• 천문학회보
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• 제44권1호
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• pp.33.2-33.2
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• 2019

Horizon Run 5 is the most massive cosmological hydrodynamic simulation ever performed until now. Owing to the large spatial volume ($717{\times}80{\times}80[cMpc/h]^3$) and the high resolution down to 1 kpc, we may study the cosmological effects on star and galaxy formations over a wide range of mass scales from the dwarf to the cluster. We have modified the public available Ramses code to harness the power of the OpenMP parallelism, which is necessary for running simulations in such a huge KISTI supercomputer called Nurion. We have reached z=2.3 from z=200 for a given simulation period of 50 days using 2500 computing nodes of Nurion. During the simulation run, we have saved snapshot data at 97 redshifts and two light cone space data, which will be used later for the study of various research fields in galaxy formation and cosmology. We will close this talk by listing possible research topics that will play a crucial role in helping us take lead in those areas.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2024년도 제69차 동계학술대회논문집 32권1호
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• pp.419-422
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• 2024

본 논문에서는 다항식 보간법의 일종인 이동최소자승법(Moving least squares, MLS)을 네트워크로 학습하여, Divergence-constrained MLS 벡터장을 효율적으로 표현하는 방법을 제안한다. 벡터장을 구성하기 위해 MLS는 스칼라가 아닌 벡터 보간을 해야 하므로 행렬과 벡터의 크기가 더 커지며, 이는 계산량이 커짐을 나타낸다. 고차 보간(High-order interpolation)이 가능한 특징은 장점이 되지만, 계산량이 매우 크기 때문에 시뮬레이션에는 활용이 어렵다. Divergence-constrained MLS를 유체 시뮬레이션에 적용한 경우가 있지만, 실제로 슈퍼컴퓨터(Supercomputer)를 해야 장면 제작이 가능하므로 효용성이 떨어진다. 본 논문에서는 이러한 문제를 해결하기 위해 네트워크 학습을 통한 Divergence-constrained MLS 벡터장을 표현할 수 있는 결과를 보여준다.

• Journal of Information Science Theory and Practice
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• 제10권spc호
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• pp.76-85
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• 2022

At the 8th National High-Performance Computing (HPC) Committee convened in 2021, the "National High-Performance Computing Innovation Strategy (draft) for the 4th Industrial Revolution Era" was deliberated and the original draft was approved. In this proposal, the Ministry of Science and ICT in KOREA announced three major plans and nine detailed projects with the vision of "Realizing the 4th industrial revolution quantum jumping by leaping into a high-performance computing powerhouse." Thereby the most important policy about national mid-term and long-term HPC development was established and called the HPC innovation strategy (hereinafter "the innovation strategy"). The three plans of the innovation strategy proposed by the government are: Strategic HPC infrastructure expansion; Secure source technologies; and Activate innovative HPC utilization. Each of the detailed projects has to be executed nationally and strategically. In this paper, we propose a strategy for the implementation of two items ("Strategic HPC infrastructure expansion" and "activate innovative HPC utilization") among these detailed plans.

• 한국CDE학회논문집
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• 제20권1호
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• pp.65-74
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• 2015

Structure and/or fluid analysis is gradually increased by an essential design process in the small and medium-sized businesses (SMBs) because of the needs for a rapid design process and the certification about the supplement of the parts by the large business (LB). In this paper, we developed the web-based ezSIM platform installed in the resources integrated system server. The ezSIM platform is based on the heterogeneous linux and windows operating system for the user-friendly connection with the part of the analysis for the SMBs. The procedure of the structure/fluid analysis service module using the public software and the license-free open code in the ezSIM platform was explained. The convenience of the ezSIM platform service was presented by the reaction rate of the graphic motion compared with that of a local PC and the solving and pre-post processing interface compared with that of the KISTI supercomputer. The web-based ezSIM platform service was identified as a useful and essential platform to the SMBs for the usage of the structure and/or fluid analysis procedure.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.5-8
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• 2005

