Fragility and Qualification of Components Using Censored Seismic Demand Data

2009 ◽  
Vol 25 (3) ◽  
pp. 719-727
Author(s):  
Avinash M. Nafday
Keyword(s):  
Earthquake Engineering ◽  
Survival Data ◽  
Technical Note ◽  
Statistical Characteristics ◽  
Seismic Demand ◽  
Random Component ◽  
Data Set ◽  
Critical Facilities ◽  
Using Data ◽  
Performance Based Earthquake Engineering

Fragility functions are vital for the risk assessment of critical facilities and to calculate component probability of damage in performance-based earthquake engineering. Seismic qualification is used to prove the adequacy of components in existing facilities or to satisfy their design criteria in new facilities. This technical note describes an approach for component fragility development and seismic qualification using data for seismic demand experienced by similar components and their resulting performance. Depending on the observed component failure or survival, the seismic demand values either exceed or fall short of the random component capacity. The concept of censoring, which captures this excess or shortfall, is introduced to model such data and account for the different statistical characteristics of failure and survival data. The censored data are analyzed by survival analysis, which provides a rigorous and efficient approach to extract information from the data set.

Epistemic Uncertainties in Component Fragility Functions

2010 ◽  
Vol 26 (1) ◽  
pp. 41-62 ◽  
Author(s):  
Brendon A. Bradley
Keyword(s):  
Quality Assurance ◽  
Earthquake Engineering ◽  
Epistemic Uncertainty ◽  
Finite Size ◽  
Seismic Demand ◽  
Fragility Functions ◽  
Seismic Performance Assessment ◽  
Fragility Function ◽  
Documentation Quality ◽  
Performance Based Earthquake Engineering

This paper is concerned with the inclusion of epistemic uncertainties in component fragility functions used in performance-based earthquake engineering. Conventionally fragility functions, defining the probability of incurring at least a specified level of damage for a given level of seismic demand, are defined by a mean and standard deviation and assumed to have a lognormal distribution. However, there exist many uncertainties in the development of such fragility functions. The sources of epistemic uncertainty in fragility functions, their consideration, combination, and propagation are presented and discussed. Two empirical fragility functions presented in literature are used to illustrate the epistemic uncertainty in the fragility function parameters due to the finite size of the datasets. These examples and the associated discussions illustrate that the magnitude of epistemic uncertainties are significant and there are clear benefits of the consideration of epistemic uncertainties pertaining to the documentation, quality assurance, implementation, and updating of fragility functions. Epistemic uncertainties should therefore always be addressed in future fragility functions developed for use in seismic performance assessment.

scholarly journals Geochemical modeling of the Cu-Ag deposits from the Lubin-Głogów Copper District (Poland) supported by lithological modeling

2017 ◽  
Vol 33 (4) ◽  
pp. 63-78 ◽  
Author(s):  
Monika Wasilewska-Błaszczyk ◽  
Jacek Mucha
Keyword(s):  
Ordinary Kriging ◽  
Geochemical Modeling ◽  
3D Models ◽  
Statistical Characteristics ◽  
Random Component ◽  
Weighting Method ◽  
Data Set ◽  
Cu Content ◽  
Geochemical Models ◽  
Inverse Distance

Abstract The most important reasons for the limited credibility of 3D geochemical models of the Cu-Ag deposits (The Lubin-Głogów Copper District) are unfavorable statistical characteristics of the main metals (Cu, Ag), and the unfavorable structure of their variability with a relatively poorly marked non-random component of variability. It is hoped that the accuracy of geochemical models can be increased by previous lithological modeling of a given deposit. This is due to significant differences in mean Cu content in both the main lithological series (carbonates, shales and sandstones) and individual lithological units within them, which justifies separate geochemical modeling of each. The paper presents the results of the comparison of the reliability of 3D modeling of Cu content carried out in both individual and main lithological units of the Cu-Ag Rudna deposit (The Lubin- Głogów Copper District). The 3D lithological models were made using ordinary kriging (main lithological units) and Plurigaussian simulation (individual lithological units). The 3D estimation of Cu content within lithological models was carried out using the ordinary kriging (OK ) and squared inverse distance (ID2) methods. The verification of the accuracy of Cu estimates in the 3D model using spot samples of the test data set has shown only a slight increase in the accuracy of the estimates of Cu content within the individual lithological units of the shale series compared to the estimates of Cu content in the whole main lithology. In most cases, 3D models of Cu content carried out using the ordinary kriging method are slightly more accurate than the analogous squared inverse distance weighting method.

