• Kyungpook Mathematical Journal
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• v.51 no.2
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• pp.139-143
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• 2011

In this paper we consider mappings ${\sigma}$ which map the binary operation symbol f to the term ${\sigma}$(f) which do not necessarily preserve the arities. We call these mappings generalized hypersubstitutions. Any generalized hypersubstitution ${\sigma}$ can be extended to a mapping $\hat{\sigma}$ on the set of all terms of type ${\tau}$ = (2). We de ne a binary operation on the set $Hyp_G$(2) of all generalized hypersubstitutions of type ${\tau}$ = (2) by using this extension The set $Hyp_G$(2) together with the identity generalized hypersubstitution ${\sigma}_{id}$ which maps f to the term f($x_1,x_2$) forms a monoid. We determine all regular elements of this monoid.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.378-381
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• 2002

We retrieved the aerosol optical thickness $\tau$$_{a}$ over land from Landsat-7/ETM+ image data using the correlation between the visible reflectance and middle IR reflectance. This band correlation method for aerosol retrieval was originally proposed fur MODIS data analysis by Kaufman et al.(1977). The results of retrieved aerosol optical thickness $\tau$$_{a}$ from Landsat-7/ETM+ data were compared with the simultaneous sky observation data at our study site. We found a good agreement between the retrieved and observed values. We presented the distribution maps of the aerosol optical thickness over land, retrieved from Landsat-7/ETM+ image data. Then, the surface reflectance map was also presented. The aerosol optical thickness over sea was retrieved assuming no reflected contribution from sea in the near IR band. In addition, we discussed some limitations when we apply the band correlation method.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.4
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• pp.194-200
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• 2012

In this paper we analyze the code sequence generating algorism defined on $GF(2^n)$ proposed by S.Bostas and V.Kumar[7] and derive the implementation functions of code sequence generator using Boolean functions which can map the vector space $F_2^n$ of all binary vectors of length n, to the finite field with two elements $F_2$. We find the code sequence generating boolean functions based on two kinds of the primitive polynomials of degree, n=5 and n=7 from trace function. We then design and implement the code sequence generators using these functions, and produce two code sequence groups. The two groups have the period 31 and 127 and the magnitudes of out of phase(${\tau}{\neq}0$) autocorrelation and crosscorrelation functions {-9, -1, 7} and {-17, -1, 15}, satisfying the period $L=2^n-1$ and the correlation functions $R_{ij}({\tau})=\{-2^{(n+1)/2}-1,-1,2^{(n+l)/2}-1\}$ respectively. Through these results, we confirm that the code sequence generators using boolean functions are designed and implemented correctly.

• The Journal of Korean Medicine
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• v.30 no.3
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• pp.1-14
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• 2009

Objectives : Alzheimer's disease (AD) is characterized by neuronal loss and extracellular senile plaque. Moreover, the cellular actions of ${\beta}$-amyloid (A${\beta}$ play a causative role in the pathogenesis of AD. This study was designed to determine whether Woo-Gui-Um, a commonly used Korean herbal medicine, has the ability to protect cortical and hippocampal neurons against A${\beta}_{25-35}$ neurotoxicity Methods : In the present study, the authors investigated the preventative effects of the water extract of Woo-Gui-Um in a mouse model of AD. Memory impairment was induced by intraventricularly (i.c.v.) injecting A${\beta}_{25-35}$ peptides into mice. Woo-Gui-Um extract was then administered orally (p.o.) for 14 days. In addition, A${\beta}_{25-35}$ toxicity on the hippocampus was assessed immunohistochemically, by staining for Tau, MAP2, TUNEL, and Bax, and by performing an in vitro study in PC12 cells. Results : Woo-Gui-Um extract had an effect to improve learning ability and memory score in the water maze task. Woo-Gui-Um extract had significant neuroprotective effects in vivo against oxidative damage and apoptotic cell death of hippocampal neurons caused by i.c.v. A${\beta}_{25-35}$. In addition, Woo-Gui-Um extract was found to have a protective effect on A${\beta}_{25-35}$-induced apoptosis, and to promote neurite outgrowth of nerve growth factor (NGF)-differentiated PC12 cells. Conclusions : These results suggest that Woo-Gui-Um extract reduces memory impairment and Alzheimer's dementia via an anti-apoptotic effect and by regulating Tau and MAP2 in the hippocampus.

