• 호남수학학술지
• /
• 제37권2호
• /
• pp.265-267
• /
• 2015

Let G be a cyclic group of prime power order. There is a natural embedding of $\mathbb{Z}$[G] into a product of rings of integers of cyclotomic fields. In this paper we determine the image of powers of the augmentation ideal.

• 호남수학학술지
• /
• 제36권1호
• /
• pp.33-41
• /
• 2014

Ko(2013, JIA 2013:473) discussed complete convergence for weighted sum of martingale difference field when all indices have the same powers in the normalization. In this paper we generalize this law to the case where different indices have different powers in the normalization.

• Korean Journal of Mathematics
• /
• 제28권2호
• /
• pp.191-203
• /
• 2020

Any powers of 11 are easily obtained from the Pascal triangle. In this work we study powering and negative powering of any k digit integers by means of certain arithmetic tables.

• 대한수학회보
• /
• 제36권1호
• /
• pp.161-169
• /
• 1999

Generalized nonnegative trigonometric polynomials are defined as the products of nonnegative trigonometric polynomials raised to positive real powers. The generalized degree can be defined in a natural way. We improve and extend the large sieve involving pth powers of trigonometric polynomials so that it holds for generalized trigonometric polynomials.

• 대한수학회논문집
• /
• 제25권2호
• /
• pp.215-224
• /
• 2010

Generalized nonnegative polynomials are defined as products of nonnegative polynomials raised to positive real powers. The generalized degree can be defined in a natural way. In this paper we extend quadrature sums involving pth powers of polynomials to those for generalized polynomials.

• 대한수학회지
• /
• 제50권3호
• /
• pp.543-555
• /
• 2013

We consider powers of lexsegment ideals with a linear resolution (equivalently, with linear quotients) which are not completely lexsegment ideals. We give a complete description of their minimal graded free resolution.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제8권4호
• /
• pp.21-26
• /
• 2003

황과 Powers(2003)는 입도분포와 공극크기분포에 로그분포함수를 적용하여, 입도분포로부터 토양수분특성을 직접 추정하는 간단한 모형을 개발하였다. 본 연구의 목적은 황과 Powers(2003)가 개발한 모형의 추정능력이 토성에 의해 영향을 받는가를 밝히는 것이다. 연구결과, 모형은 토성에 의해 영향을 받았고, 특히 토양내 세립질 분율이 커질수록 모형의 추정능력은 감소하였다. 또한 입도와 공극크기사이의 관계를 비선형으로 가정한 비선형모형이 선형모형보다 토성에 관계없이 그 추정능력이 크게 나타났다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 A
• /
• pp.391-393
• /
• 2000

This paper presents an new algorithm for the economic load dispatch considering the reliability level constraints of composite power system under deregulated electricity market. It is the traditional ELD problem that generation powers have been dispatched In order to minimize total fuel cost subjected to constraints which sum of powers generated must equal the received load and no violating lower and upper limit constraints on generation. Under deregulated electricity market, however, generation powers of a pool have to be reallocated newly in order to satisfy the reliability differentiated level required at a load point because of a reliability differentiated electricity service which is a part of the priority service. In this study, new economic load dispatch algorithm for reallocating the generation powers of a pool in order to satisfy the reliability differentiated level under deregulated competitive electricity market is proposed. The uncertainties of not only generators but also transmission lines are considered fer the reliability evaluation. The characteristics and effectiveness of this methodology are illustrated by the case studies on MRBTS and IEEE-RTS.

• 한국산업융합학회 논문집
• /
• 제3권3호
• /
• pp.219-228
• /
• 2000

In order to evaluate the applicability of thermosyphon as an equipment of heat transfer to the case where natural of low temperature and low density is necessary and to propose the possibility of using natural energy being clean and inexhaustible, a thermosypon using methanol as working fluid was constructed and its transfer characteristics were analysed. The wall temperature of the thermosyphon was maintained relatively uniform after rapid increase until after being heated about ten minutes regardless of the level of input powers to the evaporating section. Inner pressure of the thermosyphon increased rapidly until after ten minutes, and then increased slowly depending on the level of input power. But heat transfer coefficient of the condensible section decreased in inverse proportion to input powers of 250~300W, showing $1008.3{\sim}829.8W/m^2{\cdot}^{\circ}C$. For the input powers of the thermosyphon within the range of 100~250W, heat transferred and heat flux increased relatively linearly showing, in the case of input powers of 250~300W, heat transfer efficiency considerable increased, showing 63.8%.

• 전기학회논문지
• /
• 제61권1호
• /
• pp.22-27
• /
• 2012

Correct and fast detection of a micro-grid (MG) islanding is essential to the MG since operation, control and protection of the MG depend on an operating mode i.e., an interconnected mode or an islanding mode. When islanding occurs, the frequency of the point of common coupling (PCC) is not the nominal frequency during the transient state owing to the frequency rise or drop of generators in the MG. Thus, the active and reactive power calculated by the frequency domain based method such as Fourier Transform might contain some errors. This paper proposes an islanding detection algorithm for the MG based on the instantaneous active and reactive powers delivered to the dedicated line in the time domain. During the islanding mode, the instantaneous active and reactive powers delivered to the dedicated line are constants, which depend on the voltage of the PCC and the impedance of the dedicated line. In this paper, the instantaneous active and reactive powers are calculated in the time domain and used to detect islanding. The performance of the proposed algorithm is verified under various scenarios including islanding conditions, fault conditions and load variation using the PSCAD/EMTDC simulator. The results indicate that the algorithm successfully detects islanding for the MG.