Skocz do pozycji: 1.

Tytuł:

The Weibull lifetime model with randomised failure-free time

Autorzy:

Sulewski, Piotr
Szymkowiak, Magdalena

Powiązania:

https://bibliotekanauki.pl/articles/2156948.pdf

Data publikacji:

2022-12-15

Wydawca:

Główny Urząd Statystyczny

Tematy:

Weibull lifetime model
randomised failure-free time
compound Weibull distributions

Opis:

The paper shows that treating failure-free time in the three-parameter Weibull distribution not a constant, but as a random variable makes the resulting distribution much more flexible at the expense of only one additional parameter.

Źródło:

Statistics in Transition new series; 2022, 23, 4; 59-76
1234-7655

Pojawia się w:

Statistics in Transition new series

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 2.

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

/5

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Skocz do pozycji: 3.

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

/5

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Skocz do pozycji: 4.

Tytuł:

Reliability of a Collective Wastewater Treatment Plant

Autorzy:

Bugajski, P.
Chmielowski, K.
Kaczor, G.

Powiązania:

https://bibliotekanauki.pl/articles/125059.pdf

Data publikacji:

2016

Wydawca:

Polskie Towarzystwo Inżynierii Ekologicznej

Tematy:

wastewater treatment plant
technological reliability
Weibull theory

Opis:

The paper discusses technological reliability of a collective wastewater treatment plant (WTP). The WTP capacity expressed as population equivalents (PE) was 22,500. The research was conducted in 2013 and 2014 and it involved the collection and physical and chemical analysis of 101 samples of raw and treated sewage. Reliability analysis was based on Weibull reliability theory. Reliability of retaining organic compounds defined as BOD5 was 68%, and for biogenic compounds, such as total nitrogen and total phosphorus, it was 92% and 88%, respectively.

Źródło:

Journal of Ecological Engineering; 2016, 17, 4; 143-147
2299-8993

Pojawia się w:

Journal of Ecological Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 5.

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

/5

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Skocz do pozycji: 6.

Tytuł:

The technical object reliability evaluation based on the parametric and momentary failures

Autorzy:

Lindstedt, P.
Manerowski, J.
Borowczyk, H.

Powiązania:

https://bibliotekanauki.pl/articles/242760.pdf

Data publikacji:

2016

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

reliability
Weibull function
parametric failure
momentary failure

Opis:

The presented paper concerns with the technical object reliability evaluation based on the parametric and momentary failures during the process of object operating. The real world data observation shows that in the case of high quality technical objects the catastrophic failure events are too rare to the credible evaluation of the object’s reliability. For that reason, the parametric and momentary failures are in the centre of attention in this paper. The set of analysed failures was obtained with the classifiers of the field data provided by the monitoring system (the failure alarms) and the diagnostic system (the functional and technical condition parameters deviation). The changes of the functioning condition potential are used to determine the symptoms of momentary failures and the changes in the potential of the technical condition to determine the symptoms of parametric failures (non-total). The assumed reliability characteristics model has the form R(t) = f(_, Rb(t), Rc(t)), (where: Rb(t) and Rc(t) – the estimators of reliability for parametric and momentary failures, symbol ‘_’ denotes catastrophic failures not covered). For the identification of R (t) as an analytical function, the estimators are computed with the field data. The Weibull distribution function due to its flexibility is often used. Such is the case in this paper. Two parameters a and b known as the scale and the shape parameters are estimated with the computerized procedure realizing least-square method. The presented examples show good fit quality even for small set of data.

Źródło:

Journal of KONES; 2016, 23, 2; 239-246
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 7.

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

/5

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Skocz do pozycji: 8.

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

/5

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Skocz do pozycji: 9.

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

/5

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Skocz do pozycji: 10.

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

/5

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Skocz do pozycji: 11.

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

/5

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Skocz do pozycji: 12.

Tytuł:

Characterizations of uniform and exponential distributions via moments of the kth record values randomly indexed

Autorzy:

Grudzień, Zofia
Szynal, Dominik

Powiązania:

https://bibliotekanauki.pl/articles/1339203.pdf

Data publikacji:

1997

Wydawca:

Polska Akademia Nauk. Instytut Matematyczny PAN

Tematy:

sample
record values
exponential
order statistics
Weibull distributions
uniform

Opis:

We characterize uniform and exponential distributions via moments of the kth record statistics. Too and Lin's (1989) results are contained in our approach.

Źródło:

Applicationes Mathematicae; 1996-1997, 24, 3; 307-314
1233-7234

Pojawia się w:

Applicationes Mathematicae

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 13.

