Equipment reliability analysis based on the Mean-rank method of two-parameter Weibull distribution

2011 ◽  
Author(s):  
Qiang Liao ◽  
Xiaoyang Wang ◽  
Dan Ling ◽  
Zhenlin Xiao ◽  
Hong-Zhong Huang
Keyword(s):  
Weibull Distribution ◽  
Reliability Analysis ◽  
Equipment Reliability ◽  
The Mean ◽  
Two Parameter

scholarly journals Best estimation for the Reliability of 2-parameter Weibull Distribution

2009 ◽  
Vol 6 (4) ◽  
pp. 705-710
Author(s):  
Baghdad Science Journal
Keyword(s):  
Maximum Likelihood ◽  
Weibull Distribution ◽  
Mean Square Error ◽  
Maximum Likelihood Method ◽  
Likelihood Method ◽  
Statistical Criterion ◽  
Mean Square ◽  
Simulation Process ◽  
The Mean ◽  
Two Parameter

This Research Tries To Investigate The Problem Of Estimating The Reliability Of Two Parameter Weibull Distribution,By Using Maximum Likelihood Method, And White Method. The Comparison Is done Through Simulation Process Depending On Three Choices Of Models (?=0.8 , ß=0.9) , (?=1.2 , ß=1.5) and (?=2.5 , ß=2). And Sample Size n=10 , 70, 150 We Use the Statistical Criterion Based On the Mean Square Error (MSE) For Comparison Amongst The Methods.

Reliability analysis of thermal core ring spun yarn using two parameter Weibull distribution

2014 ◽  
Vol 105 (10) ◽  
pp. 1042-1049 ◽  
Author(s):  
R. Ramachandran ◽  
B.S Dasaradan ◽  
R. Murugan ◽  
P. Kanakaraj
Keyword(s):  
Weibull Distribution ◽  
Reliability Analysis ◽  
Spun Yarn ◽  
Ring Spun Yarn ◽  
Two Parameter

scholarly journals The 8-item Morisky medication adherence scale: validation of a Portuguese version in HIV patients

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
A Aguiar ◽  
C Piñeiro ◽  
R Serrão ◽  
R Duarte
Keyword(s):  
Medication Adherence ◽  
Psychometric Properties ◽  
Reliability Analysis ◽  
Cronbach’S Alpha ◽  
Portuguese Version ◽  
Cronbach's Alpha ◽  
Adherence To Medication ◽  
Morisky Medication Adherence Scale ◽  
Adherence Scale ◽  
The Mean

Abstract Background Antiretroviral therapy (ART) has the most effective treatment for people with HIV, but its effectiveness depends on the individual medication adherence. Morisky Medication Adherence Scale (MMAS-8) is one of the most widely used scales to assess patient adherence. Thus, we aimed to validate a Portuguese version of MMAS-8 and determine its psychometric properties in HIV positive patients. Methods A cross-sectional survey was conducted in Centro Hospitalar Universitário São João (Porto, northern Portugal) at the infectious diseases department. After authorization to use the scale - granted by the author - and, a standard forward-backwards procedure to translate MMAS-8 to Portuguese, the questionnaire was applied to 233 patients with HIV doing ART. Reliability was assessed using Cronbach's alpha and test-retest reliability. Three levels of adherence were considered: 0 to < 6 (low), 6 to < 8 (medium), 8 (high). Results In the studied sample, the mean age was 45.03 years (SD = 11.63), 80.3% men, 19.3% women and 1 transgender, and 53.8% had ≤9 years of education. The mean number of prescribed ART per patient was 1.76. The mean score for the medication adherence scale was 7.29 (SD = 6.74). For the reliability analysis, 12 patients were excluded due to missing data (n = 221). Regarding the level of adherence, 22.5% were low adhering, 71.6% medium and 5.9% high. Corrected item-total correlations showed that 1 item does not correlate very well with the overall scale and was dropped. Scale reliability analysis for the remaining 7 items revealed an overall Cronbach's alpha of 0.661. Women had a protective effect on adherence (OR = 0.31;95%CI:0.15-0.66). Number of years doing ART, age of participants, and type of residence didn't show to be correlated with adherence. Conclusions MMAS-8 is a reliable and valid measure to detect patients at risk of non-adherence. A satisfactory Cronbach's alfa (0.661) was obtained. In general, adherence to medication was medium or high. Key messages This scale can be applied nationwide in other different hospitals, as it could serve as a tool for measuring adherence to ART that can allow for better health care to the ones that are low adhering. A Portuguese version of the MMAS-8 was created for measuring adherence to ART that maintained a similar structure to the original MMAS-8 and good psychometric properties.

