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Wyszukujesz frazę "time models" wg kryterium: Temat


Tytuł:
Structural changes in eggs prices in European Union member states
Autorzy:
Jaworski, Stanisław
Powiązania:
https://bibliotekanauki.pl/articles/453565.pdf
Data publikacji:
2010
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Katedra Ekonometrii i Statystyki
Tematy:
Correspondence analysis
Correlation
Dendrogram
Structural time series models
Opis:
The work relates to changes of the eggs prices in European Union member states since 2004 to 2010. The analysis is based on annually, monthly and weekly average eggs prices. Correspondence analysis is applied to analyze the direction and structure of the changes with reference to all considered states. The unexpected and violent price changes are captured with respect to particular states. Moreover in the reference to chosen states, the model of structural time series analysis is applied to show the price changes in a more detail.
Źródło:
Metody Ilościowe w Badaniach Ekonomicznych; 2010, 11, 1; 90-99
2082-792X
Pojawia się w:
Metody Ilościowe w Badaniach Ekonomicznych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Remuneration and working time of teachers in Poland ‒ compared to other European countries
Wynagrodzenie i czas pracy nauczycieli w Polsce ‒ na tle innych krajów europejskich
Autorzy:
Miko-Giedyk, Justyna
Powiązania:
https://bibliotekanauki.pl/articles/2040188.pdf
Data publikacji:
2021-11-04
Wydawca:
Uniwersytet Kazimierza Wielkiego w Bydgoszczy
Tematy:
wynagrodzenie nauczycieli
czas pracy nauczycieli
modele czasu pracy
teachers remuneration
teachers working time
working time models
Opis:
The paper discusses the remuneration and working time of Polish teachers in relation to other European countries. The basis for comparison is constituted by international reports and national documents, but they should not be construed without insight into definition differences and in isolation from national specifics. Purely statistical comparison without knowledge of the context may lead to erroneous conclusions. For example, when it comes to the presentation of teachers’ statutory working time, there are several models for defining it in European countries, and the direct ranking of countries defining working time in terms of obligatory teaching hours only (Poland, Austria, Belgium, Finland) next to countries (Denmark, Estonia, Malta) that use a definition of general working time may distort the actual situation.
W artykule omawiane są kwestie wynagrodzenia i czasu pracy polskich nauczycieli w odniesieniu do innych krajów europejskich. Bazą wyjściową do porównania są międzynarodowe raporty oraz dokumenty krajowe, jednak nie należy ich interpretować bez wniknięcia w różnice definicyjne i w oderwaniu od specyfiki państwowej. Komparacja czysto statystyczna bez znajomości kontekstu może prowadzić do wyciągnięcia błędnych wniosków. Na przykład, jeśli chodzi o przedstawianie ustawowego czasu pracy nauczycieli, w krajach europejskich istnieje kilka modeli go określających i bezpośrednie uszeregowanie państw, w których czas pracy definiuje się przez pryzmat tylko pensum dydaktycznego (Polska, Austria, Belgia, Finlandia), obok krajów (Dania, Estonia, Malta), gdzie określa się ogólny czas pracy, co może powodować zniekształcenie rzeczywistości.
Źródło:
Szkoła - Zawód - Praca; 2021, 21; 54-71
2082-6087
Pojawia się w:
Szkoła - Zawód - Praca
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability conditions for fractional-order linear equations with delays
Autorzy:
Mozyrska, D.
Ostalczyk, P.
Wyrwas, M.
