• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.465-474
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• 2012

In this study, a dynamic simulation model that considers many spherical particles and multibody dynamics (MBD) entities is developed. Plenteous spherical particles are solved using the Discrete Element Method (DEM) technique and simulated on a GPU board in a PC. A fast algorithm is used to calculate the Hertzian contact forces between many spherical particles, and NVIDIA CUDA is used to increase the calculation speed. The explicit integration method is applied to solve the many spheres. MBD entities are simulated by recursive formulation. Constraints are reduced by recursive formulation, and the implicit generalized alpha method is applied to solve the dynamic model. A new algorithm is developed to simulate the DEM and MBD models simultaneously. As a numerical example, a truck car model and gear model are developed. The results show that the proposed algorithm using a general-purpose GPU in a PC has many advantages.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.233-233
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• 2011

ECR 이온원을 가볍고 작게 하면서 운전을 단순화함으로써 유지보수를 최소화하는 것은 특히 의료용 중입자 가속기에서 매우 중요한 조건 중 하나가 된다. 탄소 다가 이온을 만들어내기 위한 의료용 중입자가속기의 이온원으로 영구자석형 ECR 이온원을 개념 설계하였다. 영구자석은 이온원 입출구에서 강력한 축방향 자장을 만들기 위한 솔레노이드 자석 두 개와 반경방향 자장을 만들어 주기 6극 자석으로 구성된다. 또한 축방향 자장 흐름을 효과적으로 만들어주기 위한 두 개의 링 형 자석을 추가하여 자장의 강도를 높였다. 그러나 영구자석으로만 만들어진 자장 구조는 제작과 동시에 고정이 되어 수정이 불가능하기 때문에 제작 후 매우 제한적인 운전영역을 가질 뿐 만 아니라 최악의 경우에는 운전조건을 찾지 못하는 경우도 발생할 수 있다. 따라서 본 설계에서는 그림과 같이 두 개의 작은 보조 솔레노이드 전자석을 추가하여, 최소한의 운전조건으로 ECR 이온원의 공명영역을 결정하는 최소 자장의 구조뿐만 아니라 축방향 자장의 세기도 각각 능동적으로 제어할 수 있도록 하였다. 또한 마이크로파원으로는 TWT (Traveling Wave Tube)를 사용하여 10 GHz에서 14 GHz 까지 다양한 주파수에서 운전이 가능할 수 있도록 설계하였다. 이러한 설계를 통하여 다양한 운전조건을 가질 수 있는 안정된 ECR 이온원을 부피가 작으면서도 유지보수를 최소화하는 구조로 만들 수 있으며, 본 이온원은 탄소 다가 이온을 만들어내기 위한 목적뿐 만 아니라 다양한 중이온을 작은 규모로 만들어내기 위한 장치에서도 사용될 수 있다.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.10
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• pp.499-506
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• 2005

The growth of networks increase the importance of electronic commerces. Since the fair exchange protocol is an important part of electronic commerces, a number of researches have been done in relation to the fair exchange protocol. As the contract signing protocol is a part of fair exchange protocol, many protocols have been proposed, but most of them were focused on two-party protocol. Only a few were on the multi-party contract signing protocol. So far the optimistic multi-party contract signing protocol presented by Baum-Waidner has the least number of rounds in asynchronous network[4]. But, the lower bound on the number of rounds required by any optimistic multi-party contract signing protocol has been not known. In this paper, we present a tight lower bound on the number of rounds for optimistic multi-party contract signing protocol.

• School Mathematics
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• v.12 no.4
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• pp.639-665
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• 2010

The purpose of this research is to seek for principles and methods of multicultural mathematics teacher education. It began with an overview of theories of multicultural education and of multicultural teacher education in order to address the questions of what is the goal of multicultural education and what constitutes the competence of multicultural teachers. Then, cases of multicultural mathematics teacher education were reviewed. Based on that, this research identified three domains of teacher competence: domains of affect, of cognition, and of behavior. This paper also presented what constitutes each domains of competence and how to promote the development of each type of teachers' multicultural competence. This paper discussed implications to multicultural teacher education in Korean society.

• The Journal of the Korea Contents Association
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• v.7 no.11
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• pp.298-308
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• 2007

While the cultural contents industry plays main role in global contents market recently, the market of Buddhist cultural property contents is still in insufficient state. Specially, despite most cultural properties is Buddhist cultural property in Korea, there is a lot of difficult problems in preserving, restoring and designing its prototype as cultural property. So, this research intends to contribute to the development of Buddhist design and Buddhist culture contents by developing the Pagoda Dharani contents using the Ten-storied Stone Pagoda on the Site of Wongaksa. The first thing is designing the Pagoda Dharani using the Ten-storied Stone Pagoda on the Site of Wongaksa. Also, using the Pagoda Dharani, we design and implement the Pagoda Dharani contents on the web. In this paper, by using the proposed the Pagoda Dharani contents, the previous activation problem of the Buddhist culture contents can be resolved.

