• 대한수학회지
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• 제50권2호
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• pp.275-306
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• 2013

For two positive integers $m$ and $n$, let $\mathcal{P}_n$ be the open convex cone in $\mathbb{R}^{n(n+1)/2}$ consisting of positive definite $n{\times}n$ real symmetric matrices and let $\mathbb{R}^{(m,n)}$ be the set of all $m{\times}n$ real matrices. In this paper, we investigate differential operators on the non-reductive homogeneous space $\mathcal{P}_n{\times}\mathbb{R}^{(m,n)}$ that are invariant under the natural action of the semidirect product group $GL(n,\mathbb{R}){\times}\mathbb{R}^{(m,n)}$ on the Minkowski-Euclid space $\mathcal{P}_n{\times}\mathbb{R}^{(m,n)}$. These invariant differential operators play an important role in the theory of automorphic forms on $GL(n,\mathbb{R}){\times}\mathbb{R}^{(m,n)}$ generalizing that of automorphic forms on $GL(n,\mathbb{R})$.

• Korean Journal of Mathematics
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• 제28권1호
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• pp.65-73
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• 2020

This article concerns a property of local rings and domains. A ring R is called weakly local if for every a ∈ R, a is regular or 1-a is regular, where a regular element means a non-zero-divisor. We study the structure of weakly local rings in relation to several kinds of factor rings and ring extensions that play roles in ring theory. We prove that the characteristic of a weakly local ring is either zero or a power of a prime number. It is also shown that the weakly local property can go up to polynomial (power series) rings and a kind of Abelian matrix rings.

• 수산경영론집
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• 제25권1호
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• pp.85-109
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• 1994

Recently, it has become a matter of importance concerning a distribution system of the fisheries products in our day, Especially, this paper disregards the fact of changes in demand and distribution system for fisheries products under the period of the high economic growth in Japan. The commercial capital of fisheries products has been modernized by the development of the public market place. The distribution system of fisheries products will rather play an important role than now. In this state, this study is to introduce the development of fish market theroy and attempts to explan the market trends in the production in Japan.

• 미술이론과 현장
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• 제10호
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• pp.105-118
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• 2010

This study discusses the community of participants in new media-based art of Taeyoon Choi, Wafaa Bilal and Mushon Zer-Aviv in relation to current discourses on social functions of art by Nicolas Bourriaud and Jacques Ranciere. Focusing on these artists' participatory projects which aim to provide alternative perspectives on wars between countries, to raise awareness about expanding surveillance systems in city spaces, or to create new public spaces on the web, this paper argues that their works hybridize entertainment culture and political activism to suggest a new model for political art.

• 한국주거학회논문집
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• 제3권1호
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• pp.1-19
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• 1992

The primary objective of this study is to find out how housing characteristics have been changed through a recent move. Two hundreds and thrity households in Cheongju City who made a move during 1990 are selected for the empherical study. The findings show that almost families moved to the dwelling with similar or better conditions than the previous ones. The patterns of housing characteristics changed through a move play the role as an intervening variable between family characteristics and changes in housing satisfaction. Also, the results in general support the concepts of housing adjustment theory. There is a small number of low income families who moved to dwelling with worse conditions. Presumably constraints might prevent their housing adjustment behavior.

• 한국정보시스템학회지:정보시스템연구
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• 제6권1호
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• pp.257-291
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• 1997

Today, executives in the company operate their organizations under highly competitive environments with dynamic technological, economic, and political changes. Under these new environment changes, they play the important role in establishing the future directions and strategic orientations of organizations. In general, executive information systems (EIS) are designed to support these roles of executives. They can help executives access and use the information they require about the organization's internal and external environments. In spite of such potential EIS support for executives, only a limited number of empirical studies have been published in this area. by employing a well-established theory of computer usage behavior (Technology Acceptance Model : TAM), this study systematically investigates the key factors in the successful utilization of an EIS. The empirical results from this study may prove useful for both IS researchers and practitioners.

• Journal of applied mathematics & informatics
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• 제26권5_6호
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• pp.1169-1183
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• 2008

In this paper, a method to find the weighted possibilistic variance and moments about the mean value of fuzzy numbers via applying a difuzzification using minimizer of the weighted distance between two fuzzy numbers is introduced. In this way, we obtain the nearest weighted point with respect to a fuzzy number, this main result is a new and interesting alternative justification to define of weighted mean of a fuzzy number. Considering this point and the weighted distance quantity, we introduce the weighted possibilistic mean (WPM) value and the weighted possibilistic variance(WPV) of fuzzy numbers. This paper shows that WPM is the nearest weighted point to fuzzy number and the WPV of fuzzy number is preserved more properties of variance in probability theory so that it can simply introduce the possibilistic moments about the mean of fuzzy numbers without problem. The moments of fuzzy numbers play an important role to estimate of parameters, skewness, kurtosis in many of fuzzy times series models.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.368-375
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• 2010

To alleviate NOx emission, a variety of approaches has been applied. In marine diesels, the application of SCR systems has been considered an effective exhaust aftertreatment method for NOx emission control. Most current SCR systems use a various catalyst for the reaction of ammonia with NOx to form nitrogen and water. In theory, it is possible to achieve 100% NOx if the NH3-to-NOx ratio is 1:1. However, the reaction has a limited non-uniformity of the exhaust gas flow and ammonia concentration distribution. Therefore it is necessary to investigate the optimum flow conditions. In order to achieve uniform flow at monolith front face, we are equipped with a various mixed device. In this paper, it is presented that the mixed devices play an important role improvement of flow patterns and particle distributions of NH3 by numerical simulation.

• 한국전산유체공학회지
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• 제15권4호
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• pp.9-16
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• 2010

To alleviate NOx emission, a variety of approaches has been applied. In marine diesels, the application of SCR systems has been considered an effective exhaust aftertreatment method for NOx emission control. Most current SCR systems use a various catalyst for the reaction of ammonia with NOx to form nitrogen and water. In theory, it is possible to achieve 100% NOx if the $NH_3$-to-NOx ratio is 1:1. However, the reaction has a limited non-uniformity of the exhaust gas flow and ammonia concentration distribution. Therefore, it is necessary to investigate the optimum flow conditions. In order to achieve uniform flow at monolith front face, we are equipped with a various mixed devices. In this paper, it is presented that the mixed devices play an important role improvement of flow patterns and particle distributions of $NH_3$ by numerical simulation.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2007년도 추계학술대회
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• pp.77-83
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• 2007

This paper presents numerical and experimental works for simultaneous pumping and mixing small liquid using asymmetric microelectrode arrays, based on AC electroosmotic flows. To this end, four arrangements of electrode pairs were considered with diagonal/herringbone shapes. Numerical simulations were made of three-dimensional geometries by using the linear theory. The results indicated that the helical flow motions induced by the electrode arrays play a significant role in the mixing enhancement. The pumping performance was influenced by the slip velocity at the center region of the channel compared to that near the side walls. To validate the numerical predictions, the microfluidic devices were made through MEMS. The flow rate was obtained by using micro PIV, increasing the applied frequency. The electrolyte was potassium chloride solution. The flow patterns above electrodes were visualized to see lateral flow for mixing. The experimental results showed good agreements with the numerical predictions.