• 제목/요약/키워드: equivalent media

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Development of Dermal Equivalent Using Mouse Fibroblasts (세포조직배양법을 이용한 쥐 인공피부의 개발)

  • Yang, Eun-Kyoung;Lee, Jae-Ho;Choe, Tae-Boo;Park, Jung-Keug
    • Microbiology and Biotechnology Letters
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    • v.21 no.4
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    • pp.381-391
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    • 1993
  • As the first stage of development of an artificial skin, fibroblasts were cultured in the collagen matrices to make a living dermal equivalent. Mouse embryonic fibroblasts were incorporated into a collagen matrices on plastic dishes containing concentrated DMEM culture media supplemented with sodium bicarbonate, hepes, antibiotics and fetal bovine serum. As the growth stimulation components, glycosaminoglycans were added: hyaluronic acid, chondroitin sulfate, heparin, chitosan were incorporated into the media at a concentration of either 1% or 5% w/w/ to collagen in order to investigate the effect on development of dermal equivalent. After the few days of incubation, gel matrics were contracted and firm dermal equivalent were formed. And the keratinocytes were cultured on top of dermal equivalent and make a three dimensional artificial skin tissue.

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A decoupling FEM for simulating near-field wave motion in two-phase media

  • Chen, S.L.;Liao, Z.P.;Chen, J.
    • Structural Engineering and Mechanics
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    • v.25 no.2
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    • pp.181-200
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    • 2007
  • A decoupling technique for simulating near-field wave motions in two-phase media is introduced in this paper. First, an equivalent but direct weighted residual method is presented in this paper to solve boundary value problems more explicitly. We applied the Green's theorem for integration by parts on the equivalent integral statement of the field governing equations and then introduced the Neumann conditions directly. Using this method and considering the precision requirement in wave motion simulation, a lumped-mass FEM for two-phase media with clear physical concepts and convenient implementation is derived. Then, considering the innate attenuation character of the wave in two-phase media, an attenuation parameter is introduced into Liao's Multi-Transmitting Formula (MTF) to simulate the attenuating outgoing wave in two-phase media. At last, two numerical experiments are presented and the numerical results are compared with the analytical ones demonstrating that the lumped-mass FEM and the generalized MTF introduced in this paper have good precision.

Effective Method for Analysis of Heterogeneous Porous Media (비균질 다공성 매질의 효율적 해석 방법)

  • Park, Chang-Geun
    • Journal of Korea Water Resources Association
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    • v.31 no.4
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    • pp.459-467
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    • 1998
  • The existing methods to analyze the heterogeneous porous media based on the similar media concept are the microscopic Miller similitude(MiS), the macroscopic Miller similitude(MaS) and the Warrick similitude(WS). The inter-relationship is found such that MiS ⊂ MaS ⊂ (⊂:subset). The proposed method is based ont eh assumption that the scale variables $\alpha$=w and the moisture content is dimensionless by introducing the effective degree of saturation instead of the degree of saturation into WS. The method, without the loss of generality in view of the inspectional analysis, can explain the heterogeneity of the media by using the scale variable $\alpha$ only. The media of $\alpha$=1 (average of $\alpha$) means the equivalent media corresponding to the heterogeneous media, while the standard deviation of $\alpha$ may explain the degree of the heterogeneity of the media under consideration. The hydraulic conductivity of the media with $\alpha$>1 is greater than that of the equivalent media, and the effective moisture content of the media with $\alpha$>1 is also greater. Based on these properties of the scale variable $\alpha$, the ideal vertical one-dimensional heterogeneous porous media is generated by using the technique of random number generation.

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A Study on Applicability of Equivalent Continuum Flow Model in DFN Media (DFN 매질에 대한 등가연속체 유동모델의 적용 가능성 평가에 관한 연구)

  • Lee, Dahye;Um, Jeong-Gi
    • Tunnel and Underground Space
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    • v.27 no.5
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    • pp.303-311
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    • 2017
  • The correlation analysis between the results obtained from DFN flow model and equivalent continuum flow model were conducted on total of 72 DFN blocks having various fracture geometry and domain size. A strong linear relation seems to exist between the two approaches under condition that normalized relative error for continuum behavior (ER) is less than 0.2, and the results from both methods are found to almost identical. To explore the field applicability of equivalent continuum flow model in DFN media, a total of 48 numerical schemes related to inflow of underground circular openings were implemented under various DFN configurations. The equivalent continuum flow model in DFN media with a constant hydraulic aperture was evaluated as valid. However, as the anisotropy increases due to variation of the hydraulic aperture, the results are likely to be overestimated compare to the DFN flow model.

Effect of Media Components and Phytohormones on in vitro Frond Proliferation of Lemna gibba G3 and 24 Additional Lemna gibba Strains

  • Moon, H.K.
    • Plant Resources
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    • v.1 no.2
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    • pp.98-104
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    • 1998
  • The effects of basal media, sucrose and phytohormone concentrations, and gelling agent combinations on in vitro frond proliferation of Lemna gibba G3 and 24 additional Lemna gibba strains were examined. Frond proliferation was equivalent on Schenk and Hidebrand. Murashige and Skoog. Nitsch and Nitsch, and Gamborg's B5 media and poor on murashige and Skoog medium in the absence of benzyladenine. With the addition of benzyladenine, Schenk and Hildebrand and Gamborg's B5 Were superior and equivalent. The addition of benzuyladenine increased equally frond proliferation at either 1 or $10{\mu}M$, however at $10{\mu}M$ fronds were severely curled or fused. Benzyladenine and thidiazuron suppressed root growth but kinetin was found to greatly enhance root growth. Gibberellic acid inhibited frond proliferation. Frond proliferation was significantly different on the four sucrose concentrations of 0, 1, 3, and 5% Among them, 3% sucrose was found to be superior. The reduced frond size observed in cultures grown on 8% sucrose could be explained by showing medium osmotic potential in excess of frond water potential. Gell agents also varied significantly in their ability to promote frond proliferation with 0.25% Gelrite or a mixture of 0.15% Gelrite and 0.4% agar. Proliferation of 25 Lemna gibba strains on medium neat optimal for Lemna gibba G3 showed a six-fold variation across strains with Lemna gobba G3 placing in the top 5 fastest proliferating strains.

