• Korean Journal of Mathematics
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• v.25 no.1
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• pp.61-70
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• 2017

In this paper, we introduce the concept of statistically sequentially quotient map which is a generalization of sequence covering map and discuss the relation with covering maps by some examples. Using this concept, we give an affirmative answer for a question by Fucai Lin and Shou Lin.

• Genomics & Informatics
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• v.4 no.4
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• pp.141-146
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• 2006

We sequenced 1,841 BAC clones by terminal sequencing, and 1,830 of these clones were characterized with regard to their human chromosomal location and gene content using Korean BAC library constructed at the Korean Science (KCGS). Sequence analyses of the 1,830 BAC clones was performed for chromosomal assignment: 1,144 clones were assigned to a single chromosome, 190 clones apparently assigned to more than one chromosome, and 496 clones to no chromosome. Evaluating gene content of the 1,144 BAC clones, we found that 706 clones represented 1,069 genes of which 415 genes existed in the BAC clones covering the full sequence of the gene, 180 genes covering a $50%{\sim}99%$, and 474 genes covering less than 50% of the gene coverage. The estimated covering size of the KBAC clones was 73,379 kilobases (kb), in total corresponding to 2.3% of haploid human genome sequence. The identified BAC clones will be a public genomic resource for mapped clones for diagnostic and functional studies by Korean scientists and investigators worldwide.

• Communications of the Korean Mathematical Society
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• v.38 no.1
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• pp.267-280
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• 2023

In this article, we show that the family of all 𝓘^𝒦-open subsets in a topological space forms a topology if 𝒦 is a maximal ideal. We introduce the notion of 𝓘^𝒦-covering map and investigate some basic properties. The notion of quotient map is studied in the context of 𝓘^𝒦-convergence and the relationship between 𝓘^𝒦-continuity and 𝓘^𝒦-quotient map is established. We show that for a maximal ideal 𝒦, the properties of continuity and preserving 𝓘^𝒦-convergence of a function defined on X coincide if and only if X is an 𝓘^𝒦-sequential space.

• Journal of the Korean Operations Research and Management Science Society
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• v.42 no.3
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• pp.1-12
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• 2017

In this paper, we generalize lifted inequalities to a 0-1 mixed-integer bilinear covering set with linear terms. This work is motivated by the observation that Generalized Bilinear Inequality (GBI) occurs in the Branch and Bound process. We find some conditions and prove the subadditivity of lifting functions for lifting to be sequence-independent. Using the theoretical results, we develop facet-defining inequalities for a GBI-defined set through three steps of lifting.

• Mycobiology
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• v.51 no.1
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• pp.16-25
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• 2023

Lecanora is one of the largest genera of lichens worldwide. These lichens can be easily seen, and are commonly found on trees and rocks. Most Korean Lecanora species belong to the Lecanora subfusca group, which has well-defined superficial thallus, red-brown apothecia, and soredia. The new species of L. neobarkmaniana grows on rocks, farinose soredia coalescing, usually covering the whole thallus, and containing atranorin and zeorin. We used internal transcribed spacer (ITS) and mitochondrial small subunit (mtSSU) sequence data to identify the phylogenetic relationship across Lecanora sequence data and found the species to form different clades. In this study, we reported some interesting findings and described the genetic relationship with other sorediate Lecanora species and the characteristics of the new species. An identification key for the Korean sorediate Lecanora species is given.

• Korean Journal of Veterinary Research
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• v.39 no.3
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• pp.545-553
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• 1999

