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Wyszukujesz frazę "weibull distribution" wg kryterium: Temat


Tytuł:
Prediction model of the pandemic spreading based on weibull distribution
Autorzy:
Guľáš, Ľuboš
Talian, Matej
Szabo, Stanislav
Semrádová, Beáta
Powiązania:
https://bibliotekanauki.pl/articles/2204124.pdf
Data publikacji:
2022
Wydawca:
STE GROUP
Tematy:
pandemics
prediction model
weibull distribution
Opis:
Pandemics have the potential to cause immense disruption of our everyday activities and has impact on the communities and societies mainly through the restrictions applied to the business activities, services, manufacturing, but also education, transportation etc. Therefore, it is important to create suitable prediction models to establish convenient methods for the planning of the operations and processes to cope with the difficulty. In this paper, the prediction model for the spread of the viral disease in term of the estimated maximal weekly confirmed cases and weekly deaths using the Weibull distribution as a theoretical model for statistical data processing is presented. The theoretical prediction model was applied and confirmed on the data available for the whole world and compared to the situation in Europe and Slovakia for the pandemic waves and can be used for the more precise prediction of the pandemic situation and to enhance planning of the activities and processes regarding to the restrictions applied during the worsening pandemic situation.
Źródło:
Management Systems in Production Engineering; 2022, 2 (30); 179--186
2299-0461
Pojawia się w:
Management Systems in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monte Carlo method for reliability of parallel system with dependent failures of component
Autorzy:
Grabski, F.
Powiązania:
https://bibliotekanauki.pl/articles/2069174.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
reliability
stochastic process
Weibull distribution
dependency
Opis:
A problem of parallel system reliability with dependent failures of components is presented in the paper. It is assumed that lifetimes of components are independent random variable having Weibull distribution. We take under consideration a parallel (in reliability meaning) system consisting of n independent at the beginning of work and identical components. We assume that a load of the working system affects on the reliability of its components and the load of the system is distributed on all working components. Therefore, a failure rate of each component is changeable during run of the system and depends on a number of working elements at this point in time. As a model of the system failures we construct a stochastic process which value at the moment t denotes the number of working components. Generally it is neither Markov nor semi-Markov process. To assess the reliability characteristics of the system we simulate this stochastic process using the Monte-Carlo method and we calculate values of nonparametric kernel density and reliability functions estimators.
Źródło:
Journal of Polish Safety and Reliability Association; 2016, 7, 1; 67--72
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimating parameters of the Weibull diameter distribution for Gmelina arborea in Nimbia Forest Reserve, Nigeria
Autorzy:
Shamaki, S. B.
Akindele, S. O.
Marshall, P. L.
LeMay, V. M.
Powiązania:
https://bibliotekanauki.pl/articles/1075794.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Gmelina arborea
Nimbia Forest Reserve
Weibull distribution
Opis:
Parameters of the Weibull diameter distribution were estimated for Gmelina (Gmelina arborea) plantation in Nimbia Forest Reserve. Stratified random sampling was employed to select five plots of 20 × 20 m from each forest bit that serves as management unit, thereby having a total of 20 plots for the study. Stump diameter (Dst), diameter at breast height (Dbh), diameter at middle and top positions (Dm and Dt) of trees, and tree height for all the selected trees were measured. Average Dbh measured was 16.33 cm and the mean tree height 6.85 m. Pseudo coefficient of determination (Pseudo R2), residual mean square error, Anderson-Darling, and Kolmogorov-Smirnov goodness-of-fit statistics were considered as model selection criteria. Weibull cumulative density function (Weibull-CDF) was the best fit method for Gmelina compared with the Weibull probability density function based on the goodness-of-fit statistics generated. The diameter distribution models produced are considered only efficient for tree stands of seven years rotation age, while additional site factors like spacing, density and silvicultural treatments are required for better models, hence the need for establishing permanent sample plots (PSP) in order to get additional information from re-measurements of the plots.