Tytuł:

Technological reliability of sewage treatment plant with the Pomiltek Mann type bioreactor

Autorzy:

Kurek, Karolina
Bugajski, Piotr
Operacz, Agnieszka
Młyński, Dariusz
Wałęga, Andrzej

Powiązania:

https://bibliotekanauki.pl/articles/292901.pdf

Data publikacji:

2020

Wydawca:

Instytut Technologiczno-Przyrodniczy

Tematy:

pollution indicators
technological reliability
wastewater treatment plant
Weibull method

Opis:

The aim of the work was to determine the technological reliability of the selected pollution indicators removal BOD₅, COD_Cr and total suspension from the sewage treatment plant working with the bioreactor Pomiltek Mann type. Wastewater treatment plant which is a subject of this study is located in Lesser Poland, in Siepraw commune. The analysis was performed using the Weibull method for basic indicators of impurities, BOD₅, COD_Cr and total suspended solids. Physico-chemical analyses of raw and treated wastewater, were carried out in the period from 2003 to 2014 (11 years). The research period included measured values of pollutions indicators in 38 samples of raw and treated sewage. For each of pollution indicators descriptive statistic, percentage reduction (n) and treatment plant reliability factors (RF) were calculated. Average reduction for BOD₅ and TSS was on level equal 94%, only for COD the average reduction was lower and was on level 89%. The reliability values determined by Weibull method, were: 75% (BOD₅), 90% (COD_Cr) and 89.5% (TSS). The reliability results have been lower than the presented by literature source, which means that work of wastewater treatment plant in Siepraw was not satisfied in 11 years of research.

Źródło:

Journal of Water and Land Development; 2020, 46; 146-152
1429-7426
2083-4535

Pojawia się w:

Journal of Water and Land Development

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 14.

Tytuł:

Effect of Infrared Drying on the Drying Kinetics and the Quality of Mango (Mangifera indica) Powder

Autorzy:

Nguyen, Phuoc-Bao-Duy
Nguyen, Thi-Van-Linh
Nguyen, Thi-Thuy-Dung

Powiązania:

https://bibliotekanauki.pl/articles/28408451.pdf

Data publikacji:

2024-03-01

Wydawca:

Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie

Tematy:

antioxidant activity
fruit powder
phenolics
pulp drying
Weibull model

Opis:

Mango powder is a nutrient-dense substance that can be used directly or as a supplement in food items. However, due to the high sugar content, the removal of moisture from mango was difficult. This study investigated an infrared drying technique for removing moisture from mango pulp to produce powder products. The experiment was designed in a three-factor full factorial design with the following variables: drying temperature (70, 75, and 80°C), maltodextrin content (0, 6, and 9 g/100 g pulp), and total soluble solid content (11 and 16°Brix). The findings indicated that the Weibull model was the most appropriate for describing the moisture removal of mango pulp during infrared drying. Higher temperature and maltodextrin content, along with reduced total soluble solid content, resulted in improved quality of the mango powder. Furthermore, the optimal drying conditions for mango powder were found as 11°Brix, 80°C, and 9% maltodextrin content, which could ensure the highest retention of total phenolics (59.874%), retention of reducing sugars (71.044%), total acidity (10.141%), and retention of DPPH radical scavenging activity (65.051%). To fully benefit from the rewards of infrared drying, it is essential to establish suitable pretreatment conditions or use additives to preserve component quality.

Źródło:

Polish Journal of Food and Nutrition Sciences; 2024, 74, 1; 69-81
1230-0322
2083-6007

Pojawia się w:

Polish Journal of Food and Nutrition Sciences

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 15.

Tytuł:

Mathematical Calculation of Material Reliability Using Surface Roughness Feature Based on Plasma Material Interaction Experiment Results

Autorzy:

Pahsa, Alper
Aydoğdu, Yıldırım
Göktaş, Fahrettin

Powiązania:

https://bibliotekanauki.pl/articles/27312789.pdf

Data publikacji:

2023

Wydawca:

Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN

Tematy:

tokamak
material reliability
Weibull
divertor
PMI
Plasma Material Interaction

Opis:

The choice of reactor structural material design must take into account the TOKAMAK fusion reactors' structural reliability. Due to their high levels of heat and energy, fusion reactions have significant deformation effects, which reduce the efficiency of energy production in reactors. Material selection, erosion and damage, heat and stress management, reliability analysis, maintenance, and inspection are crucial elements in determining how reliable fusion reactors are. The focus of this work is on material selection and reliability analysis based on these parameters. The most common wall materials used in fusion reactors are tungsten, beryllium, steel, or graphite. It is advised to utilize aluminum because harmful Beryllium dust limits the study of this element. For this purpose, a target of aluminum samples is established with a plasma of He ions created by glow discharge. The dependability of the samples is determined by calculating the Weibull Distribution and measuring the roughness of the sample surfaces following exposure.

Źródło:

Eksploatacja i Niezawodność; 2023, 25, 3; art. no. 169815
1507-2711

Pojawia się w:

Eksploatacja i Niezawodność

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 16.

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

/5

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Skocz do pozycji: 17.

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

/5

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Skocz do pozycji: 18.

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

/5

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Skocz do pozycji: 19.

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

/5

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Skocz do pozycji: 20.

