• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권2호
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• pp.514-535
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• 2019

Information-centric networks operate under the assumption that all network components have built-in caching capabilities. Integrating the caching strategies of information centric networking (ICN) with wireless virtualization improves the gain of virtual infrastructure content caching. In this paper, we propose a framework for software-defined information centric virtualized wireless device-to-device (D2D) networks. Enabling D2D communications in virtualized ICN increases the spectral efficiency due to reuse and proximity gains while the software-defined network (SDN) as a platform also simplifies the computational overhead. In this framework, we propose a joint virtual resource and cache allocation solution for latency-sensitive applications in the next-generation cellular networks. As the formulated problem is NP-hard, we design low-complexity heuristic algorithms which are intuitive and efficient. In our proposed framework, different services can share a pool of infrastructure items. We evaluate our proposed framework and algorithm through extensive simulations. The results demonstrate significant improvements in terms of visiting latency, end user QoE, InP resource utilization and MVNO utility gain.

• 센서학회지
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• 제31권5호
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• pp.318-323
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• 2022

Barium titanate (BaTiO₃) is considered to be a beneficial ceramic material for multilayer ceramic capacitor (MLCC) applications because of its high dielectric constant and low dielectric loss. Numerous attempts have been made to improve the physical properties of BaTiO₃ in response to recent market trends by employing multicomponent alloying strategies. However, owing to its significant number of atomic combinations and unpredictable physical properties, finding a traditional experimental approach to develop multicomponent systems is difficult; the development of such systems is also time-consuming. In this study, 168 new structures were fabricated using special quasi-random structures (SQSs) of Ba_1-xCa_xTi_1-yZryO₃, and 1680 physical properties were extracted from first-principles calculations. In addition, we built an integrated database to manage the computational results, and will provide big data solutions by performing data analysis combined with AI modeling. We believe that our research will enable the global materials market to realize digital transformation through datalization and intelligence of the material development process.

• Advances in aircraft and spacecraft science
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• 제7권3호
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• pp.187-202
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• 2020

The exhaust nozzle serves back pressure of Pulse detonation combustor, so combustion chamber gets sufficient pressure for propulsion. In this context recent researches are focused on influence of nozzle effect on single cycle detonation wave propagation and propulsion performance of PDE. The effects of various nozzles like convergent-divergent nozzle, convergent nozzle, divergent nozzle and without nozzle at exit section of detonation tubes were computationally investigated to seek the desired propulsion performance. Further the effect of divergent nozzle length and half angle on detonation wave structure was analyzed. The simulations have been done using Ansys 14 Fluent platform. The LES turbulence model was used to simulate the combustion wave reacting flows in combustor with standard wall function. From these numerical simulations among four acquaint nozzles the highest thrust augmentation could be attained in divergent nozzle geometry and detonation wave propagation velocity eventually reaches to 1830 m/s, which is near about C-J velocity. Smaller the divergent nozzle half angle has a significant effect on faster detonation wave propagation.

• 한국실천공학교육학회논문지
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• 제3권2호
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• pp.18-26
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• 2011

계산화학이란 컴퓨터를 이용한 계산을 통하여 이론 화학의 문제를 다루는 화학의 한 분야로 화학실험실을 컴퓨터로 옮겨 놓은 것이라고 말할 수 있다. 컴퓨터 처리 능력이 향상됨에 따라 거대 분자 구조의 복잡한 계산과 시뮬레이션을 수행하여야 하는 계산화학분야에서의 고성능 컴퓨터 활용은 매우 중요하다. 분자 구조 계산과 시뮬레이션 등의 작업을 위하여 고성능 컴퓨터를 이용하려면 Unix 명령어와 콘솔을 활용하여야 하는데 화학과목을 배우는 이공계 학생들 대부분은 컴퓨터 비전공자로서 Unix에 관하여 모르는 경우가 대부분이다. 그래서 Unix 명령어를 모르더라도 계산화학 실습이 가능한 웹 기반 계산화학 실습 교육 지원 시스템이 필요하다. 본 논문에서 개발한 웹 기반 계산화학 실습 교육 지원 시스템(e-Chem)은 다른 웹 포털 플랫폼보다 표준 지향적이고 콘텐츠 관리 및 협업 기능이 뛰어난 자바 오픈소스인 Liferay 포털 플랫폼을 활용하여 개발하였다. 본 시스템을 활용하면 컴퓨터 비전공자들도 쉽게 계산화학 실습 수업에 참여할 수 있고, Unix 명령어 등을 배우는 시간을 절약할 수 있으며, 친숙한 웹 인터페이스로 학습 효과도 높아질 것으로 기대된다.

