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期刊论文 3

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2017 2

2011 1

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大规模多输入多输出；球面波假设；非稳定性；生灭过程；散射体可见区域法 1

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Seismic fragility curves for structures using non-parametric representations

Chu MAI, Katerina KONAKLI, Bruno SUDRET

《结构与土木工程前沿（英文）》 2017年 第11卷 第2期   页码 169-186 doi: 10.1007/s11709-017-0385-y

摘要： Fragility curves are commonly used in civil engineering to assess the vulnerability of structures to earthquakes. The probability of failure associated with a prescribed criterion (e.g., the maximal inter-storey drift of a building exceeding a certain threshold) is represented as a function of the intensity of the earthquake ground motion (e.g., peak ground acceleration or spectral acceleration). The classical approach relies on assuming a lognormal shape of the fragility curves; it is thus parametric. In this paper, we introduce two non-parametric approaches to establish the fragility curves without employing the above assumption, namely binned Monte Carlo simulation and kernel density estimation. As an illustration, we compute the fragility curves for a three-storey steel frame using a large number of synthetic ground motions. The curves obtained with the non-parametric approaches are compared with respective curves based on the lognormal assumption. A similar comparison is presented for a case when a limited number of recorded ground motions is available. It is found that the accuracy of the lognormal curves depends on the ground motion intensity measure, the failure criterion and most importantly, on the employed method for estimating the parameters of the lognormal shape.

关键词： earthquake engineering     fragility curves     lognormal assumption     non-parametric approach     kernel density estimation     epistemic uncertainty    

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Estimation of load and resistance factors using the third-moment method based on the 3P-lognormal distribution

Yan-Gang ZHAO, Zhao-Hui LU

《结构与土木工程前沿（英文）》 2011年 第5卷 第3期   页码 315-322 doi: 10.1007/s11709-011-0117-7

摘要： 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 used. In this article, the third-moment reliability index, based on the three-parameter lognormal (3P-lognormal) distribution, is investigated. A simple method based on the third-moment method for estimating load and resistance factors is then proposed, and a simple formula for the target mean resistance is also presented to avoid iterative computations. Unlike the currently used method, the proposed method can be used to determine load and resistance factors, even when the probability density functions (PDFs) of the basic random variables are not available. Moreover, the proposed method does not require the iterative computation of derivatives or any design points. Thus, the method provides a more convenient and effective way to estimate load and resistance factors in practical engineering applications. Numerical examples are presented to demonstrate the advantages of the proposed third moment method for determining load and resistance factors.

关键词： load and resistance factors     third-moment method     three-parameter lognormal (3P-lognormal) distribution     target mean resistance     simple formula    

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基于非稳定性的5G大规模MIMO信道建模 Article

Jian-qiao CHEN, Zhi ZHANG, Tian TANG, Yu-zhen HUANG

《信息与电子工程前沿（英文）》 2017年 第18卷 第12期   页码 2101-2110 doi: 10.1631/FITEE.1700028

摘要： 本文提出一种新型的大规模多输入多输出（massive multiple-input multiple-output, MIMO）通信系统信道模型，同时考虑了球面波假设以及随着天线阵列和时间变化的散射体非稳定特性。由于大规模天线阵列的引入，会导致接收端的不同天线阵子的到达角和多普勒频移不同，因此，采用球面波假设来刻画近场效应。此外，为在接收端刻画不同散射体对天线阵子的可见性，本文提出一种散射体可见区域法同时，对应于理论模型，本文提出了一种有限散射体仿真信道模型。最后，以统计特性作为指标，研究了球面波假设和散射体非稳定性对massive MMO信道模型的影响。研究结果表明，本文提出的信道模型可以很好地刻画massive MIMO信道特性。

关键词： 大规模多输入多输出；球面波假设；非稳定性；生灭过程；散射体可见区域法    

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标题 作者 时间 类型 操作

Seismic fragility curves for structures using non-parametric representations

Chu MAI, Katerina KONAKLI, Bruno SUDRET

期刊论文

Estimation of load and resistance factors using the third-moment method based on the 3P-lognormal distribution

Yan-Gang ZHAO, Zhao-Hui LU

期刊论文

基于非稳定性的5G大规模MIMO信道建模

Jian-qiao CHEN, Zhi ZHANG, Tian TANG, Yu-zhen HUANG

期刊论文