• 제목/요약/키워드: mixed-effects model

검색결과 484건 처리시간 0.025초

Surface Topography를 이 용한 평행 스러스트 베어링의 혼합윤활 해석 (An Analysis of Mixed Lubrication in Thrust Bearing by Surface Topography)

  • 이동길;임윤철
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1999년도 제30회 추계학술대회
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    • pp.136-145
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    • 1999
  • This paper describes the surface roughness effect in parallel thrust bearing. In mixed lubrication, some contacts will take place between asperities, and partial lubrication will occur. An average Reynolds Equation is utilized to determine effects of surface roughness on partially lubricated contacts. By using an autocorrelation function for the surface profile, surface model is generated numerically Although the two surfaces are parallel in thrust bearing separated by thin film, the pressure peak is formed due to asperites. By means of surface profile parameters, it is shown that which surface is optimal for the parallel thrust bearing.

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A Study on Assessment of Composite Couplings for Helicopter Rotor Blades with Multi-cell Sections

  • Jung, Sung-Nam;Park, Il-Ju;Shi, Eui-Sup;Chopra, Inderjit
    • International Journal of Aeronautical and Space Sciences
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    • 제4권1호
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    • pp.9-18
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    • 2003
  • In this work, a closed-form analysis is performed for the structural response of coupled composite blades with multi-cell sections. The analytical model includes the effects of shell wall thickness, transverse shear, torsion warping and constrained warping. The mixed beam approach based on Reissner's semi-complementary energy functional is used to derive the beam force-displacement relations. The theory is validated against experimental test data and other analytical results for coupled composite beams and blades with single-cell box-sections and two-cell airfoils. Correlation of the present method with experimental results and detailed finite element results is found to be very good.

Kernel Poisson Regression for Longitudinal Data

  • Shim, Joo-Yong;Seok, Kyung-Ha
    • Journal of the Korean Data and Information Science Society
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    • 제19권4호
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    • pp.1353-1360
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    • 2008
  • An estimating procedure is introduced for the nonlinear mixed-effect Poisson regression, for longitudinal study, where data from different subjects are independent whereas data from same subject are correlated. The proposed procedure provides the estimates of the mean function of the response variables, where the canonical parameter is related to the input vector in a nonlinear form. The generalized cross validation function is introduced to choose optimal hyper-parameters in the procedure. Experimental results are then presented, which indicate the performance of the proposed estimating procedure.

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Is the Peak-Affect Important in Fast Processing of Visual Images in Printed Ads?: A Comparative Study on the Affect Integration Theories

  • Bu, Kyunghee;Lee, Luri
    • Asia Marketing Journal
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    • 제24권3호
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    • pp.96-108
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    • 2022
  • This study investigates how affects elicited by visual images in print ads are integrated to form a liking for the ads. Assuming a sequential rather than simultaneous processing of still-cut images, we adopt the 'think-aloud' method to capture consumers' spontaneous responses to visual images. We hypothesize that not only would consumers show mixed affects toward a still-cut visual image but that they would also integrate their serial affects heuristically rather than simply averaging the affects as suggested by the compensatory hypothesis. By comparing the effects of two contradictory affect integration hypotheses (i.e., peak-affect and mood-maintenance) with compensatory integration, using a single regression model, we found that peak-negative along with mood maintenance integration of serial affects for a print ad works best in the formation of ad liking. The results also support our initial premise that people can have mixed valence even toward a still-cut ad.

The Shifts of Masculine Domination in Vietnam: Examining Mixed and Hybrid Characteristics in Feminist Texts on Vietnamese Newspapers in the Early Twentieth Century

  • CAO Kim-Lan
    • 수완나부미
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    • 제15권2호
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    • pp.155-185
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    • 2023
  • This paper aims to identify the shifts of masculine domination, illuminating Vietnamese men and women's actual position in society through surveying the mixed and hybrid characteristics described in the feminist texts in the early twentieth century. This paper concentrates on the feminist writings of the two exceptionally male intellectuals Nguyễn Văn Vĩnh (1882-1936) and Phan Khôi (1887-1959). in order to implement these goals, the paper first examines the popular phenomenon of ventriloquism among Vietnamese male intellectuals, whose dominant attitudes may still be unveiled in feminist texts. Secondly, the paper focuses on surveys of men's direct discourse in constructing the model of women's liberation. From these two contents, this paper answers the following questions: Why have Vietnamese men become feminists? What were the causes, purposes, and effects of this phenomenon? To look at the nature of Vietnamese feminism, this paper will show the shifts of masculine domination in Vietnam as another form of protecting men's privileges. All analyses in this study will ground discussion on the economic, political, and social contexts and conditions of Vietnam in the early twentieth century.

Major SNP Marker Identification with MDR and CART Application

  • Lee, Jea-Young;Choi, Yu-Mi
    • Communications for Statistical Applications and Methods
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    • 제15권2호
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    • pp.265-271
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    • 2008
  • It is commonly believed that diseases of human or economic traits of livestock are caused not by single genes acting alone, but multiple genes interacting with one another. This issue is difficult due to the limitations of parametric-statistic methods of gene effects. So we introduce multifactor-dimensionality reduction(MDR) as a methods for reducing the dimensionality of multilocus information. The MDR method is nonparametric (i. e., no hypothesis about the value of a statistical parameter is made), model free (i. e., it assumes no particular inheritance model) and is directly applicable to case-control studies. Application of the MDR method revealed the best model with an interaction effect between the SNPs, SNP1 and SNP3, while only one main effect of SNP1 was statistically significant for LMA (p < 0.01) under a general linear mixed model.