Tytuł:

Using the Weibull ++ software in water supply network failure analysis

Autorzy:

Żywiec, Jakub

Powiązania:

https://bibliotekanauki.pl/articles/105442.pdf

Data publikacji:

2019

Wydawca:

Politechnika Rzeszowska im. Ignacego Łukasiewicza. Oficyna Wydawnicza

Tematy:

failure
reliability
water supply
Weibull++
zaopatrzenie w wodę
niezawodność
uszkodzenie

Opis:

The water supply network is a basic element of the water distribution subsystem and its task is to provide consumers with water of appropriate quality, in the required quantity, under appropriate pressure, at any time and at an acceptable price. To fulfil these tasks, the water supply network should have an appropriate level of operational reliability. The paper presents an analysis of the causes of water pipes failures using the Weibull++ software. The analysis was based on the operational data from 2018 obtained from the water supply company. The data included the failure book specifying the date and place of the failure, the cause of the failure, diameter and material of the damaged pipe. The probability density function for the failure of water pipes and its cumulative distribution function have been determined. The impact of individual types of failure causes on the failure of the water supply network was determined. The results provide information about the probability of failures of the water supply network depending on their cause. These results can be used in further analyses of the reliability and safety of water supplies to consumers.

Źródło:

Czasopismo Inżynierii Lądowej, Środowiska i Architektury; 2019, 66, 3; 37-45
2300-5130
2300-8903

Pojawia się w:

Czasopismo Inżynierii Lądowej, Środowiska i Architektury

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 21.

Tytuł:

Rock bursts prediction based on analyzing maximal phenomena of seismic emission in the INGEO system
Możliwości predykcji wstrząsów na podstawie analizy zjawisk maksymalnych emisji sejsmicznej w systemie INGEO

Autorzy:

Cianciara, B.
Isakow, Z.
Siciński, K.
Cianciara, A.

Powiązania:

https://bibliotekanauki.pl/articles/1361960.pdf

Data publikacji:

2016

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

emisja sejsmiczna
metoda hazardu
strumień zdarzeń
model Weibull`a
wstrząsy
zagrożenie sejsmiczne
seismic emission
hazard method
stream of events
Weibull model
rock bursts
seismic hazard

Opis:

Predicting the time of rock bursts in the INGEO system is based on the analysis of seismic emission registered in a seismic-acoustic system. Emission signals are generated by rock mass fracturing due to mining exploitation. Such emission is characterized by huge activity of different phenomena which enables to carry out a correct statistical analysis with the use of the hazard method, achieving suitably high resolution of interpretation results. The hazard method is based on the analysis of maxmal phenomena, i.e. phenomena of maximal energy. The use of this method allows to eliminate disturbances to a large extent and, at the same time, enables to assess the probability of high-energy phenomena (rock bursts). The hazard analysis is conducted on the basis of two essential qualities of seismic emission, such as energy of phenomena and intervals between successive phenomena. These qualities are random variables of statistical distribution described by the Weibull model. Using this model one can estimate the parameters of statistical distribution of those qualities which are the basis to determine hazard parameters. The analysis is conducted based on measurement data collected from the T window, i.e. time interval measured by hours. The window is moved with the d step and the calculations are repeated. The hazard parameters were used to define the risk function FWt(QE,T) which is the measure of rock bursts hazard. This function depends on real time t which is determined as the time of the T window right edge. It is also the basis to work out rock burst hazard criteria. It is important to note that the moment a rock burst occurs is a random variable and can be determined with the accuracy of its confidence interval, with certain probability.
Predykcja czasu wystąpienia wstrząsów w systemie INGEO oparta jest na analizie emisji sejsmicznej rejestrowanej w systemie sejsmoakustycznym. Sygnały emisji są generowane pękaniem górotworu wywołanym eksploatacją. Emisja taka charakteryzuje się dużą aktywnością zjawisk, która umożliwia prowadzenie poprawnej analizy statystycznej metodą hazardu, uzyskując również odpowiednio wysoką rozdzielczość wyników interpretacji. Metoda hazardu oparta jest na analizie zjawisk maksymalnych, czyli zjawisk o maksymalnej energii. Zastosowanie tej metody daje znaczną eliminację zakłóceń, a jednocześnie umożliwia ocenę prawdopodobieństwa wystąpienia zjawisk wysokoenergetycznych (wstrząsów). Analiza hazardu realizowana jest na podstawie dwóch podstawowych cech emisji sejsmicznej, a mianowicie: energii zjawisk, oraz odstępów czasu między kolejnymi zjawiskami. Cechy te są zmiennymi losowymi o rozkładzie statystycznym, który jest opisywany modelem Weibull`a. Na podstawie tego modelu prowadzona jest estymacja parametrów rozkładu statystycznego tych cech, które stanowią podstawę do wyznaczania parametrów hazardu. Analiza realizowana jest w oparciu o dane pomiarowe pobierane z okna T, czyli przedziału czasu rzędu godzin. Okno to jest przesuwane z krokiem d i powtarzane są obliczenia. Wykorzystując parametry hazardu zdefiniowano funkcję ryzyka FWt(QE,T), będącą miarą zagrożenia wystąpieniem wstrząsów. Funkcja ta jest zależna od czasu realnego t, który jest określony, jako czas prawego brzegu okna T. Stanowi ona podstawę do opracowania kryteriów stanu zagrożenia tąpaniami, jak również jej przebieg może być wykorzystany do oceny czasu wystąpienia wstrząsów. Należy podkreślić, że moment wystąpienia wstrząsu jest zmienną losową i może być wyznaczony z dokładnością do swojego przedziału ufności, z określonym prawdopodobieństwem.

