• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.09a
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• pp.31-34
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• 2005

분자 위치제어 메모리 시스템에 대하여 고전적인 분자동역학을 이용하여 결합에너지 및 다양한 외부전압의 형태에 따른 셔틀 풀러렌 동작에 관하여 연구하였다. 단일 나노피포드 형(single-nanopeapod type)은 질화붕소 나노튜브(boron-nitride nano tube) 속에 세 개의 엔도풀러렌(endo-fullerene)과 양쪽 끝에 구리 전극이 채워져 있는 구조를 갖고 있는 구조를 갖고 있다. 결론적으로, 분자동역학 시뮬레이션 결과로부터 이 나노메모리 시스템은 비휘발성임을 알 수 있었다. 안정적인 bit 변화를 위해서는 단일 나노피포드 형은 0.1 eV/$\AA$ 외부전압이 필요로 함을 알 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.516-520
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• 2009

This study describes aerodynamic characteristics for the HAWT (Horizontal Axis Wind Turbine) rotor blade using general CFD(Computational Fluid Dynamics) code. The boundary conditions for analysis are validated with the experimental result by the NREL (National Renewable Energy Laboratory)/NASA Ames wind tunnel test for S809 airfoil. In the case of wind turbine rotor blade, complex phenomena are appeared such as flow separation and re-attachment. Those are handled by using a commercial flow analysis tool. The 2-equation k-$\omega$ SST turbulence model and transition model appear to be well suited for the prediction. The 3-dimensional phenomena in the HAWT rotor blade is simulated by a commercial 3-D aerodynamic analysis tool. Tip vortex geometry and Radial direction flows along the blade are checked by the analysis.

• Journal of the Korean Vacuum Society
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• v.14 no.1
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• pp.40-48
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• 2005

Bucky shuttle memory systems were investigated by the classical molecular dynamics(MD) simulations. Energetics and operating response of the shuttle-memory-elements u?ere examined by MD simulations of the C/sub 60/ shuttle in the nanomemory systems under various external force fields. Single-nanopeapod type was consisting of three fullerenes encapsulated in (10, 10) boron-nitride nanotube and filled Cu electrode. Studied systems could be applied to nonvolatile memory. MD simulation results showed that the stable bit flops could be achieved from the external force fields of 0.1 eV/Å for single-nanopeapod type.

• Journal of the Korean Institute of Telematics and Electronics
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• v.18 no.5
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• pp.1-9
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• 1981

Experimental results on a 4-bit charge-coupled A/D converter are described. Major operations in the successive approximation algorithm are implemented in a monolithic chip, CCADC, which was fabricated usir p-channel CCD technology, with its die size of 4,200 mil2 Typical operating frequency range has been found out to be from 500Hz to 200kHz. In that frequency range, no missing code has been found in the whole signal range of 2.4 volts for ramp signal slewing at 1 LSB/(sampling time). A discussion is made on several layout techniques to conserve the nominal binary ratio of (8:4:2:1) among the areas of four adjacent potential wells (M wells), whose charge storing capacities correspond to each bit magnitude - 3.6 pC, 1.8 pC, 0.9 pC, and 0.45 pC nominal in the order of MSB to the LSB. The effect of 'dump slot', which is responsible for the excessive nonlinearity (2$\frac{1}{2}$LSB) in the A/D converter, is explained. A novel input scheme called 'slot zero insertion' to circumvent the deleterious effects of the dump slot is described with the experimental results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.74-82
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• 2008

In this paper, we propose a P2P based IPTV system using a multiple chain architecture. Proposed system is robust to the peer churn. As opposed to the internet the IPTV network managed by a single ISP has fewer bandwidth constraints and end-to-end connectivity. So, we emphasize preferentially robustness of a P2P network in IPTV environment. A single chain structure which was proposed previously emphasizes simplicity, however there exists considerable delay time at the end part of peers as the number of peers increasing. As a solution to the problem, we propose the scheme which seperates the chain into several levels and again divides each level into spans to diminish a delay time. Though the chain is separated into level and span, basic structure of proposed scheme is still a chain structure. So the scheme simplifies the recovery procedure caused by join or departure of peers. We will show the improved performance of proposed scheme rather than single chain structure with respect to the delay time and reliability.

• Water for future
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• v.21 no.4
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• pp.399-406
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• 1988

Presented in this paper is a brief summary of the basic theory and observation from a laboratory investigation aimed at determining flow characteristics and ice jam topography in a sinuous channel, and in a single-bend channel. The sinuous channel comprised thirteen $90^{\circ}$ bends and was of comparatively small s\aspect ratio. The single-bend channel was a $180^{\circ}$ bend, which was an order of magnitude large in width as well as aspect ratios than the sinuous channel. The simulated ices were polyethylene and polypropylene beads and block. The streamwise velocities near the bottom were larger than that of surface in sinuous channel and forming ice jam in sinuous channel, this phenoumena were found strongly. Jams were generally thicker along the inner bank of bends. The path of maximum-streamwise velocity was displaced towards approachs side of the inner bank of bends. Radial variation of jam thickness was to be regular by increasing size of ice fragments. The rate of jam head progression around outer bank of the single bend was faster than that of inner bank and its velocity was roughly steady. With increasing Froude number, jm thickness became less uniformly distributed; being generally thicker along the inner bank and near the jam's toe. Two-layer model might be adaptable for the computing the streamwise velocity in shallow river bends. Two cells of secondary flow cound be expected in ice covered-river bends.

• Korean Journal of Social Welfare Studies
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• v.48 no.1
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• pp.91-111
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• 2017

Purposes of this study, summoning thoughts and activities of Toynbee Hall of the UK and Hull House of the US held in between the end of 19C and the early 20C, are two folded: first, it is to examine the momentum and aims for which 'social' work was progressively established at that time; second, it is to look for implications for today's social work practice through understanding their characteristic activities and the context in which 'social' work was devised as an alternative in the two nations. The study method mainly relies on literature review, but further goes on to analyze the spirit of the age when settlement house was constructed as a welfare space and activities, leadership demonstrated in there, and to draw meanings for today, in terms of three dimensions: aim and location, professionality and education, and social action. Some of useful findings are: first, the COS and settlement house need to be considered in a continuum of socially responsive remedies against poverty and social work practice was developed in the process of 'suggestion-performance-critique-alternative suggestion-emergence of social work', rather than contrasting the two as opposite roots of social work practice. Second, settlement house was a socially constructed welfare space that contained intersectional dynamics of class, gender, personal vs. social, private vs. public, surrounding poverty issue. Third, besides differences between the two settlements, both purported for public goods and well-being and tried to realize the 'social' in that society. Lastly, this study explored historical meanings of settlement house as the welfare space with critical questions and discussed implications for social work practice today.