Defect Chemistry of the Mixed Conducting Cage Compound Ca12Al14O33

  • Janek, J.;Lee, D.K.
    • 한국세라믹학회지
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    • 제47권2호
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    • pp.99-105
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    • 2010
  • The electrical transport properties of mayenite ($Ca_{12}Al_{14}O_{33}$ or $12CaO{\cdot}7Al_2O_3$; mostly abbreviated as $C_{12}A_7$) can be controlled in a wide range by varying the oxygen deficiency: At high temperatures mayenite becomes either an oxygen solid electrolyte, a mixed ionic/electronic conductor or an inorganic electride with metal-like properties upon chemical reduction (removing oxygen). The underlying defect chemistry can be understood on the basis of a relatively simple model-despite the complex cage structure: A point defect model based on the assumption that the framework $[Ca_{12}Al_{14}O_{32}]^{2+}$ acts as a pseudo-donor describes well the high temperature transport properties. It accounts for the observed conductivity plateau at higher oxygen activities and also describes the experimentally observed oxygen activity dependence of the electronic conductivity with -1/4 slope at temperatures between 800 and $1000^{\circ}C$. Doping effects in mayenite are still not well explored, and we review briefly the existing data on doping by different elements. Hydration of mayenite plays a crucial role, as Mayenite is hygroscopic, which may be a major obstacle for technical applications.

Average Flow Model을 이용한 Kurtosis에 따른 Flow Factors에 관한 연구 (Effects of Kurtosis on the Flow Factors Using Average Flow Model)

  • 강민호;김태완;구영필;조용주
    • Tribology and Lubricants
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    • 제17권3호
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    • pp.236-243
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    • 2001
  • In this study, flow factors are evaluated in terms of kurtosis using random rough surface generated numerically. As h/$\sigma$become large ø$\sub$x/, ø$\sub$y/, ø$\sub$fp/, approach to 1 and ø$\sub$s/, ø$\sub$fs/ to 0 asymptotically regardless of kurtosis. ø$\sub$x/, ø$\sub$y/, ø$\sub$fp/ increase with increasing kurtosis in the mixed lubrication regime. ø$\sub$s/, ø$\sub$fs/ is associated with an additional flow transport due to the combined effect of sliding and roughness. As h/$\sigma$ decreases ø$\sub$s/, ø$\sub$fs/ increase up to a certain point, and then decrease toward zero. This behavior can be attributed to the increasing number of contacts in the mixed lubrication regime. ø$\sub$x/ in the presence of elastic deformation on the surface is larger than ø$\sub$x/ in the absence of it because local film thickness(h$\sub$T/) increases by elastic deformation.

3차원 PCB 채널내에서의 복사-혼합대류 열전달 특성 (Heat Transfer Characteristics of Radiation-Mixed Convection in a Three-Dimensional PCB Channel)

  • 이주형;박경우;박희용
    • 설비공학논문집
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    • 제8권4호
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    • pp.561-575
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    • 1996
  • The interaction of turbulent mixed convection and surface radiation in a three-dimensional channel with the heated blocks is analyzed numerically. Two blocks are maintained at high temperature and the other bottom and horizontal walls are insulated. S-4 method is employed to calculate the effect of the radiative heat transfer. The low Reynolds number k-$\varepsilon$ model proposed by Launder and Sharma is used to estimate the turbulent influence on the heat transfer enhancement. From above modeling, the effects of various channel specifications on the flow and heat transfer characteristics are investigated. The variables used for the present study are Reynolds number, block spacing, the channel height spacing for block and the emissivity. Average Nusselt numbers along the block surfaces are correlated and presented in terms of Reynolds number, emissivity and dimensionless geometric parameters. For the range of conditions in this study, average Nusselt numbers along the block surfaces are strongly influenced by the Reynolds numbers and channel height spacing for block but weakly influenced by the block spacing and the emissivity of the adiabatic walls.

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Computational Study of the Mixed Cooling Effects on the In-Vessel Retention of a Molten Pool in a Nuclear Reactor

  • Kim, Byung-Seok;Ahn, Kwang-Il;Sohn, Chang-Hyun
    • Journal of Mechanical Science and Technology
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    • 제18권6호
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    • pp.990-1001
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    • 2004
  • The retention of a molten pool vessel cooled by internal vessel reflooding and/or external vessel reactor cavity flooding has been considered as one of severe accident management strategies. The present numerical study investigates the effect of both internal and external vessel mixed cooling on an internally heated molten pool. The molten pool is confined in a hemispherical vessel with reference to the thermal behavior of the vessel wall. In this study, our numerical model used a scaled-down reactor vessel of a KSNP (Korea Standard Nuclear Power) reactor design of 1000 MWe (a Pressurized Water Reactor with a large and dry containment). Well-known temperature-dependent boiling heat transfer curves are applied to the internal and external vessel cooling boundaries. Radiative heat transfer has been considered in the case of dry internal vessel boundary condition. Computational results show that the external cooling vessel boundary conditions have better effectiveness than internal vessel cooling in the retention of the melt pool vessel failure.