Źródło:

Mining – Informatics, Automation and Electrical Engineering; 2016, 54, 4; 5-10 [tekst ang.], 50-55 [tekst pol.]
2450-7326
2449-6421

Pojawia się w:

Mining – Informatics, Automation and Electrical Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 22.

Tytuł:

Gas turbine reliability estimation to reduce the risk of failure occurrence with a comparative study between the two-parameter Weibull distribution and a new modified Weibull distribution

Autorzy:

Djeddi, Ahmed Zohair
Hafaifa, Ahmed
Iratni, Abdelhamid
Kouzou, Abdellah

Powiązania:

https://bibliotekanauki.pl/articles/2096209.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN

Tematy:

failure analysis
malfunction analysis
availability
reliability estimation
failure occurrence
maintenance plan
gas turbine
two-parameter Weibull
modified Weibull
analiza uszkodzeń
dostępność
ocena niezawodności
turbina gazowa

Opis:

Responding to the needs of quality and robustness of analysis and management of degradation of equipment, to increase their life cycle and to expand these facilities to become more and more sophisticated and agronomic. This work proposes a contribution to increase the survival of a gas turbine, installed in a gascompression plant, with a comparative study between the two-parameter Weibull distribution. A new modified Weibull distribution was proposed also to reduce the risk of occurrence of failure in this rotating machine. A Statistical analysis and validation on the synthesis of turbine's reliability data and failures were considered, with a particular focus on the use of this data to increase the availability of this type of machine. So, developing a maintenance plan based on their reliability indices for scheduled inspections.

Źródło:

Diagnostyka; 2022, 23, 1; 1--18
1641-6414
2449-5220

Pojawia się w:

Diagnostyka

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 23.

Tytuł:

Zastosowanie rozkładu Weibulla do oceny wytrzymałości nasion grochu
Application of Weibull distribution for assessment of pea seed strength

Autorzy:

Łysiak, G.

Powiązania:

https://bibliotekanauki.pl/articles/291143.pdf

Data publikacji:

2006

Wydawca:

Polskie Towarzystwo Inżynierii Rolniczej

Tematy:

właściwości wytrzymałościowe
rozkład Weibulla
groch
strength-related properties
Weibull statistics
pea

Opis:

W pracy przedstawiono wyniki analiz wybranych właściwości wytrzymałościowych nasion grochu przy wykorzystaniu statystyki Weibulla. Pojedyncze nasiona o wilgotności w zakresie 4-14% ściskano na maszynie wytrzymałościowej Zwick. Określono wartości sił i odkształceń w momencie pęknięcia nasiona oraz na podstawie rozkładu ich wyników określono wartości parametrów m i rozkładu Weibulla. Wartości parametru kształtu m malały wraz ze wzrostem wilgotności nasion. Większy spadek obserwowano w przypadku rozkładu wartości odkształceń do punktu pęknięcia. Wraz ze wzrostem wilgotności zmniejszały się prostoliniowo wartości parametru dla sił w momencie pęknięcia oraz rosły nieliniowo dla odkształceń. Obserwowane różnice wskazują na możliwości rozszerzenia oceny zachowania materiałów biologicznych w procesie ściskania o informacje uzyskane przy zastosowaniu do analiz statystyki Weibulla.
The work presents the results of analyses of selected strength-related properties of pea seeds by using Weibull statistics. Single seeds with humidity from 4 to 14% were squeezed in Zwick testing machine. The force and deformation values were established in the moment when the seeds broke, and based on the distribution of the results the values of the parameters m and ⎴ of Weibull distribution were determined. The shape parameter m values decreased with the increased humidity of the seeds. More significant drop was observed in the case of distribution of deformation values up to the breaking point. Together with the increase of humidity, the parameter values ⎴ dropped rectilinearly for the forces at the moment of breaking and rose in a nonlinear way for the deformations. The observed differences indicate the possibilities of extending the assessment of behaviour of biological materials in the process of squeezing by the information obtained by using Weibull statistics for the analyses.

Źródło:

Inżynieria Rolnicza; 2006, R. 10, nr 6(81), 6(81); 41-48
1429-7264

Pojawia się w:

Inżynieria Rolnicza

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 24.

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

/5

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Skocz do pozycji: 25.

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

/5

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Skocz do pozycji: 26.

