• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.9
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• pp.50-59
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• 1997

This paper is on the generalized singular perturbation approximation (GSPA) preserving the discrete positive real property. We transform the discrete positive real(PR) system into a stochastically banlanced system and get the reduced order discrete system from the GSPA of the full order stochastically balanced system. eSPECIALLY, WHEN THE FREE PARAMETER OF THE gspa IS .+-.1, we show that the reduced order discrete system retains stability, minimality, and positive real and stochstically balancing properties. And we derived the .inf.-norm error bound with the reduced order discrete strictly positive real(SPR) system by the proposed method. Finally, we give an example to ascertain the properties of the proposed reduced order discrete system and to compare with the conventional methods.

• Journal of applied mathematics & informatics
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• v.14 no.1_2
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• pp.51-67
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• 2004

A matrix pair $(X_0,\;Y_0)$ is called a Hermitian nonnegative-definite(respectively, positive-definite) solution to the matrix equation $GXG^*\;+\;HYH^*\;=\;C$ with unknown X and Y if $X_{0}$ and $Y_{0}$ are Hermitian nonnegative-definite (respectively, positive-definite) and satisfy $GX_0G^*\;+\;HY_0H^*\;=\;C$. Necessary and sufficient conditions for the existence of at least a Hermitian nonnegative-definite (respectively, positive-definite) solution to the matrix equation are investigated. A representation of the general Hermitian nonnegative-definite (respectively positive-definite) solution to the equation is also obtained when it has such solutions. Two presented examples show these advantages of the proposed approach.

• Bulletin of the Korean Mathematical Society
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• v.33 no.4
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• pp.545-551
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• 1996

It is well known in the theory of distributions and proved in [GS, S] that $$ (i) (Bochner-Schwartz) Every positive definite (tempered) distribution is the Fourier transform of a positive tempered measure \mu. $$ $$ (ii) (Schwartz kernel theorem) Let B(\varphi, \psi) be a bilinear distribution. Then for some u \in D'(R^n \times R^n) B(\varphi, \psi) = u(\varphi(x)\bar{\psi}(y)) for every \varphi, \psi \in C_c^\infty. $$ $$ (iii) A translation invariant positive definite bilinear distribution B(\varphi, \psi) is of the form B(\varphi, \psi) = \smallint \varphi(x)\psi(x) d\mu(x) for every \varphi, \psi \in C_c^\infty (R^n), where \mu is a positive tempered measure.

• Journal of the Korean Mathematical Society
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• v.54 no.6
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• pp.1667-1682
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• 2017

In this paper, the Hermitian positive definite solutions of the matrix equation $X^s+A^*X-^tA=Q$, where Q is an $n{\times}n$ Hermitian positive definite matrix, A is an $n{\times}n$ nonsingular complex matrix and $s,t{\in}[1,{\infty})$ are discussed. We find a matrix interval which contains all the Hermitian positive definite solutions of this equation. Also, a necessary and sufficient condition for the existence of these solutions is presented. Iterative methods for obtaining the maximal and minimal Hermitian positive definite solutions are proposed. The theoretical results are illustrated by numerical examples.

• Korean Journal of Veterinary Service
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• v.22 no.2
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• pp.159-167
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• 1999

This survey was conducted for the serological confirmation on large outbreak of bovine brucellosis in two dairy farms. Serological tests were performed by the plate agglutination test, tube agglutination test, enzyme linked immunosorbent assay(ELISA), complement fixation, ,test(CFT) and rose bengal plate test(RBPT). Total 200 heads(134 heads in farm A and 66 heads in farm B) were tested. The primigravida and positive group have been raised separately in the farm A and both group have been raised together in the farm B.. The result were summarized as follows ; 1. Positive ratios in positive herds of farms by the tube agglutination test were 68.3% in farm A and 53.2% in farm B. 2. Seroconversion to brucella was observed in the primigravidas group in farm B, but was not observed in the primigravidas group in farm A. 3. All calves born in positive herd were serologically negative at time of test. 4. Positive ratio of ELISA in farm A was higher than that of tube agglutination test. 5. Number of positive reactors by the CFT, RBPT in farm A were equal to those of tube agglutination test.

