• Kyungpook Mathematical Journal
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• 제61권4호
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• pp.727-735
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• 2021

In this paper, we will study the structure of the quotient ring R/P of an arbitrary ring R by a prime ideal P. We do so using differential identities involving generalized derivations of R. We enrich our results with examples that show the necessity of their assumptions.

• 한국경영과학회지
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• 제21권3호
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• pp.63-74
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• 1996

Ordering plays an important role in solving an LP problem with sparse matrix by the interior point method. Since ordering is NP-complete, we try to find an efficient method. The objective of this paper is to present an efficient heuristic ordering method for implementation of the minimum deficiency method. Both the ordering method and the data structure play important roles in implementation. First we define a new heuristic pseudo-deficiency ordering method and a data structure for the method-quotient graph and cliqued storage. Next we show an experimental result in terms of time and nonzero numbers by NETLIB problems.

• 대한수학회보
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• 제38권2호
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• pp.347-355
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• 2001

Let ($X, \omega$) be a closed symplectic 4-manifold. Let a finite cyclic group G act semifreely, holomorphically on X as isometries with fixed point set $\Sigma$(may be empty) which is a 2-dimension submanifold. Then there is a smooth structure on the quotient X'=X/G such that the projection $\pi$:X$\rightarrow$X' is a Lipschitz map. Let L$\rightarrow$X be the Spin$^c$ -structure on X pulled back from a Spin$^c$-structure L'$\rightarrow$X' and b_2^$+(X')>1. If the Seiberg-Witten invariant SW(L')$\neq$0 of L' is non-zero and $L=E\bigotimesK^-1\bigotimesE$ then there is a G-invariant pseudo-holomorphic curve u:$C\rightarrowX$,/TEX> such that the image u(C) represents the fundamental class of the Poincare dual $c_1$(E). This is an equivariant version of the Taubes' Theorem.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 춘계학술논문 발표대회
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• pp.137-139
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• 2007

Recently, the research on durability of concrete proceed rapidly in the building industry. Deterioration due to do-icing salts occurs in practice in bridge structure, dike, barrier and similar structure. This paper reports the results of effect of chlorides on the freeze-thaw properties of concrete bridge deck in winter. The case fresh water condition where the concrete will receives a freez-thaw effect compared to decrease of durability quotient a lot occurs is a possibility of knowing from brine condition.

• Structural Engineering and Mechanics
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• 제13권2호
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• pp.231-239
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• 2002

The problem of dynamic analysis of truss structures based on probability is studied in this paper. Considering the randomness of both physical parameters (elastic module and mass density) of structural materials and geometric dimension of bars respectively or simultaneously, the stiffness and mass matrixes of the elements and structure have been built. The structure dynamic characteristic based on probability is analyzed, and the expressions of numeral characteristics of inherence frequency random variable are derived from the Rayleigh's quotient. The method of structural dynamic analysis based on probability is developed. Finally, two examples are given.

• 말소리와 음성과학
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• 제2권3호
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• pp.47-63
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• 2010

This study provides a description of the glottal characteristics of the word-initial low vowels /a, $\ae$/ in terms of a set of acoustic parameters and discusses glottal configuration as their acoustic correlates. Furthermore, it examines the effect of prosodic boundary on the glottal properties of the vowels, seeking an account of the possible role of prosodic structure based on prosodic theory. Acoustic parameters reported to indicate glottal characteristics were obtained from the measurements made directly from the speech spectrum on recordings of Korean and English collected from 45 speakers. They consist of two separate groups of native Korean and native English speakers, each including both male and female speakers. Based on the three acoustic parameters of open quotient (OQ), first-formant bandwidth (B1), and spectral tilt (ST), comparisons were made between the speech of males and females, between the speech of native Korean and native English speakers, and between Korean and English produced by native Korean speakers. Acoustic analysis of the experimental data indicates that some or all glottal parameters play a crucial role in differentiating the speech groups, despite substantial interspeaker variations. Statistical analysis of the Korean data indicates prosodic strengthening with respect to the acoustic parameters B1 and OQ, suggesting acoustic enhancement in terms of the degree of glottal abduction and the glottal closure during a vibratory cycle.