Źródło:
World Scientific News; 2019, 118; 209-219
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigation of production-related characteristics regarding their influence on the fatigue strength of additively manufactured components
Autorzy:
Zeißig, Michaela
Jablonski, Frank
Powiązania:
https://bibliotekanauki.pl/articles/2204622.pdf
Data publikacji:
2023
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
additive manufacturing
fatigue strength
Weibull distribution
FEM
Opis:
In order to further enhance the application of additive manufacturing (AM) processes, such as the laser powder bed fusion (L-PBF) process, reliable material data are required. However, the resulting specimen properties are significantly influenced by the process parameters and may also vary depending on the material used. Therefore, the prediction of the final properties is difficult. In the following, the effect of residual stresses on the fatigue strength of 316L steel, a commonly used steel in AM, is investigated using a Weibull distribution. The underlying residual stress distributions as a result of the building process are approximated for two building directions using finite element (FE) models. These imply significantly different distributions of tensile and compressive residual stresses within the component. Apart from the residual stresses, the impact of the mean stress sensitivity is discussed as this also influences the predicted fatigue strength values.
Źródło:
Acta Mechanica et Automatica; 2023, 17, 2; 288--291
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Experimental Comparison of Popular Estimation Methods for the Weibull, Gamma and Gompertz Distributions
Autorzy:
Żerda, Iwona
Powiązania:
https://bibliotekanauki.pl/articles/1373468.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
parameter estimation
Weibull distribution
gamma distribution
Gompertz distribution
MSE
Opis:
The aim of this study was to describe some parametric estimation methods for the Weibull, gamma and Gompertz distributions and to identify among them estimators the most efficient in practical applications. Techniques which are considered as traditional methods, like the maximum likelihood (MLE) and the method of moments (MM) estimation but also some newer and less commonly used techniques like the Lmoment estimator (LME), least-square estimator (LSE), generalized spacing estimator (GSE) and percentile estimator (PE) were presented. The application of each method was demonstrated in a simulation study using data sets generated for different distribution parameters and sample sizes. Discussed estimators were compared in terms of their efficiency and bias measured by mean-square errors (MSE) based on the simulations results.
Źródło:
Schedae Informaticae; 2011, 20; 67-82
0860-0295
2083-8476
Pojawia się w:
Schedae Informaticae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gas turbine reliability model based on tangent hyperbolic reliability function
Autorzy:
Djeddi, A. Z.
Hafaifa, A.
Salam, A.
Powiązania:
https://bibliotekanauki.pl/articles/280120.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
reliability estimation
reliability algorithms
lifetime distribution
Weibull distribution
availability
Opis:
The present work deals with the exploration of a new model proposed for the reliability analysis of industrial production systems. This proposed model is mainly based on the tangent hyperbolic function, where the survival function is determined and used in the lifetime distribution modeling taking into account of estimation the parameters of the proposed function. On the other side, tests validation is performed using the real data of a gas turbine installation. The obtained results allow the modeling of damage effects, hence the prediction of the performance of the examined gas turbine using the proposed model gives good results in terms of validity.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 723-730
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Moc testu Kołmogorowa dla weryfikowania hipotezy o wykładniczym rozkładzie prawdopodobieństwa
Power Kolmogorov test to verify the hypothesis of exponential distribution
Autorzy:
Rogowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/315448.pdf
Data publikacji:
2013
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
rozkład Weibulla
test Kołmogorowa
Weibull distribution
Kolmogorov test
Opis:
W artykule oszacowano metodą symulacyjną moc testu λ Kołmogorowa dla hipotezy złożonej o wykładniczym rozkładzie prawdopodobieństwa wobec hipotezy alternatywnej, że rozkład prawdopodobieństwa w populacji jest rozkładem Weibulla (dla wybranych wartości parametru kształtu i liczności próby n = 100). Obliczono również numerycznie granicę dolną mocy testu z wykorzystaniem rozkładu granicznego.
The article estimated using simulation power λ Kolmogorov test for the composite hypothesis of ex ponential probability distribution against the alternative hypothesis that the probability distribution of the population is Weibull distribution (with the selected shape parameter and sample size n=100). Also calculated numerically lower limit power test by using the limiting distribution.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2013, 14, 3; 1193-1202
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Demand forecasting in a business based on experts’ opinions – an application of weibull distributions
Autorzy:
Dittmann, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/424785.pdf
Data publikacji:
2013
Wydawca:
Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu
Tematy:
demand
demand forecasting
experts’ opinions
Weibull distribution applications
Opis:
Demand forecasts in a business may be constructed by various methods, e.g. by using Type-I formal models, or by using type-II formal models based on experts’ opinions. The experts can be the business’s managers or persons from outside of the studied business. The experts can not only construct forecasts, but also subjectively specify the probability of them coming true. In this article, the Weibull distribution is described, a distribution that may be applied in the process of constructing product demand forecasts for a business. The methodology for constructing a point forecast is explained, along with the methods for evaluating the chances of the forecast coming true and the methods for judging the probability connected with sales profitability.
