• Title/Summary/Keyword: $Theta^*$

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Active and Reactive Power Control Method for Grid-Connected Three-Phase PWM Inverter (계통 연계형 3상 PWM 인버터의 유·무효전력제어 방법)

  • Ahn, Hyun-Jin;Jung, Young-Gook;Lim, Young-Cheol;Oh, Seung-Yeol;Kim, Kwang-Heon
    • Proceedings of the KIPE Conference
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    • 2010.11a
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    • pp.263-264
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    • 2010
  • 본 연구에서는 3상 계통 연계형 인버터의 유 무효전력제어를 통해 부하에 필요한 전력을 공급하며 계통과 인버터를 안정적으로 연계하는 방법을 다루고 있다. 부하 변동 및 계통전압과 인버터 전압의 위상차 ${\theta}$에 따라 PSIM 시뮬레이션을 수행하였으며, 타당성을 입증하였다

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Relaxed Saint-Venant principle for thermoelastic micropolar diffusion

  • Marin, Marin;Abbas, Ibrahim;Kumar, Rajneesh
    • Structural Engineering and Mechanics
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    • v.51 no.4
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    • pp.651-662
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    • 2014
  • The main goal of this study is to extend the domain of influence result to cover the micropolar thermoelastic diffusion. So, we prove that for a finite time t>0 the displacement field $u_i$, the microrotation vector ${\varphi}_i$, the temperature ${\theta}$ and the chemical potential P generate no disturbance outside a bounded domain $B_t$.

A GENERALIZED APPROACH TOWARDS NORMALITY FOR TOPOLOGICAL SPACES

  • Gupta, Ankit;Sarma, Ratna Dev
    • Korean Journal of Mathematics
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    • v.29 no.3
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    • pp.501-510
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    • 2021
  • A uniform study towards normality is provided for topological spaces. Following Császár, 𝛄-normality and 𝛄(𝜃)-normality are introduced and investigated. For 𝛄 ∈ 𝚪13, 𝛄-normality is found to satisfy Urysohn's lemma and provide partition of unity. Several existing variants of normality such as 𝜃-normality, 𝚫-normality etc. are shown to be particular cases of 𝛄(𝜃)-normality. In this process, 𝛄-regularity and 𝛄(𝜃)-regularity are introduced and studied. Several important characterizations of all these notions are provided.

BAILEY PAIRS AND STRANGE IDENTITIES

  • Lovejoy, Jeremy
    • Journal of the Korean Mathematical Society
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    • v.59 no.5
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    • pp.1015-1045
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    • 2022
  • Zagier introduced the term "strange identity" to describe an asymptotic relation between a certain q-hypergeometric series and a partial theta function at roots of unity. We show that behind Zagier's strange identity lies a statement about Bailey pairs. Using the iterative machinery of Bailey pairs then leads to many families of multisum strange identities, including Hikami's generalization of Zagier's identity.

NEW CONGRUENCES FOR ℓ-REGULAR OVERPARTITIONS

  • Jindal, Ankita;Meher, Nabin K.
    • Journal of the Korean Mathematical Society
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    • v.59 no.5
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    • pp.945-962
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    • 2022
  • For a positive integer ℓ, $\bar{A}_{\ell}(n)$ denotes the number of over-partitions of n into parts not divisible by ℓ. In this article, we find certain Ramanujan-type congruences for $\bar{A}_{r{\ell}}(n)$, when r ∈ {8, 9} and we deduce infinite families of congruences for them. Furthermore, we also obtain Ramanujan-type congruences for $\bar{A}_{13}(n)$ by using an algorithm developed by Radu and Sellers [15].

REPRESENTATIONS BY QUATERNARY QUADRATIC FORMS WITH COEFFICIENTS 1, 2, 11 AND 22

  • Bulent, Kokluce
    • Bulletin of the Korean Mathematical Society
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    • v.60 no.1
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    • pp.237-255
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    • 2023
  • In this article, we find bases for the spaces of modular forms $M_2({\Gamma}_0(88),\;({\frac{d}{\cdot}}))$ for d = 1, 8, 44 and 88. We then derive formulas for the number of representations of a positive integer by the diagonal quaternary quadratic forms with coefficients 1, 2, 11 and 22.

A Flexible Query Processing System for XML Regular Path Expressions (XML 정규 경로식을 위한 유연한 질의 처리 시스템)

  • 김대일;김기창;김유성
    • Journal of KIISE:Databases
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    • v.30 no.6
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    • pp.641-650
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    • 2003
  • The eXtensible Markup Language(XML) is emerging as a standard format of data representation and exchange on the Internet. There have been researches about storing and retrieving XML documents using the relational database which has techniques in full growth about large data processing, recovery, concurrency control and so on. Since in previous systems same structure information and fundamental operation are used for processing of various kinds of XML queries, only some specific query can be efficiently processed not all types of query. In this paper, we propose a flexible query processing system. To process query efficiently, the proposed system analyzes regular path expression queries, and uses $\theta$-join operation using region numbering values to check ancestor-descendent relationship and equi-join operation using parent's region start value to check parent-child relationship. Thus, the proposed system processes efficiently XML regular path expressions. From the experimental results, we show that proposed XML query processing system is more efficient than previous systems.

Assessment of Maximum Spreading Models for a Newtonian Droplet Impacting on a Solid Surface (고체 표면에 충돌하는 뉴턴 액적에 대한 최대 액막 직경 모델 검토)

  • An, Sang-Mo;Lee, Sang-Yong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.6
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    • pp.633-638
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    • 2012
  • The maximum spreading is the maximum extent to which a drop can spread after impacting on a surface. It is one of the crucial factors determining the spraying performance in many applications. In this study, the existing maximum spreading models for a Newtonian liquid droplet impacting on a dry solid surface were reviewed and compared with the experimental results over the ranges of $4{\leq}Re{\leq}11700$, $23{\leq}We{\leq}786$, and $37.9^{\circ}{\leq}{\theta}_s{\leq}107.1^{\circ}$. The surface wettability was found to have only a minor influence on the maximum spreading, compared to the liquid viscosity and impact velocity. Among the models tested, the Roisman (2009) model showed the best agreement with the experimental results, matching 80% of the measured data within ${\pm}5%$.