1,721,763 research outputs found
School effectiveness as related to organizational climate and leadership style.
Get PDFby Cheng Yin Cheong.Title in Chinese:Bibliography: leaves 172-189Thesis (M.A.Ed.)--Chinese University of Hong Kong, 198
Gang tie zhan shi.
No full text武兆堤, 蘇里, 吳茵原著 ; 成蔭改編."榮獲一九五一年第六屆國際電影節和平獎".Wu Zhaoti, Su Li, Wu Yin yuan zhu ; Cheng Yin gai bian."Rong huo yi jiu wu yi nian di liu jie guo ji dian ying jie he ping jiang"
Intensity Measures for Seismic Response Prediction and associated Ground Motion Selection and Modification
Get PDFBased on the research of the first generation of Performance-Based Earthquake engineering methodology (PBEE), Pacific Earthquake Engineering Research Centre (PEER) has developed the second generation procedure aiming at a more robust methodology of PBEE where the process is broken into several logical elements that can be studied and resolved in a rigorous and consistent manner. Due to the inherent uncertainty properties of earthquake occurrence, e.g. earthquake intensity, ground motion features, nonlinear dynamic behaviour of structures and etc., it allows that the new generation of PBEE methodology should be formalized within a probabilistic basis. To apply this methodology it requires an interactive effort of multi-disciplinary experts, such as geology engineers, seismologist, structural engineers, loss experts and etc. For structural engineers the most interest can be relevant to the selection and estimation of two parameters in PBEE, i.e. Intensity Measures (IM) and Engineering Demand Parameters (EDP), which reflect ground motion hazard and structural response in terms of deformations, accelerations, or other response quantities of the building excited by input ground motions.
The EDPs are strongly dependent on the Intensity Measure (IM) used to perform the selection of ground motions. The IM as an intermediate variable connecting seismic analysis and structural analysis plays a very important role for structural engineers. An ideal IM should generally be of efficiency and sufficiency. The efficiency means it yields low dispersion of values of engineering demand parameter (EDP), while the sufficiency implies that EDP predicted with the candidate IM should be only dependent on this IM, not be conditionally dependent on properties of ground motions, like magnitude, source to site distance, fault mechanism etc. Therefore it implies the need of comparison among different intensity measures (IMs), in particular the comparison of dispersion of the EDP in relation to each IM. To this purpose a set of IMs 27 IMs, including those commonly adopted and some modified IMs based on the existed ones, are investigated in order to find optimum IMs for predicting various EDPs. Not only is IMs for predicting the structural response of widely studied fixed base buildings are investigated, but also IMs for predicting structural response of the base-isolated buildings are initiatively studied. 80 ordinary and 59 pulse-like ground motion records are used to run nonlinear dynamic analyses on the 4-storey and 6-storey frame concrete buildings and these buildings equipped with base-isolation system on them. The EDPs considered in this study include the Maximum Inter-storey Drift Ratio (MIDR), the Maximum Roof Drift Ratio (MRDR) and the Maximum Base Displacement (MBD, only for base-isolated buildings).
Base on the results from this study some energy-based intensity measures have been shown to be good predictors of both structural and non-structural damage for base-isolated structures. However, they are not usually employed in probabilistic seismic demand analyses because of the lack of reliable Ground Motion Prediction Equations (GMPEs). In order to define seismic hazard and thus to calculate demand hazard curves it is essential, in fact, to establish a GMPE for the earthquake intensity. In the light of this need, new GMPEs are proposed here for the energy-based intensity measure, in particular elastic input energy equivalent velocity spectra i.e. VEIa and VEIr. The new GMPE is developed by taking advantage of the more comprehensive NGA database with more completed meta-data compiled in recent years. This prediction equation has a wider magnitude and distance applicable range, considers the effect of soil site by VS30 and fault mechanism, and etc.
