• Phonetics and Speech Sciences
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• v.5 no.3
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• pp.39-46
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• 2013

This study examined the perception of two Korean vowels using F1/F2 manipulated synthetic vowels. Previous studies indicated that there is an overlap between the acoustic spaces of Korean /o/ and /u/ in terms of the first two formants. A continuum of eleven synthetic vowels were used as stimuli. The experiment consisted of three tasks: an /o/ identification task (Yes-no), an /u/ identification task (Yes-no), and a forced choice identification task (/o/-/u/). ROC(Receiver Operating Characteristic) analysis and logistic regression were performed to calculate the boundary criterion of the two vowels along the stimulus continuum, and to predict the perceptual judgment on F1 and F2. The result indicated that the location between stimulus no.5 (F1 = 342Hz, F2 = 691Hz) and no.6 (F1 = 336Hz, F2 = 700Hz) was estimated as a perceptual boundary region between /o/ and /u/, while stimulus no.0 (F1=405Hz, F2=666Hz) and no.10 (F1=321Hz, F2=743Hz) were at opposite ends of the continuum. The influence of F2 was predominant over F1 on the perception of the vowel categories.

• Communications of the Korean Mathematical Society
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• v.34 no.3
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• pp.951-965
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• 2019

Let $f:X{\rightarrow}X$ be a continuous map on a compact metric space (X, d) and for an arbitrary $x{\in}X$, $${\mathcal{SC}}_d(x,f):=\{y{\mid}x{\text{ can be strong }}d-{\text{chain to }}y\}$$. We give an example to show that ${\mathcal{SC}}_d(x,f)$ is dependent on the metric d on X but it is a closed and f-invariant set. We prove that if ${\mathcal{SC}}_d(x,f){\supseteq}{\Omega}(f)$ or f has the asymptotic-average shadowing property, then ${\mathcal{SC}}_d(x,f)=X$. Also, we show that if f has the shadowing property, then ${\lim}\;{\sup}_{n{\in}{\mathbb{N}}}\{f^n\}={\mathcal{SC}}_d(f)$ where ${\mathcal{SC}}_d(f)=\{(x,y){\mid}y{\in}{\mathcal{SC}}_d(x,f)\}$. For each $n{\in}{\mathbb{N}}$, we give an example in which ${\mathcal{SCR}}_d(f^n){\neq}{\mathcal{SCR}}_d(f)$. In spite of it, we prove that if $f^{-1}:(X,d){\rightarrow}(X,d)$ is an equicontinuous map, then ${\mathcal{SCR}}_d(f^n)={\mathcal{SCR}}_d(f)$ for all $n{\in}{\mathbb{N}}$.

• Journal of applied mathematics & informatics
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• v.24 no.1_2
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• pp.357-366
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• 2007

Let G(V, E) be a simple graph, and let f be an integer function on V with $1{\leq}f(v){\leq}d(v)$ to each vertex $v{\in}V$. An f-edge cover-coloring of a graph G is a coloring of edge set E such that each color appears at each vertex $v{\in}V$ at least f(v) times. The f-edge cover chromatic index of G, denoted by ${\chi}'_{fc}(G)$, is the maximum number of colors such that an f-edge cover-coloring of G exists. Any simple graph G has an f-edge cover chromatic index equal to ${\delta}_f\;or\;{\delta}_f-1,\;where\;{\delta}_f{=}^{min}_{v{\in}V}\{\lfloor\frac{d(v)}{f(v)}\rfloor\}$. Let G be a connected and not complete graph with ${\chi}'_{fc}(G)={\delta}_f-1$, if for each $u,\;v{\in}V\;and\;e=uv{\nin}E$, we have ${\chi}'_{fc}(G+e)>{\chi}'_{fc}(G)$, then G is called an f-edge covered critical graph. In this paper, some properties on f-edge covered critical graph are discussed. It is proved that if G is an f-edge covered critical graph, then for each $u,\;v{\in}V\;and\;e=uv{\nin}E$ there exists $w{\in}\{u,v\}\;with\;d(w)\leq{\delta}_f(f(w)+1)-2$ such that w is adjacent to at least $d(w)-{\delta}_f+1$ vertices which are all ${\delta}_f-vertex$ in G.