Tytuł:

Fracture Statistics Using Three-Parameter and Two-Parameter Weibull Distributions for Fe-0.4C-1.5Cr-1.5Ni-0.8Mn-0.2Mo Structural Sintered Steel

Autorzy:

Fiał, C.
Ciaś, A.
Czarski, A.
Sułowski, M.

Powiązania:

https://bibliotekanauki.pl/articles/353218.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

sintered structural steels
mechanical properties
Weibull statistics
maximum likelihood
threshold parameter

Opis:

A statistical analysis is presented of tensile and bending strengths of a porous sintered structural steel which exhibits non-linear, quasi-brittle, behaviour. It is the result of existing natural flaws (pores and oxide inclusions) and of the formation of fresh flaws when stress is applied. The analysis is by two- and three-parameter Weibull statistics. Weibull modulus, a measure of reliability, was estimated by the maximum likelihood method for specimen populations < 30. Probability distributions were compared on the basis of goodness to fit using the Anderson-Darling tests. The use of the two-parameter Weibull distribution for strength data of quasi-brittle sintered steels is questioned, because there is sufficient evidence that the 3-parameter distribution fits the data better.

Źródło:

Archives of Metallurgy and Materials; 2016, 61, 3; 1547-1554
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 27.

Tytuł:

Average capacity analysis of FSO system with Airy beam as carrier over exponentiated Weibull channels

Autorzy:

Li, Yi
Chu, Xingchun
Han, Zhongxiang
Tang, Hanling
Song, Xinkang

Powiązania:

https://bibliotekanauki.pl/articles/2202763.pdf

Data publikacji:

2023

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

Airy beam
free-space optical communication
channel capacity
exponentiated Weibull model

Opis:

Based on scintillation index of Airy beam and exponentiated Weibull channel model, analytical expressions of average channel capacity for free-space optical (FSO) communication links with Airy beam as signal carrier under weak atmospheric turbulence and on-off keying modulation scheme are derived. The average capacity at various propagation distances, transverse scale factors and exponential decay factors has been evaluated. And we compared the average capacity of FSO links with Airy beam and Gaussian beam as signal carrier. The results show that the average capacity of FSO links with Airy beam as carrier increases with the increase of mean signal-to-noise ratio and decreases uniformly with the increase of propagation distance. When the transverse scale factor of Airy beam is about 2 cm, a higher average capacity can be obtained. And the smaller the exponential decay factor of Airy beam, the larger the average capacity. Under the same source power or source width, the average capacity of FSO links with Airy beam as carrier is significantly higher than that of FSO links with Gaussian beam as carrier. The results of this research have some reference significance for the application of Airy beam in FSO communication system.

Źródło:

Optica Applicata; 2023, 53, 1; 35--48
0078-5466
1899-7015

Pojawia się w:

Optica Applicata

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 28.

Tytuł:

Characterisation of some generalised continuous distributions by doubly truncated moments

Autorzy:

Athar, Haseeb
Ahsanullah, Mohammad
Ali, Mohd. Almech

Powiązania:

https://bibliotekanauki.pl/articles/2204096.pdf

Data publikacji:

2023

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

truncated moment
characterisation
probability distribution
Weibull
power function
Frechet
Pareto
Lindley

Opis:

The characterisation of probability distribution plays an important role in statistical studies. There are various methods of characterisation available in the literature. The characterisation using truncated moments limits the observations; hence, researchers may save time and cost. In this paper, the characterisation of three general forms of continuous distributions based on doubly truncated moments has been studied. The results are given simply and explicitly. Further, the results have been applied to some well-known continuous distributions.

Źródło:

Operations Research and Decisions; 2023, 33, 1; 1--19
2081-8858
2391-6060

Pojawia się w:

Operations Research and Decisions

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 29.

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

/5

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Skocz do pozycji: 30.

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

/5

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Skocz do pozycji: 31.

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

/5

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Skocz do pozycji: 32.

Tytuł:

Overview of Fading Channel Modeling

Autorzy:

Noga, K. M.
Pałczyńska, B.

Powiązania:

https://bibliotekanauki.pl/articles/226840.pdf

Data publikacji:

2010

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

communication channel
random variables
simulation
Nakagami-m fading
Rayleigh fading
Weibull fading

Opis:

VisSim and LabVIEW based approaches are proposed and implemented to demonstrate fading in the communication systems. The introduction to fading, models for flat fading like Rayleigh, Weibull, Nakagami-m and the results of simulations are presented.

Źródło:

International Journal of Electronics and Telecommunications; 2010, 56, 4; 339-344
2300-1933

Pojawia się w:

International Journal of Electronics and Telecommunications

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 33.

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

/5

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Skocz do pozycji: 34.

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

/5

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Skocz do pozycji: 35.

Tytuł:

A problem of predictivie scheduling of jobs in a production system

Autorzy:

Wosik, I.

