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Wyszukujesz frazę "autoregressive integrated moving average" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Best Time Series In-sample Model for Forecasting Nigeria Exchange Rate
Autorzy:
Gaddafi, Adamu Babali
Akpensuen, Shiaondo Henry
Shitu, Abdulrazaq Ahmed
Malle, Ahmad Atiku
Adamu, Muhammed
Bukar, Muhammad Goni
Powiązania:
https://bibliotekanauki.pl/articles/1031300.pdf
Data publikacji:
2021
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
ARIMA
Autoregressive Integrated Moving Average Model
Autoregressive Moving Average Model
Autoregressive models
Box-Jenkins Methodology
CBN
Exchange rate
Model
Moving Average Models
Nigeria
Opis:
In this work we considered data on official Nigeria exchange rates (Naira to British Pound sterling) from January 2003 to December 2019. Four competing models ARIMA (1, 1, 1), ARIMA (2, 1, 1), ARIMA (1, 1, 0) and ARIMA (1, 1, 2) were identified for the exchange rates series. Diagnostic analysis revealed that all the competing models adequately represent the exchange rate series. However, on the basis of out-of-sample model selection and evaluation ARIMA (1, 1, 1) was selected as the optimal model with minimum information criteria for the exchange rate series. A 24 months forecast indicates that the Naira will continue to depreciate. The policy implication of our study is that the Central Bank of Nigeria (CBN), should devalue the Naira in order to not only re-establish exchange rate stability but also encourage local manufacturing and encourage foreign capital inflows.
Źródło:
World Scientific News; 2021, 151; 45-63
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessing the representative elementary volume of rock types by X-ray computed tomography (CT) – a simple approach to demonstrate the heterogeneity of the Boda Claystone Formation in Hungary
Autorzy:
Abutaha, Saja M.
Geiger, János
Gulyás, Sándor
Fedor, Ferenc
Powiązania:
https://bibliotekanauki.pl/articles/2204358.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
Hounsfield Unit
HU
autoregressive integrated moving average
ARIMA
Statistical Process Control
SPC technique
skala Hounsfielda
model ARIMA
statystyczna kontrola procesu
SPC
Opis:
X-ray computed tomography (CT) can reveal internal, three-dimensional details of objects in a non-destructive way and provide high-resolution, quantitative data in the form of CT numbers. The sensitivity of the CT number to changes in material density means that it may be used to identify lithology changes within cores of sedimentary rocks. The present pilot study confirms the use of Representative Elementary Volume (REV) to quantify inhomogeneity of CT densities of rock constituents of the Boda Claystone Formation. Thirty-two layers, 2 m core length, of this formation were studied. Based on the dominant rock-forming constituent, two rock types could be defined, i.e., clayey siltstone (20 layers) and fine siltstone (12 layers). Eleven of these layers (clayey siltstone and fine siltstone) showed sedimentary features such as, convolute laminations, desiccation cracks, cross-laminations and cracks. The application of the Autoregressive Integrated Moving Averages, Statistical Process Control (ARIMA SPC) method to define Representative Elementary Volume (REV) of CT densities (Hounsfield unit values) affirmed the following results: i) the highest REV values corresponded to the presence of sedimentary structures or high ratios of siltstone constituents (> 60%). ii) the REV average of the clayey siltstone was (5.86 cm3) and (6.54 cm3) of the fine siltstone. iii) normalised REV percentages of the clayey siltstone and fine siltstone, on the scale of the core volume studied were 19.88% and 22.84%; respectively. iv) whenever the corresponding layer did not reveal any sedimentary structure, the normalised REV values would be below 10%. The internal void space in layers with sedimentary features might explain the marked textural heterogeneity and elevated REV values. The drying process of the core sample might also have played a significant role in increasing erroneous pore proportions by volume reducation of clay minerals, particularly within sedimentary structures, where authigenic clay and carbonate cement were presumed to be dominant.
Źródło:
Geologos; 2021, 27, 3; 157--172
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wavelets for time series analysis - a survey and new results
Autorzy:
Mielniczuk, J.
Wojdyłło, P.
