• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.54 no.6
• /
• pp.274-283
• /
• 2005

This paper presents a new method to derive energy function based on vector product. Using this method, an energy function to consider transfer conductances and capacitors is derived. Then we recommend a voltage collapse criteria to predict the voltage collapse in power systems by using the energy margin derived by the proposed energy function. This energy function is applied to a 2-bus power system reflecting transfer conductances and capacitors. We show that the energy function derived based on vector product can be applied in order to analyze power system stability and the energy margin can be utilized as a criterion of voltage collapse by simulation for the 2-bus system.

• Journal of the Korean Statistical Society
• /
• v.35 no.2
• /
• pp.213-224
• /
• 2006

We investigate the influence of subjects or observations on regression coefficients of generalized estimating equations using the influence function and the derivative influence measures. The influence function for regression coefficients is derived and its sample versions are used for influence analysis. The derivative influence measures under certain perturbation schemes are derived. It can be seen that the influence function method and the derivative influence measures yield the same influence information. An illustrative example in longitudinal data analysis is given and we compare the results provided by the influence function method and the derivative influence measures.

• Journal of applied mathematics & informatics
• /
• v.12 no.1_2
• /
• pp.129-142
• /
• 2003

In this paper we study the chromatic sum functions for rooted nonseparable simple maps on the plane. The chromatic sum function equation for such maps is obtained . The enumerating function equation of such maps is derived by the chromatic sum equation of such maps. From the chromatic sum equation of such maps, the enumerating function equation of rooted nonseparable simple bipartite maps on the plane is also derived.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.10
• /
• pp.1175-1182
• /
• 1999

This paper shows that a well-defined energy function can be developed to reflect the transfer conductances for multi-machine power systems under an assumption that all transmission lines have uniform R/X rations. The energy function is derived by introducing a pure reactive equivalent system for the given system. In this study, a static energy function reflecting transfer conductances is also derived as well as the transient energy function. The proposed static energy function is applied to voltage stability analysis and tested for various sample systems. The test results show that the accuracy of voltage stability analysis can be considerable improved by reflecting transfer conductances into the energy function.

• Communications for Statistical Applications and Methods
• /
• v.15 no.4
• /
• pp.509-516
• /
• 2008

We derive the influence function on the coefficient of variation. Empirical influence function and Sample influence function are used to verify the validity of the derived influence function. To show the validity of the influence function, we carry out simulations with random samples from normal distribution $N(20,1^2)$ and $N(20,5^2)$, respectively. The simulation result proves that the derived influence function is very accurate in estimating changes in the coefficient of variation when an observation is deleted.

• Korean Journal of Mathematics
• /
• v.22 no.2
• /
• pp.325-337
• /
• 2014

In 1911 Schur[6] derived degree and character formulas for projective representations of the symmetric groups remarkably similar to the corresponding formulas for ordinary representations. Morris[3] derived a recurrence for evaluation of spin characters and Stembridge[8] gave a combinatorial reformulation for Morris' recurrence. In this paper we give combinatorial interpretations for the orthogonality relations of spin characters based on Stembridge's combinatorial reformulation for Morris' rule.

• Journal of the Korean Mathematical Society
• /
• v.53 no.1
• /
• pp.147-159
• /
• 2016

In this paper, subordination results of analytic function $f{\in}{\mathcal{A}}_p$ involving linear operator ${\mathcal{K}}^{{\delta},{\lambda}}_{c,p}$ are obtained. By applying the differential subordination method, results are derived under some sufficient subordination conditions. On using some hypergeometric identities, corollaries of the main results are derived. Furthermore, convolution preserving properties for a class of multivalent analytic function associated with the operator ${\mathcal{K}}^{{\delta},{\lambda}}_{c,p}$ are investigated.

• Earthquakes and Structures
• /
• v.9 no.2
• /
• pp.305-320
• /
• 2015

The present paper is devoted to study SH-wave propagation in heterogeneous layer laying over an inhomogeneous isotropic elastic half-space. The dispersion relation for propagation of said waves is derived with Green's function method and Fourier transform. As a special case when the upper layer and lower half-space are homogeneous, our derived equation is in agreement with the general equation of Love wave. Numerically, it is observed that the velocity of SH-wave increases with the increase of inhomogeneity parameter.

• Journal of Korean Neurosurgical Society
• /
• v.40 no.4
• /
• pp.267-272
• /
• 2006

Objective : There have been recent reports that mesenchymal stromal cells that are harvested from adipose tissue are able to differentiate into neurons. In the present study, we administered adipose tissue derived stem cells in rats with cerebral infarction in order to determine whether those stem cells could enhance the recovery of motor function. Methods : Cerebral infarction was induced by intraluminal occlusion of middle cerebral artery in rats. The adipose tissue-derived mesenchymal stem cells were harvested from inguinal fat pad and proliferated for 2 weeks in DMEM media. Approximately $1{\times}10^6$ cells were injected intravenously or into subdural space of the peri-lesional area. The rotor rod test was performed at preoperative state[before MCA occlusion], and 1, 2, 3, 4, 6, 8 and 10 weeks after the cell therapy. Results : The motor functions that were assessed by rotor rod test at 1 week of the cell therapy were nearly zero among the experimental groups. However, there was apparent motor function recovery after 2 weeks and 4 weeks of cell injection in intravenously treated rats and peri-lesionaly treated rats, respectively, while there was no significant improvement till 8 weeks in vehicle treated rats. Conclusion : These results demonstrate that the adipose derived stem cell treatment improves motor function recovery in rats with cerebral infarction.

• BMB Reports
• /
• v.48 no.2
• /
• pp.103-108
• /
• 2015

Trichomoniasis caused by the parasitic protozoan Trichomonas vaginalis is the most common sexually transmitted disease in the world. Dendritic cells are antigen presenting cells that initiate immune responses by directing the activation and differentiation of naive T cells. In this study, we analyzed the effect of Trichomonas vaginalis-derived Secretory Products on the differentiation and function of dendritic cells. Differentiation of bone marrow-derived dendritic cells in the presence of T. vaginalis-derived Secretory Products resulted in inhibition of lipopolysaccharide-induced maturation of dendritic cells, down-regulation of IL-12, and up-regulation of IL-10. The protein components of T. vaginalis-derived Secretory Products were shown to be responsible for altered function of bone marrow-derived dendritic cells. Chromatin immunoprecipitation assay demonstrated that IL-12 expression was regulated at the chromatin level in T. vaginalis-derived Secretory Products-treated dendritic cells. Our results demonstrated that T. vaginalis- derived Secretory Products modulate the maturation and cytokine production of dendritic cells leading to immune tolerance.