A 474-base pair segment covering the hypervariable region of VP2 gene from six Korean infectious bursal disease virus(K-IBDV) isolates(K1, K2, SH/92, 225, 269, 310) and one attenuated IBDV(DAE) were amplified using RT-PCR, sequenced, and compared with published sequences for IBDV. K-IBDV isolates(K1, K2, SH/92, 225, 269) and foreign very virulent(vv) IBDV strains had 94.93~100% amino acid sequence similarity. K-IBDV isolate 310 and other K-IBDV isolates had 84.31~86.07% amino acid sequence similarity. Attenuated strain(DAE), like other attenuated strain, has substitution at positions 279(D to N) and 284(A to T) as well as in the serine-rich heptapeptide region. Five K-IBDV isolates except 310 isolate share unique amino acid residues at positions 222(A), 256(I), 294(I) which are not present in other standard and attenuated strains. At the two hydrophilic region, K-IBDV isolates except 310 isolate had identical amino acids comparing with Belgium vv IBDV 894VB but had four amino acid substitutions comparing with Chinese vv IBDV F9502. The SWSASGS heptapeptide is conserved in all K-IBDV isolates. The sequence of K-IBDV isolate 310 was markedly different from other IBDV strains, evolving from a separate lineage than the others. By phylogenetic analysis, Five K-IBDV isolates except 310 isolate were categorized in one group with foreign vv IBDV isolates but K-IBDV isolate 310 was categorized in a separate group which was differentiated from other compared IBDV strains.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1773-1777
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• 2006

We evaluated the usefulness of DNA microarray as a comparative genomics tool, and tested the validity of the cutoff values for defining absent genes in test genomes. Three genome-sequenced E. coli strains (K-12, EDL933, and CFT073) were subjected to comparative genomic hybridization with DNA microarrays covering almost all ORFs of the reference strain K-12, and the microarray results were compared with the results obtained from in silico analyses of genome sequences. For defining the K-12 ORFs absent in test genomes (reference strain-specific ORFs), we applied and evaluated the cutoff level of -1. The average sequence similarity between ORFs, to which corresponding spots showed a log-ratio of>-1, was $96.9{\pm}4.8$. The numbers of spots showing a log-ratio of <-1 (P<0.05, t-test) were 90 (2.5%) and 417 (10.6%) for the EDL933 genome and the CFT073 genome, respectively. Frequency of false negatives (FN) was ca. 0.2, and the cutoff level of -1.3 was required to achieve the FN of 0.1. The average sequence similarity of the false negative ORFs was $77.8{\pm}14.8$, indicating that the majority of the false negatives were caused by highly divergent genes. We concluded that the microarray is useful for identifying missing or divergent ORFs in closely related prokaryotic genomes.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.117.2-117
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• 2003

The importance and diversity of the genus Stemphylium highlights the need for accurate identification of species. However, many Stemphylium isolates have been misidentified due to the use of spore size as the only identifying character. Molecular phylogenetic analyses were performed on fifty-four isolates covering 9 Stemphylium species collected in Korea. Phylogenetic analysis of the translation elongation factor -1 alpha (EF-1) and the calmodulin gene sequence data showed that Stemphylium species were segregated into seven distinct groups, most of w hichcorrelated with species identified by morphology. Analysis of EF-1 in particular was useful for establishing well- supported relationships among the species of Stemphylium.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.135-135
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• 2002

Purpose： To assess diagnostic accuracy of dynamic contrast enhanced MR mammography in differentiating between benign and malignant lesions. Materials and methods： Ninety-three patients with suspicious mammographic, sonographic or palpable findings underwent pre- or postoperative contrast-enhanced MR imaging of breast using three dimensional fast low-angle shot (3D FLASH) sequence (16/4 msec［repetition time / echo time］, 20 flip angle, 3mm slice thickness with no slice gap, 256 by 256 in-plane matrix) covering whole breasts. T1 weighted images were obtained before and after bolus administration of gadopentetate dimeglumine (0.15 mmol/kg). Subtraction images and time-signal intensity curves of region of interest were obtained sequentially and correlated with pathologic diagnoses of lesions.

• Journal of Electrical Engineering and Technology
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• v.7 no.2
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• pp.151-156
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• 2012

The current study presents a zero-one integer programming approach to determine the minimum break point set for the coordination of directional relays. First, the network is reduced if there are any parallel lines or three-end nodes. Second, all the directed loops are enumerated to reduce the iteration. Finally, the problem is formulated as a set-covering problem, and the break point set is determined using the zero-one integer programming technique. Arbitrary starting relay locations and the arbitrary consideration of relay sequence to set and coordinate relays result in navigating the loops many times and futile attempts to achieve system-wide relay coordination. These algorithms are compared with the existing methods, and the results are presented. The problem is formulated as a setcovering problem solved by the zero-one integer programming approach using LINGO 12, an optimization modeling software.