Powiązania:
https://bibliotekanauki.pl/articles/201130.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fractional calculus
discrete-time models with delays
stability
rachunek różniczkowy
model dyskretny
stabilność
Opis:
The problem of stability of the Gr¨unwald-Letnikov-type linear fractional-order discrete-time systems with delays is discussed. For the stability analysis of the considered systems the Z -transform is used. The sufficient conditions for the asymptotic stability of the considered systems are presented. Using conditions related to eigenvalues of the matrices defining the linear difference systems, one can determine the regions of location of eigenvalues of matrices associated to the systems in order to guarantee the asymptotic stability of the considered systems. Some of these regions are illustrated with relevant examples.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 4; 449-454
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discrete identification of continuous non-linear andnon-stationary dynamical systems that is insensitive to noise correlation and measurement outliers
Autorzy:
Kozłowski, Janusz
Kowalczuk, Zdzisław
Powiązania:
https://bibliotekanauki.pl/articles/27312014.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
instrumental variable
non-linear continuous-time models
optimization
supervisory systems
security systems
system identification
Opis:
The paper uses specific parameter estimation methods to identify the coefficients of continuous-time models represented by linear and non-linear ordinary differential equations. The necessary approximation of such systems in discrete time in the form of utility models is achieved by the use of properly tuned ‘integrating filters’ of the FIR type. The resulting discrete-time descriptions retain the original continuous parameterization and can be identified, for example, by the classical least squares procedure. Since in the presence of correlated noise, the estimated parameter values are burdened with an unavoidable systematic error (manifested by asymptotic bias of the estimates), in order to significantly improve the identification consistency, the method of instrumental variables is used here. In our research we use an estimation algorithm based on the least absolute values (LA) criterion of the least sum of absolute values, which is optimal in identifying linear and non-linear systems in the case of sporadic measurement errors. In the paper, we propose a procedure for determining the instrumental variable for a continuous model with non-linearity (related to the Wienerian system) in order to remove the evaluation bias, and a recursive sub-optimal version of the LA estmator. This algorithm is given in a simple (LA) version and in an instrumental variable version (IV-LA), which is robust to outliers, removes evaluation bias, and is suited to the task of identifying processes with non-linear dynamics (semi-Wienerian/NLID). In conclusion, the effectiveness of the proposed algorithmic solutions has been demonstrated by numerical simulations of the mechanical system, which is an essential part of the suspension system of a wheeled vehicle.
Źródło:
Archives of Control Sciences; 2023, 33, 2; 391--411
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
PRECISE ESTIMATES OF RUIN PROBABILITIES
Autorzy:
Rudź, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/453317.pdf
Data publikacji:
2015
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Katedra Ekonometrii i Statystyki
Tematy:
discrete time risk models
ruin probabilities
approximations
Solvency II
Opis:
In this paper we investigate a sequence of accurate approximations of ruin probabilities in discrete time models. We prove its convergence to the exact ruin probability without any restrictive assumptions on the claim distribution. Numerical studies show that the sequence, from the first term on, accurately approximates ruin probabilities. A formula for ruin probabilities in the finite horizon is also proposed.
Źródło:
Metody Ilościowe w Badaniach Ekonomicznych; 2015, 16, 2; 80-88
2082-792X
Pojawia się w:
Metody Ilościowe w Badaniach Ekonomicznych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A data-driven approach to predict hydrometeorological variability and fluctuations in lake water levels
Autorzy:
Tan Kesgin, Remziye I.
Demir, Ibrahim
Kesgin, Erdal
Abdelkader, Mohamed
Agaccioglu, Hayrullah
Powiązania:
https://bibliotekanauki.pl/articles/28411608.pdf
Data publikacji:
2023
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
evaporation
lake water level
precipitation
stochastic time series models
water transfer
Opis:
Beyşehir Lake is the largest freshwater lake in the Mediterranean region of Turkey that is used for drinking and irrigation purposes. The aim of this paper is to examine the potential for data-driven methods to predict long-term lake levels. The surface water level variability was forecast using conventional machine learning models, including autoregressive moving average (ARMA), autoregressive integrated moving average (ARIMA), and seasonal autoregressive integrated moving average (SARIMA). Based on the monthly water levels of Beyşehir Lake from 1992 to 2016, future water levels were predicted up to 24 months in advance. Water level predictions were obtained using conventional time series stochastic models, including autoregressive moving average, autoregressive integrated moving average, and seasonal autoregressive integrated moving average. Using historical records from the same period, prediction models for precipitation and evaporation were also developed. In order to assess the model’s accuracy, statistical performance metrics were applied. The results indicated that the seasonal autoregressive integrated moving average model outperformed all other models for lake level, precipitation, and evaporation prediction. The obtained results suggested the importance of incorporating the seasonality component for climate predictions in the region. The findings of this study demonstrated that simple stochastic models are effective in predicting the temporal evolution of hydrometeorological variables and fluctuations in lake water levels.
