On the performance evaluation of a hierarchical-structure prototype product using inconsistent prior information and limited test data

2019 ◽  
Vol 485 ◽  
pp. 362-375 ◽  
Author(s):  
Lechang Yang ◽  
Yanling Guo ◽  
Zifan Kong
Keyword(s):  
Performance Evaluation ◽  
Hierarchical Structure ◽  
Test Data ◽  
Prior Information

A Non-Stationary Uncertainty Model and Bayesian Calibration of Strain-Life Models

2020 ◽  
Author(s):  
Arinan Dourado ◽  
Firat Irmak ◽  
Felipe Viana ◽  
Ali Gordon
Keyword(s):  
Fatigue Life ◽  
Test Data ◽  
Model Calibration ◽  
Prior Information ◽  
Bayesian Framework ◽  
Applied Strain ◽  
Prediction Intervals ◽  
Bayesian Calibration ◽  
Uncertainty Model ◽  
Inconel 617

Abstract The Coffin-Manson-Basquin-Haford (CMBH) model is a well-accepted strain-life relationship to model fatigue life as a function of applied strain. In this paper, we propose a non-stationary uncertainty model for the CMBH model, alongside a Bayesian framework for model calibration and estimation of confidence and prediction intervals. Using Inconel 617 coupon test data, we compared our approach to traditional stationary variance models. The proposed uncertainty model successfully captures the fact that the variance of fatigue life decreases as the applied strain decreases. Additionally, a discussion on how to use the proposed Bayesian framework to compensate for the lack of data by using prior information coming from a similar alloys is also presented considering Hastealloy-X and Inconel 617 coupon data.

An Investigation of Air-Cooled Steam Condenser Performance Under Windy Conditions Using Computational Fluid Dynamics

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
M. T. F. Owen ◽  
D. G. Kröger
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Performance Evaluation ◽  
Test Data ◽  
Reliable Method ◽  
Numerical Results ◽  
Pressure Jump ◽  
Fan Performance ◽  
Computational Fluid Dynamics Cfd ◽  
Full Scale Tests

The development of an efficient and reliable method of evaluating the performance of an air-cooled steam condenser (ACC) under windy conditions using computational fluid dynamics (CFD) is presented. A two-step modeling approach is employed as a result of computational limitations. The numerical ACC model developed in this study makes use of the pressure jump fan model, among other approximations, in an attempt to minimize the computational expense of the performance evaluation. The accuracy of the numerical model is verified through a comparison of the numerical results to test data collected during full-scale tests carried out on an operational ACC. Good correlation is achieved between the numerical results and test data. The effect of wind on ACC performance at El Dorado Power Plant (Nevada, USA) is investigated. It is found that reduced fan performance due to distorted flow at the inlet of the upstream fans is the primary contributor to the reduction in ACC performance associated with increased wind speed in this case. The model developed in this study has the potential to allow for the evaluation of large ACC installations and provides a reliable platform from which further investigations into improving ACC performance under windy conditions can be carried out.

Metadata-Based Information Management Framework for Grids

2011 ◽  
pp. 147-166
Author(s):  
Wie Jie ◽  
Tianyi Zang ◽  
Terence Hung ◽  
Stephen Turner ◽  
Wentong Cai
Keyword(s):  
Performance Evaluation ◽  
Information Management ◽  
Hierarchical Structure ◽  
Virtual Organization ◽  
Information Service ◽  
Experimental Results ◽  
Data Organization ◽  
Organization Model ◽  
Management Framework ◽  
Cross Domain

Information service is a key component of a Grid environment and crucial to the operation of Grids. This chapter presents an information management framework for a Grid virtual organization (VO). This information management framework is a hierarchical structure which consists of VO layer, site layer and resource layer. We propose different models of information data organization for information management in Grids and simulation experiments were conducted to evaluate the performance of these models. Based on the experimental results, we further introduce the data organization model for our information management framework. A performance evaluation conducted on a cross-domain Grid testbed indicates that our information management framework presents good scalability with large number of concurrent users and large amount of information aggregated. In this chapter some application experiences of using the information management framework are also presented.

MULTILEVEL MODELS IN EDUCATIONAL PROCESS PERFORMANCE EVALUATION

2006 ◽  
Vol 12 (2) ◽  
pp. 25-36
Author(s):  
Zoran Ivanović ◽  
Tea Baldigara
Keyword(s):  
Performance Evaluation ◽  
Regression Model ◽  
Hierarchical Structure ◽  
Multilevel Models ◽  
Educational Process ◽  
Process Performance ◽  
Satisfaction Evaluation ◽  
Set Up ◽  
Students Satisfaction

The scope of the paper is to present how multilevel models can be used in educational process performance evaluation. In the first part educational process is defined, with a particular attention to educational process performance, efficiency effectiveness and hierarchical structure of the educational process. The second part of the paper is dedicated to multilevel models, their characteristics and application. The last part of the paper shows how a basic two-level regression model can be set up and used in students’ satisfaction evaluation.