How to Assess Prognostic Models for Survival Data: A Case Study in Oncology

2003 ◽  
Vol 42 (05) ◽  
pp. 564-571 ◽  
Author(s):  
M. Schumacher ◽  
E. Graf ◽  
T. Gerds
Keyword(s):  
Test Data ◽  
Survival Data ◽  
Prediction Error ◽  
Classification Scheme ◽  
Neural Nets ◽  
Brier Score ◽  
Data Set ◽  
Independent Test ◽  
Artificial Neural

Summary Objectives: A lack of generally applicable tools for the assessment of predictions for survival data has to be recognized. Prediction error curves based on the Brier score that have been suggested as a sensible approach are illustrated by means of a case study. Methods: The concept of predictions made in terms of conditional survival probabilities given the patient’s covariates is introduced. Such predictions are derived from various statistical models for survival data including artificial neural networks. The idea of how the prediction error of a prognostic classification scheme can be followed over time is illustrated with the data of two studies on the prognosis of node positive breast cancer patients, one of them serving as an independent test data set. Results and Conclusions: The Brier score as a function of time is shown to be a valuable tool for assessing the predictive performance of prognostic classification schemes for survival data incorporating censored observations. Comparison with the prediction based on the pooled Kaplan Meier estimator yields a benchmark value for any classification scheme incorporating patient’s covariate measurements. The problem of an overoptimistic assessment of prediction error caused by data-driven modelling as it is, for example, done with artificial neural nets can be circumvented by an assessment in an independent test data set.

scholarly journals An approach to quantify the influence of ground motion uncertainty on elastoplastic system acceleration in incremental dynamic analysis

2017 ◽  
Vol 20 (11) ◽  
pp. 1744-1756 ◽  
Author(s):  
Peng Deng ◽  
Shiling Pei ◽  
John W. van de Lindt ◽  
Hongyan Liu ◽  
Chao Zhang
Keyword(s):  
Dynamic Analysis ◽  
Ground Motion ◽  
Earthquake Engineering ◽  
Structural Response ◽  
Incremental Dynamic Analysis ◽  
Degree Of Freedom ◽  
Maximum Acceleration ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Performance Based Earthquake Engineering

Inclusion of ground motion–induced uncertainty in structural response evaluation is an essential component for performance-based earthquake engineering. In current practice, ground motion uncertainty is often represented in performance-based earthquake engineering analysis empirically through the use of one or more ground motion suites. How to quantitatively characterize ground motion–induced structural response uncertainty propagation at different seismic hazard levels has not been thoroughly studied to date. In this study, a procedure to quantify the influence of ground motion uncertainty on elastoplastic single-degree-of-freedom acceleration responses in an incremental dynamic analysis is proposed. By modeling the shape of the incremental dynamic analysis curves, the formula to calculate uncertainty in maximum acceleration responses of linear systems and elastoplastic single-degree-of-freedom systems is constructed. This closed-form calculation provided a quantitative way to establish statistical equivalency for different ground motion suites with regard to acceleration response in these simple systems. This equivalence was validated through a numerical experiment, in which an equivalent ground motion suite for an existing ground motion suite was constructed and shown to yield statistically similar acceleration responses to that of the existing ground motion suite at all intensity levels.

Risk-based capital regulation revisited: evidence from the early 2000s

2015 ◽  
Vol 23 (2) ◽  
pp. 115-134 ◽  
Author(s):  
Thomas L. Hogan ◽  
Neil R. Meredith ◽  
Xuhao (Harry) Pan
Keyword(s):  
Design Methodology ◽  
Banking Regulation ◽  
Bank Performance ◽  
Capital Regulation ◽  
Data Set ◽  
Content Type ◽  
Future Performance ◽  
Capital Ratios ◽  
Using Data ◽  
Capital Regulations

Purpose – The purpose of this study is to replicate Avery and Berger’s (1991) analysis using data from 2001 through 2011. Although risk-based capital (RBC) regulation is a key component of US banking regulation, empirical evidence of the effectiveness of these regulations has been mixed. Among the first studies of RBC regulation, Avery and Berger (1991) provide evidence from data on US banks that new RBC regulations outperformed old capital regulations from 1982 through 1989. Design/methodology/approach – Using data from the Federal Reserve’s Call Reports, the authors compare banks’ capital ratios and RBC ratios to five measures of bank performance: income, standard deviation of income, non-performing loans, loan charge-offs and probability of failure. Findings – Consistent with Avery and Berger (1991), the authors find banks’ risk-weighted assets to be significant predictors of their future performance and that RBC ratios outperform regular capital ratios as predictors of risk. Originality/value – The study improves on Avery and Berger (1991) by using an updated data set from 2001 through 2011. The authors also discuss some potential limitations of this method of analysis.

