CMV-Sa showed different reactions to all the tested plants, except Capsicum annuum and Cucumis sativus, when compar-ed with those of CMV-Mf (subgroup I) and CMV-PaFM (subgroup II). Remarkably, in Nicotiana tabacum cvs. Samsun, Xanthi-nc and Ky-57, CMV-Sa induced local necrotic ring spots on the inoculated leaves and venal wave pattern and mosaic on the upper leaves. RNA analysis, serology, and RT-PCR of CP gene showed that CMV-Sa belonged to subgroup I of CMV. However, restriction enzyme analysis of the cDNA using AluI, HhaI, HincII, HindIII, HinfI and MspI showed that CMV-Sa was distinct from that of CMV-Mf. Based on comparison of the nucleotide of CP gene and deduced amino acid sequences between other CMV strains, CMV-Sa was closely related to CMV-Mf with 93.7% and 97.2 % identity, respectively.

• Korean Journal Plant Pathology
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• v.14 no.4
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• pp.308-313
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• 1998

Reverse transcription and polymerase chain reaction (RT-PCR) techiniques were used to identification and differentiation of cucumber mosaic virus isolated from Forsythia koreana (CMV-Fk). RT-PCT used by two set of 20-mer primers one was CMV-common primers and another was CMV subgroup I-specific primers designed in a conserved region of the 3' end of CMV RNA3, amplified about 490 bp and 200 bp DNA fragments from CMV-Fk, respectively. CMV could be detected by RT-PCR at a dilution as low as 10-4 in forsythia crude sap extracts. Restriction enzyme analysis of RT-PCR products using EcoRI and MspI showed that CMV-Fk belonged to CMV subgroup I. But, analysis of RNA fingerprinting by arbitrarily primed polymerase chain reaction (RAP-PCR) showed heterogeneity of RNA3 between CMV-Fk and CMV-Y as a member of subgroup I.

• Bulletin of the Korean Mathematical Society
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• v.48 no.6
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• pp.1147-1155
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• 2011

In J. Korean Math. Soc, Zhang, Xu and other authors investigated the following problem: what is the structure of finite groups which have many normal subgroups? In this paper, we shall study this question in a more general way. For a finite group G, we define the subgroup $\mathcal{A}(G)$ to be intersection of the normalizers of all non-cyclic subgroups of G. Set $\mathcal{A}_0=1$. Define $\mathcal{A}_{i+1}(G)/\mathcal{A}_i(G)=\mathcal{A}(G/\mathcal{A}_i(G))$ for $i{\geq}1$. By $\mathcal{A}_{\infty}(G)$ denote the terminal term of the ascending series. It is proved that if $G=\mathcal{A}_{\infty}(G)$, then the derived subgroup G' is nilpotent. Furthermore, if all elements of prime order or order 4 of G are in $\mathcal{A}(G)$, then G' is also nilpotent.

• 모자간호학회지
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• v.4 no.1
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• pp.41-51
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• 1994

The purposes of this study were to identify responses of nursing students following clinical maternity nursing practice, to develop data of further effective clinical maternity nursing practice, to understand nursing students perceive the natural maturation process toward pregnancy delivery and puerperal process, to help the nursing students achieve personality growth and development through clinical maternity nursing practice. The subjects were 35 senior nursing students from the Department of Nursing Science of Chung-Ang University. The data were collected from the 1st semester (Feb.22$\sim$June 9) to the 2nd semester(Aug.23$\sim$Nov.10), 1993 through self-reporting using an open ended questionnaire about perception and feelings regarding the normal delivery process. The data analysis used descriptive method. Results of the study were as follows : 1. Following clinical practice in maternity nursing, the responses of the nursing students were collected included both positive and negative aspects. The positive responses were classified in to four categories and each category included subgroups. One group, labelled as $\ulcorner$The birth of noble life$\lrcorner$ had a subgroup, (I felt the mystery and wonder of life), another group, $\ulcorner$After delivery, comfort and satisfaction$\lrcorner$ with the subgroup (I can bear to see the comfort and relief beyond pain) (C/S is better than vaginal delivery) (Very easy), the 3rd group, $\ulcorner$ I realized family friendship and support$\lrcorner$ with subgroup (Honorable, Magnificient) (I thank my parents ) (It's good to looking at my husband's support), and the 4th group, $\ulcorner$The birth of a healthy baby$\lrcorner$, with its subgroup, (baby looks pretty and healthy). 2. The negative responses were classified in eight categories and each category included subgroups. One group labelled as $\ulcorner$Fear$\lrcorner$, had subgroups of (Terrible, Horrible) (Shock) (Dread), another group, $\ulcorner$Tension$\lrcorner$, and its subgroup, (I became tense about stories heard before clinical practice), the 3rd group, $\ulcorner$surprise$\lrcorner$ and its subgroup (I was surprised at the delivery process), the 4th group, $\ulcorner$Power lessness$\lrcorner$ and its subgroup, (I watched the labor pain impatiently), the 5th group $\ulcorner$Apathy$\lrcorner$ ; and its subgroup, (I didn't feel the empathy for the labor pain of the pregnant women), the 6th group, $\ulcorner$Disgust$\lrcorner$ and its subgroup, (Disgust, Embarrassed), the 7th group, $\ulcorner$Inevitable destiny$\lrcorner$ and its subgroups (necessity of self-sacrifice and difficulty) (I accepted it as a women's destiny) (I can't do it), the last group, $\ulcorner$There seems to be trouble$\lrcorner$ and its subgroup, (It seems to have been a little too hard for mother and baby). Suggestions for further studies are as follows : 1. Nursing students should receive intensive education about $\ulcorner$The birth of noble life$\lrcorner$ $\ulcorner$After delivery, comfort and satisfaction$\lrcorner$ $\ulcorner$I realized family friendship and support$\lrcorner$ $\ulcorner$The birth of a healthy baby$\lrcorner$, so that a more positive attitude can be developed before clinical maternity nursing. 2. Nursing students should be given an orientation which is reality based and related clinical maternity nursing (using for A.V. Materials), so that they will not feel they tension, of the negative categories. 3. Nursing students should be received articles on Pain Relief Method, so that they will be prepared activie and positive in the clinical practice, and therefore they will not feel the powerlessness, of the negative categories. 4. F/U for responses of nursing students should be checked following clinical maternity nursing to evaluate the effects of the instruction.