Powiązania:

https://bibliotekanauki.pl/articles/408943.pdf

Data publikacji:

2011

Wydawca:

Politechnika Śląska

Tematy:

awarie
dystrybucje Weibulla
klasyczna technika regresji
failures
Weibull distributions
classical regression technique

Opis:

In the paper a classical model of failures is considered in that successive failurefree times are supposed to have Weibull distributions and are followed by exponentially distributed times of repairs. It is assumed that parameters of these distributions, in general, change with time. Basing on information about the number of failures, failure-free times, repair times, in a number of periods of the same duration in the past parameters of the model are estimated. Next, predictions of the most important reliability characteristics are found using classical regression technique.

Źródło:

Wybrane Problemy Inżynierskie; 2011, 2; 369-374
2083-1021

Pojawia się w:

Wybrane Problemy Inżynierskie

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 36.

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

/5

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Skocz do pozycji: 37.

Tytuł:

Investigation of Indentation Fracture Toughness (KIC) and Weibull Parameters of 0.25Li2O.2SiO2-0.75BaO.2SiO2 Glass-Ceramic

Autorzy:

Ertuğ, B.
Çetiner, B. R.
Gökçe, H.
Erkmen, Z. E.
Öveçoğlu, M. L.

Powiązania:

https://bibliotekanauki.pl/articles/351907.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

lithium barium silicate glass-ceramic
indentation fracture toughness
hardness
statistical analysis
weibull modulus

Opis:

In the present study, mechanical properties of 0.25Li₂O.2SiO₂-0.75BaO.2SiO₂ glass-ceramic were investigated. The trans-formations‘ temperatures were determined by DTA instrument. The optimum nucleation temperature was found to be 540°C. This suggested the crystallization temperatures as 675, 720 and 800°C. After carrying out crystallization heat treatments, Vickers indentation test was applied. In order to determine the indentation fracture toughness (K_IC), crack half-length ‚c‘ of the samples was measured. To calculate K_IC, Young’s modulus, E and the measured hardness, H_v were used. Using K_IC and probability of fracture ‚P‘, ln ln[1/(1 − P)] – ln K_IC graph was drawn based on the Weibull distribution equation. Consequently, Weibull modulus, ‚m‘ and scale parameter, ‚K₀‘ were determined and compared with each other.

Źródło:

Archives of Metallurgy and Materials; 2017, 62, 4; 1963-1968
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 38.

Tytuł:

Reducing Melt Surface Turbulence by Employing Surge and Filter in a Conventional Non-Pressurizing Gating System: Simulation and Experiment

Autorzy:

Baghani, Amir
Kheirabi, Ali
Bahmani, Ahmad
Khalilpour, Hamid

Powiązania:

https://bibliotekanauki.pl/articles/2049678.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

aluminum casting
filter
surge
oxide bifilms
failure analysis
Weibull module
mold filling simulation

Opis:

Tensile strength of aluminum castings has been improved by employing surge and filter in a conventional non-pressurizing gating system. For this purpose, three non-pressurizing bottom-gating systems were designed where the first design was a simple design with no filter and no surge, in the second design filter and in the third one surge was added to the end of runner. Tensile strength, Weibull module, scanning electron microscopy, chemical analysis, and melt pattern during the mold filling were thoroughly analyzed to compare these three designs. it was observed that employing filter and surge in the gating system reduces flow kinetic energy and consequently avoid surface turbulence and air entrainment, which leads to castings with fewer defects and higher reliabilities. Finally, it found that appropriate use of surge in the running system can be as effective as employing a filter in reducing melt front velocity.

Źródło:

Archives of Metallurgy and Materials; 2021, 66, 2; 397-405
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 39.

Tytuł:

Record-based inference and associated cost analysis for the Weibull distribution

Autorzy:

Doostparast, M.

Powiązania:

https://bibliotekanauki.pl/articles/205931.pdf

Data publikacji:

2015

Wydawca:

Polska Akademia Nauk. Instytut Badań Systemowych PAN

Tematy:

cost analysis
likelihood function
record data
total time on test
Weibull model
lifetime model

Opis:

In statistical process control, record schemes are used to reduce the total time on test for the inspection inquiry. In these schemes, units are examined sequentially and successive minimum values are recorded. On the basis of record data, Samaniego and Whitaker (1986) obtained the maximum likelihood (ML) estimate of the mean for an exponential distribution. Since the two parameter Weibull model, as an extension of the exponential distribution, has a wide range of application, Hoinkes and Padgett (1994) derived the record-based ML estimators for the parameters of interest in this model. This paper shows that the ML estimates of the Weibull parameters do not always exist for the basis of records. Thus, a new scheme is proposed, in which the ML estimates of the parameters always exist. An analytic cost-based comparison between the usual and the New scheme is also carried out. Finally, some concluding remarks and open problems are formulated.

Źródło:

Control and Cybernetics; 2015, 44, 1; 163-177
0324-8569

Pojawia się w:

Control and Cybernetics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 40.

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

/5

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Skocz do pozycji: 41.

