861 Hits in 7.5 sec

Modified weighted least-squares estimators for the three-parameter Weibull distribution

K.E. Ahmad
1994 Applied Mathematics Letters  
In certain cases, maximum likelihood estimation can break down for the three-parameter Weibull model, as no local maximum of the likelihood exists.  ...  To avoid these difficulties, we suggest a modification of the weighted least-squares estimators for the three-parameter Weibull distribution.  ...  Weibull [l] showed that the distribution is also useful in describing the "wear-out" or fatigue failures. Lieblein and Zelen [2] used it as a model for ball bearing failures.  ... 
doi:10.1016/0893-9659(94)90072-8 fatcat:6femsmiz5jcqpotqisvgfxhbwi

Preventive Replacement Decisions for Dragline Components Using Reliability Analysis

Nuray Demirel, Onur Gölbaşı
2016 Minerals  
On this basis, this paper offered a comprehensive reliability assessment for two draglines currently operating in the Tunçbilek coal mine and discussed preventive replacement for wear-out components of  ...  Overburden stripping operations are one of the integral parts in surface coal mine productions.  ...  Acknowledgments: This research study was partially supported by The Scientific and Technological Research Council of Turkey (TUBITAK) with project number 111M320.  ... 
doi:10.3390/min6020051 fatcat:pky5nits2vf7zculyh2a75pilq

Proposal of Physical-Statistical Model of Thermal Aging Respecting Threshold Value

Jakub Souček, Pavel Trnka, Jaroslav Hornak
2017 Energies  
The main aim of this paper is to introduce a new physical-statistical model of thermal aging respecting the threshold value.  ...  Much effort has been devoted to preparing statistical or physical methods of Electrical Insulating System (EIS) life time estimation in the real operation of electrical machinery.  ...  The Weibull distribution is used in cases where the investigated object cannot accept the assumption of a constant failure rate.  ... 
doi:10.3390/en10081120 fatcat:5mr52hb5wnhldipglika2bpogq

Assessment of the life cycle of masonry walls in residential buildings

Jacek Korentz, Beata Nowogońska, D. Beben, A. Rak, Z. Perkowski
2018 MATEC Web of Conferences  
This is very important, especially in the case of the analysing the cycle of the further existence of buildings no longer in use, as well as newly designed ones.  ...  The process of modeling reliability should have a mathematical basis enabling the problem to be described in detail.  ...  The model is based on the Rayleigh distribution, which is a specific case of the Weibull distribution for the scale parameter =2.  ... 
doi:10.1051/matecconf/201817401025 fatcat:wowhy45h5vhstihurhxzccvhhi

Model Implementation Report (II): Statistical Model Selection and Implementation Report

Jacobo De Uña Álvarez, Paula Saavedra Nieves, Manuel Oviedo De La Fuente, Beatriz Pateiro, Basim Al-Najjar, Hatem Algabroun, Henrik Kjellberg, Mikael Jonsson
2019 Zenodo  
TSA can predict the time when a variable of interest (target parameter such as vibration in a critical component, such as a cutting tool) overcomes a specific threshold.  ...  Its aim is to detect deviations in the condition of a component at an early stage in order to act for keeping the probability of failure of machine/significant component low until a condition-based replacement  ...  to wear-out failures.  ... 
doi:10.5281/zenodo.3582856 fatcat:tyyowmo2ifhf5lflmbyrnakfzq

Reliability and Survival Analyses of Mobile OS Via Weibull Model

Julliard Ralihalizara, Ph.D et al., Julliard Ralihalizara, Ph.D et al.,, TJPRC
2020 International Journal of Information Systems Management Research and Development  
Weibull model.  ...  The obtained results give some indication of the pattern in which security updates and patches reach the end-user.  ...  The corresponding Cumulative Distribution Function (CDF) is given by [22] : 𝐹(𝑥) = 1 − 𝑒 (2) Parameters Estimation Three main techniques are going to be used to estimate the scale and the shape parameter  ... 
doi:10.24247/ijismrddec20202 fatcat:3mzs4wl4azaynfdehqtsxf4ovm

Integration of Expert Judgment into Remaining Useful Lifetime Prediction of Components

Peter Schuh, Hendrik Stern, Kirsten Tracht
2014 Procedia CIRP  
These instances are based upon a prognosis of the remaining useful lifetime of the components investigated but their usability is limited because of insufficient failure time data.  ...  Furthermore a parameter study analyzes the model's effectiveness, which produces promising results.  ...  Acknowledgements The results presented in this paper were developed in the research project "Service logistics for wind turbines (17446)  ... 
doi:10.1016/j.procir.2014.07.014 fatcat:qe7khd73mre43ak2rxs26ne24m

Automatic calculation of thresholds for load dependent condition indicators by modelling of probability distribution functions – maintenance of gearboxes used in mining conveying system

