• Title/Summary/Keyword: 확산 이론

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Measurement of optical coefficients of multiple scattering media by using frequency domain spectroscopy (주파수 영역 분광법을 이용한 다중산란 매질의 광학계수 측정)

  • 전계진;윤길원;김건식;전성만;박승한
    • Korean Journal of Optics and Photonics
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    • v.10 no.5
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    • pp.357-363
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    • 1999
  • A frequency domain spectroscopic system was constructed to investigate the optical properties of multiple scattering media. The alternating current (AC) and phase lag components of backscattered light were measured by using the heterodyne detection method. Absorption and transport scattering coefficients were computed from the values based on diffusion theory. Predictions showed excellent matches in comparison with actual values of absorption and scattering. Predictable ranges of the optical coefficients were analyzed in terms of the distance between light source and detector, and modulation frequencies. A proposed compact experimental set-up using laser diodes can be utilized to estimate non-invasively the optical properties of multiple scattering media such as biological tissues.

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A Conflict Control for Private Participation in Geographic Information System Projects (지리정보체계 민간투자사업의 갈등조정방안)

  • Yang, Kwang-Sik
    • Journal of the Korean Association of Geographic Information Studies
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    • v.10 no.3
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    • pp.70-79
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    • 2007
  • The current system for private participation in infrastructure can be applied for geographic information system(GIS) projects. But there are some limits to promote the private sector's participation GIS projects. The purpose of the study is to explain the major causes of conflict and conflict control for private participation in geographic information system projects. First, the theoretical perspectives for private participation in geographic information system projects and conflict issues were represented. Second, this paper presents the causes of conflict and conflict control on the basis of case study. In conclusion, the policy is developed for the promotion of private participation in geographic information system projects.

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A transmission distribution estimation for real time Ebola virus disease epidemic model (실시간 에볼라 바이러스 전염병 모형의 전염확률분포추정)

  • Choi, Ilsu;Rhee, Sung-Suk
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.1
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    • pp.161-168
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    • 2015
  • The epidemic is seemed to be extremely difficult for accurate predictions. The new models have been suggested that show quite different results. The basic reproductive number of epidemic for consequent time intervals are estimated based on stochastic processes. In this paper, we proposed a transmission distribution estimation for Ebola virus disease epidemic model. This estimation can be easier to obtain in real time which is useful for informing an appropriate public health response to the outbreak. Finally, we implement our proposed method with data from Guinea Ebola disease outbreak.

Media Education Methodology in Smart Media Era (스마트 미디어 시대의 미디어 교육 방안)

  • Do, Joonho
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.18 no.5
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    • pp.245-250
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    • 2018
  • The diffusion of smart media based on Internet has brought great changes on existing media business model. This changes also affect the core competence of jobs in media industry. This study performed two focus group interviews among professionals in media industry. The interviews examined the changes that media professionals recognize in the field and requirement changes to meet the job core competence. The interviews also examined the media education method in university that can respond to the changes in the media industry. Breaking away from the classical theory oriented education, university should develop the curriculum that can support competence required in the media industry. Media education in university should focus on fostering problem solving ability that can work regarding various issues in new media environment.

Chloride Ingress through Cracks in Concrete: from Experiment to Modeling Strategy (균열을 통한 콘크리트의 염소이온 침투: 실험에서 해석기법까지)

  • Yoon, In-Seok;Sung, Jae-Duck
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.467-468
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    • 2010
  • Over the past few decades, considerable numbers of studies on the durability of concrete have been carried out extensively. The majority of these researches have been performed on sound uncracked concrete, although most of in-situ concrete structures have more or less micro-cracks. It is only recent approach that the attention has shifted towards the influence of cracks and crack width on the penetration of chloride into concrete. The penetration of chlorides into concrete through the cracks can make a significant harmful effect on reinforcement corrosion. Author of this study examined the effect of cracks on chloride penetration by short term experiment. However, it is necessary to accomplish the effect by long term experiment to get reliable goal. In this study, the long term and short term experiments were carried out. This can be useful for establishing new species model of chloride penetration through cracks in concrete.

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Effects of As Ions Implanted in Si Substrates on the Titanium -Silicides Formation (Si기판에 주입된 As이온이 Titanium-Silicides 형성에 미치는 영향 -Ⅰ-)

  • Chung, Ju-Hyuck;Choi, Jin-Seog;Paek, Su-Hyon
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.6
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    • pp.57-62
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    • 1989
  • Sputter-deposited Ti film on Si substrates which were implanted with various doses of As was annealed at the temperature of 600-900$^{circ}C$ for 20 sec in Ar atmosphere. The sheet resistance of Ti-silicides was measured by 4-point probe, the thickness by $alpha$-step, and observed the behavior of As dopant in Si substrates by ASR. With increasing As doses, the thickness of Ti-silicides decreased and the sheet resistance of Ti-silicides increased. And we discussed the relationships between the above results and the factors of Si diffusion.