Źródło:
Econometrics. Ekonometria. Advances in Applied Data Analytics; 2013, 1(39); 52-60
1507-3866
Pojawia się w:
Econometrics. Ekonometria. Advances in Applied Data Analytics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statystyczna analiza awarii pojazdów samochodowych
Failure analysis of cars
Autorzy:
RUMIANOWSKI, Roman
Powiązania:
https://bibliotekanauki.pl/articles/456949.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Rzeszowski
Tematy:
statystyka
rozkład Weilbulla
niezawodność
statistics
Weibull distribution
failure analysis
Opis:
Opracowanie prezentuje zastosowanie rozkładu Weibulla do analizowania częstości wystę-powania awarii w używanych samochodach osobowych. W artykule prezentowane są przykłady dystrybuanty rozkładu awaryjności dla kilku wybranych modeli samochodów.
The paper presents a model for calculating the occurrence of failures in cars using the Weibull distribution. Empirical cumulative distribution curve is analyzed for a few car models.
Źródło:
Edukacja-Technika-Informatyka; 2016, 7, 1; 13-17
2080-9069
Pojawia się w:
Edukacja-Technika-Informatyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mixed control chart adapted to the truncated life test based on the Weibull distribution
Autorzy:
Khan, N.
Aslam, M.
Kim, K.-J.
Jun, C. -H.
Powiązania:
https://bibliotekanauki.pl/articles/406432.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
life test
Weibull distribution
attribute chart
binomial distribution
average run length
Opis:
The design of a new mixed attribute control chart adapted to a truncated life test has been pre-sented. It was assumed that the lifetime of a product follows the Weibull distribution and the number of failures was observed using a truncated life test, where the test duration was specified as a fraction of the mean lifespan. The proposed control chart consists of two pairs of control limits based on a binomial distribution and one lower bound. The average run length of the chart was determined for various levels of shift constants and specified parameters. The efficiency of the chart is compared with an existing control chart in terms of the average run length. The application of the proposed chart is discussed with the aid of a simulation study.
Źródło:
Operations Research and Decisions; 2017, 27, 1; 43-55
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for estimating the probability distribution of the lifetime for new technical equipment based on expert judgement
Autorzy:
Andrzejczak, Karol
Bukowski, Lech
Powiązania:
https://bibliotekanauki.pl/articles/2038033.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
uncertainty
expert elicitation of lifetime
quantile function
Weibull distribution
Opis:
Managing the exploitation of technical equipment under conditions of uncertainty requires the use of probabilistic prediction models in the form of probability distributions of the lifetime of these objects. The parameters of these distributions are estimated with the use of statistical methods based on historical data about actual realizations of the lifetime of examined objects. However, when completely new solutions are introduced into service, such data are not available and the only possible method for the initial assessment of the expected lifetime of technical objects is expert methods. The aim of the study is to present a method for estimating the probability distribution of the lifetime for new technical facilities based on expert assessments of three parameters characterizing the expected lifetime of these objects. The method is based on a subjective Bayesian approach to the problem of randomness and integrated with models of classical probability theory. Due to its wide application in the field of maintenance of machinery and technical equipment, a Weibull model is proposed, and its possible practical applications are shown. A new method of expert elicitation of probabilities for any continuous random variable is developed. A general procedure for the application of this method is proposed and the individual steps of its implementation are discussed, as well as the mathematical models necessary for the estimation of the parameters of the probability distribution are presented. A practical example of the application of the developed method on specific numerical values is also presented.
Źródło:
Eksploatacja i Niezawodność; 2021, 23, 4; 757-769
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An inflationary inventory model with time dependent demand with Weibull distribution deterioration and partial backlogging under permissible delay in payments
Autorzy:
Basu, M.
Sinha, S.
