• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.701-707
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• 2005

Delta sequences play an important role in convergence and approximation theory. Much of classical approximation theory is based on delta sequence. The rate of convergence of certain types of these sequences in Sobolev spaces has recently been studied. Here we estimate convergence rate of convolution type delta sequence in higher dimension.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.550-558
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• 2018

This paper presents the current limit strategy of voltage controller of delta-connected H-bridge static synchronous compensator (STATCOM) under an unbalanced voltage fault event. When phase to ground fault happens, the feasibility to heighten the magnitude of sagging phase voltage is considered by using symmetric transformation method in delta-structure STATCOM. And the efficiency to cover the maximum physical current limit of switching device is considered by using vector analysis method that calculate the zero sequence current for balancing the cluster energy in delta connected H-bridge STATCOM. The result is simple and obvious. Only positive sequence current has to be used to support the unbalanced voltage sag. Although the relationship between combination of the negative sequence voltage with current and zero sequence current is nonlinear, the more negative sequence current is supplying, the larger zero sequence current is required. From the full-model STATCOM system simulation, zero sequence current demand is identified according to a ratio of positive and negative sequence compensating current. When only positive sequence current support voltage sag, the least zero sequence current is needed.

• 생명과학회지
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• 제24권10호
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• pp.1046-1054
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• 2014

${\beta}$-1,3-glucanase는 다양한 바이오공정에 널리 사용되어지는 효소로서 산업적 이용가치 증대를 위해 ${\beta}$-1,3-glucanase의 대량생산이 요구되어 지고 있다. 본 연구에서는 반복서열 ${\delta}$-sequence에 의한 integration를 통해 Aspergillus oryzae유래의 ${\beta}$-1,3-glucanase (EXGA)의 과발현 유도를 연구하였다. 먼저 효모내의 여러 염색체상에 EXGA 유전자를 integration하기 위해 $pRS{\delta}K$-exgA와 $pRS{\delta}K$-exgA 플라스미드를 구축하였다. 이 플라스미드는 유전자의 구성적 발현을 위한 ADH1 프로모터, 분비생산을 위한 signal sequence와 ${\beta}$-1,3-glucanase유전자의 integration을 위한 ${\delta}$-sequence를 포함하고 있다. 먼저 $pRS{\delta}K$-exgA 플라스미드를 $BY4742{\Delta}exg1$ 균주에 형질전환하고, 재조합 ${\beta}$-1.3-glucanase가 안정하게 과발현 및 분비생산됨을 확인하였다. 다음으로 geneticin 선별을 통한 integration 유도와 ${\beta}$-1,3-glucanase 활성과의 관계를 조사해보기 위해 $pRS{\delta}K$-exgA 플라스미드를 $BY4742{\Delta}exg1$ (YKY082) 균주에 도입한 결과, geneticin 농도 증가에 따라 ${\beta}$-1,3-glucanase 활성도 증가되었고, geneticin 농도 0.8 mg/ml가 ${\beta}$-1,3-glucanase과발현에 적합한 농도임을 확인 할 수 있었다. 이어서 $pRS{\delta}K$-exgA 플라스미드는 연속적 ${\delta}$-integration에 의해 효모세포 내에 도입되어, 한번, 두번, 세번 그리고 네번의 integration에 의해 ${\beta}$-1,3-glucanase의 비활성은 0.063, 0.095, 0.131 그리고 0.165 unit/ml/$OD_{600}$로 증가되었다. 또한 연속적 integration에 의해 ${\beta}$-1,3-glucanase의 활성이 증가됨에 따라 다양한 염색체에 도입된 EXGA 유전자의 복제수(integration 빈도)도 같이 증가되었음을 확인하였다. 따라서 본 연구 결과는 반복적 ${\delta}$-sequence integration방법을 통해 재조합 ${\beta}$-1,3-glucanase의 활성을 점진적으로 안정하게 증가시킬 수 있음을 제시하였다.

• 대한수학회논문집
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• 제21권2호
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• pp.261-272
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• 2006

In this paper, we define the sequence spaces: $[V,{\lambda},f,p]_0({\Delta}^r,E,u),\;[V,{\lambda},f,p]_1({\Delta}^r,E,u),\;[V,{\lambda},f,p]_{\infty}({\Delta}^r,E,u),\;S_{\lambda}({\Delta}^r,E,u),\;and\;S_{{\lambda}0}({\Delta}^r,E,u)$, where E is any Banach space, and u = ($u_k$) be any sequence such that $u_k\;{\neq}\;0$ for any k , examine them and give various properties and inclusion relations on these spaces. We also show that the space $S_{\lambda}({\Delta}^r, E, u)$ may be represented as a $[V,{\lambda}, f, p]_1({\Delta}^r, E, u)$ space. These are generalizations of those defined and studied by M. Et., Y. Altin and H. Altinok [7].