In this paper, the electromechanical displacements of curved piezoelectric actuators composed of PZT ceramic and laminated composite materials are calculated based on high performance computing technology and the optimal configuration of composite curved actuator is examined. To accurately predict the local pre-stress in the device due to the mismatch in coefficients of thermal expansion, carbon-epoxy and glass-epoxy as well as PZT ceramic are numerically modeled by using hexahedral solid elements. Because the modeling of these thin layers increases the number of degrees of freedom, large-scale structural analyses are performed through the PEGASUS supercomputer, which is installed in our laboratory. In the first stage, the curved shape of the actuator and the internal stress in each layer are obtained by the cured curvature analysis. Subsequently, the displacement due to the piezoelectric force (which is resulted from applied voltage) is also calculated. The performance of composite curved actuator is investigated by comparing the displacements obtained by the variation of thickness and elastic modulus of laminated composite layers. In order to consider the finite deformation in the first analysis stage and include the pre-stress due to curing process in the second stage, nonlinear finite element analyses are carried out.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권10호
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• pp.4738-4753
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• 2018

Efficient rendezvous node selection and routing algorithm (RNSRA) for wireless sensor networks with mobile sink that visits rendezvous node to gather data from sensor nodes is proposed. In order to plan an optimal moving tour for mobile sink and avoid energy hole problem, we develop the RNSRA to find optimal rendezvous nodes (RN) for the mobile sink to visit. The RNSRA can select the set of RNs to act as store points for the mobile sink, and search for the optimal multi-hop path between source nodes and rendezvous node, so that the rendezvous node could gather information from sensor nodes periodically. Fitness function with several factors is calculated to find suitable RNs from sensor nodes, and the artificial bee colony optimization algorithm (ABC) is used to optimize the selection of optimal multi-hop path, in order to forward data to the nearest RN. Therefore the energy consumption of sensor nodes is minimized and balanced. Our method is validated by extensive simulations and illustrates the novel capability for maintaining the network robustness against sink moving problem, the results show that the RNSRA could reduce energy consumption by 6% and increase network lifetime by 5% as comparing with several existing algorithms.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.466-469
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• 2011

최근에는 열유체, 물리, 화학, 구조동역학, 전산설계 등의 응용과학 분야의 교육 및 연구에 실제 실험이 아닌 슈퍼컴퓨터 및 고성능 네트워크 기반의 사이버 인프라에서 과학적 가정에 의해 복잡한 공학문제를 수치적 모델링과 컴퓨터 시뮬레이션을 통해 해결하는 계산과학을 이용하는 최적의 방법론 및 기법들의 연구의 필요성이 증대되고 있다. 본 논문에서는 컴퓨팅 시뮬레이션 기법을 활용한 실험 체험형 교육의 일환으로, 이공계 교수, 학생, 연구자, 산업체 인력 등이 사이버 인프라스트럭처 기반으로 최신 시뮬레이션 SW를 활용하여 차세대 교육 연구를 융합할 수 있는 EDISON 개방형 통합 플랫폼을 제시한다. EDISON 플랫폼은 사용자들에게 보다 쉽고, 편하고, 효과적인 서비스 제공을 위해 3계층(EDISON 응용 프레임워크, EDISON 미들웨어, EDISON 인프라 자원)으로 구성되고 5개 분야(열유체, 화학, 물리, 구조동역학, 전산설계) 문제해결 환경을 위한 교육 연구용 웹 포털 서비스를 제공한다.