Compatibility Check of the Prior Information on Low Voltage Switchgear

2013 ◽  
Vol 330 ◽  
pp. 830-833 ◽  
Author(s):  
Bing Yue Liu ◽  
Jing Qin Wang
Keyword(s):  
Test Data ◽  
Prior Information ◽  
Historical Data ◽  
Low Voltage ◽  
Wilcoxon Rank Sum Test ◽  
Novel Method ◽  
The Law

Generally, the test data of the low voltage switchgear are very few. In order to assess the reliability more accurately, historical data are used to maximum the capacity of the test data. The premise of using the prior information is the prior data and test data should approximately come from the same overall. This is just the problem of compatibility check. In this paper, the method of fitting data and the law of testing the distribution are used to analyze both the priori and test data. Furthermore, we present a novel method of using Wilcoxon rank sum test to check the compatibility of the prior and test data of the low voltage switchgear. Both methods lead to the conclusion that the prior and the test data of the low voltage switchgear are compatible.

Bayesian Reliability Assessment Based on Dirichlet Prior Information

2010 ◽  
Vol 108-111 ◽  
pp. 1147-1151
Author(s):  
Hong Sheng Su
Keyword(s):  
Test Data ◽  
Prior Distribution ◽  
Prior Information ◽  
Reliability Assessment ◽  
Bayesian Theory ◽  
New Method ◽  
Small Samples ◽  
Complex Products ◽  
Dirichlet Prior ◽  
Direct Solid

To resolve the reliability assessment of the large-sized complex products under small samples, with the aid of the Dirichlet prior distribution and Bayesian theory, a new method is proposed in this paper. The method can fully apply Dirichlet prior information and test data to estimate the reliabilities of the products, and forecasting the success times during the products test. Compared other methods, it is simple, direct, solid, and high-effective. The investigations show that the method is quit handy and effective.

Study of the correlation between the performances of lunar vehicle wheels predicted by the Nepean wheeled vehicle performance model and test data

2008 ◽  
Vol 222 (11) ◽  
pp. 1939-1954 ◽  
Author(s):  
J Y Wong ◽  
V M Asnani
Keyword(s):  
Performance Evaluation ◽  
Test Data ◽  
Performance Indicator ◽  
Normal Load ◽  
Future Generation ◽  
Performance Model ◽  
Wire Mesh ◽  
Vehicle Performance ◽  
Wheeled Vehicle ◽  
Pneumatic Wheel

This paper describes the results of a study of the correlation between the performances of wheels for lunar vehicles predicted using the Nepean wheeled vehicle performance model (NWVPM), developed under the auspices of Vehicle Systems Development Corporation, Ottawa, Canada, and the corresponding test data presented in ‘Performance evaluation of wheels for lunar vehicles’, Technical Report M-70-2, prepared for George C. Marshall Space Flight Center, National Aeronautics and Space Administration (NASA), USA, by the US Army Engineer Waterways Experiment Station (WES). The NWVPM was originally developed for design and performance evaluation of terrestrial off-road wheeled vehicles. The purpose of this study is to assess the potential of the NWVPM for evaluating wheel candidates for the new generation of extra-terrestrial vehicles. Two versions of a wire-mesh wheel and a hoop-spring wheel, which were considered as candidates for lunar roving vehicles for the NASA Apollo program in the late 1960s, together with a pneumatic wheel were examined in this study. The tractive performances of these wheels and of a 4×4 test vehicle with the pneumatic wheels on air-dry sand were predicted using the NWVPM and compared with the corresponding test data obtained under Earth's gravity and previously documented in the above-named report. While test data on wheel or vehicle performances obtained under Earth's gravity may not necessarily be representative of those on extra-terrestrial bodies, because of the differences in gravity and in environmental conditions, such as atmospheric pressure, it is still a valid approach to use test data obtained under Earth's gravity to evaluate the predictive capability of the NWVPM and its potential applications to predicting wheel or wheeled rover performances on extra-terrestrial bodies. Results of this study show that, using the ratio ( P20/ W) of the drawbar pull to normal load at 20 per cent slip as a performance indicator, there is a reasonable correlation between the predictions and experimental data. This indicates that the NWVPM has the potential as an engineering tool for evaluating wheel candidates for a future generation of extra-terrestrial vehicles, provided that appropriate input data are available.

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