• Journal of the Chungcheong Mathematical Society
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• v.24 no.2
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• pp.239-245
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• 2011

In this paper, we will study the tension field of the function related to a Riemannain submersion ${\pi}\;:\;N{\rightarrow}M$ with totally geodesic fibres. In case that the Riemannain submersion ${\pi}\;:\;N{\rightarrow}M$ particularly has a smooth map $f\;:\;M{\rightarrow}N$ which happens to be a section, we will show that tension field ${\tau}(f)$ of the energy functional can be decomposed into the horizontal and vertical parts.

• Journal of the Korean Mathematical Society
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• v.42 no.1
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• pp.129-134
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• 2005

Lpt X be a reduced Stein space and L a holomorphic line bundle on X. L is spanned by its global sections and the associated holomorphic map $h_L\;:\;X{\to}P(H^0(X, L)^{\ast})$ is an embedding. Choose any locally convex vector topology ${\tau}\;on\;H^0(X, L)^{\ast}$ stronger than the weak-topology. Here we prove that $h_L(X)$ is sequentially closed in $P(H^0(X, L)^{\ast})$ and arithmetically Cohen -Macaulay. i.e. for all integers $k{\ge}1$ the restriction map ${\rho}_k\;:\;H^0(P(H^0(X, L)^{\ast}),\;O_{P(H^0(X, L)^{\ast})}(k)){\to}H^0(h_L(X),O_{hL_(X)}(k)){\cong}H^0(X, L^{\otimes{k}})$ is surjective.

• East Asian mathematical journal
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• v.24 no.1
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• pp.35-43
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• 2008

Let E be a uniformly convex Banach space and K be a nonempty closed convex subset of E. Let ${\{T_i\}}^N_{i=1}$ be N nonexpansive self-mappings of K with $F\;=\;{\cap}^N_{i=1}F(T_i)\;{\neq}\;{\theta}$ (here $F(T_i)$ denotes the set of fixed points of $T_i$). Suppose that one of the mappings in ${\{T_i\}}^N_{i=1}$ is semi-compact. Let $\{{\alpha}_n\}\;{\subset}\;[{\delta},\;1-{\delta}]$ for some ${\delta}\;{\in}\;(0,\;1)$ and $\{{\beta}_n\}\;{\subset}\;[\tau,\;1]$ for some ${\tau}\;{\in}\;(0,\;1]$. For arbitrary $x_0\;{\in}\;K$, let the sequence {$x_n$} be defined iteratively by $\{{x_n\;=\;{\alpha}_nx_{n-1}\;+\;(1-{\alpha}_n)T_ny_n,\;\;\;\;\;\;\;\;\; \atop {y_n\;=\;{\beta}nx_{n-1}\;+\;(1-{\beta}_n)T_nx_n},\;{\forall}_n{\geq}1,}$, where $T_n\;=\;T_{n(modN)}$. Then {$x_n$} convergence strongly to a common fixed point of the mappings family ${\{T_i\}}^N_{i=1}$. The result presented in this paper generalized and improve the corresponding results of Chidume and Shahzad [C. E. Chidume, N. Shahzad, Strong convergence of an implicit iteration process for a finite family of nonexpansive mappings, Nonlinear Anal. 62(2005), 1149-1156] even in the case of ${\beta}_n\;{\equiv}\;1$ or N=1 are also new.

• Journal of Ginseng Research
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• v.46 no.4
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• pp.515-525
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• 2022