Jacek Wodecki, Pawel Stefaniak, Anna Michalak, Agnieszka Wylomanska
2017 Vibroengineering PROCEDIA  
Limit values for gearbox vibration-based condition indicators are key to determine in order to be able to estimate moment when object is in a need of maintenance.  ...  In this paper, we present the case of belt conveyor's gearbox for which PDFs of diagnostic features overlap each other because of strong influence of time varying operating conditions on spectral features  ...  The idea of estimation the parameters is described in [6] .  ... 
doi:10.21595/vp.2017.19036 fatcat:lnx4b5ponrahnjz74vubdq3v7q

Statistical Methods for Planning Diesel Engine Overhauls in the U. S. Coast Guard

C. M. Milkie, A. N. Perakis
2004 Naval engineers journal (Print)  
The evidence indicates a constant failure useful life region, but the increasing failure rate from the Weibull models suggests that the periodic overhauls do not prevent wearout failures.  ...  As a result, the Coast Guard should consider refining diesel engine overhaul policy in order to prevent increasing age-related failures.  ...  Spectrographic analysis detects an increase in wear metals above an established threshold.  ... 
doi:10.1111/j.1559-3584.2004.tb00266.x fatcat:andacm5tujhldpkwfvpbrfc3nm

Risk-informed support vector machine regression model for component replacement—A case study of railway flange lubricator

Frederick Appoh, Akilu Yunusa-Kaltungo
2021 IEEE Access  
In this study, a novel SVR with a Weibull failure threshold that allows adaptive updating of the hyper-parameters whenever new data becomes available, thereby offering a dynamic failure threshold prediction  ...  Given the estimated worst-case (maximum), estimated wear rates and threshold failure results, a riskinformed maintenance interval of 4000 train kilometres was proposed, as shown in Table 4 .  ...  On this project, he will primarily contribute his expertise in H&S and T&L towards the successful realization of the project milestones.  ... 
doi:10.1109/access.2021.3088586 fatcat:wm2pfdcvmvd2bh7r26kvq6gmcy


2014 Nuclear Engineering and Technology  
The GPM fits a parametric function to the collected observations of a prognostic parameter and extrapolates the fit to a failure threshold.  ...  This requires a number of run-to-failure cases with tracked prognostic parameters; these data may not be readily available for many systems.  ...  ACKNOWLEDGEMENTS The authors would like to acknowledge the Lloyds Register Foundation and the International Joint Research Center for the Safety of Nuclear Energy for partial funding of this research.  ... 
doi:10.5516/net.04.2014.722 fatcat:o63e6llqprhuvkbsfdnn5yfe64

How do heterogeneities in operating environments affect field failure predictions and test planning?

Zhi-Sheng Ye, Yili Hong, Yimeng Xie
2013 Annals of Applied Statistics  
We show that in the presence of the heterogeneous operating conditions, the hazard rate function of the field failure time distribution exhibits a range of shapes.  ...  In this paper we model the heterogeneous environments together with their effects on the product failures as a frailty term to link the lab failure time distribution and field failure time distribution  ...  Acknowledgments We would like to thank the editor, the associate editor, and one referee for their helpful comments on this paper. The work by Ye was partially supported by the Sate Key Laboratory  ... 
doi:10.1214/13-aoas666 fatcat:3awpyji2bnbmzd3nshuhintax4

Weibull, κ-Weibull and other probability distributions

Amelia Carolina Sparavigna
2022 Zenodo  
As a consequence, the κ-Weibull function turns out to be quite relevant for generalizations of the Weibull approach to modeling failure times.  ...  Here we will consider a function of κ-statistics, the κ-Weibull distribution, and compare it to the well-known Weibull distribution.  ...  part is a decreasing failure rate, known as early failures. 2) The second part is a constant failure rate, known as random failures. 3) The third part is an increasing failure rate, known as wear-out  ... 
doi:10.5281/zenodo.6421884 fatcat:357giiqftrdfvh25xemwd3shgm

An evaluation method of preventive renewal strategies of railway vehicles selected parts

Jakub Lewandowski, Stanisław Młynarski, Robert Pilch, Maksymilian Smolnik, Jan Szybka, Grzegorz Wiązania
2021 Eksploatacja i Niezawodnosc  
of parts that are important in the operation of complex renewable technical objects.  ...  The aim of the work was to develop a method of verification of the preventive renewal strategies, which enables a simulation evaluation of the effects of the application of a specific schedule of inspections  ...  wear threshold, which is an estimate of a risk of the occurrence of a serious failure.  ... 
doi:10.17531/ein.2021.4.10 fatcat:iabt2sixibbzllyvyntnd2hlpa

Current Computational Trends in Equipment Prognostics

J. Wesley Hines, Alexander Usynin
2008 International Journal of Computational Intelligence Systems  
The trends are organized into three major types of prognostic models: failure data models, stressor models, and degradation models.  ...  Methods in each of these categories are presented and examples are given.  ...  These components have an equal probability of failing for each instant of time. They do not degrade or wear out and are characterized by a single parameter: the constant failure rate λ (t) = λ .  ... 
doi:10.1080/18756891.2008.9727607 fatcat:knyo6mqnovdyrop3lcuogiibpa
« Previous Showing results 1 — 15 out of 861 results