• Journal of Information Technology Applications and Management
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• v.19 no.4
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• pp.213-225
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• 2012

The identified research result can be outlined more specifically as follows: first, informativeness of SNS was giving positive impact to some degree on the user satisfaction; second, connectivity of SNS was giving very positive impact on the user satisfaction; third, accessibility was giving very positive impact on the user satisfaction; forth, usability of SNS was giving very positive impact on the user satisfaction; fifth, amusement of SNS was giving very positive impact on the user satisfaction; the satisfaction level of SNS users gave positive impact on the further intention of SNS users. It was identified, however, that interactiveness of SNS was the factor that did not give much impact on the user satisfaction. This result comes from the analysis that SNS is convenient to actively explore and get further information that users wish to find, while they are insufficient in function to provide the information other users require or exchange information among users through the SNS.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.4
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• pp.136-139
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• 2003

The positive column of a discharge tube filled with a mixture of mercury-xenon has a tendency to become contracted at room temperature. However, once the tube temperature is raised over 50 [$^{\circ}C$], the positive column changes from a contracted state to a diffused state. The xenon emission is stronger in the contracted positive column than in the diffused column. Alternatively, the mercury emission is more intense in the diffused positive column, and the luminance of the phosphor coating on the inner surface of the tube is higher than that in the contracted positive column. Moreover, higher luminance can be obtained by increasing the xenon pressure.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.304-305
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• 2013

We report a positive exchange bias (HE) in thinmultilayered filmscontaining nano-oxide layer. The positive HE, obtained for our system results from an antiferromagnetic coupling between the ferromagnetic (FM) CoFe and the antiferromagnetic (AFM) CoO layers, which spontaneously form on top of the nano-oxide layer (NOL). The shift in the hysteresis loop along the direction of thecooling field and the change in the sign of exchange bias are evidence of antiferromagnetic interfacial exchange coupling between the CoO and CoFe layers. Our calculation indicates that uncompensated oxygen moments in the NOL results in antiferromagnetic interfacial exchange coupling between the CoO and CoFe layers. One of the interesting features observed with our system is that it displays the positive HE even above the bulk Neel temperature (TN) of CoO. Although the positive HEsystem has a different AFM/FM interfacial spin structure compare to that of the negative HE one, the results of the angular dependence measurements show that the magnetization reversal mechanism can be considered within the framework of the coherent rotation model.

• Journal of the Korean Home Economics Association
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• v.36 no.1
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• pp.13-21
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• 1998

Coping resources may be a crucial aspect in single mothers' and their childrens' adjustment. Using a survey data collected from 275 pairs of single mothers and their children, this study investigated the perceived effects of economic resoures, family relational resources, and social support on positive changes of both mothers and their children. Results revealed that both mothers and their children perceived positive changes of themselves and their children(mothers) relatively high. The degrees of positive changes of mothers were influenced mostly by family relational resources. In the same token, the degrees of positive changes of children were also affected by family relational resources. Overall, the findings suggested the importance of relational resources in explaining the positive changes of single mothers and their children.

• Korean Journal of Child Studies
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• v.23 no.6
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• pp.15-32
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• 2002

Child's temperament, cognitive ability, social competence, mother's affective child rearing and positive expression, father's positive expression, and teacher's positive expression were the variables investigated in relation to the structure of children's emotional competence (EC). Subjects were 20 teachers and 236 five-year-old children and their parents. Data were analyzed by LISREL (Linear Structural Relations), a statistical program for structural equation modeling. Results showed that boys' social competence and mother's affective rearing behavior directly influenced the EC of boys; boys temperament and cognitive ability, and positive expressions of their teachers indirectly influenced the EC of boys. Girls' temperament and social competence directly influenced the EC of girls; their cognitive ability, mother's affective child rearing behavior, and positive expressions of mothers and fathers indirectly influenced the EC of girls.