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Wyszukujesz frazę "Linear regression" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Comparison of classical and Theil-Kendall methods in assessing the significance of linear trend of precipitation in south-eastern Poland
Autorzy:
Węglarczyk, S.
Powiązania:
https://bibliotekanauki.pl/articles/101285.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
annual precipitation total
annual daily maximum precipitation
Upper Vistula River
ordinary least squares linear regression
Kendall-Theil linear regression
Opis:
Two methods of linear trend estimation: the ordinary least squares (OLS, parametric) and Theil-Kendall (TK, nonparametric) are compared in the paper. The comparison was made using 65 time series of annual totals, Pa , and annual daily maximum, Pmax, of precipitation, 30-year long each, recorded in the south-eastern part of Poland (the Upper Vistula catchment). The OLS and TK slope coefficients of trends revealed high similarity for both Pa and Pmax series. The signs of slopes are the same for 64 sites for Pa and 63 sites for Pmax with positive signs prevailing: the numbers of decreasing trends for Pa OLS and TK slopes were 3 and 4, respectively, and, for Pmax, 13 for both OLS and TK slopes. In trend significance testing, both methods produced similar results for Pa time series: out of 16 significant trends, 13 were determined with both OLS and TK at the same sites. For Pmax series such agreement was found for 4 trends out of 10. Spatial distribution of significant trends showed a kind of clustering in certain parts of the investigated area.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2016, IV/2; 1439-1450
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of trend changes in degree-day values of heating and cooling: broiler breeding case
Autorzy:
Yucel, A.
Atilgan, A.
Erdem, N.
Oz, H.
Powiązania:
https://bibliotekanauki.pl/articles/101664.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
broiler
linear regression analysis
spearman rank correlation test
temperature
trend analysis
Opis:
An ideal broiler house should be designed to minimize the effects of weather changes and to keep indoor conditions at the comfort temperature of the animals. In this case, this should be done with minimum cost and possible lowest operating costs. Degree-day methods are used in order to have knowledge of the energy need of any structure. With this method, the measured values or meteorological data can be used to give information about the heating and cooling energy quantities of structures. Depending on the climate change in recent years, the changes need to be examined that have taken place in order to provide optimum comfort in animal barn. Isparta province and districts were selected as the study area. The longterm average daily temperature values are used from meteorological stations of the selected region. The heating and cooling degree day values were calculated for selected balance temperatures in broiler breeding. Linear Regression Analysis and Spearman Rank Correlation Test were conducted to determine the changes of these values due to climate change. In conclusion, it was determined that there were statistically significant trends at 5% significance level in Egirdir (21°C), Isparta (31-29-25 and 23°C), Kasimlar (18°C), Senirkent (31-29-25-23 and 21°C), Sutculer (all selected balance temperature values) and Yalvac (31-29-25-23 and 21°C) in terms of heating degree-day values, and in Atabey (29-25-23-21 and 18°C), Barla (25-23 and 21°C), Isparta (23-21 and 18°C), Senirkent (29- 25-23-21 and 18°C), Sutculer (29-25-23-21 and 18°C), Sarkikaraagac (25-23-21 and 18°C), Uluborlu (25-23-21 and 18°C) and Yalvac (25-23-21 and 18°C) in terms of cooling degree-day values. As a result, it has been concluded that more energy consumption will be a concern for heating and cooling of the broiler house that will be built in the province of Isparta.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2017, II/2; 645-660
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent trends in annual maximum flows within the Upper Vistula River catchment
Autorzy:
Całek, Mateusz
Węglarczyk, Stanisław
Powiązania:
https://bibliotekanauki.pl/articles/101564.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
annual maximum flow
Upper Vistula River
Kendall-Theil linear regression
autocorrelation
variance correction approach
Opis:
All uninterrupted time series of annual maximum flows of size at least 30 recorded in the period 1951-2016 in the Upper Vistula River catchment, were taken into trend analysis. Each of the 138 time series ended not earlier than in 2012. To estimate the trend, the nonparametric Theil-Kendall linear regression method was used. After removing the trend, lag-1 Kendall rank autocorrelation coefficient was calculated and, if the coefficient was significant at 5% level, was used to correct the variance of the Kendall S statistic which otherwise remained unchanged. Finally, the variance-corrected Mann-Kendall trend test was used, detecting 22 significant (at 5% level) linear trends of which only two were the effect of autocorrelation. All 138 significant and non-significant trends showed certain areal clustering clearly visible on the map of the catchment, which suggested dividing the area into three parts according the direction of trend and/or the number of statistically significant trends. Generally, the trends in the southern of the Upper Vistula River catchment are increasing, the opposite is true for the northern part. This finding does not concern the north-west part of the catchment where both kinds of trends are observed, which may be explained by strong anthropogenic influence.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2019, II/1; 25-37
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The efficiency of some forecasting methods applied to annual minimum flow series
Autorzy:
Weglarczyk, S.
Powiązania:
https://bibliotekanauki.pl/articles/61400.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
forecasting method
Holt-Winters model
water level
annual minimum water level
Vistula River
tributary
local linear regression model
river
LOESS model
Opis:
Four methods of forecasting: „no-change", LOESS, local linear regression and Holt-Winters were applied to annual minimum water levels observed at ten cross-sections of two tributaries of the Vistula river. The 1-, 2-, ..., 5-year forecasts were made for each year after some initial year, and four quality measures: bias, root mean square error, mean absolute error and maximum absolute error were calculated for each time series and lead time. The naïve model turned out to be always the worst in it bias and almost always very good, sometimes the best regarding the other measures.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2011, 12
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on riverbed evolution on the Nida river at the Pinczow and Wislica gauging station
Autorzy:
Lapuszek, M.
Powiązania:
https://bibliotekanauki.pl/articles/62286.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
riverbed
evolution
Nida River
river regulation
linear regression
river network
catchment
erosion
denudation
hydrology
fluvial system
long-term evolution
bottom
stream bed
Opis:
The long-term evolution of the river beds of Nida River in Pińczów and Wiślica gauging station as well as an analysis of the causes of significant cases of lowering of the bottom of stream beds are presented in the paper. The intensity of river bed evolution as a stochastic process is described with the use of a statistical model. The analysis of the intensity of the process of river bed erosion was conducted under the assumption that the observed long-term trend of the lowest annual water levels reflect the elevation of the river bottom in the same years. The recorded observations at the Pińczów and Wiślica gauging stations on the Nida River, covering over 70-year period of time, are analyzed. Observations of the variability in the studied bottom levels over the decades allow concluding that the great transformation of riverbeds occurred there. The observations and calculations show that in Pińczów multistream or meandering river bed changed into straight channel and the process of shallowing of the river bed appeared. At the Wiślica gauging station the process of riverbed erosion with the variable intensity was observed. The research shows that the causes of these changes observed in Pińczów and Wiślica are not natural, but rather of human activity.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2011, 12
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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