• 제목/요약/키워드: Model K

검색결과 79,998건 처리시간 0.081초

Immunohistochemical analysis of effects of UVA exposure to the human fibroblasts in the skin equivalent model

  • Kazuhiro Shimizu;Fumihide Ogawa;Bae, Sang-Jae;Yoichiro Hamasaki;Ichiro Katayama
    • Journal of Photoscience
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    • 제9권2호
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    • pp.500-502
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    • 2002
  • In vitro and in vivo studies have reported the induction of matrix metaloproteinase (MMP)-1 in the fibroblasts by ultraviolet (UV) A irradiation. We constructed the skin equivalent model using HaCaT cells as keratinocytes and human neonatal dennal fibroblasts as fibroblasts in the present study. The induction of MMP-l in the fibroblasts was confirmed immunohistochemically 6 hours after UVA irradiation using this model. This model was simply composed of human keratinocytes and fibroblasts. To our knowledge, there have been a few papers concerning the skin equivalent model in the field of photobiology. The effect of UVA exposure to fibroblasts through keratinocytes was examined using this model. The cross-talk can be examined between keratinocytes and fibroblasts. This model can be a useful tool in the field of photobiology.

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Deformation-based Strut-and-Tie Model for reinforced concrete columns subject to lateral loading

  • Hong, Sung-Gul;Lee, Soo-Gon;Hong, Seongwon;Kang, Thomas H.K.
    • Computers and Concrete
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    • 제17권2호
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    • pp.157-172
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    • 2016
  • This paper presents a Strut-and-Tie Model for reinforced concrete (RC) columns subject to lateral loading. The proposed model is based on the loading path for the post-yield state, and the geometries of struts and tie are determined by the stress field of post-yield state. The analysis procedure of the Strut-and-Tie Model is that 1) the shear force and displacement at the initial yield state are calculated and 2) the relationship between the additional shear force and the deformation is determined by modifying the geometry of the longitudinal strut until the ultimate limit state. To validate the developed model, the ultimate strength and associated deformation obtained by experimental results are compared with the values predicted by the model. Good agreements between the proposed model and the experimental data are observed.

Numerical model for nonlinear analysis of composite concrete-steel-masonry bridges

  • Baloevic, Goran;Radnic, Jure;Grgic, Nikola;Matesan, Domagoj;Smilovic, Marija
    • Coupled systems mechanics
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    • 제5권1호
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    • pp.1-20
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    • 2016
  • This paper firstly briefly describes developed numerical model for both static and dynamic analysis of planar structures made of concrete, steel and masonry. The model can simulate the main nonlinearity of such individual and composite structures. The model is quite simple and based on a small number of material parameters. After that, three real composite concrete-steel-masonry bridges were analyzed using the presented numerical model. It was concluded that the model can be useful in practical analysis of composite bridges. However, future verifications of the presented numerical model are desirable.

VoIP Call Quality Assessment Model for Ubiquitous Environment (유비쿼터스 환경에 적합한 VoIP 통화 품질 측정 모델)

  • Choi Seoung-Kwon;Song Jong-Myoung;Kim Song-Young;Lee Byung-Rok;Cho Yong-Hwan
    • Proceedings of the Korea Contents Association Conference
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    • 한국콘텐츠학회 2005년도 춘계 종합학술대회 논문집
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    • pp.487-490
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    • 2005
  • In this paper, proposed VoIP call quality Assessment model for Ubiquitous environment that apply the recency Effect and bust packet loss model. It is model that improved E-Model's problems for elaborate and reliable assessment. A new model makes the accurate VoIP call quality assessment possible by applying the burst packet loss and recency effect. Advanced E-model apply bust packet loss model potentialized elaborate and reliable assessment.

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Numerical Analyses on Wall-Attaching Offset Jet with Algebraic Reynolds Stress Model (대수 레이놀즈 응력모델에 의한 단이 진 벽면분류에 대한 수치해석)

  • Seo, Ho-Taek;Bu, Jeong-Suk
    • Transactions of the Korean Society of Mechanical Engineers B
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    • 제24권12호
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    • pp.1615-1624
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    • 2000
  • Algebraic Reynolds Stree (ARS) model is applied in order to analyze the turbulent flow of wall-attaching offset jet and to evaluate the predictability of model. The applied numerical schemes are the upwind scheme and the skew-upwind scheme. The numerical results show a good prediction in the first order calculations(i.e., reattachment length, mean velocity, pressure), however, slight deviations in the second order(i.e., kinetic energy and turbulence intensity). Comparing with the previous results using the k-$\varepsilon$ model, the ARS model predicts better than the standard k-$\varepsilon$ model, however, slightly worse than the k-$\varepsilon$ model including the streamline curvature modification. Additionallay this study can reconfirm that the skew-upwind scheme has approximately 25% improved predictability than the upwind scheme.

