• 제목/요약/키워드: Central Moment

검색결과 155건 처리시간 0.038초

내진설계용 편심방식 가지배관 고정장치의 좌굴 실험 (Buckling Experiment of Eccentric Seismic Bracing Devices for Branch Lines)

  • 오창수;김지훈;공하성
    • 대한안전경영과학회지
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    • 제26권1호
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    • pp.9-14
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    • 2024
  • Restraints of Branch Lines are used as earthquake-resistant support devices for fire-fighting pipes along with sway brace devices. The central types are aligned and fixed in a straight line with center of the pipe, but the eccentric types are fixed to on side of the pipe, so a bending moment occurs. In this study, three specimens each of central type and eccentric type were installed at an angle of 45° from the vertical and a monotonic compression load of 1340N was applied. All central type samples satisfied 17.8mm of the allowable displacement, but all eccentric type samples failed to meet the target load and buckled. Therefore, when considering the performance of eccentric type restraints, both compressive load and bending moment must be considered. Even through material mechanics calculations, the yield stress of eccentric type - 3/8 inch all threaded steel bolt - exceeds 320Mpa of the allowable stress. A experiment standards need to be established for eccentric type restraints.

Seismic performance of moment connections in steel moment frames with HSS columns

  • Nunez, Eduardo;Torres, Ronald;Herrera, Ricardo
    • Steel and Composite Structures
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    • 제25권3호
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    • pp.271-286
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    • 2017
  • The use of Hollow Structural Sections (HSS) provides an alternative for steel buildings in seismic zones, with the advantage over WF columns that the HSS columns have similar resistance along both axes and enhanced performance under flexure, compression and torsion with respect to other columns sections. The HSS columns have shown satisfactory performance under seismic loads, such as observed in buildings with steel moment frames in the Honshu earthquake (2011). The purpose of this research is to propose a new moment connection, EP-HSS ("End-plate to Hollow Structural Section"), using a wide flange beam and HSS column where the end plate falls outside the range of prequalification established in the ANSI/AISC 358-10 Specification, as an alternative to the traditional configuration of steel moment frames established in current codes. The connection was researched through analytical, numerical (FEM), and experimental studies. The results showed that the EP-HSS allowed the development of inelastic action on the beam only, avoiding stress concentrations in the column and developing significant energy dissipation. The experiments followed the qualification protocols established in the ANSI/AISC 341-10 Specification satisfying the required performance for highly ductile connections in seismic zones, thereby ensuring satisfactory performance under seismic actions without brittle failure mechanisms.

A Study of Control Chart for Skewness

  • Lee, Jung Jin
    • 품질경영학회지
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    • 제23권4호
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    • pp.1-12
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    • 1995
  • Sample skewness has not received much attention from researchers to design a control chart. In this paper, control charts based on two skewness measures are studied to control a manufacturing process. One skewness measure is the third central moment about mean, the other is the third L-moment which is a linear combination of order statistics. Since the exact sampling distributions of two skewness measures are unknown, empirical sampling distributions are studied using simulation. The sampling distributions are used to design control charts for skewness and performance of two skewness measures is compared.

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Some Results About $NBU_{mgf}$ Class of Life Distributions

  • Ahmad, I.A.;Kayid, M.
    • International Journal of Reliability and Applications
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    • 제5권4호
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    • pp.155-162
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    • 2004
  • A new class of life distributions is studied. This class is defined based on comparing the residual life to the whole life in the moment generating function order giving "the new better than used in the moment generating function order ageing class ($NBU_{mgf}$)". Some new results of this class are given including some closere properties and characterizations. Finally testing exponentially against the $NBU_{mgf}$ class is also addressed.

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Experimental and numerical investigation on the behavior of concrete-filled rectangular steel tubes under bending

  • Zhang, Tao;Gong, Yong-zhi;Ding, Fa-xing;Liu, Xue-mei;Yu, Zhi-wu
    • Structural Engineering and Mechanics
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    • 제78권3호
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    • pp.231-253
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    • 2021
  • Pure bending loading conditions are not frequently occurred in practical engineering, but the flexural researches are important since it's the basis of mechanical property researches under complex loading. Hence, the objective of this paper is to investigate the flexural behavior of concrete-filled rectangular steel tube (CFRT) through combined experimental and numerical studies. Flexural tests were conducted to investigate the mechanical performance of CFRT under bending. The load vs. deflection curves during the loading process was analyzed in detail. All the specimens behaved in a very ductile manner. Besides, based on the experimental result, the composite action between the steel tube and core concrete was studies and examined. Furthermore, the feasibility and accuracy of the numerical method was verified by comparing the computed results with experimental observations. The full curves analysis on the moment vs. curvature curves was further conducted, where the development of the stress and strain redistribution in the steel tube and core concrete was clarified comprehensively. It should be noted that there existed bond slip between the core concrete and steel tube during the loading process. And then, an extensive parametric study, including the steel strength, concrete strength, steel ratio and aspect ratio, was performed. Finally, design formula to calculate the ultimate moment and flexural stiffness of CFRTs were presented. The predicted results showed satisfactory agreement with the experimental and FE results. Additionally, the difference between the experimental/FE and predicted results using the related design codes were illustrated.