Tytuł:

The Half-Logistic Odd Power Generalized Weibull-G Family of Distributions

Autorzy:

Peter, Peter O.
Chipepa, Fastel
Oluyede, Broderick
Makubate, Boikanyo

Powiązania:

https://bibliotekanauki.pl/articles/2119924.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

half logistic distribution
half logistic-G distribution
Weibull generalized-G distribution
maximum likelihood estimation

Opis:

We develop and study in detail a new family of distributions called Half- logistic Odd Power Generalized Weibull-G (HLOPGW-G) distribution, which is a linear combination of the exponentiated-G family of distributions. From the special cases considered, the model can fit heavy tailed data and has non-monotonic hazard rate functions. We further assess and demonstrate the performance of this family of distributions via simulation experiments. Real data examples are given to demonstrate the applicability of the proposed model compared to several other existing models.

Źródło:

Central European Journal of Economic Modelling and Econometrics; 2022, 1; 1-35
2080-0886
2080-119X

Pojawia się w:

Central European Journal of Economic Modelling and Econometrics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 42.

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

/5

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Skocz do pozycji: 43.

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

/5

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Skocz do pozycji: 44.

Tytuł:

Duration-Based Approach to VaR Independence Backtesting

Autorzy:

Małecka, Marta

Powiązania:

https://bibliotekanauki.pl/articles/465936.pdf

Data publikacji:

2014

Wydawca:

Główny Urząd Statystyczny

Tematy:

VaR backtesting
Markov test, Haas test
TUFF test
Weibull test
gamma test
EACD test

Opis:

Dynamic development in the area of value-at-risk (VaR) estimation and growing implementation of VaR-based risk valuation models in investment companies stimulate the need for statistical methods of VaR models evaluation. Following recent changes in Basel Accords, current UE banking supervisory regulations require internal VaR model backtesting, which provides another strong incentive for research on relevant statistical tests. Previous studies have shown that commonly used VaR independence Markov-chain-based testing procedure exhibits low power, which constitutes a particularly serious problem in the case of finite-sample settings. In the paper, as an alternative to the popular Markov test an overview of the group of duration-based VaR backtesting procedures is presented along with exploration of their statistical properties while rejecting a non-realistic assumption of infinite sample size. The Monte Carlo test technique was adopted to provide exact tests, in which asymptotic distributions were replaced with simulated finite sample distributions. A Monte Carlo study, based on the GARCH model, was designed to investigate the size and the power of the tests. Through the comparative analysis we found that, in the light of observed statistical properties, the duration-based approach was superior to the Markov test.

Źródło:

Statistics in Transition new series; 2014, 15, 4; 627-636
1234-7655

Pojawia się w:

Statistics in Transition new series

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 45.

Tytuł:

Characterizations of the inverse Weibull distribution and generalized extreme value distributions by moments of kth record values

Autorzy:

Pawlas, Piotr
Szynal, Dominik

Powiązania:

https://bibliotekanauki.pl/articles/1208208.pdf

Data publikacji:

2000

Wydawca:

Polska Akademia Nauk. Instytut Matematyczny PAN

Tematy:

sample
record values
kth record values
order statistics
generalized extreme value distributions
inverse Weibull distribution

Opis:

We give characterization conditions for the inverse Weibull distribution and generalized extreme value distributions by moments of kth record values.

Źródło:

Applicationes Mathematicae; 2000, 27, 2; 197-202
1233-7234

Pojawia się w:

Applicationes Mathematicae

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 46.

Tytuł:

A method for obtaining the preventive maintenance interval in the absence of failure time data

Autorzy:

Sánchez-Herguedas, Antonio
Mena-Nieto, Ángel
Rodrigo-Muñoz, Francisco

Powiązania:

https://bibliotekanauki.pl/articles/2175137.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN

Tematy:

ship maintenance
preventive interval
maintenance model
semi-Markovian process
incomplete data
Weibull function
maintenance costs

Opis:

One of the ways to reduce greenhouse gas emissions and other polluting gases caused by ships is to improve their maintenance operations through their life cycle. The maintenance manager usually does not modify the preventive intervals that the equipment manufacturer has designed to reduce the failure. Conditions of use and maintenance often change from design conditions. In these cases, continuing using the manufacturer's preventive intervals can lead to non-optimal management situations. This article proposes a new method to calculate the preventive interval when the hours of failure of the assets are unavailable. Two scenarios were created to test the effectiveness and usefulness of this new method, one without the failure hours and the other with the failure hours corresponding to a bypass valve installed in the engine of a maritime transport surveillance vessel. In an easy and fast way, the proposed method allows the maintenance manager to calculate the preventive interval of equipment that does not have installed an instrument for measuring operating hours installed.

Źródło:

Eksploatacja i Niezawodność; 2022, 24, 3; 564--573
1507-2711

Pojawia się w:

Eksploatacja i Niezawodność

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 47.

Tytuł:

Bayesian reliability models of Weibull systems: State of the art

Autorzy:

Zaidi, A.
Ould Bouamama, B.
Tagina, M.