Background: The incidence of ischemic cerebrovascular disease is increasing in recent years and has been one of the leading causes of neurological dysfunction and death. Ginsenoside Rg1 has been found to protect against neuronal damage in many neurodegenerative diseases. However, the effect and mechanism by which Rg1 protects against cerebral ischemia-reperfusion injury (CIRI) are not fully understood. Here, we report the neuroprotective effects of Rg1 treatment on CIRI and its possible mechanisms in mice. Methods: A bilateral common carotid artery ligation was used to establish a chronic CIRI model in mice. HT22 cells were treated with Rg1 after OGD/R to study its effect on [Ca²⁺]_i. The open-field test and poleclimbing experiment were used to detect behavioral injury. The laser speckle blood flowmeter was used to measure brain blood flow. The Nissl and H&E staining were used to examine the neuronal damage. The Western blotting was used to examine MAP2, PSD95, Tau, p-Tau, NOX2, PLC, p-PLC, CN, NFAT1, and NLRP1 expression. Calcium imaging was used to test the level of [Ca²⁺]_i. Results: Rg1 treatment significantly improved cerebral blood flow, locomotion, and limb coordination, reduced ROS production, increased MAP2 and PSD95 expression, and decreased p-Tau, NOX2, p-PLC, CN, NFAT1, and NLRP1 expression. Calcium imaging results showed that Rg1 could inhibit calcium overload and resist the imbalance of calcium homeostasis after OGD/R in HT22 cells. Conclusion: Rg1 plays a neuroprotective role in attenuating CIRI by inhibiting oxidative stress, calcium overload, and neuroinflammation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.10
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• pp.1254-1261
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• 1997

Pulse boiling, the unsteady periodic boiling phenomenon appearing in the evaporator of thermosyphons was investigated by many researchers. In the present study investigations were conducted to examine the evolution of flow patterns at the evaporator, and changes in thermodynamic state that each of liquid pool and vapor experiences through 1 cycle of pulse boiling process. For wall and liquid pool the degree of superheat for the onset of nucleation was examined. It revealed that the degree of superheat increased with the increase of pulse period, reaching to 16.5 deg.C and 23 deg.C for liquid pool and evaporator wall respectively at .tau.=80 sec. The data on flow patterns obtained through series of operation tests were plotted in the coordinates of heat flux and vapor pressure to get a regime map. Further this map could be used to figure out the conditions of pulse boiling for a thermosyphon.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.38-38
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• 2018

본 논문에서는 분포형 강우-유출 모형인 GRM(Grid based Rainfall-runoff Model)의 확장성과 편의성 향상을 위한 소프트웨어 개발에 대해서 기술하였다. 본 연구에서는 크게 3가지를 수행하였다. 첫 번째는 기존의 GRM은 HyGIS, MapWindow GIS 등과 같은 GIS 소프트웨어 및 Microsoft MDB와 코드 수준에서 통합된 형태로 개발되었으며, 이러한 특성은 GRM을 이용한 다양한 응용시스템 개발시 제약 조건으로 작용하였다. 본 연구에서는 GRM 모형을 GIS 및 데이터베스와 코드 수준에서 분리하여 GRMCore.dll을 개발하였다. GRMCore.dll은 콘솔 모드 및 GUI에서 유출해석을 실행할 수 있는 소프트웨어와 실시간 유출해석시스템 등과 같이 유출 해석을 위한 다양한 응용 소프트웨어 개발에 공통적으로 활용될 수 있다. 두 번째는 최근 들어 세계적으로 가장 많이 사용되고 있는 오픈소스 GIS 인 QGIS의 plugin으로 GRM 모형의 GUI(QGIS-GRM)를 개발하였으며, GRM 모형의 입력자료 구축을 위해 TauDEM을 이용해서 Drainage Tool을 개발하였다. Drainage Tool에서는 격자별 흐름방향, 하천망, 유역 등과 같은 수문학적 공간정보를 DEM을 이용하여 구축할 수 있다. 세 번째는 개발된 소프트웨어를 오픈소스로 공개하였다. 공개 대상은 GRM 모형, QGIS-GRM, Drainage Tool 등이며, 각 소프트웨어에 대한 매뉴얼을 포함하고 있다. 소스코드의 공개는 세계적으로 널리 이용되고 있는 오픈소스 플랫폼인 Github(https://github.com/floodmodel/)를 이용하였다. 본 연구를 통해서 기존에는 특정 소프트웨어에 코드 수준에서 의존적이던 GRM 모형의 독립성을 향상시켰으며, 이를 통해 다양한 응용 소프트웨어 개발에 대한 적용성을 높일 수 있었다. 또한 QGIS 기반의 GUI 개발, 모형 입력자료 구축 도구의 개발, 개발된 소프트웨어의 오픈소스화 등을 통해서 사용자들이 좀 더 쉽게 GRM 모형을 활용할 수 있게 하였다.