scholarly journals Finsler Geometry for Two-Parameter Weibull Distribution Function

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Emrah Dokur ◽  
Salim Ceyhan ◽  
Mehmet Kurban
Keyword(s):  
Probability Density Function ◽  
Weibull Distribution ◽  
Probability Density ◽  
Density Function ◽  
Finsler Space ◽  
Finsler Geometry ◽  
Cumulative Probability ◽  
Two Dimensional ◽  
Energy Potential ◽  
Two Parameter

To construct the geometry in nonflat spaces in order to understand nature has great importance in terms of applied science. Finsler geometry allows accurate modeling and describing ability for asymmetric structures in this application area. In this paper, two-dimensional Finsler space metric function is obtained for Weibull distribution which is used in many applications in this area such as wind speed modeling. The metric definition for two-parameter Weibull probability density function which has shape (k) and scale (c) parameters in two-dimensional Finsler space is realized using a different approach by Finsler geometry. In addition, new probability and cumulative probability density functions based on Finsler geometry are proposed which can be used in many real world applications. For future studies, it is aimed at proposing more accurate models by using this novel approach than the models which have two-parameter Weibull probability density function, especially used for determination of wind energy potential of a region.

Two parameters are required for a Budyko function to describe the land-atmosphere interaction

2021 ◽  
Author(s):  
Daeha Kim ◽  
Jong Ahn Chun
Keyword(s):  
Land Surface ◽  
River Basins ◽  
Control Surface ◽  
Primary Control ◽  
Evaporative Demand ◽  
Atmosphere Interaction ◽  
The Mean ◽  
Two Parameters ◽  
Two Parameter ◽  
Surface Changes

<p>While the Budyko framework has been a simple and convenient tool to assess runoff (Q) responses to climatic and surface changes, it has been unclear how parameters of a Budyko function represent the vertical land-atmosphere interactions. Here, we explicitly derived a two-parameter equation by correcting a boundary condition of the Budyko hypothesis. The correction enabled for the Budyko function to reflect the evaporative demand (E<sub>p</sub>) that actively responds to soil moisture deficiency. The derived two-parameter function suggests that four physical variables control surface runoff; namely, precipitation (P), potential evaporation (E<sub>p</sub>), wet-environment evaporation (E<sub>w</sub>), and the catchment properties (n). We linked the derived Budyko function to a definitive complementary evaporation principle, and assessed the relative elasticities of Q to climatic and land surface changes. Results showed that P is the primary control of runoff changes in most of river basins across the world, but its importance declined with climatological aridity. In arid river basins, the catchment properties play a major role in changing runoff, while changes in E<sub>p</sub> and E<sub>w</sub> seem to exert minor influences on Q changes. It was also found that the two-parameter Budyko function can capture unusual negative correlation between the mean annual Q and E<sub>p</sub>. This work suggests that at least two parameters are required for a Budyko function to properly describe the vertical interactions between the land and the atmosphere.</p>

scholarly journals Bayesian Method for Estimating Weibull Parameters for Wind Resource Assessment in the Equatorial Region: a Comparison Between Two-parameter and Three-parameter Weibull Distributions

2021 ◽  
Author(s):  
M. G. M. Khan ◽  
M. Rafiuddin Ahmed
Keyword(s):  
Weibull Distribution ◽  
Bayesian Approach ◽  
Resource Assessment ◽  
Equatorial Region ◽  
Weibull Parameters ◽  
Wind Speeds ◽  
Wind Resource Assessment ◽  
Low Wind Speeds ◽  
Wind Resource ◽  
Two Parameter

