• 호남수학학술지
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• 제32권1호
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• pp.177-192
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• 2010

We study the concepts of congruent number problems and elliptic curves. We research the structure of the group of elliptic curves and find out a method of the computation of L($E_n$, 1) and L'($E_n$, 1) by using SAGE program. In this paper, we obtain the first few congruent numbers for n ${\leq}$ 2500.

• 호남수학학술지
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• 제35권3호
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• pp.351-372
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• 2013

In this paper, we study a distinction the two generating functions : ${\varphi}^k(q)=\sum_{n=0}^{\infty}r_k(n)q^n$ and ${\varphi}^{*,k}(q)={\varphi}^k(q)-{\varphi}^k(q^2)$ ($k$ = 2, 4, 6, 8, 10, 12, 16), where $r_k(n)$ is the number of representations of $n$ as the sum of $k$ squares. We also obtain some congruences of representation numbers and divisor function.

• Journal of Information Technology Applications and Management
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• 제18권1호
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• pp.1-14
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• 2011

Mixed reality (MR) representation of accounting numbers is used as an alternative way of virtually engaging users of real three dimensional graphics of financialdata. An experiment was conducted to compare the usability and knowledge drawn from utilizing a table of numbers versus MR representations. The results showed that when MR was used, the participants' ratings of the firm's financial status and performance were more congruent with those of experts than when a table was employed. Also, MR was seen as providing less complex information with a shorter amount of time being spent and was perceived as being easy and useful.

• 한국수학사학회지
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• 제28권2호
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• pp.85-102
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• 2015

Elliptic curves are a common theme among various fields of mathematics, such as number theory, algebraic geometry, complex analysis, cryptography, and mathematical physics. In the history of elliptic curves, we can find number theoretic problems on the one hand, and complex function theoretic ones on the other. The elliptic curve theory is a synthesis of those two indeed. As an overview of the history of elliptic curves, we survey the Diophantine equations of 3rd degree and the congruent number problem as some of number theoretic trails of elliptic curves. We discuss elliptic integrals and elliptic functions, from which we get a glimpse of idea where the name 'elliptic curve' came from. We explain how the solution of Diophantine equations of 3rd degree and elliptic functions are related. Finally we outline the BSD conjecture, one of the 7 millennium problems proposed by the Clay Math Institute, as an important problem concerning elliptic curves.

• 식물분류학회지
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• 제52권4호
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• pp.214-218
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• 2022

Eleocharis R. Br. (Cyperaceae) is characterized by unbranched culms, one terminal spikelet, bisexual flowers, and bristly perianths, occurring mainly in circumboreal marshes and wetlands. There are about 250 species worldwide, and 15 taxa in Korea have been recognized. Chromosomes in Cyperaceae are known to be holocentric, missing constricted centromeres during cell division. For the first time, we report the chromosome counts of Eleocharis from Korean populations of E. attenuata f. laeviseta (Nakai) H. Hara (2n = 20); E. parvula (Roem. & Schult.) Link ex Bluff, Nees & Schauer (2n = 10); E. ussuriensis Zinserl. (2n = 16); and E. valleculosa var. setosa Ohwi (2n = 16). The populations exhibit variations in their chromosome sizes from ca.1.7 ㎛ to ca. 6 ㎛, categorized as gradient and bimodal karyotypes. The karyotypes observed are congruent with previous phylogenetic groups proposed. To clarify the traditional and phylogenetic classification of Korean Eleocharis, further taxonomic and chromosomal investigations with additional taxon sampling efforts are required.

• 성인간호학회지
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• 제19권2호
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• pp.329-337
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• 2007

Purpose: Increasing numbers of Koreans have immigrated to the United States since the late 1960s. The first generation of Korean immigrants or their parents become old and institutionalized in American nursing home setting. Although the Korean elders would experience many cultural differences in the nursing home, no study to date has investigated their everyday lives on how they live through their later lives within a different cultural environment from their own. Methods: Using ethnographic methodology, the purpose of this paper was to illustrate Korean residents' experiences and daily lives in a nursing home located in an east coastal city in the U.S. Participant observation, filed notes, semi-structured interviews were utilized by means of data collection. Eighteen Korean residents were observed, and five of them and two nurses participated in informal qualitative interviews. Results: The overriding theme from the findings is "thrown in a different world." Three sub-themes include "constant struggles in making themselves understood", "dealing with culturally inappropriate nursing care," and "maintaining their own ways of life". Conclusions: The discovered themes reflect culturally isolated lives of the participants and open a venue for designing a culturally congruent nursing care for Korean elders living in the U.S. nursing homes.