Powiązania:
https://bibliotekanauki.pl/articles/969730.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
inflation
partial backlogging
Weibull distribution
permissible delay in payments
Opis:
This paper proposes to present a general inventory model with due consideration to the factors of time dependent partial backlogging and time dependent deterioration. It also takes into account the impact of inflation, time-dependent demand and permissible delay in payments.
Źródło:
Control and Cybernetics; 2007, 36, 1; 203-217
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimisation of the preventive maintenance plan of a series components system with Weibull hazard function
Autorzy:
Duarte, J. C.
Soares, C. G.
Powiązania:
https://bibliotekanauki.pl/articles/2069578.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
availability
hazard function
Weibull distribution
preventive maintenance
series components
Opis:
In this paper we propose an algorithm to calculate the optimum frequency to perform preventive maintenance in equipment that exhibits Weibull hazard function and constant repair rate in order to ensure its availability. Based on this algorithm we have developed another one to solve the problem of maintenance management of a series system based on preventive maintenance over the different system components. We assume that all components of the system still exhibit Weibull hazard function and constant repair rate and that preventive maintenance would bring the system to the as good as new condition. The algorithm calculates the interval of time between preventive maintenance actions for each component, minimizing the costs, and in such a way that the total downtime, in a certain period of time, does not exceed a predetermined value.
Źródło:
Journal of Polish Safety and Reliability Association; 2007, 1; 67--73
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Design Wave Heights Determined on the Basis of Long- and Short-term Measurement Data
Autorzy:
Szmytkiewicz, M.
Szmytkiewicz, P.
Marcinkowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/241214.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
wave measurements
reconstruction of waves in the Baltic
Weibull distribution
Gumbel distribution
Opis:
The objective of this study is to determine differences between design wave heights determined on the basis of short- and long-term wave trains. Wave parameters measured over a period of 7.47 years in the vicinity of Coastal Research Station Lubiatowo were used as short-term wave data, while wave parameters determined through the so-called wave reconstruction for a period of 44 years for the same region and depth were used as long-term wave data. The results of the calculations lead to the conclusions the significant wave height distributions obtained for short and long-term wave data are similar.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2018, 65, 2; 123-142
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The modified Bagdonavičius-Nikulin goodness-of-fit test statistic for the right censored distributional validation with applications in medicine and reliability
Autorzy:
Yousof, Haitham M.
Ali, M. Masoom
Aidi, Khaoula
Ibrahim, Mohamed
Powiązania:
https://bibliotekanauki.pl/articles/18105193.pdf
Data publikacji:
2023-09-08
Wydawca:
Główny Urząd Statystyczny
Tematy:
inverted Weibull distribution
censored validation
Bagdonavičius-Nikulin
goodness-of-fit testing
Opis:
A modified version of Bagdonavičius-Nikulin goodness-of-fit statistical test is presented for validation under the right censor case. Simulation via Barzilai-Borwein algorithm is performed for assessing the right-censorship estimation method. Four right censored data sets are analyzed under the new modified test statistic for checking the distributional validation.
Źródło:
Statistics in Transition new series; 2023, 24, 4; 1-18
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sudden death testing versus traditional censored life testing. A Monte-Carlo study
Autorzy:
Motyka, R.
Powiązania:
https://bibliotekanauki.pl/articles/969717.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
sudden death testing
time terminated life test
Weibull distribution
Monte Carlo method
Opis:
This paper considers two competing methods intended to shorten lifetime tests. The first method, due to L.G. Johnson, is known in reliability engineering as "sudden death testing". Its competitor is a widely known time-terminated, right-censored test. Times of tests carried out according to these methods are set equal. Then, methods are compared in terms of variances and biases of lifetime parameter estimators. In addition, median, mode, skewness and kurtosis of estimator distributions are also calculated and compared. All data needed came from a large-scale Monte-Carlo numerical experiment.
Źródło:
Control and Cybernetics; 2007, 36, 1; 241-250
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The application of probability density function in modeling of wind speed on the Polish Batlic Coast
Autorzy:
Czernecki, B.