Abstract The two-parameter Weibull distribution has garnered much attention in the assessment of wind energy potential. The estimation of the shape and scale parameters of the distribution has brought forth a successful tool for the wind energy industry. However, it may be inappropriate to use the two-parameter Weibull distribution to accurately characterize wind speed at every location, especially at sites where the frequency of low speed is high, such as the Equatorial region. In this work, for the robustness in wind resource assessment, we first propose a Bayesian approach in estimating Weibull parameters. Secondly, we compare the techniques of wind resource assessment using both two and three-parameter Weibull distributions for different sites in the Equatorial region. The Bayesian inference approach is adopted using Markov Chain Monte Carlo (MCMC) algorithms. Simulation studies conducted in this research confirms that the Bayesian approach seems to be a new robust alternative technique for accurate estimation of Weibull parameters. An appropriate Weibull distribution and the application of the Bayesian approach in estimating distribution parameters were determined using data from six sites in the Equatorial region from 1° N of Equator to 19° South of Equator. Results revealed that a three-parameter Weibull distribution is a better fit for wind data having a greater percentage of low wind speeds (0-1 m/s) and low skewness. However, wind data with a smaller percentage of low wind speeds and high skewness showed better results using a two-parameter Weibull distribution. The results also demonstrate that the proposed Bayesian approach to estimate Weibull parameters is extremely useful in the analysis of wind power potential, as it provides more accurate results while characterizing lower wind speeds.

scholarly journals Analysis of distribution of precipitation duration and amounts in Legnica in the period of 1966–2015

2019 ◽  
Vol 41 (1) ◽  
pp. 69-76
Author(s):  
Teresa Jakubczyk
Keyword(s):  
Weibull Distribution ◽  
Mean Value ◽  
Half Century ◽  
Late Autumn ◽  
Individual Sequences ◽  
Pascal Distribution ◽  
The Mean

Abstract The paper presents the results of analysis of duration of precipitation sequences and the amounts of precipitation in individual sequences in Legnica. The study was aimed at an analysis of potential trends and regularities in atmospheric precipitations over the period of 1966–2015. On their basis a prediction attempt was made for trends in subsequent years. The analysis was made by fitting data to suitable distributions – the Weibull distribution for diurnal sums in sequences and the Pascal distribution for sequence durations, and then by analysing the variation of the particular indices such the mean value, variance and quartiles. The analysis was performed for five six-week periods in a year, from spring to late autumn, analysed in consecutive five-year periods. The trends of the analysed indices, observed over the fifty-year period, are not statistically significant, which indicates stability of precipitation conditions over the last half-century.

Jaya algorithm in estimation of P[X > Y] for two parameter Weibull distribution

2022 ◽  
Vol 7 (2) ◽  
pp. 2820-2839
Author(s):  
Saurabh L. Raikar ◽  
◽  
Dr. Rajesh S. Prabhu Gaonkar ◽  
Keyword(s):  
Maximum Likelihood ◽  
Maximum Likelihood Estimation ◽  
Weibull Distribution ◽  
Least Squares ◽  
Weighted Least Squares ◽  
Real Life ◽  
Likelihood Estimation ◽  
Estimation Methods ◽  
Jaya Algorithm ◽  
Two Parameter

<abstract> <p>Jaya algorithm is a highly effective recent metaheuristic technique. This article presents a simple, precise, and faster method to estimate stress strength reliability for a two-parameter, Weibull distribution with common scale parameters but different shape parameters. The three most widely used estimation methods, namely the maximum likelihood estimation, least squares, and weighted least squares have been used, and their comparative analysis in estimating reliability has been presented. The simulation studies are carried out with different parameters and sample sizes to validate the proposed methodology. The technique is also applied to real-life data to demonstrate its implementation. The results show that the proposed methodology's reliability estimates are close to the actual values and proceeds closer as the sample size increases for all estimation methods. Jaya algorithm with maximum likelihood estimation outperforms the other methods regarding the bias and mean squared error.</p> </abstract>

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