Źródło:
Journal of Water and Land Development; 2023, 58; 158--170
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Behaviour of fractional discrete-time consensus models with delays for summator dynamics
Autorzy:
Girejko, E.
Mozyrska, D.
Wyrwas, M.
Powiązania:
https://bibliotekanauki.pl/articles/201408.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fractional calculus
consensus
single-summator
double-summator
discrete-time models with delays
rachunek ułamkowy
konsensus
model dyskretny
opóźnienia
Opis:
The leader-following consensus problem of fractional-order multi-agent discrete-time systems with delays is considered. In the systems, interactions between agents are defined like in Krause and Cucker-Smale models, but the memory is included by taking both the fractional-order discrete-time operator on the left hand side of the nonlinear systems and the delays. Since in practical problems only bounded number of delays can be considered, we study the fractional order discrete-time models with a finite number of delays. The models of opinions under consideration are investigated for single- and double-summator dynamics of discrete-time by means of analytical methods as well as computer simulations.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 4; 403-410
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Review of the book ,,The analysis and forecasting of time series. Practical introduction on the basis of the R environment by: A. Zagdanski and A. Suchwałko
Autorzy:
Burnecki, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/747794.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
time series models
forecasting
data analysis
modele szeregów czasowych
prognozowanie
analiza danych
Opis:
Niniejsza książka stanowi praktyczne wprowadzenie do modelowania w środowisku R różnorodnych danych zbieranych w regularnych odstępach czasu. Książka adresowana jest do wszystkich zainteresowanych modelami szeregów czasowych a szczególnie do studentów i absolwentów kierunków ścisłych, ekonomicznych oraz technicznych.
This book provides a practical introduction to the R environment variety of modeling data collected at regular intervals. The book is addressed to anyone interested in time series models, and mainly to students and graduates of scientific, economic and technical faculties. 
Źródło:
Mathematica Applicanda; 2016, 44, 2
1730-2668
2299-4009
Pojawia się w:
Mathematica Applicanda
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Predicting the seasonality of passengers in railway transport based on time series for proper railway development
Autorzy:
Borucka, Anna
Guzanek, Patrycja
Powiązania:
https://bibliotekanauki.pl/articles/2098132.pdf
Data publikacji:
2021
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
rail transport
passenger flow
time series models
transport kolejowy
przepływ pasażerów
modele szeregów czasowych
Opis:
Planning the frequency of rail services is closely related to forecasting the number of passengers and is part of the comprehensive analysis of railway systems. Most of the research presented in the literature focuses only on selected areas of this system (e.g. urban agglomerations, urban underground transport, transfer nodes), without presenting a comprehensive evaluation that would provide full knowledge and diagnostics of this mode of transport (i.e. railway transport). Therefore, this article presents methods for modelling passenger flow in rail traffic at a national level (using the example of Poland). Time series models were used to forecast the number of passengers in rail transport. The error, trend, and seasonality (ETS) exponential smoothing model and the model belonging to the ARMA class were used. An adequate model was selected, allowing future values to be forecast. The autoregressive integrated moving average (ARIMA) model follows the tested series better than the ETS model and is characterised by the lowest values of forecast errors in relation to the test set. The forecast based on the ARIMA model is characterised by a better detection of the trends and seasonality of the series. The results of the present study are considered to form the basis for solving potential rail traffic problems, which depend on the volume of passenger traffic, at the central level. The methods presented can also be implemented in other systems with similar characteristics, which affects the usability of the presented solutions.
