• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.409-411
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• 2003

요즘 값싼 PC들을 빠른 네트웍으로 묶어 놓은 성능을 얻고자하는 클러스터 컴퓨팅에 대한 연구가 활발히 이루어지면서 CPU나 메모리. 네트웍보다 상대적으로 느린 디스크에서 데이터를 읽어 효율적으로 파일 서비스를 하는 분산 파일 시스템이 개발되었다. 기존 분산 파일 시스템 중 클러스터 컴퓨팅에서 많이 사용하는 Linux 운영 체제에서 병렬 I/O를 사용하여 사용자에게 빠른 파일 서비스를 제공하여 주는 PVFS가 개발되었다. 기존 PVFS에서는 캐쉬 시스템을 제공하고 있지 않기 때문에 읽기 성능을 향상시키기 위하여 PVFS를 위한 상호 협력 캐치를 설계하고 구현하였다. PVFS를 위한 상호 협력 캐쉬는 클라이언트의 파일 캐쉬를 공유하여 파일 요구를 처리하는 기법으로 읽기 성능은 크게 향상되었다. 하지만 쓰기의 경우에는 다른 클라이언트에서 가지고 있던 모든 데이터를 찾아 해제하는 부하가 있기 때문에 성능이 좋지 않다. 따라서 본 논문에서는 PVFS를 위한 상호 협력 캐쉬에서 쓰기 성능 향상 기법인 두 단계 프로토콜을 제시하고 구현한다. 그리고 두 단계 프로토콜을 기존 PVFS와 PVFS를 위한 상호 협력 캐쉬 시스템과 성능을 비교, 분석한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.709-711
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• 2004

최근 단백질간의 상호작용의 중요성의 이해와 함께 축적되어 가는 단백질 정보들 간의 상호작용을 예측하기 위하여 통계학적 모델인 Support Vector Machine(SVM)을 사용한 예측 실험이 활발하다. 하지만 이는 거대한 생물 데이터를 처리하기 위해 많은 연산시간을 필요로 한다. 즉, 방대하게 존재하는 데이터를 처리하기 위해 SVM을 통한 실험은 정확한 결과뿐만 아니라 빠른 처리속도를 요구하게 되었다. 따라서 본 논문에서는 SVM의 개선을 통해 빠른 처리속도로 데이터를 처리하는 incremental SVM과 이를 병렬화 하여 더욱 빠른 처리시간을 가지는 Parallel SVM(PSVM)을 소개하고 실험해 본다. 즉, 단백질 상호작용에 사용되어지는 데이터를 PSVM을 사용한 실험을 통하여 정확성과 처리속도를 측정, 비교함으로써 단백질 상호작용 예측에 적합한지를 검증해본다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.785-787
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• 2008

생명체의 생명현상을 주관하는 각종 화학반응들은 단백질이 관여하고 있다. 단백질은 일정한 질서에 따라 서로 조립되기도 하고, 기능적으로 연관돼 네트워크를 이루고 있다. 이 네트워크를 구성하는 단백질-단백질 상호작용은 단백질의 기능과 밀접하게 관련되어 있다. 즉, 상호작용하는 단백질은 같은 기능을 수행할 가능성이 크다. 이러한 사실은 단백질-단백질 상호작용을 통해 기능이 알려지지 않은 미지 단백질의 기능을 예측할 수 있게 한다. 대표적인 연구로는 이웃 노드에 존재하는 기능분포를 이용하는 이웃노드 카운트(Neighborhood Counting)방식과 특정 기능의 나타날 빈도를 계산하여 기능을 예측하는 카이-제곱(Chi-Square)방식 등이 있다. 본 논문에서는 단백질 기능 예측의 정확성을 높이기 위해 이들 두 방식의 장점을 취합한 보완된 카이-제곱 방식을 제안한다. 그리고 다양한 단백질 상호작용 네트워크 데이터를 비교 분석하여 보완된 카이-제곱 방식이 기능 예측의 정확성이 높음을 증명한다.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.6
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• pp.27-34
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• 2010

Recently, high-speed railway systems have gained increased interest as a means of environmental friendly transportation, and numerous bridges for high-speed railways have been constructed accordingly. However, bridge design for high-speed railways requires more consideration than conventional railway design because fast-moving trains will lead to significant impact on bridge structures. Thus, this research proposes a revised design considering both bridge-rail longitudinal interaction and dynamic effect of trains to ensure stability of fast travelling trains. To validate the proposed design algorithm, numerical analyses are performed and compared using a constructed 250 m long bridge with 5 spans for a high-speed railway. From the numerical results, the proposed optimum design of high-speed railway bridges exhibits the most economic life-cycle-cost (LCC) when compared with several existing design approaches.