VBIC Model Application and Parameter Extraction and Optimization for SiGe HBT

  • Lee, Sang-Heung;Park, Chan-Woo;Lee, Seung-Yun;Lee, Ja-Yol;Kang, Jin-Yeong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • 제28권8A호
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    • pp.650-656
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    • 2003
  • In 1995, a group of representatives from the integrated circuits and computer-aided design industries presented a industry standard bipolar model called the VBIC model. The VBIC model includes the improved Early effect, quasi-saturation, substrate parasitic, avalanche multiplication, and self-heating which are not available in the conventional SGP model. This paper applies VBIC model for SiGe HBT device and develops an accurate and efficient methodology to extract all the DC and AC parameters of the VBIC model for SiGe HBT device at room temperature. Simulated results by the extracted VBIC model parameter are compared with the measurement data and show very good agreement in both DC and s-parameters prediction.

A Determination of the Reference Model for the Model Following System using an Expert System (전문가 시스템을 이용한 모델 추종 시스템의 기준 모델 선정)

  • Moon, Dong-Wook;Hwang, Young-Moon;Kang, Young-Ho;Lee, Hoo-Min;Kim, Lark-Kyo
    • Proceedings of the KIEE Conference
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    • 대한전기학회 1996년도 하계학술대회 논문집 B
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    • pp.1069-1072
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    • 1996
  • In modern control engineering, the model following system is a typical method. The model following system's performance is due to algorithm of control law, accuracy of modeling to the plant, and dynamics of the reference model. But the determination of the reference model depends on knowledge of an expert. Using an expert system, the determination method of the reference model was proposed in this paper. So, the reference model can be selected by user who has no Knowledge of dynamics and parameters.

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Computation of a Turbulent Natural Convection in a Rectangular Cavity with the Low-Reynolds-Number Differential Stress and Flux Model

  • Choi, Seok-Ki;Kim, Eui-Kwang;Wi, Myung-Hwan;Kim, Seong-O
    • Journal of Mechanical Science and Technology
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    • 제18권10호
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    • pp.1782-1798
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    • 2004
  • A numerical study of a natural convection in a rectangular cavity with the low-Reynolds-number differential stress and flux model is presented. The primary emphasis of the study is placed on the investigation of the accuracy and numerical stability of the low-Reynolds-number differential stress and flux model for a natural convection problem. The turbulence model considered in the study is that developed by Peeters and Henkes (1992) and further refined by Dol and Hanjalic (2001), and this model is applied to the prediction of a natural convection in a rectangular cavity together with the two-layer model, the shear stress transport model and the time-scale bound ν$^2$- f model, all with an algebraic heat flux model. The computed results are compared with the experimental data commonly used for the validation of the turbulence models. It is shown that the low-Reynolds-number differential stress and flux model predicts well the mean velocity and temperature, the vertical velocity fluctuation, the Reynolds shear stress, the horizontal turbulent heat flux, the local Nusselt number and the wall shear stress, but slightly under-predicts the vertical turbulent heat flux. The performance of the ν$^2$- f model is comparable to that of the low-Reynolds-number differential stress and flux model except for the over-prediction of the horizontal turbulent heat flux. The two-layer model predicts poorly the mean vertical velocity component and under-predicts the wall shear stress and the local Nusselt number. The shear stress transport model predicts well the mean velocity, but the general performance of the shear stress transport model is nearly the same as that of the two-layer model, under-predicting the local Nusselt number and the turbulent quantities.

Design and Implementation of Model Manager for Flexible Supply Network Planning Model (유연한 공급망 계획 모형 작성을 위한 모형관리자의 설계 및 구현)

  • Yang, Young-Chul;Jang, Yang-Ja;Park, Chan-Kwon;Park, Jin-Woo
    • IE interfaces
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    • 제15권1호
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    • pp.40-48
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    • 2002
  • Recently, in the competitive environments, every company recognizes the importance of supply network planning models. However, there are so many problems in correctly applying mathematical model to the real world. Because mathematical modeling packages charge planning managers with understanding the models and responsibility for generating plans, fast and accurate model cannot be generated with ease. In this paper, we design the model management system that helps planning managers flexibly create and modify mathematical models and manage model versions. We implement the system with model base concept.