• 한국학교수학회논문집
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• 제20권2호
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• pp.119-139
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• 2017

고대 그리스 시대 작도는 현 교육에서의 작도 이상의 의미를 지닌 것이었다. 본 연구는 이러한 사실에 입각하여 현 교과서의 작도 의미를 살펴보고, 이와 대비되는 에서의 작도 의미를 추출해 보았다. 더불어 에서의 작도 의미를 현 교육에 반영하였을 때 나타나는 이점을 숙고해 보고, 그 이점을 활용하는 방안을 제안하였다. 그 결과 현 교과서의 작도는 삼각형의 합동 조건 도입과 이해를 위한 수단임을 확인할 수 있었다. 반면, 에서 작도는 4가지 의미를 지니고 있었다. 공준으로 타당성을 확보한 추상적 활동, 도형의 존재성 입증 및 논증에서 보조선 도입의 타당성 확보 수단, 보조선 도입 이외의 논증 개입 자제, 수와 대수를 다루는 수단이 곧 작도였다. 이로부터 논증에 보조선 도입의 타당성 확보 수단으로서의 작도 활용의 이점을 논의하였다. 아울러 Euclid 도구로 작도 불가능한 보조선에 대하여 가상적 도구의 개입에 의한 작도 관점을 제시하였다.

• Asia Marketing Journal
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• 제15권4호
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• pp.161-186
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• 2014

There are many cases of rebranding and its numbers are growing. However, rebranding is still under research in the academic field, and there is no guideline on the effective way to change brand name. The objective of this paper is to integrate two inconsistent predictions from categorization theory and schema incongruity theory: a negative linear relationship (categorization theory) versus an inverted-U-shape relationship (schema incongruity theory) between brand name incongruity and consumer evaluation into one framework. Specifically, this study examines how the effect of incongruity between an existing brand name and a new brand name (hereafter called "brand name incongruity") on the new brand name attitude differs depending on a consumer's individual characteristics (need for cognition). The experiment demonstrates that consumers with a high need for cognition show a better attitude towards a new brand name when the brand name was rebranded moderately incongruent compared to congruent or extremely incongruent. Thus, the experiment demonstrates that there is an inversed U-shape relationship between brand name incongruity and new brand name evaluation for consumers with a high need for cognition. On the contrary, consumers with a low need for cognition show a better attitude towards a new brand name when the brand name is rebranded congruently compared to incongruent conditions (moderate incongruity and extreme incongruity). This result indicates that there is a negative linear relationship between brand name incongruity and new brand name evaluation. Key theoretical and managerial implications of the present study are as follows. This study integrates two alternative views of research on incongruity evaluation into one framework by demonstrating that need for cognition moderates the relationship between brand name incongruity and consumer evaluation. This present study provides a conceptual basis for understanding consumer evaluation towards a new brand name. Next, though rebranding is a very important decision making of brand management, there is no guideline on how to change a brand name. The findings of this research can suggest which degree of change is optimal when rebranding in order to utilize and strengthen existing brand equity. More specifically, when our target customer has high need for cognition, moderately incongruent rebranding can be optimal, whereas for those with low need for cognition, rebranding in accordance with existing brand name will be optimal.

• 식물분류학회지
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• 제41권4호
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• pp.353-360
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• 2011

엽록체 DNA(trnL-F IGS, trnL intron, trnH-psbA)와 핵 DNA(RNApol2_i23)의 염기서열을 분석하여 둥굴레복합체를 대상으로 계통분류학적 연구를 실시하였다. 유럽산 분류군들은 한 분계조로 뚜렷하게 유집되었고, 이들은 한국산 분류군 중에서 둥굴레, 왕둥굴레, 풍도둥굴레 등과 유집되었다. 풍도둥굴레, 왕둥굴레와 제주산의 둥굴레중 하나가 한 분계조로 유집되어 육지로부터 지리적으로 격리된 섬 지역에서 진행되는 둥굴레로부터의 종분화를 추정해 볼 수 있었다. 둥굴레복합체에 속하는 분류군들은 기본염색체수를 기준으로 2개의 소그룹(x= 9와 x = 10)으로 구분되고 있다. 비록 기본염색체수가 줄어드는 방향으로 진화하는 속 내 분류군들의 진화경향과는 일치하지 않으나, 2개 그룹의 구분에 대해서는 분자적인 자료, 특히 핵 DNA 염기서열 분석결과가 이를 강력하게 지지하였다. 반면에 엽록체 DNA는 분류군을 구분하는 해상도가 낮게 나타났다. 속내 분류군들의 진화나 계통관계를 밝히기 위하여 차후에 좀 더 많은 재료에 대한 세포학적, 형태학적, 지리학적 자료가 축적되어야 할 것이다.