Powiązania:
https://bibliotekanauki.pl/articles/970989.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
long-range dependence
decorrelation property
spectral density
time series
wavelets
fractional Gaussian noise (FGN)
fractional autoregressive integrated moving average (FARIMA)
Hurst exponent
falka
Opis:
In the paper we review stochastic properties of wavelet coefficients for time series indexed by continuous or discrete time. The main emphasis is on decorrelation property and its implications for data analysis. Some new properties are developed as the rates of correlation decay for the wavelet coefficients in the case of long-range dependent processes such as the fractional Gaussian noise and the fractional autoregressive integrated moving average processes. It is proved that for such processes the within-scale covariance of the wavelet coefficients at lag k is O(k^2(H-N)-2), where H is the Hurst exponent and N is the number of vanishing moments of the wavelet employed. Some applications of decorrelation property are briefly discussed.
Źródło:
Control and Cybernetics; 2005, 34, 4; 1093-1125
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A combined method for wind power generation forecasting
Autorzy:
Le, Tuan-Ho
Powiązania:
https://bibliotekanauki.pl/articles/1955200.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
autoregressive integrated moving average
exponential smoothing methods
forecasting
response surface methodology
wind power
autoregresyjna zintegrowana średnia ruchoma
metody wygładzania wykładniczego
prognozowanie
metodologia powierzchni odpowiedzi
energia wiatrowa
Opis:
Most of the existing statistical forecasting methods utilize the historical values of wind power to provide wind power generation prediction. However, several factors including wind speed, nacelle position, pitch angle, and ambient temperature can also be used to predict wind power generation. In this study, a wind farm including 6 turbines (capacity of 3.5 MW per turbine) with a height of 114 meters, 132-meter rotor diameter is considered. The time-series data is collected at 10-minute intervals from the SCADA system. One period from January 04th, 2021 to January 08th, 2021 measured from the wind turbine generator 06 is investigated. One period from January 01st, 2021 to January 31st, 2021 collected from the wind turbine generator 02 is investigated. Therefore, the primary objective of this paper is to propose a combined method for wind power generation forecasting. Firstly, response surface methodology is proposed as an alternative wind power forecasting method. This methodology can provide wind power prediction by considering the relationship between wind power and input factors. Secondly, the conventional statistical forecasting methods consisting of autoregressive integrated moving average and exponential smoothing methods are used to predict wind power time series. Thirdly, response surface methodology is combined with autoregressive integrated moving average or exponential smoothing methods in wind power forecasting. Finally, the two above periods are performed in order to demonstrate the efficiency of the combined methods in terms of mean absolute percent error and directional statistics in this study.
Źródło:
Archives of Electrical Engineering; 2021, 70, 4; 991-1009
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wykorzystanie metody moving block bootstrap w prognozowaniu szeregów czasowych z wahaniami okresowymi
The Use of the Moving Block Bootstrap Method in Periodic Time Series Forecasting
Autorzy:
Kończak, Grzegorz
Miłek, Michał
Powiązania:
https://bibliotekanauki.pl/articles/586452.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Ekonomiczny w Katowicach
Tematy:
Analiza szeregów czasowych
Metody statystyczne
Modele ARIMA
Prognozowanie matematyczne
Szeregi czasowe
Autoregressive integrated moving average (ARIMA) models
Mathematical forecasting
Statistical methods
Time-series
Time-series analysis
Opis:
The aim of the analysis of the time series is, among others, to facilitate the formulation of prognosis. The basis for the inference of the future variables are their future realizations. There are various methods used in time series forecasting, such as for example naïve method, Holt-Winters models, ARIMA models and various simulation methods. One of the most popular and widely used simulation method in statistical research is the bootstrap method proposed by B. Efron. It is usually applied in measuring the estimates of the variance and testing the hypotheses in cases when the distribution of the test statistic is unknown. This method does not require for the selected samples to be from the standard normal distribution population. Due to the construction of the random samples in this method, there is usually no possibility to directly apply it in the analysis of the periodic time series. In the literature written on this subject, there are the proposals to introduce some modifications to the bootstrap method that would provide the possibility to conduct such analyses. One of such methods is the moving block bootstrap. In the present essay, we will present the proposal to apply this method to create the confidential intervals for the periodic time series forecasts. The results gathered by applying that method are compared with the results obtained via the classic construction of the confidential intervals for the forecasts and on the confidential intervals based on ARIMA models.
Źródło:
Studia Ekonomiczne; 2014, 203; 91-100
2083-8611
Pojawia się w:
Studia Ekonomiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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