• Journal of the Korean Geotechnical Society
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• v.29 no.6
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• pp.19-31
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• 2013

In engineering practices, the superstructure was analyzed under a fixed boundary condition and the foundation was designed by considering the loading condition of superstructure. It may result in overestimation of forces, the bending moment, settlement of superstructure and foundation. In this study, an interactive analytical method is proposed for the interaction between the superstructure and the piled raft. The overall objective of this study is focused on the application of interactive analysis method for predicting behavior of entire structures. And a series of numerical analyses are performed to verify the interactive analysis routine in comparison to the unified analysis method. Through the comparative studies, it is found that the iterative and interactive analysis gave similar results of settlement and raft bending moment compared with those of finite element analysis. And it is also found that the proposed design method considering interaction between superstructure and foundation is capable of predicting reasonably well the behavior of entire structures. It can be effectively used to the design of a superstructure-piled raft foundation system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.3
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• pp.295-308
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• 2004

In this study, several Soil-Structure-Interaction (SSI) analyses were performed using the developed FE-BE coupling method and the seismic response behavior of the structure's systems was determined. For the verification of the fundamental solution which is used in this analysis method, a dynamic analysis of the homogeneous ground was performed and it was compared to the results of Estorff et al. In order to verify the seismic response analysis, the results are compared with those of another commercial code. Several kindd of SSI analyses were performed and the seismic response associated with the rile foundation, seismic waves and a consideration of the ground nonlinearity were determined. As a result, it was found that the pile foundations didn't greatly helpful during the seismic event.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4A
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• pp.307-314
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• 2010

In this paper, a receive diversity combining technique is proposed for single-carrier frequency division multiple access (SC-FDMA)-based cooperative relay systems when discrete Fourier transform (DFT) spreading sizes for mobile station (MS) and relay station (RS) are different. The proposed technique is composed of a DFT spreading size adjustment block, a phase rotation compensation block, a channel phase compensation block, and a receive diversity combining block. The proposed technique is robust to multipath channels and can be operated with a relatively small computational complexity because receive diversity combining is performed with scalar operations in the frequency-domain. It is shown by computer simulation that the proposed receive diversity combining techniques achieve a performance gain over the conventional maximal ratio combining (MRC) techniques for SC-FDMA-based cooperative relay systems.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.101-106
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• 2016

A number of non-structured data associated with lectures in the field of university education have been generated and it is an important consideration of the students's written comments lecture evaluation. The purpose of this study is to find student interaction factors associated with the student evaluation of teaching at universities, and to provide some insights into improving the student evaluation program based on the results. So, this study consists of three steps that create interaction score, collect student's written comments satisfaction, and analyze an individual professor score. There are a number of limitations to this study. The limitation is that the study was conducted on a narrow sample of the overall student population.

• The Journal of the Korea Contents Association
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• v.19 no.12
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• pp.471-482
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• 2019

The purpose of this study was to analyze the effect on the level of subject interest and interaction when supporting scaffolding considering learner characteristics in PBL. For the study, the participants were 86 college students. The research procedure was as follows. First, we divided the experimental group and the comparative group. A primary PBL was used to measure prior levels of subject interest and interaction. Secondary PBL was performed to verify treatment effect. In the second PBL, the experimental group received cognitive, metacognitive, and motivation scaffolding that reflected the learner's characteristics. The control group received random scaffolding. Subject interest and interaction were measured after the end of the second PBL. Collected data were analyzed using ANCOVA. As a result, the interest and interaction level of the experimental group was analyzed to be higher than that of the control group.

• Journal of the Korean Society for Railway
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• v.18 no.4
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• pp.363-373
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• 2015

The purpose of this study is to develop a nonlinear algorithm for the dynamic interaction analysis of KTX trains and bridge girders with consideration of separation and flange contact phenomena between wheel and rail. For this, three interaction models between wheel-rail are implemented and compared through numerical examples. That is, the spring model and the non-jump model are briefly explained, and a nonlinear contact model is then proposed to accurately simulate interaction forces of the train-bridge system. Dynamic interaction analysis of a simply supported girder and trains is performed and the analyzed results are presented and compared for the proposed contact model and the other model types. Particularly, flange contact phenomena in the nonlinear contact model are demonstrated under a specific condition.