• Journal of the Chungcheong Mathematical Society
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• 제22권3호
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• pp.375-382
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• 2009

Several common stationary point theorems for two classes of contractive type multivalued mappings in a complete bounded metric space are given. The results presented in this paper generalize and extend some known results in literature.

• Bulletin of the Korean Chemical Society
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• 제30권4호
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• pp.945-947
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• 2009

• Bulletin of the Korean Mathematical Society
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• 제47권2호
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• pp.251-261
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• 2010

This paper deals with a predator-prey model with Holling type III response function and cross-diffusion subject to the homogeneous Neumann boundary condition. We first give a priori estimates (positive upper and lower bounds) of positive steady states. Then the non-existence and existence results of non-constant positive steady states are given as the cross-diffusion coefficient is varied, which means that stationary patterns arise from cross-diffusion.

• Bulletin of the Korean Mathematical Society
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• 제57권5호
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• pp.1151-1164
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• 2020

The aim of this paper is to establish Liouville type results for the stationary MHD equations. In particular, we show that the velocity and magnetic field, belonging to some Lorentz spaces, must be zero. Moreover, we also obtain Liouville type theorem for the case of axially symmetric MHD equations. Our results generalize previous works by Schulz [14] and Seregin-Wang [18].

• The Plant Pathology Journal
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• 제30권2호
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• pp.215-219
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• 2014

The GacS/GacA two component system regulates various traits related to the biocontrol potential of plant-associated pseudomonads. The role of the sensor kinase, GacS, differs between strains in regulation of motility. In this study, we determined how a gacS mutation changed cell morphology and motility in Pseudomonas chlororaphis O6. The gacS mutant cells were elongated in stationary-phase compared to the wild type and the complemented gacS mutant, but cells did not differ in length in logarithmic phase. The gacS mutant had a two-fold increase in the number of flagella compared with the wild type strain; flagella number was restored to that of the wild type in the complemented gacS mutant. The more highly flagellated gacS mutant cells had greater swimming motilities than that of the wild type strain. Enhanced flagella formation in the gacS mutant correlated with increased expression of three genes, fleQ, fliQ and flhF, involved in flagellar formation. Expression of these genes in the complemented gacS mutant was similar to that of the wild type. These findings show that this root-colonizing pseudomonad adjusts flagella formation and cell morphology in stationary-phase using GacS as a major regulator.

• Korean journal of applied entomology
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• 제27권4호
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• pp.200-210
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• 1988

ABSTRACT Brown planthopper collection data by 151 light traps located throughout the southern part of Korean peninsula for 7 years from 1981 thru 1987 were analysed with each immigration wave in relation to daily weather charts when the immigration occurred, and summarized as below. 1) Most of the main immigration took place during the mid and late July, though there were some variations from year to year. 2) Number of the BPH collected at one time, and the number of the area where those immigrants where collected were increased when it occurred closer to the end of July. 3) Weather conditions when the immigration took place were divided into 4 types; (a) depression with stationary front passed over the central peninsula (A type, 12 times); (b) depression with stationary front passed over the southern sea (B type, 5 times); (c) stationary front passed over the central peninsula(C type, 7 times); (d) without depression and stationary front (D type, 2 times). 4) Whatever the types of the weather, those immigrations started to land from south-west part of the peninsula, and those numbers of immigrants were also grater at those south-western areas. 5) When common weather factors were counted from each weather chart of the days when thcse immigrations took place, presence of wind from south-west was 26 times, presence of stationary front was 24 times, and presence of depression was 17 times out of all 26 cases of immigration. 6) Therefore, it could be concluded that the immigration of the BPH into Korea is simply accompanied by the north$.$easterly flowing air currents, connected from south-east part of China through Korean peninsula. And other factors seem to be related with inducing their landing.anding.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제4권1호
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• pp.101-107
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• 2000

In this paper we establish an upper bound for the estimation error variance of a continuous stream with a stationary variogram V which is assumed to be of the r-Holder type (Lipschitzian) on [-d, d]. Functional properties for the mapping ${\xi}(t):=E[(X-X(t))^2]$, $t{\in}[0,d]$, are also given.

• Bulletin of the Korean Mathematical Society
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• 제35권2호
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• pp.209-225
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• 1998

In this paper we obtain sharp upper and lower bounds of small ball oprobabilities for Gaussian processes with stationary increments, whose results are essential to estabilish Chung type laws of iterated logarithm.

• Journal of the Korean Mathematical Society
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• 제36권3호
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• pp.509-525
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• 1999

In this paper we obtain sharp upper and lower bounds of samll ball and large deviation probabilities for the increments of Gaussian processes with stationary increments, whose results are essential to establish Chung type laws of iteratted logarithm.

• Journal of the Korean Statistical Society
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• 제27권1호
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• pp.57-66
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• 1998

In the analysis of time series it is an important issue to determine whether a time series under study is stationary. For the test of the stationary of the time series the Dickey-Fuller (DF) type tests have been mainly used. In this paper, we consider the regular unit root tests and seasonal unit root tests based on the generalized Durbin-Watson (DW) statistics when the errors are independent. The limiting distributions of the proposed DW-type test statistics are the functionals of standard Brownian motions. We also obtain the finite distributions and powers of the DW-type test statistics and compare the performances with the DF-type tests. It is observed that the DW-type test statistics have good behaviors against the DF-type test statistics especially in the nonzero (seasonal) mean model.