• Research in Plant Disease
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• v.10 no.4
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• pp.248-259
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• 2004

A total 115 isolates of Fusarium species from ginseng roots of 'rotted', and soils collected during 1982-1985 in Korea, were identified and classified into 11 species with the Snyder & Hansen System (with reference to Gerlach-Nirenberg's Modified System). The most dominant of these species were F. solani (55 isolates), F. oxysporum (35 isolates), and F. moniliforme (10 isolates) sensu Snyder & Hansen. The other 8 species (15 isolates) were very rarely isolated and previously identified as F. roseum sensu Snyder & Hansen (1945); these were F. equiseti, F. avenaceum, F. graminum, F. arthrosporioides, F. sambucinum, F. reticulatum, F. semitectum and F. poa. Tested for the ability to infect the roots of ginseng (3 yr. old plants) in field condition with the mycelial inoculum, only one isolate of F. solani (34 isolates tested) and one isolate of F. oxysporum (24 isolates tested) were weakly pathogenic to ginseng roots. Any of the isolates (7 isolates tested) of F. moniliforme [Liseola section] were not pathogenic to ginseng. However, all the isolates of tested of the species of Phytophthora cactorum, Pythium ultimum, and Cylindrocarpon destructans were highly pathogenic to ginseng roots. The species of Fusarium solani and Cylindrocarpon destructans were supposed to be a host dominant disease agent in ginseng plant.

• The Korean Journal of Mycology
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• v.25 no.3 s.82
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• pp.202-208
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• 1997

In this study, we evaluated the use of RAPD method to discriminate among strains of Fusarium species including F. oxysporum and f. sp. of F. oxysporum. As a result of the amplication, fifteen primers showed total 180 bands ranging from 0.2 to 3 Kb. Among those 180 bands, 126 polymorphic bands were used for bionominal matrix code (0, 1), and UPGMA dendrogram analysis. Fusarium oxysporum isolate 355 showed high similarity with F. oxysporum isolate 358 at 0.9603. Fusarium roseum isolate 87 and F. oxysporum isolate 358, F. o. f. sp. lycopersici isolate 69 and F. o. f. sp. melongena 68 showed low similarity of 0.3809. Fusarium oxysporum isolate 361 and F. o. f. sp. raphani isolate 218 showed similarity of 0.8730, F. oxysoprum isolate 354 and unidentified Fusarium sp. isolate 228 showed similarity matrix of 0.7936, and F. roseum isolate 87 and F. o. f. sp. raphani isolate 57 showed similarity matrix of 0.5873.

• The Korean Journal of Mycology
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• v.48 no.3
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• pp.297-312
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• 2020

Wilted soybean plants were collected from soybeans cultivation fields in Korea from 2014 to 2016. Fusarium spp., Colletotrichum spp., Rhizoctonia spp., Macrophomina sp., Phytophthora spp., and Calonectria ilicicola were obtained from the infected samples. Out of these, Fusarium spp. were the dominant species (79.1%). In total, 53 isolates were identified as F. solani species complex, F. oxysporum species complex, F. graminearum species complex, and F. fujikuroi species complex based on mycological characteristics. Sequence typing analysis was conducted using translation elongation factor 1 alpha (TEF) to confirm the identification of isolates. All isolates were identified as F. solani, F. oxysporum, F. commune, F. asiaticum, and F. fujikuroi based on phylogenetic analysis of TEF sequences. Pathogenicity of 44 isolates was tested on three cultivars of soybean using the root dip inoculation method. Out of 5 Fusarium species, only F. asiaticum could not cause the symptoms or be weak. Ten isolates were selected based on pathogenic characters and species identification to investigate the host range and screen soybean cultivars for resistance. Fusarium solani, F. oxysporum, and F. commune were aggressive only to soybean, and F. fujikuroi was aggressive to kidney bean, yellow cowpea, black cowpea, adzuki bean as well as soybean. All 13 Korean soybean cultivars were susceptible to F. commune and F. fujikuroi. Out of 13 cultivars, cv. Janggi, cv. Poongsannamul, and cv. Socheongja were resistant to Fusarium wilt, while cv. Hwanggeumol and Chamol were susceptible to Fusarium wilt.