• Nuclear Engineering and Technology
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• 제52권7호
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• pp.1557-1564
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• 2020

In this paper, 3D model-based interactive gamma ray shielding package (MIGSHIELD) is developed in virtual reality platform for windows operating system. In MIGSHIELD, the computational methodology is based on point kernel algorithm (PK), several key parameters of PK are obtained using new technique and new methods. MIGSHIELD has interactive capability with virtual world. The main features made in the MIGSHIELD are (i) handling of physical information from virtual world, (ii) handling of arbitrary shapes radioactive source, (iii) calculating the mean free path of gamma ray, (iv) providing interactive function between PK and virtual world, (v) making better use of PK for virtual simulation, (vi) plug and play. The developed package will be of immense use for calculations involving radiation dose assessment in nuclear safety and contributing to fast radiation simulation for virtual nuclear facilities.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.285-288
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• 2005

We propose a novel programmable miniature vision module based on a custom designed analog VLSI (aVLSI) chip. The vision module consists of the optical flow vision sensor embedded with commercial off-the-shelves digital hardware; in our case is the Intel XScale PXA270 processor enforced with a programmable gate array device. The aVLSI sensor provides gray-scale imager data as well as smooth optical flow estimates, thus each pixel gives a triplet of information that can be continuously read out as three independent images. The particular computational architecture of the custom designed sensor, which is fully parallel and also analog, allows for efficient real-time estimations of the smooth optical flow. The Intel XScale PXA270 controls the sensor read-out and furthermore allows, together with the programmable gate array, for additional higher level processing of the intensity image and optical flow data. It also provides the necessary standard interface such that the module can be easily programmed and integrated into different vision systems, or even form a complete stand-alone vision system itself. The low power consumption, small size and flexible interface of the proposed vision module suggests that it could be particularly well suited as a vision system in an autonomous robotics platform and especially well suited for educational projects in the robotic sciences.

• Structural Engineering and Mechanics
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• 제37권1호
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• pp.17-37
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• 2011

This paper presents a new Internet-based computational framework for the realistic simulation of multi-scale response of structural systems. Two levels of parallel processing are involved in this frame work: multiple local distributed computing environments connected by the Internet to form a cluster-to-cluster distributed computing environment. To utilize such a computing environment for a realistic simulation, the simulation task of a structural system has been separated into a simulation of a simplified global model in association with several detailed component models using various scales. These related multi-scale simulation tasks are distributed amongst clusters and connected to form a multi-level hierarchy. The Internet is used to coordinate geographically distributed simulation tasks. This paper also presents the development of a software framework that can support the multi-level hierarchical simulation approach, in a cluster-to-cluster distributed computing environment. The architectural design of the program also allows the integration of several multi-scale models to be clients and servers under a single platform. Such integration can combine geographically distributed computing resources to produce realistic simulations of structural systems.

• Structural Engineering and Mechanics
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• 제39권6호
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• pp.767-793
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• 2011

An efficient edge-based smoothed finite element method (ES-FEM) has been recently developed for solving solid mechanics problems. The ES-FEM uses triangular elements that can be generated easily for complicated domains. In this paper, the complexity study of the ES-FEM based on triangular elements is conducted in detail, which confirms the ES-FEM produces higher computational efficiency compared to the FEM. Therefore, the ES-FEM offers an excellent platform for adaptive analysis, and this paper presents an efficient adaptive procedure based on the ES-FEM. A smoothing domain based energy (SDE) error estimate is first devised making use of the features of the ES-FEM. The present error estimate differs from the conventional approaches and evaluates error based on smoothing domains used in the ES-FEM. A local refinement technique based on the Delaunay algorithm is then implemented to achieve high efficiency in the mesh refinement. In this refinement technique, each node is assigned a scaling factor to control the local nodal density, and refinement of the neighborhood of a node is accomplished simply by adjusting its scaling factor. Intensive numerical studies, including an actual engineering problem of an automobile part, show that the proposed adaptive procedure is effective and efficient in producing solutions of desired accuracy.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.190-192
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• 2019

컴퓨터과학을 전공하는 학습자뿐만 아니라 비전공 학습자도 실생활 문제를 통해 자신의 아이디어를 앱으로 구현하기를 원한다. 이에 앱 제작 경험이 거의 없는 대학교 2학년 학생을 대상으로 컴퓨팅 사고력 향상을 위한 모바일 플랫폼 앱 개발 교수 학습 방법을 연구하였다. 소프트웨어 교수 학습 모델 중 개발 중심 모델(Discovery-Design-Development)의 교수 학습 절차를 적용하고 개발 도구로는 Android Studio 통합 개발 환경(IDE)을 사용하여 모바일 플랫폼 앱 개발 교수 학습 프로젝트를 설계하고 컴퓨팅 사고력 향상에 도움을 주었는지 평가하였다. 설계된 교수 학습 방법을 적용한 결과 학습자들은 프로젝트 산출물이 emulator를 통해 앱으로 구현되어 수업의 흥미 및 만족도가 높았고 컴퓨팅 사고력 향상에 효과가 있는 것으로 나타났다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2018년도 추계학술발표대회
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• pp.849-851
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• 2018

계산과학공학은 사용자에게 다양한 계산 공학 문제의 해결을 위한 수치적 해석을 컴퓨터 자원을 이용하여 해셕 결과를 도출해 내는 과정이다.현재 EDISON 서비스의 시뮬레이션 환경은 통합적인 하나의 소프트웨어로 구성되어 있지 않고 각 모듈 별로 서비스를 연계하고 데이터를 공유할 수 있도록 시스템 플랫폼을 구축하고 있는 중이다. 하나의 계산과학공학 시뮬레이션 서비스를 제공하기 위해서는 각 모듈간의 유기적인 서비스 공유가 필요하다. 따라서 본 논문에서는 각 모듈간의 서비스 공유 및 시스템 리소스 사용을 위해 모듈간의 커뮤니케이션을 위한 인터페이스를 설계하고, 각 시스템 모듈을 등록하여 플랫폼 내 시뮬레이션 시스템을 구축하였다.