Powiązania:

https://bibliotekanauki.pl/articles/330104.pdf

Data publikacji:

2012

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

modelowanie hierarchiczne
system Weibulla
sieci bayesowskie
diagnostyka uszkodzeń
hierarchical modeling
reliability
Weibull
Bayesian networks
fault diagnosis

Opis:

In the reliability modeling field, we sometimes encounter systems with uncertain structures, and the use of fault trees and reliability diagrams is not possible. To overcome this problem, Bayesian approaches offer a considerable efficiency in this context. This paper introduces recent contributions in the field of reliability modeling with the Bayesian network approach. Bayesian reliability models are applied to systems with Weibull distribution of failure. To achieve the formulation of the reliability model, Bayesian estimation of Weibull parameters and the model's goodness-of-fit are evoked. The advantages of this modelling approach are presented in the case of systems with an unknown reliability structure, those with a common cause of failures and redundant ones. Finally, we raise the issue of the use of BNs in the fault diagnosis area.

Źródło:

International Journal of Applied Mathematics and Computer Science; 2012, 22, 3; 585-600
1641-876X
2083-8492

Pojawia się w:

International Journal of Applied Mathematics and Computer Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 48.

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

/5

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Skocz do pozycji: 49.

Tytuł:

Effect of vortex runner gating system on the mechanical strength of Al-12SI alloy castings
Wpływ kanału układu wlewowego na wytrzymałość mechaniczną odlewów ze stopu Al-12Si

Autorzy:

Ahmad, R.
Hashim, M. Y.

Powiązania:

https://bibliotekanauki.pl/articles/352629.pdf

Data publikacji:

2011

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

odlewy piaskowe
wytrzymałość mechaniczna
analiza Weibulla
układ wlewowy
gating systems
sand casting
mechanical strength
Weibull analysis

Opis:

Gating system design is an essential element in casting process which affects significantly the molten metal flow behavior, heat transfer and solidification of the melt. Optimum gating design will lead to a good quality of casting product. One of the major components in gating system is runner. This study was conducted to determine the effect of vortex runner diameter gating system on the mechanical strength of Al-12Si alloy casting. Simulation was conducted to study the behavior of the fluid flow and the results obtained showed close agreement with the results obtained from the experiment. Experimental results showed that the casting product with bigger vortex runner diameter gating system led to the improvement of average bending strength.
Układ wlewowy to podstawowy element w procesie odlewania, który znacząco wpływa na płynięcie ciekłego metalu, transport ciepła oraz krzepnięcie metalu. Optymalny układ wlewowy gwarantuje dobra jakość odlanego produktu. Jednym z głównych elementów układu wlewowego jest kanał wlewowy. Celem pracy było zbadanie wpływu średnicy kanału układu wlewowego na wytrzymałosc mechaniczna odlewów ze stopu Al-12Si. Celem zbadania zachowania przecieczy przeprowadzono symulacje i otrzymane wyniki wykazują dobrą zgodność z wynikami otrzymanymi doświadczalnie. Wyniki doswiadczeń pokazały, że zastosowanie większej srednicy kanału układu wlewowego prowadzi do poprawy średniej wytrzymałości odlewów na zginanie.

Źródło:

Archives of Metallurgy and Materials; 2011, 56, 4; 991-991
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 50.

Tytuł:

Reliability Assessment of Main Engine Subsystems Considering Turbocharger Failure as a Case Study

Autorzy:

Anantharaman, M.
Khan, F.
Garaniya, V.
Lewarn, B.

Powiązania:

https://bibliotekanauki.pl/articles/116356.pdf

Data publikacji:

2018

Wydawca:

Uniwersytet Morski w Gdyni. Wydział Nawigacyjny

Tematy:

main engine
main propulsion
turbocharger
turbocharger failure
main propulsion engine
Markov model
Weibull failur model
reliability

Opis:

Safe operation of a merchant vessel is dependent on the reliability of the vessel’s main propulsion engine. Reliability of the main propulsion engine is interdependent on the reliability of several subsystems including lubricating oil system, fuel oil system, cooling water system and scavenge air system. Turbochargers form part of the scavenge sub system and play a vital role in the operation of the main engine. Failure of turbochargers can lead to disastrous consequences and immobilisation of the main engine. Hence due consideration need to be given to the reliability assessment of the scavenge system while assessing the reliability of the main engine. This paper presents integration of Markov model (for constant failure components) and Weibull failure model (for wearing out components) to estimate the reliability of the main propulsion engine. This integrated model will provide more realistic and practical analysis. It will serve as a useful tool to estimate the reliability of the vessel’s main propulsion engine and make efficient and effective maintenance decisions. A case study of turbocharger failure and its impact on the main engine is also discussed.

Źródło:

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2018, 12, 2; 271-276
2083-6473
2083-6481

Pojawia się w:

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

Dostawca treści:

Biblioteka Nauki

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