• 대한수학회지
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• 제47권6호
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• pp.1269-1282
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• 2010

We in this note consider a new concept, so called $\pi$-McCoy, which unifies McCoy rings and IFP rings. The classes of McCoy rings and IFP rings do not contain full matrix rings and upper (lower) triangular matrix rings, but the class of $\pi$-McCoy rings contain upper (lower) triangular matrix rings and many kinds of full matrix rings. We first study the basic structure of $\pi$-McCoy rings, observing the relations among $\pi$-McCoy rings, Abelian rings, 2-primal rings, directly finite rings, and ($\pi-$)regular rings. It is proved that the n by n full matrix rings ($n\geq2$) over reduced rings are not $\pi$-McCoy, finding $\pi$-McCoy matrix rings over non-reduced rings. It is shown that the $\pi$-McCoyness is preserved by polynomial rings (when they are of bounded index of nilpotency) and classical quotient rings. Several kinds of extensions of $\pi$-McCoy rings are also examined.

• 한국수학교육학회지시리즈A:수학교육
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• 제48권3호
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• pp.235-263
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• 2009

The purpose of the study was to investigate the influence of children's understanding of fractions in mathematics problem solving. Kieren has claimed that the concept of fractions is not a single construct, but consists of several interrelated subconstructs(i.e., part-whole, ratio, operator, quotient and measure). Later on, in the early 1980s, Behr et al. built on Kieren's conceptualization and suggested a theoretical model linking the five subconstructs of fractions to the operations of fractions, fraction equivalence and problem solving. In the present study we utilized this theoretical model as a reference to investigate children's understanding of fractions. The case study has been conducted with 6 children consisted of 4th to 5th graders to detect how they understand factions, and how their understanding influence problem solving of subconstructs, operations of fractions and equivalence. Children's understanding of fractions was categorized into "part-whole", "ratio", "operator", "quotient", "measure" and "result of operations". Most children solved the problems based on their conceptual structure of fractions. However, we could not find the particular relationships between children's understanding of fractions and fraction operations or fraction equivalence, while children's understanding of fractions significantly influences their solutions to the problems of five subconstructs of fractions. We suggested that the focus of teaching should be on the concept of fractions and the meaning of each operations of fractions rather than computational algorithm of fractions.

• Asian Journal of Business Environment
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• 제10권3호
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• pp.23-33
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• 2020

Purpose: The purpose of this study is for the leading sector, a pattern of shifting structure of the economic sector, and community export competitiveness on the economy Malinau Regency. Research design, data, and methodology: The type of data used is secondary data with a quantitative approach of 2009-2018. The study data used Location Quotient (LQ), Shift Share Analysis (SSA), and Revealed Comparative Advantage (RCA) analysis tools. Results: There are 6 leading sectors: agriculture; electricity, gas, and clean water; building and construction; trade, hotels, and restaurants. That has been classified has changed the economic structure of the Malinau Regency from the secondary sector to the tertiary and primary sectors in 10 years. While, community export competitiveness of the Malinau Regency through RCA Analysis, see if the export products of coal and excavation (types A, B, C) are shown to have a higher comparative advantage with comparative advantage. This shows that only a few commodities that can provide the good performance of export. Conclusions: Analysis of economic growth in the Malinau Regency after regional autonomy shows that there has been a shift in the economic structure of the economy which is dominated by the structure of the primary sector.

• 한국콘텐츠학회논문지
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• 제9권12호
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• pp.279-290
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• 2009

본 연구는 대전 충청지역의 산업구조와 특성을 분석한 후 지역경제의 혁신여건과 지역별(광역자치단체중심) 혁신역량지수의 측정을 통하여 지역경제가 보유하고 있는 혁신역량을 파악하고 하고자 하였다. 혁신역량지수는 유럽연합(EU)의 분류에 따라 인적자원부문, 지식창출부문, 지식의 전달 및 응용부문, 그리고 혁신지원 금융 산출 시장부문으로 구분하여 산출하였으며, 이를 9개 광역자치단체별로 측정 비교분석함으로써 정책적 시사점을 찾아보고자 하였다. 그 결과 지역별 총합혁신역량지수는 대전이 2.977로 가장 높고 다음이 서울로 2.650을 보임으로서 대전과 서울에 혁신활동이 집중되어 있음을 파악하였다. 그리고 충남과 충북의 혁신역량지수도 비교적 높은 서울의 76~78% 수준을 보였다. 그러나 여타 지역의 혁신역량지수는 서울이나 대전의 50~60%에 그치고 있어 지역 간 격차가 뚜렷이 존재하고 있는 것으로 분석되었다. 특히 지역 간 격차가 심한 영역은 지식창출부문으로서 대전은 0.866인데 비하여 부산은 0.085로 무려 10배나 차이가 나고 있으며, 다음은 지식의 전달 및 응용부문과 혁신지원 금융 산출 시장부문의 격차가 상대적으로 크게 나타났다. 그러나 인적자원부문의 혁신지수는 지역 간 격차가 상대적으로 적게 나타나고 있는 것으로 파악되었다.