Twitter users exhibited coping behaviours during the COVID-19 lockdown: an analysis of tweets using mixed methods

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ruchi Mittal ◽  
Wasim Ahmed ◽  
Amit Mittal ◽  
Ishan Aggarwal
Keyword(s):  
Data Analysis ◽  
The Body ◽  
Data Set ◽  
Content Type ◽  
Twitter Data ◽  
Long Run ◽  
The World ◽  
Twitter Users ◽  
The Government ◽  
Using Data

Purpose Using data from Twitter, the purpose of this paper is to assess the coping behaviour and reactions of social media users in response to the initial days of the COVID-19-related lockdown in different parts of the world. Design/methodology/approach This study follows the quasi-inductive approach which allows the development of pre-categories from other theories before the sampling and coding processes begin, for use in those processes. Data was extracted using relevant keywords from Twitter, and a sample was drawn from the Twitter data set to ensure the data is more manageable from a qualitative research standpoint and that meaningful interpretations can be drawn from the data analysis results. The data analysis is discussed in two parts: extraction and classification of data from Twitter using automated sentiment analysis; and qualitative data analysis of a smaller Twitter data sample. Findings This study found that during the lockdown the majority of users on Twitter shared positive opinions towards the lockdown. The results also found that people are keeping themselves engaged and entertained. Governments around the world have also gained support from Twitter users. This is despite the hardships being faced by citizens. The authors also found a number of users expressing negative sentiments. The results also found that several users on Twitter were fence-sitters and their opinions and emotions could swing either way depending on how the pandemic progresses and what action is taken by governments around the world. Research limitations/implications The authors add to the body of literature that has examined Twitter discussions around H1N1 using in-depth qualitative methods and conspiracy theories around COVID-19. In the long run, the government can help citizens develop routines that help the community adapt to a new dangerous environment – this has very effectively been shown in the context of wildfires in the context of disaster management. In the context of this research, the dominance of the positive themes within tweets is promising for policymakers and governments around the world. However, sentiments may wish to be monitored going forward as large-spikes in negative sentiment may highlight lockdown-fatigue. Social implications The psychology of humans during a pandemic can have a profound impact on how COVID-19 shapes up, and this shall also include how people behave with other people and with the larger environment. Lockdowns are the opposite of what societies strive to achieve, i.e. socializing. Originality/value This study is based on original Twitter data collected during the initial days of the COVID-19-induced lockdown. The topic of “lockdowns” and the “COVID-19” pandemic have not been studied together thus far. This study is highly topical.

Abstract 17847: Gasping is a Valid Predictor Of ROSC and Hospital Discharge for In-hospital Cardiac Arrest Occurring on the Ward

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Luca Marengo ◽  
Wolfgang Ummenhofer ◽  
Gerster Pascal ◽  
Falko Harm ◽  
Marc Lüthy ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Ventricular Fibrillation ◽  
Hospital Discharge ◽  
Survival Data ◽  
Neurological Outcome ◽  
Rapid Response Team ◽  
Spontaneous Circulation ◽  
University Hospital ◽  
Data Set ◽  
Hospital Cardiac Arrest

Introduction: Agonal respiration has been shown to be commonly associated with witnessed events, ventricular fibrillation, and increased survival during out-of-hospital cardiac arrest. There is little information on incidence of gasping for in-hospital cardiac arrest (IHCA). Our “Rapid Response Team” (RRT) missions were monitored between December 2010 and March 2015, and the prevalence of gasping and survival data for IHCA were investigated. Methods: A standardized extended in-hospital Utstein data set of all RRT-interventions occurring at the University Hospital Basel, Switzerland, from December 13, 2010 until March 31, 2015 was consecutively collected and recorded in Microsoft Excel (Microsoft Corp., USA). Data were analyzed using IBM SPSS Statistics 22.0 (IBM Corp., USA), and are presented as descriptive statistics. Results: The RRT was activated for 636 patients, with 459 having a life-threatening status (72%; 33 missing). 270 patients (59%) suffered IHCA. Ventricular fibrillation or pulseless ventricular tachycardia occurred in 42 patients (16% of CA) and were associated with improved return of spontaneous circulation (ROSC) (36 (97%) vs. 143 (67%; p<0.001)), hospital discharge (25 (68%) vs. 48 (23%; p<0.001)), and discharge with good neurological outcome (Cerebral Performance Categories of 1 or 2 (CPC) (21 (55%) vs. 41 (19%; p<0.001)). Gasping was seen in 128 patients (57% of CA; 46 missing) and was associated with an overall improved ROSC (99 (78%) vs. 55 (59%; p=0.003)). In CAs occurring on the ward (154, 57% of all CAs), gasping was associated with a higher proportion of shockable rhythms (11 (16%) vs. 2 (3%; p=0.019)), improved ROSC (62 (90%) vs. 34 (55%; p<0.001)), and hospital discharge (21 (32%) vs. 7 (11%; p=0.006)). Gasping was not associated with neurological outcome. Conclusions: Gasping was frequently observed accompanying IHCA. The faster in-hospital patient access is probably the reason for the higher prevalence compared to the prehospital setting. For CA on the ward without continuous monitoring, gasping correlates with increased shockable rhythms, ROSC, and hospital discharge.

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