• The Journal of the Korea Contents Association
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• v.8 no.8
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• pp.293-302
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• 2008

Multiculuralism becomes the presentive term of Korea. And school is interested in multicutural education very much. The reason for this is connected to the fact of increasing intermarriages, immigrant laborers, and their children. So, the academic world is producing various research papers and public institution is proposing and practicing several policies. Particularly multicultural education is recognized as the very important intervening strategy on multicutral society and studied. The purpose of this paper is to suggest the ideas of teaching-learning experience selection for multicutural education in Korea. So the study contents of this paper are as follows ; First, it is to analyze the concepts of multicultural education and its' research trends. Second, it is to review the prior models of theorizing multicultural education and the models of curriculum development and teaching design. Finally, it is to inquiry the model of teaching-learning experience selection for multicutural education. Above all, we think that it is necessary to develop the model of multicutural teaching-learning experience selection classified by objects involved in multicutural education.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.321-331
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• 2014

This research purposed to verify the effects of children's peer attachment, community spirit, and multi-cultural acceptability on their adaptation to school. Also, I verified the difference of school life adaptation according to the degrees of peer communication, trust, alienation, community spirit, and multi-cultural acceptability. This research utilized Korean Children and Adolescent Panel Survey data to get more comprehensive and objective research result. As a result, the children who had higher peer attachment relationships (with more peer communication and better trust), higher community spirit, and higher level of multi-cultural awareness and acceptability adapted to school better. In particular, peer attachment had the highest effect on the children's school adaptation, community spirit next, followed by multi-cultural acceptability. Therefore, children's education needs to enhance their intimacy with peer groups, compliance with basic norms in school communities, and arouse rightful multi-cultural awareness in order to help them adapt to school better.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.345-355
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• 2016

As Korea has been rapidly transformed to be a multi cultural society, it becomes essential for nursing provider to develop cultural competency. The purpose of this study was to identify impact of self-reflection, critical thinking disposition and multi cultural experience on nursing student's cultural competence. A convenience sample of 148 nursing students was obtained from a university in Gyeonggi Province. Data was analyzed using Pearson correlation and multiple regression. Significant relationships were found between self-reflection, critical thinking disposition, multi cultural experience and cultural competence in nursing student. The result of multiple regression indicates that critical thinking disposition (${\beta}=0.27$, p=.005), self-reflection (${\beta}=0.21$, p=.040) were the most consistent predictors of cultural competence and explained 26.0%. Thus, it is necessary to develop multi cultural education program including self-reflection and critical thinking disposition. The findings suggest the necessity to explore further various factors affecting the cultural competence and to conduct research for establishment a theoretical model.

• The Korean Journal of Financial Studies
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• v.10 no.1
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• pp.145-170
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• 2004

Roll의 비판 이후 실행된 많은 국내외 연구결과 CAPM으로 설명이 되지 않는 이례 현상(Anomaly)들이 발견되고 있다. 이례 현상들은 다 요인 모형(multi-factor model)과 같은 추가 위험 요인이론, 표본차이이론, 과잉반응 및 특성이론들로 설명되고 있고 이러한 이례 현상들은 재무관리의 지속적인 관심사인 미래의 주가수익률 예측과 밀접한 관계에 있다. 본 연구에서는 이례 현상들이 주가수익률에 미치는 영향을 알아보기 써하여 Haugen and Baker(1996)의 다 요인 및 수익률 추정 방법론을 국내 증권시장에 적용한 다 요인 모형과 $\beta$, 기업규모, PBR, 과거 1년 주가 수익률에 의한 단일 요인 모형을 이용하여 개별 기업의 포트폴리오 구성기준을 결정하고 이 기준에 의거하여 월별로 편입 주식들을 재조정한 포트폴리오들의 년간 누적 실제수익률 예측력을 비교 분석한 결과 다음과 같은 결과를 얻었다. 첫째, 다 요인모형의 경우 기대수익률이 높은 주식으로 구성된 포트폴리오가 기대수익률이 낮은 주식으로 구성된 포트폴리오보다 실제 년간 수익률이 높게 나타난 반면, $\beta$, 기업규모, PBR, 과거 1년 주가 수익률의 요인에 의한 단일 모형을 적용한 포트폴리오는 이들 순위와 실제 수익률간에는 상관성이 높지 않게 나타나 다요인 모형이 주가 수익률 예측력에 있어서 단일요인 모형보다 우수한 것으로 판단된다. 단일모형 중에서는 PBR을 이용한 포트폴리오가 $\beta$ 단일모형보다 좋은 주가수익률 예측력을 보여 주었다. 둘째, 주가 수익률을 결정하는 유의성있는 요인들은 당기순이익의 증감, 당해연도의 당기순이익의 분포, 자산증가율, 매매 유동성, 매출액 변동, 거래량 추세, 기업크기(시가총액), 과거 1개월간의 주가수익률, 자기자본증가율등으로 나타났다.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.10
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• pp.343-348
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• 2015

Due to the need for multilingual e-mail address, EAI Working Group of the IETF has created a wide range of standards associated with e-mail address internationalization(EAI) since 2006. One of the authors and colleagues designed and implemented the mail server, SMTPUTF8, that supports EAI RFC protocols. SMTPUTF8 mail server is composed of new SMTP and POP3 servers supporting EAI RFC protocols. However, SMTPUTF8 did not include a new IMAP server supporting EAI RFC protocol. Recently many people are using smart phones to read and send e-mail messages in a mobile environment. IMAP server is more useful than POP3 server in a mobile environment. Therefore, in this paper, the authors have designed and implemented IMAP server and client app that complies with the IMAP standard (RFC) published by EAI WG of IETF to support multilingual e-mail address. This IMAP server is added to the SMTPUTF8 mail server so that users can access e-mail messages via IMAP client app in a mobile environment.