A NOTE ON SOME HIGHER ORDER CUMULANTS IN k PARAMETER NATURAL EXPONENTIAL FAMILY

  • KIM, HYUN CHUL
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제3권2호
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    • pp.157-160
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    • 1999
  • We show the cumulants of a minimal sufficient statistics in k parameter natural exponential family by parameter function and partial parameter function. We nd the cumulants have some merits of central moments and general cumulants both. The first three cumulants are the central moments themselves and the fourth cumulant has the form related with kurtosis.

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Scaling Limits for Associated Random Measures

  • Kim, Tae-Sung;Hahn, Kwang-Hee
    • Journal of the Korean Statistical Society
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    • 제21권2호
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    • pp.127-137
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    • 1992
  • In this paper we investigate scaling limits for associated random measures satisfying some moment conditions. No stationarity is required. Our results imply an improvement of a central limit theorem of Cox and Grimmett to associated random measure and an extension to the nonstationary case of scaling limits of Burton and Waymire. Also we prove an invariance principle for associated random measures which is an extension of the Birkel's invariance principle for associated process.

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Parameter Estimation of Perillyl Alcohol in RP-HPLC by Moment Analysis

  • Row Kyung Ho;Lee Chong Ho;Kang Ji Hoon
    • Biotechnology and Bioprocess Engineering:BBE
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    • 제7권1호
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    • pp.16-20
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    • 2002
  • Parameter estimations were made for the reversed-phase adsorption of perillyl alcohol (POH), a potent anti-cancer agent, on octadecylsilyl-silica gel (ODS). The average particle diameter of ODS was about $15\;{\mu}m$, and the particles were packed in the column $(3.9\;\times\;300mm)$. The mobile phase used was a mixture of acetonitrile and water, in which the acetonitrile ranged between 50 and $70\;(v/v\;\%)$. The first absolute moment and the second central moment were determined from the chromatographic elution curves by moment analysis. Experiments were carried out using POH solutions within the linear adsorption range. The fluid-to-particle mass transfer coefficient was estimated using the Wilson-Geankoplis equation. The axial dispersion coefficient and the intra particle diffusivity were determined from the slope and intercept of a plot of H vs $1/u_0$, respectively. The contributions of each mass-transfer step were axial dispersion, fluid-to-particle mass transfer, and intraparticle diffusion.

An Exploration of a Performer's Organic Action

  • BongHee, Son
    • International Journal of Advanced Culture Technology
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    • 제10권4호
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    • pp.383-388
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    • 2022
  • This thesis explores the principle of a performer's organic action by means of his/her bodily responses on stage. This research has been developed to define the nature of a performer's central task in order to constitute empirical understanding of acting and the purpose of training in addressing the question of what sort of qualitative bodily training is necessary to be in a state of the full body involvement. This study investigates to articulate a performer's fundamental task at the most rudimentary level by utilizing those theatre artists' concepts with practical assumptions. In particular, the key terms, happen and change signifies the quality of a performer's body that has to fit into the given environment in which the performer's body can be subordinated through the moment on stage. Here, we argue that a performer's essential task parallel to make the following moment to happen and change by means of progressing a set of the next moment. In this manner, we also argue that a moment of displaying the performer's conscious effort, forceful and externalizing the visible elements under the use of erroneous language leads his/her body not to function on stage, a state of disengagement from his/her body. Finally, we provide a way to facilitate a performer's organic action by focused on his/her lived experience to create the functional moment which is opposite to the predominance of a representation, maintaining the performer's intellectual sense.

Estimation of load and resistance factors based on the fourth moment method

  • Lu, Zhao-Hui;Zhao, Yan-Gang;Ang, Alfredo H.S.
    • Structural Engineering and Mechanics
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    • 제36권1호
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    • pp.19-36
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    • 2010
  • The load and resistance factors are generally obtained using the First Order Reliability Method (FORM), in which the design point should be determined and derivative-based iterations have to be used. In this paper, a simple method for estimating the load and resistance factors using the first four moments of the basic random variables is proposed and a simple formula for the target mean resistance is also proposed to avoid iteration computation. Unlike the currently used method, the load and resistance factors can be determined using the proposed method even when the probability density functions (PDFs) of the basic random variables are not available. Moreover, the proposed method does not need either the iterative computation of derivatives or any design points. Thus, the present method provides a more convenient and effective way to estimate the load and resistance factors in practical engineering. Numerical examples are presented to demonstrate the advantages of the proposed fourth moment method for determining the load and resistance factors.