• 마이크로전자및패키징학회지
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• 제23권2호
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• pp.37-42
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• 2016

전력가격의 상승으로 데이터센터의 운영비 부담이 늘어나는 가운데, 슈퍼컴퓨터에 저전력 프로세서를 사용하여 데이터센터의 전력소모를 감소시키는 연구가 활발하다. 일반적으로 모바일 기기 등의 운용환경을 기준으로 신뢰성 평가가 이루어지는 저전력 프로세서를 슈퍼컴퓨터에 사용하는 경우 상대적으로 가혹한 운용환경으로 인해 물리적, 기계적 신뢰성 문제가 발생할 수 있다. 이 논문은 슈퍼컴퓨터 운용 환경을 바탕으로 저전력 프로세서 패키지의 수명을 평가하였다. 먼저 문헌조사, 고장모드 및 치명도 분석을 통해 저전력 프로세서 패키지의 주요 고장원인으로 온도 사이클을 선정하였다. 부하-온도 관계를 확인하기 위해 단계적인 부하를 가하며 프로세서의 온도를 측정하였다. 가장 보수적인 운용조건을 가정하고 온도 사이클에 관련된 고장물리 모델을 이용한 결과 저전력 프로세서 패키지의 기대수명은 약 3년 이하로 예측되었다. 실험 결과를 바탕으로 저전력 프로세서 패키지의 기대수명을 향상하는 방법을 제시하였다.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2003년도 제2차 연례학술대회 발표논문집
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• pp.1-1
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• 2003

It is clear that computers will play a key role in the biology of the future. Even now, it is virtually impossible to keep track of the key proteins, their names and associated gene names, physical constants(e.g. binding constants, reaction constants, etc.), and hewn physical and genetic interactions without computational assistance. In this sense, computers act as an auxiliary brain, allowing one to keep track of thousands of complex molecules and their interactions. With the advent of gene expression array technology, many experiments are simply impossible without this computer assistance. In the future, as we seek to integrate the reductionist description of life provided by genomic sequencing into complex and sophisticated models of living systems, computers will play an increasingly important role in both analyzing data and generating experimentally testable hypotheses. The future of bioinformatics is thus being driven by potent technological and scientific forces. On the technological side, new experimental technologies such as microarrays, protein arrays, high-throughput expression and three-dimensional structure determination prove rapidly increasing amounts of detailed experimental information on a genomic scale. On the computational side, faster computers, ubiquitous computing systems, high-speed networks provide a powerful but rapidly changing environment of potentially immense power. The challenges we face are enormous: How do we create stable data resources when both the science and computational technology change rapidly? How do integrate and synthesize information from many disparate subdisciplines, each with their own vocabulary and viewpoint? How do we 'liberate' the scientific literature so that it can be incorporated into electronic resources? How do we take advantage of advances in computing and networking to build the international infrastructure needed to support a complete understanding of biological systems. The seeds to the solutions of these problems exist, at least partially, today. These solutions emphasize ubiquitous high-speed computation, database interoperation, federation, and integration, and the development of research networks that capture scientific knowledge rather than just the ABCs of genomic sequence. 1 will discuss a number of these solutions, with examples from existing resources, as well as area where solutions do not currently exist with a view to defining what bioinformatics and biology will look like in the future.

• 한국융합학회논문지
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• 제8권10호
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• pp.61-66
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• 2017

최근 IoT기술은 '언제, 어디서나, 편리하게' 라는 키워드와 함께 급속도로 발전하고 있다. 이와 더불어 IoT 시스템에 대한 보안이슈가 폭발적으로 증가하고 있으며 그에 대한 피해도 커지는 상황이다. 이에 본 논문에서는 IoT 시스템 보안 요구사항을 정의하는 표준화와 보안기술개발 현황을 파악하고 ICT에서 국제적으로 통용되는 CC평가를 이용하여 안전하게 IoT 시스템을 개발하는 방안을 제시한다. 이를 위하여 우선 IoT 시스템과 서비스 측면의 보안목적을 분석 하였다. 향후 이를 토대로 보안기능요구사항을 설계하고 대응관계 통하여 보안목적의 이론적 근거가 증명할 수 있으며 IoT 시스템에 대한 보호프로파일설계가 가능하다. 이는 관리자, 개발자, 사용자 측면의 보안요구집합을 참조할 수단으로 사용되므로 본 논문에서 제시하고자하는 개발 방법론에 대한 충분한 근거가 된다.