• Journal of applied mathematics & informatics
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• 제16권1_2호
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• pp.633-641
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• 2004

In this paper we deal with functions in higher dimension. We provide several convergence theorem for approximation by convolution type delta sequence. We also give sufficient and necessary condition for Gibbs phenomenon to exist.

• Kyungpook Mathematical Journal
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• 제50권3호
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• pp.389-397
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• 2010

In this paper we introduce the new generalized difference sequence space $\ell_\infty$($\Delta_v^n$, M,p,q,s), $\bar{c}$($\Delta_v^n$,M,p,q,s), $\bar{c_0}$($\Delta_v^n$,M,p,q,s), m($\Delta_v^n$,M,p,q,s) and $m_0$($\Delta_v^n$,M,p,q,s) defined over a seminormed sequence space (X,q). We study some of it properties, like completeness, solidity, symmetricity etc. We obtain some relations between these spaces as well as prove some inclusion result.

• Kyungpook Mathematical Journal
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• 제51권4호
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• pp.385-393
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• 2011

The aim of this paper is to introduce and study the sequence spaces [w, ${\theta}$, F, p, q]$_{\infty}({\Delta}_{\upsilon}^m)$, [w, ${\theta}$, F, p, q]$_1({\Delta}_{\upsilon}^m)$ and [w, ${\theta}$, F, p, q]$_0({\Delta}_{\upsilon}^m)$, which arise from the notions of generalized difference sequence space, lacunary convergence, invariant mean and a sequence of Moduli $F=(f_k)$. We establish some inclusion relations between these spaces under some conditions.

• 대한수학회논문집
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• 제20권4호
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• pp.723-729
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• 2005

Let F be a non-trivial non-Archimedian field. The sequence spaces $\Gamma\;(F)\;and\;{\Gamma}^{\ast}(F)$ were defined and studied by Soma-sundaram[4], where these spaces denote the spaces of entire and analytic sequences defined over F, respectively. In 1997, these spaces were generalized by Mursaleen and Qamaruddin[1] by considering an arbitrary sequence $U\;=\;(U_k),\;U_k\;{\neq}\;0 \;(\;k\;=\;1,2,3,{\cdots})$. They characterized some classes of infinite matrices considering these new classes of sequences. In this paper, we further generalize the above mentioned spaces and define the spaces $\Gamma(u,\;F,\;{\Delta}),\;{\Gamma}^{\ast}(u,\;F,\;{\Delta}),\;l_p(u,\;F,\;{\Delta})$), and $b_v(u,\;F,\;{\Delta}$). We also study some matrix transformations on these new spaces.

• Kyungpook Mathematical Journal
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• 제55권4호
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• pp.909-931
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• 2015

This paper presents some new paranormed sequence spaces $X(r,s,t,p;{\Delta})$ where $X{\in}\{l_{\infty}(p),c(p),c_0(p),l(p)\}$ defined by using generalized means and difference operator. It is shown that these are complete linear metric spaces under suitable paranorms. Furthermore, the ${\alpha}$-, ${\beta}$-, ${\gamma}$-duals of these sequence spaces are computed and also obtained necessary and sufficient conditions for some matrix transformations from $X(r,s,t,p;{\Delta})$ to X. Finally, it is proved that the sequence space $l(r,s,t,p;{\Delta})$ is rotund when $p_n$ > 1 for all n and has the Kadec-Klee property.

• 천문학회보
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• 제41권2호
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• pp.58.3-58.3
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• 2016

The Kepler space mission provides quantitative and qualitative photometric time series of oscillating stars. It is possible to examine statistical study with seismic properties of solar-like stars. Global seismic properties - large frequency separation (${\Delta}{\nu}$), frequency of maximum power (${\nu}_{max}$) and amplitude of Gaussian envelope (A) widely have been used to determine empirical scaling relations for inferring the stellar physical quantities - mass, age and temperature. We aim to confirm whether width of Gaussian envelope on power excess (${\delta}{\nu}_{env}$) can be used with parameter of scaling relation before redgiant phase using Kepler data. Therefore we analyze the characteristics of ${\delta}{\nu}_{env}$ of 129 solar-like stars from main-sequence to subgiant. We have demonstrated that ${\delta}{\nu}_{env}$ has highly correlations with global parameters - ${\Delta}{\nu}$ and ${\nu}max$. We have also found the break of ${\delta}{\nu}_{env}-{\Delta}{\nu}$ and ${\nu}_{max}$ relations.