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Wyszukujesz frazę "continuous distribution" wg kryterium: Temat


Wyświetlanie 1-9 z 9
Tytuł:
Testing the annual rainfall dispersion in Chaiyaphum, Thailand, by using confidence intervals for the coefficient of variation of an inverse gamma distribution
Autorzy:
Panichkitkosolkul, Wararit
Powiązania:
https://bibliotekanauki.pl/articles/19892780.pdf
Data publikacji:
2023-09-08
Wydawca:
Główny Urząd Statystyczny
Tematy:
statistical test
measure of dispersion
continuous distribution
simulation
meteorology
Opis:
In Thailand, droughts are regular natural disasters that happen nearly every year due to several factors such as precipitation deficiency, human activity, and the global warming. Since annual rainfall amount fits an inverse gamma (IG) distribution, we wanted to try testing annual rainfall dispersion via the coefficient of variation (CV). Herein, we propose two statistics for testing the CV of an IG distribution based on the Score and Wald methods. We evaluated their performances by means of the Monte Carlo simulations conducted under several shape parameter values for an IG distribution based on empirical type I error rates and powers of the tests. The simulation results reveal that the Wald-method test statistic performed better than the Score-method one in terms of the attained nominal significance level, and is thus recommended for analysis in similar scenarios. Furthermore, the efficacy of the proposed test statistics was illustrated by applying them to the annual rainfall amounts in Chaiyaphum, Thailand.
Źródło:
Statistics in Transition new series; 2023, 24, 4; 109-122
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Bivariate Copula-based Model for a Mixed Binary-Continuous Distribution: A Time Series Approach
Autorzy:
Bień-Barkowska, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/483353.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
copula function
mixed binary-continuous distribution
ACD models
market microstructure
Opis:
In this paper we present a copula-based model for a binary and a continuous variable in a time series setup. Within this modeling framework both marginals can be equipped with their own dynamics whereas the contemporaneous dependence between both processes can be flexibly captured via a copula function. We propose a method for testing the goodness-offit of such a time series model using probability integral transforms (PIT). This verification procedure allows not only a verification of the goodness-offit of the estimated marginal distribution for a continuous variable but also the conditional distribution of a continuous variable given the outcome of its binary counterpart (i.e. the adequacy of the copula choice). We test the model on an empirical example: investigating the relationship between trading volume and the indicators of arbitrarily ’large’ price movements on the interbank EUR/PLN spot market.
Źródło:
Central European Journal of Economic Modelling and Econometrics; 2012, 4, 2; 117-142
2080-0886
2080-119X
Pojawia się w:
Central European Journal of Economic Modelling and Econometrics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Analysis of the Influence of Longitudinal Stress Changes on Band Dimensions During Continuous Rolling Process
Autorzy:
Sygut, P.
Klimecka-Tatar, D.
Borkowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/356263.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
continuous rolling process in grooves
nonuniform temperature distribution
tension and concentration of band
FEM
Opis:
The paper presents the results of studies on the effect of nonuniform temperature distribution over the length of feedstock on the variation of longitudinal stresses in the rolling direction and band dimension change during the continuous rolling process. The studies were performed based on actual engineering data for a 160x160 mm square cross-section feedstock of steel S355J0. Numerical modelling of the rolling process was performed using Forge 2008®, a finite-element based computer program. Thermovision measurements and bars geometrical dimension changes were carried out in a domestic steelworks.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 1; 183-188
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimating the population mean using a continuous sampling design dependent on an auxiliary variable
Autorzy:
Wywiał, Janusz L.
Powiązania:
https://bibliotekanauki.pl/articles/1059051.pdf
Data publikacji:
2020-12-04
Wydawca:
Główny Urząd Statystyczny
Tematy:
continuous sampling design
Horvits-Thompson estimator
inclusion density
sampling scheme
bivariate gamma distribution
ratio estimator
Opis:
Continuous distribution of variables under study and auxiliary variables are considered. The purpose of the paper is to estimate the mean of the variable under study using a sampling design which is dependent on the observation of a continuous auxiliary variable in the whole population. Auxiliary variable values observed in this population allow to estimate the inclusion density function of the sampling design. The variance of the continuous version of the Horvitz-Thompson estimator under the proposed sampling design is compared with the variance of the mean of a simple random sample. The accuracy of the estimation strategies is analysed by means of simulation experiments.