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Computer Simulation of Pt-GaAs Schottky Barrier Diode (Pt-GaAs Schottky Barrier Diode의 Computer Simulation)

  • Yoon, Hyun-Ro;Hong, Bong-Sik
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.27 no.3
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    • pp.101-107
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    • 1990
  • In this work, one-dimensional simulation is carried out for PT-GaAs Schottky barrier diodes with finite difference method. Shockley's semiconductor governing equations: Poisson equation and current continuity equation are discertized, and linearized by Newton-Raphson method. The linear system of equation is solved by Gaussian elimination method until convergence is achieved. The boundary condition for this equation is taken from thermionic emission-diffusion theory. Simulation is done for PT-GaAs epitaxial-layer Schottky barrier diodes. The claculated results of electron and potential distribution are shown. Simulation results show exellent agreement with experiments.

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Molecular Diffusion of Water in Paper(III) -Theoretical analysis on vapor sorption properties of fiber surface - (종이내 수분확산 (제3보) -종이 표면의 수증기-흡습성에 관한 이론적 고찰-)

  • Yoon, Sung-Hoon;Jeon, Yang;Park, Jong-Moon
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.31 no.1
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    • pp.61-71
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    • 1999
  • The study aimed at the theoretical analysis of vapor sorption properties of, pp.rmaking fibers. Water vapor affinity and sorption thermodynamic properties of fiber constituents were evaluated based on Henry's law and Hildebrand's solubility theory. Theoretical equilibrium moisture content(ThEMC) on fiber surface was estimated using functional group contribution. Crystallinity of cellulose in fiber significantly controlled the water vapor solubility. Comparisons of the measured equilibrium moisture content data and the estimated ThEMC data coincidently suggested the fact that crystallinity of cellulose in fibers was around 60% to 70%. Carbohydrates constituents including amorphous cellulose and hemicellulose in fibers showed higher vapor solubility than lignin molecules. High correlation existed between ThEMC and vapor solubility as well as between ThEMC and solubility parameter. In the thermodynamic analysis on water-vapor sorption process in fibers, the sorption enthalpy increased as RH increased, whereas sorption entropy and free energy decreased with increasing RH.

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Research on Developing Instructional Design Models for Enhancing Smart Learning (스마트 러닝 교수학습 설계모형 탐구)

  • Lim, Keol
    • The Journal of Korean Association of Computer Education
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    • v.14 no.2
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    • pp.33-45
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    • 2011
  • According to recent needs for 'smart learning', the concept of smart learning was reviewed by device, environmental, and theoretical approaches. The principle of smart learning includes three elements: First, rich instructional resources as learning contents. Second, participatory learning environments with interactions among teachers and learners as learning methods. Third, practical and realistic contexts as learning environments. Based on those characteristics, instructional designs for smart learning can be summed up as learning objectives, learning resources, instructional environments, instruction process design, instruction method development, implementation, and evaluation. As a conclusion, it is required to systematically develop instructional designs addressing specific learning settings to facilitate smart learning.

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An Empirical Analysis of Utilization and Performance of e-Trade with an Integrated Acceptance Model (전자무역의 활용수준과 성과 분석을 위한 통합 모형에 관한 실증연구)

  • Son, Tae-Kyu;Hong, Sa-Neung
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.53
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    • pp.233-264
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    • 2012
  • This study proposes and verifies an integrated model that reflects and helps to explain complexities and comprehensiveness of e-Trade in practice. The primary objective was to widen and deepen our understanding about the phenomena of paperless trading which will enable us to formulate an effective means to promote the adoption and utilization of e-Trade infrastructure. This investigation combined and extended the theories and models of TAM, TOE framework, and TTF in order to identify and hypothesize the causal relationships between factors of technology, organization and environment, and the usage level and performance of e-Trade. The previous research on e-Trade was reviewed and incorporated into the extended model. The integrated model was tested based on the survey data collected from a sample of 417 trading firms. Overall, the regression and path analysis demonstrated the usefulness of the proposed model as a conceptual framework for better understanding and explanation of e-Trade. The result of the analysis implies the relevancy of the factors of technology, organization and environment for facilitating usage of and increasing performance of e-Trade. However, rejection of a few hypothesized relationships implies the necessity of extensive promotion and education about the related laws and regulations, and education, supervision and incentives for e-Trade practitioners.

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