However when the energy-based IMs are used in the selection and modification of ground motions for structural dynamic analyses, the uniform hazard spectrum derived from their GMPEs only gives the marginal distribution without information of joint occurrence of spectral values at different periods. In fact the uniform hazard spectrum of spectral acceleration is widely demonstrated to cause conservative results. Therefore the correlation of the elastic input energy spectral values at different periods is initiatively evaluated and the analytical predictive equation is also proposed to calculate the correlation of elastic input energy spectral values. Using the correlation their conditional mean spectrum recognized as a more appropriate target spectrum for ground motions selections can be developed. On the other hand this correlation also can be used to calculate the predicted mean value and the dispersion of some integral intensity measures (such as VEIaSI, VEIrSI, MVEIaSI, MVEIrSI), achieving the application of these IMs in Performance-Based Earthquake Engineering.
Finally, we made a practical Matlab implementation for ground motion selection and modification. Here it is called RELACS (REaL ACcelerogram Selection). The total ground motion database used in RELACS, with more available ground motion records, is composed of three large ground motion database, i.e. NGA (Next Generation Attenuation) database, SISMA (Site of Italian Strong Motion Accelerograms) database, and ESGM (European Strong Ground Motion) Database. The RELACS brings to engineers and researchers more convenience to select ground motion accelerograms, using nowadays widely adopted GMSM methods in terms of not only some commonly used acceleration-based IMs and some other scalar intensity measures but also some energy-based IMs that have been approved good predictors for the response of base-isolated buildings. The RELACS contains two consecutive steps: selection according to the geophysical parameters; and selection according to the elastic response parameters (IMs). The user can easily obtain the acceleration time-history, and the acceleration spectrum, the velocity spectrum and the displacement spectrum of the ground motion record selected using the RELACS
sj-docx-1-jaf-10.1177_0148558X211055883 – Supplemental material for Impact of Tournament Incentives on Management Earnings Forecasts
No full textSupplemental material, sj-docx-1-jaf-10.1177_0148558X211055883 for Impact of Tournament Incentives on Management Earnings Forecasts by Xin Cheng, Dan Palmon, Yinan Yang and Cheng Yin in Journal of Accounting, Auditing & Finance</p
Correlation of elastic input energy equivalent velocity spectral values
No full textRecently, two energy-based response parameters, i.e., the absolute and the relative elastic input energy equivalent velocity, have been receiving a lot of research attention. Several studies, in fact, have demonstrated the potential of these intensity measures in the prediction of the seismic structural response. Although some ground motion prediction equations have been developed for these parameters, they only provide marginal distributions without information about the joint occurrence of the spectral values at different periods. In order to build new prediction models for the two equivalent velocities, a large set of ground motion records is used to calculate the correlation coefficients between the response spectral values corresponding to different periods and components of the ground motion. Then, functional forms adopted in models from the literature are calibrated to fit the obtained data. A new functional form is proposed to improve the predictions of the considered models from the literature. The components of the ground motion considered in this study are the two horizontal ones only. Potential uses of the proposed equations in addition to the prediction of the correlation coefficients of the equivalent velocity spectral values are shown, such as the prediction of derived intensity measures and the development of conditional mean spectra
Prediction of energy-based intensity measures in performance-based earthquake engineering
No full textintensity measures for predicting the structural seismic demand in the framework of Performance-Based Earthquake Engineering (PBEE). Two representatives of those parameters are relative and
absolute elastic input energy. In order to apply these two intensity measures into practical application in PBEE. Two efforts have been made in this study. Firstly, new improved ground motion prediction equations (GMPEs) was established for them by taking advantage of a large set of strong ground motions selected from the NGA database and considering the influence of more effects. Secondly, since these GMPEs only consider the marginal distribution of individual spectral values without giving any information about the joint distribution of the spectral values at different periods, we proposed new models for the prediction of the correlation coefficients of the energy-based spectral
values at different periods or/and directions. In the end, some possible applications of the proposed models are discussed
Du shu cao tang ming shi: si juan.
No full text順德簡朝亮述."排印留版存讀書草堂, 上海中華書局承印"--Title page verso.Shunde Jian Zhaoliang shu."Pai yin liu ban cun Du shu cao tang, Shanghai Zhonghua shu ju cheng yin"--Title page verso
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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