• Korean Journal of Environmental Biology
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• v.33 no.3
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• pp.290-305
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• 2015

Ten new species of the genus Falcileptoneta are described; Falcileptoneta bifurca n. sp., F. boeunensis n. sp., F. chiakensis n. sp., F. cornuta n. sp., F. digitalis n. sp., F. hansanensis n. sp., F. juwangensis n. sp., F. moakensis n. sp., F. naejangenesis n. sp., and F. unmunensis n. sp. And six species previously known as Leptoneta spiders are transferred to Falcileptoneta as fo11ows; Falcileptoneta coreana (Paik and Namkung, 1969), F. hwanseonensis (Namkung, 1987), F. secula (Namkung, 1987), F. simboggulensis (Paik, 1971), F. yebongsanensis (Kim, Lee and Namkung, 2004), and F. yongdamgulensis (Paik and Namkung, 1969), all n. comb.

• Journal of the Chungcheong Mathematical Society
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• v.29 no.1
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• pp.177-186
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• 2016

For a map $f:A{\rightarrow}X$, there are concepts of $H^f$-spaces, $T^f$-spaces, which are generalized ones of H-spaces [17,18]. In general, Any H-space is an $H^f$-space, any $H^f$-space is a $T^f$-space. For a principal fibration $E_k{\rightarrow}X$ induced by $k:X{\rightarrow}X^{\prime}$ from ${\epsilon}:PX^{\prime}{\rightarrow}X^{\prime}$, we obtain some sufficient conditions to having liftings $H^{\bar{f}}$-structures and $T^{\bar{f}}$-structures on $E_k$ of $H^f$-structures and $T^f$-structures on X respectively. We can also obtain some results about $H^f$-spaces and $T^f$-spaces in Postnikov systems for spaces, which are generalizations of Kahn's result about H-spaces.

• Bulletin of the Korean Mathematical Society
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• v.27 no.2
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• pp.127-131
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• 1990

Let f:R.rarw.R be a continuous function on the real line R, and denote the n-th iterate of f by f$^{n}$ :f$^{1}$=f and f$^{n}$ =f.f$^{n-1}$ for n>1. A point x.mem.R is a periodic point of f of period k>0 if f$^{k}$ (x)=x but f$^{i}$ (x).neq.x for all 01, then it must also have a fixed point, by the intermediate Theorem. Also the question has an intriguing answer which was found by ths Russian mathematician Sharkovky [6] in 1964.

• The Pure and Applied Mathematics
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• v.3 no.2
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• pp.163-171
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• 1996

Observing that a locally weakly Lindel$\"{o}$f space is a quasi-F space if and only if it has an F-base, we show that every dense weakly Lindel$\"{o}$f subspace of an almost-p-space is C-embedded, every locally weakly Lindel$\"{o}$f space with a cocompact F-base is a locally compact and quasi-F space and that if Y is a dense weakly Lindel$\"{o}$f subspace of X which has a cocompact F-base, then $\beta$Y and X are homeomorphic. We also show that for any a separating nest generated intersection ring F on a space X, there is a separating nest generated intersection ring g on $\phi_{Y}^{-1}$(X) such that QF(w(X, F)) and ($\phi_{Y}^{-1}$(X),g) are homeomorphic and $\phi_{Y}_{x}$(g$^#$)=F$^#$.