Powiązania:
https://bibliotekanauki.pl/articles/108544.pdf
Data publikacji:
2014
Wydawca:
Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
Tematy:
wind speed
Weibull distribution
canonical correlation analysis
statistical downscaling
Polish Baltic Coast
Opis:
The aim of the research was to identify the potential for the use of probability density functions (PDF) in modeling of near-surface wind speed. The approaches of Empirical Orthogonal Functions (EOF) and Canonical Correlation Analysis (CCA) are used in combination with 2-parametric Weibull distribution. The downscaling model was built using a diagnosed relationship between sea level pressure (SLP) patterns over Europe and the Northern Atlantic and estimated monthly values of Weibull parameters at 9 stations along the Polish Baltic Coast. The obtained scale (A) and shape (k) parameters make it possible to describe temporal variations of wind fields and their theoretical probability values. This may have further application in the modeling of extreme wind speeds for seasonal forecasting, climate prediction or in historical reconstructions. The model evaluation was done separately for the calibration (1971-2000) and validation periods (2001-2010). The scale parameter was reconstructed reasonably, while there were some problematic issues with the shape parameter, especially in the validation period. The quality of the developed models is generally higher for the winter season, due to larger SLP gradients, whereas the results for the spring and summer seasons were less satisfactory. Despite this, the 99th percentile of theoretical wind speeds are in most cases satisfactory, due to the lesser importance of the shape parameter for typical distributions in the analyzed region.
Źródło:
Meteorology Hydrology and Water Management. Research and Operational Applications; 2014, 2, 2; 23-33
2299-3835
2353-5652
Pojawia się w:
Meteorology Hydrology and Water Management. Research and Operational Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Lost Opportunity: Recovering the End of Major League Baseballs 1994 Strike Shortened Season
Autorzy:
Hass, Zachary
Woyczyński, Wojbor A.
Yanosko, Chris
Becker, Eric
Powiązania:
https://bibliotekanauki.pl/articles/747320.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Poisson mixed effects regression, simulations, baseball statistics, discrete Weibull distribution, Markov chains.
Opis:
The 1994 Major League Baseball (MLB) Season ended prematurely when the players went on strike on August 12th, due to a labor disagreement with team owners. This paper describes the model estimation for predicting the runs scored in each of the unplayed games and gives the results of 1,000 simulations. Of particular interest are the Cleveland Indians and the Montreal Expos. The Expos were on pace to have the best season in franchise history (and the best record in the league), while the Indians were poised to begin a very successful run that could have ended the city's World Championship drought dating from 1948.
Źródło:
Mathematica Applicanda; 2012, 40, 2
1730-2668
2299-4009
Pojawia się w:
Mathematica Applicanda
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of methods applied to measuring the lightning impulse breakdown voltage of insulating pressboard impregnated with mineral oil and natural ester
Autorzy:
Klarecki, Artur
Rózga, Paweł
Stuchała, Filip
Powiązania:
https://bibliotekanauki.pl/articles/2052181.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
lightning impulse voltage
high voltage
measurement methods
dielectric liquids
insulating pressboard
Weibull distribution
Opis:
The aim of this paper is to compare three different methods of analysis of results of lightning impulse breakdown voltage measurements of solid materials such as insulating pressboard. These three methods are the series method, the step method and the up-and-down method which are applied to withstand voltage estimation commonly in high voltage engineering. To obtain the data needed for the analysis a series of experimental studies was carried out. It included studies of mineral oil and natural ester impregnating 1 mm of thick cellulose-based pressboard. In order to show the distribution of breakdown voltage the Weibull distribution was additionally applied in data analysis. The results were also assessed from the viewpoint of dielectric liquid used for impregnation. The studies carried out showed that series and step methods give comparable results opposite to the up-and-down method. The latest overstates the results for mineral oil impregnated pressboard and understates for natural ester impregnated pressboard when juxtaposing them with the rest of the methods applied. In addition, there is lack of possibility to assess the withstand voltage for the up-and-down method directly from the vector of random variable. It is possible only as a result of a specially developed equation which always arouses doubt. From the methods applied it seems that the step method can be a great substitution for the series method as intuitive, fast in application and limiting the number of samples in solid insulation material testing.
Źródło:
Metrology and Measurement Systems; 2021, 28, 4; 693-709
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ kształtu ziaren na łączny rozkład ich wielkości wyznaczony metodą licznika Coultera
Influence of the particles shape on joined distribution of their size determined by Coulter Counter method
Autorzy:
Peszko, B.
Niedoba, T.