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Analysis of Receiving Responses for a Bistatic Ground-Penetrating Radar System by Using Equivalent Network Model (등가회로망 모델을 이용한 Bistatic 지하탐사 레이더 시스템의 수신응답 해석)

  • Hyeon, Seung-Yeop;Kim, Sang-Uk;Kim, Se-Yun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.37 no.6
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    • pp.44-53
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    • 2000
  • The receiving responses of a bistatic GPR system are analyzed by using three-dimensional FDTD method and equivalent network model. The conventional delta-gap feed model may be inaccurate because of neglecting the impedance matching characteristics between the antenna and the transmission line. In this paper, the feed model is improved by considering the physical characteristics of the actual GPR. The actually received voltage is calculated by employing the equivalent network model in angular frequency-domain, which is composed by using the results of three-dimensional FDTD analysis for an actual bistatic GPR system. The validity of the presented model is assured by showing the convergence of the computed results to the measured data.

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MMSE based Wiener-Hopf Equation

  • Cho, Juphil;Lee, Il Kyu;Cha, Jae Sang
    • International Journal of Internet, Broadcasting and Communication
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    • v.4 no.1
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    • pp.18-22
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    • 2012
  • In this paper, we propose an equivalent Wiener-Hopf equation. The proposed algorithm can obtain the weight vector of a TDL(tapped-delay-line) filter and the error simultaneously if the inputs are orthogonal to each other. The equivalent Wiener-Hopf equation was analyzed theoretically based on the MMSE(minimum mean square error) method. The results present that the proposed algorithm is equivalent to original Wiener-Hopf equation. In conclusion, our method can find the coefficient of the TDL (tapped-delay-line) filter where a lattice filter is used, and also when the process of Gram-Schmidt orthogonalization is used. Furthermore, a new cost function is suggested which may facilitate research in the adaptive signal processing area.

Energy harvesting from conducted electromagnetic interference of fluorescent light for Internet of Things application

  • Hyoung, Chang-Hee;Hwang, Jung-Hwan
    • ETRI Journal
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    • v.44 no.5
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    • pp.759-768
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    • 2022
  • A novel energy harvesting technique that uses conducted electromagnetic interference as an energy source is presented. Conducted EMI generated from fluorescent light using a switched-mode power supply was measured and modeled as an equivalent voltage source. Two types of rectifier circuits-a bridge rectifier and a voltage doubler-were used as the harvesting devices for conducted EMI source. The matching networks were designed based on the equivalent model, and the harvested power was improved. The implemented energy harvester produces a regulated power over 68.9 mW and current over 15.1 mA while a regulated voltage can be selected between 3.3 V and 5 V. The proposed system shows the highest harvesting power indoor environment and can provide enough power for the Internet of Things devices.

Involvement of Social Media in Disaster Management during the Wenchuan and Ya'an Earthquakes

  • Li, Leah Xiufang
    • Asian Journal for Public Opinion Research
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    • v.1 no.4
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    • pp.249-267
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    • 2014
  • Social media is being increasingly utilized in disaster relief work to identify safety issues, locate displaced-victims, and seek or provide support for those who need help. The presence of social media in disaster management has changed significantly in recent years, as it was not prevalent in the 2008 Wenchuan earthquake, but had become a powerful force in the 2013 Ya'an earthquake. This paper discusses the development of social media in disaster management via making a comparison between how it functioned in the two earthquakes. It examines the following aspects: who are the stakeholders that use social media in the earthquake management; how do they adopt this means in response to the earthquakes; and what are the outcomes of adopting social media with regards to public engagement and collaboration in an emergency event. As Sina Weibo acts as the equivalent of China's Twitter, the methodology relies on an analysis of posts in Weibo. The outcomes primarily show that: (1) authorities, celebrities and the public actively adopted social media for the purpose of information dissemination and resource mobilization; and (2) social media users are both content consumers and content generators in the times of earthquakes. The study concludes that social media as a backchannel communication tool is helpful for government institutions, corporations, and nonprofit organizations to build relationships with their stakeholders in the disaster management cycle. The result will interest academics and emergency management practitioners who are concerned with improving disaster communication.

New Scattering Matrix Model for Modeling Ferrite Media Using the TLM Method

  • Zugari, Asmaa;El Adraoui, Soufiane;Yaich, Mohamed Iben;Khalladi, Mohsine
    • ETRI Journal
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    • v.34 no.4
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    • pp.536-541
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    • 2012
  • This paper aims to extend the transmission line matrix method with a hybrid symmetrical condensed node (HSCN) to model ferrite media in the time domain. To take into account the anisotropy and dispersive properties of ferrite media, equivalent current sources are incorporated into supplementary stubs of the original HSCN. The scattering matrix of the proposed HSCN is provided, and the validity of this approach is demonstrated for both transversely and longitudinally magnetized ferrites. Agreement is achieved between the results of this approach and those of the theoretical and the finite-difference time-domain method.