Źródło:
Statistics in Transition new series; 2020, 21, 5; 1-16
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of the shape of turbulence inhibitors on the hydrodynamic conditions occuring in a tundish
Wpływ kształtu inhibitora turbulencji na warunki hydrodynamiczne panujące w kadzi pośredniej
Autorzy:
Merder, T.
Powiązania:
https://bibliotekanauki.pl/articles/355771.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tundish
continuous casting
numerical modeling
residence time distribution (RTD)
kadź pośrednia
odlewanie ciągłe
modelowanie numeryczne
charakterystyka RTD
Opis:
The article presents results of the research that was carried out taking into account the influence of the (impact pads) turbulence inhibitor geometry and its equipment of the working space on the hydrodynamic conditions occurring in T-type tundish. Four different turbulence inhibitors were discussed. They differ in shape and configuration of external walls. The research was conducted basing on the numerical simulations as well as on tests performed on physical water model. As a result of calculations the velocity field distribution, turbulence field and marker concentration distribution in the liquid steel for the tested geometrical variants of turbulence inhibitors were obtained. Worked out RTD curves (Residence Time Distribution) allowed to determine the kinetics of steel mixing (the range of transient zone was estimated), and the percentage participation of the particular flow zones. The test carried out on the water model concerned one of the tested turbulence inhibitors. Research was done to verify the parameter settings of the numerical model applied in calculations. Obtained results gave valuable information about the work of the object after applying different turbulence inhibitors.
Artykuł przedstawia wyniki badań wpływu geometrii i sposobu zabudowy inhibitora turbulencji na warunki hydrodynamiczne panujące w przestrzeni roboczej kadzi pośredniej typu T. Rozpatrywano cztery warianty geometryczne inhibitora turbulencji. Inhibitory turbulencji różniły się kształtem i ukształtowaniem ścian wewnętrznych. Badania zrealizowano w oparciu o technikę modelowania numerycznego, oraz eksperyment na fizycznym modelu wodnym. W wyniku obliczeń uzyskano pola prędkości, turbulencji oraz rozkładu stężeń znacznika wprowadzonego do ciekłej stali w przestrzeni kadzi pośredniej dla rozpatrywanych wariantów geometrycznych inhibitora turbulencji. Opracowane charakterystyki RTD (Residence Time Distribution) umożliwiły określenie kinetyki mieszania stali (oszacowano zakres strefy przejściowej), oraz udziały procentowe poszczególnych stref przepływu. Badania uzupełniono o eksperyment na fizycznym modelu wodnym. Dotyczył on jednego z proponowanych wariantów inhibitora turbulencji. Wykonano je w celu weryfikacji doboru parametrów modelu numerycznego w przyjętych w obliczeniach. Uzyskane wyniki dostarczyły cennych informacji o pracy obiektu po zastosowaniu różnych inhibitorów turbulencji.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 4; 1111-1117
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An asymptotic expansion for the distribution of the supremum of a random walk
Autorzy:
Sgibnev, M. S.
Powiązania:
https://bibliotekanauki.pl/articles/1206084.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
random walk
supremum
submultiplicative function
characteristic equation
absolutely continuous component
oscillating random walk
stationary distribution
asymptotic expansions
Banach algebras
Laplace transform
Opis:
Let ${S_n}$ be a random walk drifting to -∞. We obtain an asymptotic expansion for the distribution of the supremum of ${S_n}$ which takes into account the influence of the roots of the equation $1-∫_ℝe^{sx}F(dx)=0,F$ being the underlying distribution. An estimate, of considerable generality, is given for the remainder term by means of submultiplicative weight functions. A similar problem for the stationary distribution of an oscillating random walk is also considered. The proofs rely on two general theorems for Laplace transforms.