Powiązania:
https://bibliotekanauki.pl/articles/349920.pdf
Data publikacji:
2009
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
licznik Coultera
rozkład Weibulla
krzywa składu ziarnowego
Coulter counter
Weibull distribution function
particle size distribution function
Opis:
Licznik Coultera jest jednym z powszechnie stosowanych urządzeń do zliczania ziaren bardzo drobnych. Ze względu na specyfikę swej konstrukcji, urządzenie to może zliczać ziarna o wielkości od 10 do 60% średnicy zamontowanej diafragmy. Aby więc uzyskać całościowy skład ziarnowy badanego materiału należy odpowiednio złożyć otrzymane składowe rozkłady składów ziarnowych. W celu aproksymacji rozkładów składowych, otrzymanych przy użyciu diafragm o różnych średnicach, w pracy zastosowano rozkład Weibulla. Dla badanego materiału, jakim był diabaz, obliczono zestaw współczynników kształtu. Współczynniki kształtu wyliczono korzystając z metod analizy obrazu oraz na podstawie wyników analizy składu ziarnowego. Otrzymane rozkłady łączne, z uwzględnieniem i bez uwzględnienia współczynnika kształtu, porównano i poddano ocenie.
Coulter Counter is one of the most common devices applied to counting ultrafine particles. Because of its construction, this device is able to count particles of sizes from 10% till 60% of the diameter of installed diaphragm. To obtain the full particle size distribution it is necessary to combine given partial distribution functions. To approximate the partial distribution functions given by various installed diaphragms, the Weibull distribution function was applied. For the researched material, which was diabase, the set of shape coefficients was calculated, which may be taken into consideration by individual partial distribution functions combination. The shape coefficients were calculated on the basis of image analysis method and of particle size distribution results. The given joined distribution functions, with and without application of shape coefficient, were compared and evaluated.
Źródło:
Górnictwo i Geoinżynieria; 2009, 33, 4; 277-285
1732-6702
Pojawia się w:
Górnictwo i Geoinżynieria
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative BER Analysis of Free Space Optical System Using Wavelength Diversity over Exponentiated Weibull Channel
Autorzy:
Shah, Dhaval
Joshi, Hardik
Kothari, Dilipkumar
Powiązania:
https://bibliotekanauki.pl/articles/2055211.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bit error rate
exponentiated weibull distribution
free space optics
FSO
wavelingth diversity
optimal combining
Opis:
Atmospheric turbulence is considered as major threat to Free Space Optical (FSO) communication as it causes irradiance and phase fluctuations of the transmitted signal which degrade the performance of FSO system. Wavelength diversity is one of the techniques to mitigate these effects. In this paper, the wavelength diversity technique is applied to FSO system to improve the performance under different turbulence conditions which are modeled using Exponentiated Weibull (EW) channel. In this technique, the data was communicated through 1.55 µm, 1.31 µm, and 0.85 µm carrier wavelengths. Optimal Combining (OC) scheme has been considered to receive the signals at receiver. Mathematical equation for average BER is derived for wavelength diversity based FSO system. Results are obtained for the different link length under different turbulence conditions. The obtained average BER results for different turbulence conditions characterized by EW channel is compared with the published result of average BER for different turbulence which is presented by classical channel model. A comparative BER analysis shows that maximum advantage of wavelength diversity technique is obtained when different turbulence conditions are modeled by EW channel.
Źródło:
International Journal of Electronics and Telecommunications; 2021, 67, 4; 665--672
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of wind turbine energy production models for rural applications
Porównanie modeli wytwarzania energii przez turbiny wiatrowe w zastosowaniach rolnicznych
Autorzy:
Kapica, J.
Powiązania:
https://bibliotekanauki.pl/articles/792976.pdf
Data publikacji:
2014
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
wind turbine
wind energy
kinetic energy
energy production
rural application
wind speed
Weibull distribution
Źródło:
Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2014, 14, 3
1641-7739
Pojawia się w:
Teka Komisji Motoryzacji i Energetyki Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of Value-at-Risk using Weibull distribution - portfolio analysis on the precious metals market
Autorzy:
Krężołek, Dominik
Powiązania:
https://bibliotekanauki.pl/articles/1808287.pdf
Data publikacji:
2021-10-18
Wydawca:
Główny Urząd Statystyczny
Tematy:
risk analysis
Value-at-Risk
metals market
GARCH-type models
two-sided Weibull distribution
Opis:
In this paper, we present a modification of the Weibull distribution for the Value-atRisk (VaR) estimation of investment portfolios on the precious metals market. The reason for using the Weibull distribution is the similarity of its shape to that of empirical distributions of metals returns. These distributions are unimodal, leptokurtic and have heavy tails. A portfolio analysis is carried out based on daily log-returns of four precious metals quoted on the London Metal Exchange: gold, silver, platinum and palladium. The estimates of VaR calculated using GARCH-type models with non-classical error distributions are compared with the empirical estimates. The preliminary analysis proves that using conditional models based on the modified Weibull distribution to forecast values of VaR is fully justified.
