• Title/Summary/Keyword: Ghost phenomenon

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Flow Simulation of High Flow Concrete using Incompressible Smoothed Particle Hydrodynamics (ISPH) Method (ISPH 기법을 이용한 고유동 콘크리트의 유동 해석)

  • Kim, Sang-Sin;Chung, Chul-Woo;Lee, Chang-Joon
    • Journal of the Korea Institute of Building Construction
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    • v.19 no.1
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    • pp.39-46
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    • 2019
  • A three-dimensional flow simulation model for high flow concrete was developed using Incompressible Smoothed Particle Hydrodynamics (ISPH), which can solved Navier-Stokes equation with the assumption of a fluid to be incompressible. For the simulation, a computer program code for ISPH was implemented with MATALB programming code. A piecewise cubic spline function was used for the kernel function of ISPH. Projetion method was used to calculate the velocity and pressure of particles as a function of time. Fixed ghost particle was used for wall boundary condition. Free surface boundaries were determined by using virtual density of particles. In order to validate the model and the code, the simulation results of slump flow test, $T_{500}$ test and L-box test were compared with experimental ones. The simulation results were well matched with the experimental results. The simulation described successfully the characteristics of the flow phenomenon according to the change of the viscosity and yield stress of high flow concrete.

Analysing the Narrative Strategy of Co-produced Transnational Romance Films (한일 공동제작 초국적 로맨스 영화의 내러티브 전략분석)

  • Cho, Jin-Hee
    • The Journal of the Korea Contents Association
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    • v.16 no.7
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    • pp.598-608
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    • 2016
  • This paper attempts to analyze the narrative strategy of co-produced transnational romance films, (2007) and (2010). These films were produced during the heyday of Korean wave, the phenomenon Korean popular culture enjoys overseas fandom. Coupling Korean male star with Japanese female star, and dramatizing their romance, the industries attempted to attract the nations' cultural consumers. International co-production has been considered as a mode of production strategic enough to penetrate into neighboring nations. One of the major benefits of international co-production is to cope with 'cultural discount' between nations. Since producers and directors from different cultural background can participate in the creative process and share ideas, they can devise quite strategic form and content to please culturally heterogeneous consumers. Korea and Japan have long been in socio-political conflict, which makes it crucial for these films' cultural producers not to stir spectators' nationalism. In other words, these films' cultural producers had to develop a narrative strategy not to analogize nations' political reality. This paper, therefore, aims to analyze the narrative structure of these films, and to specify narrative strategy in detail.

Quantitative Analysis of Magnetization Transfer by Phase Sensitive Method in Knee Disorder (무릎 이상에 대한 자화전이 위상감각에 의한 정량분석법)

  • Yoon, Moon-Hyun;Sung, Mi-Sook;Yin, Chang-Sik;Lee, Heung-Kyu;Choe, Bo-Young
    • Investigative Magnetic Resonance Imaging
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    • v.10 no.2
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    • pp.98-107
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    • 2006
  • Magnetization Transfer (MT) imaging generates contrast dependent on the phenomenon of magnetization exchange between free water proton and restricted proton in macromolecules. In biological materials in knee, MT or cross-relaxation is commonly modeled using two spin pools identified by their different T2 relaxation times. Two models for cross-relaxation emphasize the role of proton chemical exchange between protons of water and exchangeable protons on macromolecules, as well as through dipole-dipole interaction between the water and macromolecule protons. The most essential tool in medical image manipulation is the ability to adjust the contrast and intensity. Thus, it is desirable to adjust the contrast and intensity of an image interactively in the real time. The proton density (PD) and T2-weighted SE MR images allow the depiction of knee structures and can demonstrate defects and gross morphologic changes. The PD- and T2-weighted images also show the cartilage internal pathology due to the more intermediate signal of the knee joint in these sequences. Suppression of fat extends the dynamic range of tissue contrast, removes chemical shift artifacts, and decreases motion-related ghost artifacts. Like fat saturation, phase sensitive methods are also based on the difference in precession frequencies of water and fat. In this study, phase sensitive methods look at the phase difference that is accumulated in time as a result of Larmor frequency differences rather than using this difference directly. Although how MT work was given with clinical evidence that leads to quantitative model for MT in tissues, the mathematical formalism used to describe the MT effect applies to explaining to evaluate knee disorder, such as anterior cruciate ligament (ACL) tear and meniscal tear. Calculation of the effect of the effect of the MT saturation is given in the magnetization transfer ratio (MTR) which is a quantitative measure of the relative decrease in signal intensity due to the MT pulse.

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