Źródło:
Studia Mathematica; 2000, 140, 1; 41-55
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Analysis of Unit Friction Force Working on the Metal Contact Surface with the Roll Change during Feedstock with Non-Uniform Temperature Distribution Rolling Process
Autorzy:
Sygut, P.
Powiązania:
https://bibliotekanauki.pl/articles/353951.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
continuous rolling process in grooves
non-uniform temperature distribution
unit friction force working on the metal contact surface with the roll
FEM
round bars quality
Opis:
The paper presents the results of theoretical studies influence of non-uniform temperature distribution along the feedstock length to the unit friction force working on the metal contact surface with the roll change during the round bars 70 mm in diameter continuous rolling process. This value is one of the major factors affecting the grooves wear during the rolling process. The studies were carried out based on the actual engineering data for 160 × 160 mm square cross-section feedstock of steel S355J0. Numerical modelling of the rolling process was performed using Forge2008®, a finite-element based computer program.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 2B; 927-932
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reaction crystallization of struvite in a continuous DTM type crystallizer with a compressed air driven jet pump
Autorzy:
Matynia, A.
Mazieńczuk, A.
Piotrowski, K.
Wierzbowska, B.
Hutnik, N.
Kozik, A.
Powiązania:
https://bibliotekanauki.pl/articles/779281.pdf
Data publikacji:
2011
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
krystalizator DTM
strumienica
sprężone powietrze
krystalizacja
usuwanie fosforanów
struwit
rozkład miarowy kryształów
model kinetyczny
continuous DTM crystallizer
jet pump
compressed air
reaction crystallization
phosphates(V) removal
struvite
crystal size distribution
SIG kinetic model
Opis:
Experimental tests covering the production of struvite MgNH4PO4ź6H2O from water solutions containing 1.0 mass % of phosphate(V) ions using magnesium and ammonium ions in stoichiometric proportions were carried out in a crystallizer of 1.2 dm3 working volume. The process temperature was 298 K. Struvite crystals of mean size Lm from ca. 14 to ca. 38 µm were produced depending on the process environment's pH (9-11) and the mean residence time of suspension in a crystallizer, τ (900-3600 s). In such defined process conditions the linear growth rate of struvite crystals changed from 1.45ź10-8 m/s (pH 9, τ 900 s) to 2.06ź10-9 m/s (pH 11, τ 3600 s) while the nucleation rate from 5.1ź10^7 to 3.2ź10^9 1/(sm3). Crystal product of the most advantageous granular characteristics was produced at pH 9 and the mean residence time 3600 s. Within this product population the largest sizes reached above 200 µm while the number of crystals smaller than 3 mm was kept below 6%.
Źródło:
Polish Journal of Chemical Technology; 2011, 13, 2; 46-53
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculation of phase-change boundary position in continuous casting
Autorzy:
Ivanova, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/380559.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solidification process
information technology
foundry industry
mathematical modeling
temperature distribution
Stefan condition
phase change boundary
continuous casting
krzepnięcie stopu
technologia informacyjna
przemysł odlewniczy
modelowanie matematyczne
rozkład temperatury
warunek Stefana
granica międzyfazowa
odlewanie ciągłe
Opis:
The problem of determination of the phase-change boundary position at the mathematical modeling of continuous ingot temperature field is considered. The description of the heat transfer process takes into account the dependence of the thermal physical characteristics on the temperature, so that the mathematical model is based on the nonlinear partial differential equations. The boundary position between liquid and solid phase is given by the temperatures equality condition and the Stefan condition for the two-dimensional case. The new method of calculation of the phase-change boundary position is proposed. This method based on the finite-differences with using explicit schemes and on the iteration method of solving of non-linear system equations. The proposed method of calculation is many times faster than the real time. So that it amenable to be used for model predictive control of continuous semifinished product solidification.
Źródło:
Archives of Foundry Engineering; 2013, 13, 4; 57-62
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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