Źródło:
Przegląd Statystyczny; 2021, 68, 2; 38-52
0033-2372
Pojawia się w:
Przegląd Statystyczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Python libraries for variance, normal distribution and Weibull distribution analysis in diagnosing and operating production systems
Zastosowanie bibliotek języka Python do analizy wariancji, rozkładu normalnego i rozkładu Weibulla w diagnostyce i eksploatacji systemów produkcyjnych
Autorzy:
Chmielowiec, Andrzej
Klich, Leszek
Powiązania:
https://bibliotekanauki.pl/articles/1955208.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
variance analysis
normal distribution
Weibull distribution
statistical analysis
python
analiza wariancji
rozkład normalny
rozkład Weibulla
analiza statystyczna
Opis:
The use of statistical methods in the diagnosis of production processes dates back to the beginning of the 20th century. Widespread computerization of processes made enterprises face the challenge of processing large sets of measurement data. The growing number of sensors on production lines requires the use of faster and more effective methods of both process diagnostics and finding connections between individual systems. This article is devoted to the use of Python libraries to effectively solve some problems related to the analysis of large data sets. The article is based on the experience related to data analysis in a large company in the automotive industry, whose annual production reaches 10 million units. The methods described in this publication were the basis for the initial analysis of production data in the plant, and the obtained results fed the production database and the created automatic anomaly detection system based on artificial intelligence algorithms.
Wykorzystywanie metod statystycznych w diagnostyce procesów produkcyjnych sięga swoimi korzeniami początków XX wieku. Powszechna informatyzacja procesów postawiła przedsiębiorstwa przed wyzwaniem przetwarzania dużych zbiorów danych pomiarowych. Rosnąca liczba czujników na liniach produkcyjnych wymaga stosowania szybszych i skuteczniejszych metod zarówno diagnostyki procesu, jak i znajdowania powiązań pomiędzy poszczególnymi systemami. Niniejszy artykuł został poświęcony wykorzystaniu bibliotek języka Python do efektywnego rozwiązywania niektórych problemów związanych z analizą dużych zbiorów danych pomiarowych. Artykuł powstał na bazie doświadczeń związanych z analizą danych w dużym przedsiębiorstwie branży motoryzacyjnej, którego roczna produkcja sięga 10 milionów sztuk. Opisane w niniejszej publikacji metody stanowiły podstawę wstępnej analizy danych produkcyjnych we wspomnianym zakładzie, a uzyskane wyniki zasiliły bazę danych produkcyjnych oraz tworzony system automatycznego wykrywania anomalii oparty na algorytmach sztucznej inteligencji.
Źródło:
Diagnostyka; 2021, 22, 4; 89-105
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The odd power generalized Weibull-G power series class of distributions: properties and applications
Autorzy:
Oluyede, Broderick
Moakofi, Thatayaone
Chipepa, Fastel
Powiązania:
https://bibliotekanauki.pl/articles/2034112.pdf
Data publikacji:
2022-03-15
Wydawca:
Główny Urząd Statystyczny
Tematy:
Weibull-g distribution
power series
Poisson distribution
logarithmic distribution
maximum likelihood estimation
Opis:
We develop a new class of distributions, namely, the odd power generalizedWeibull-G power series (OPGW-GPS) class of distributions. We present some special classes of the proposed distribution. Structural properties, have also been derived. We conducted a simulation study to evaluate the consistency of the maximum likelihood estimates. Moreover, two real data examples on selected data sets, to illustrate the usefulness of the new class of distributions. The proposed model outperforms several non-nested models on selected data sets.
Źródło:
Statistics in Transition new series; 2022, 23, 1; 89-108
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł

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