Źródło:
Transport Problems; 2021, 16, 1; 51--61
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Forecasting municipal waste accumulation rate and personal consumption expenditures using vector autoregressive (VAR) model
Autorzy:
Bień, Jurand
Powiązania:
https://bibliotekanauki.pl/articles/23966648.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
wskaźnik akumulacji odpadów
wydatki konsumpcyjne
prognozowanie
analiza szeregów czasowych
wielowymiarowe szeregi czasowe
model autoregresji wektorowej
waste accumulation rate
consumption expenditures
forecasting
time-series analysis
multivariate time series models
vector autoregression model
Opis:
Accurate forecasting of municipal solid waste (MSW) generation is important for the planning, operation and optimization of municipal waste management system. However, it’s not easy task due to dynamic changes in waste volume, its composition or unpredictable factors. Initially, mainly conventional and descriptive statistical models of waste generation forecasting with demographic and socioeconomic factors were used. Methods based on machine learning or artificial intelligence have been widely used in municipal waste projection for several years. This study investigates the trend of municipal waste accumulation rate and its relation to personal consumption expenditures based on the yearly data achieved from Local Data Bank (LDB) driven by Polish Statistical Office. The effect of personal consumption expenditures on the municipal waste accumulation rate was analysed by using the vector autoregressive model (VAR). The results showed that such method can be successfully used for this purpose with an approximate level of 2.3% Root Mean Square Error (RMSE).
Źródło:
Production Engineering Archives; 2022, 28, 2; 150--156
2353-5156
2353-7779
Pojawia się w:
Production Engineering Archives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Volatility Persistence and Predictability of Squared Returns in GARCH(1,1) Models
Autorzy:
Triacca, Umberto
Powiązania:
https://bibliotekanauki.pl/articles/483247.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
GARCH Models
returns
time series
volatility persistence
Opis:
Volatility persistence is a stylized statistical property of financial time-series data such as exchange rates and stock returns. The purpose of this letter is to investigate the relationship between volatility persistence and predictability of squared returns.
Źródło:
Central European Journal of Economic Modelling and Econometrics; 2009, 1, 3; 285-291
2080-0886
2080-119X
Pojawia się w:
Central European Journal of Economic Modelling and Econometrics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The theorems of Koenig and Birkhoff and their connection with the minimization of the duration time of the measurements of automatic telecommunication channels
Autorzy:
Perz, Szczepan
Zaremba, Leszek
Powiązania:
https://bibliotekanauki.pl/articles/748569.pdf
Data publikacji:
1982
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Channel models (including quantum), Discrete-time control systems, Hypergraphs, Matrix equations and identities, Matrices of integers, Stochastic matrices
Opis:
.
A problem (P) of minimization of the duration time of the measurements of automatic telecommunication channels is considered. P is a discrete optimization problem solved by graph theory methods. It is defined by (i)-(v), where: (i) for each i, 1≤i≤p, and j, 1≤1≤p, there are given k ij channels to be measured between node ”i” and node ”j”; (ii) measurement of one channel lasts one unit; (iii) there are exactly two devices, say A, B, in each node (the case where there is an arbitrary number of devices A, B in each node may be easily reduced to this case); (iv) the channel between node ”i” and node ”j” may be measured only by use of device A being present in node ”i” and device B in node ”j”; (v) in each time both devices A or B may measure only one channel. To solve P, some knowledge of hypergraphs as well as functional analysis (the Krein-Milman theorem) and linear algebra (the Koenig theorem) is necessary. The Koenig theorem is proved in a simple manner similarly as the dual Koenig theorem (which is a new result). As corollaries the Birkhoff theorem about bistochastic matrices and the dual Birkhoff theorem are deduced.
Źródło:
Mathematica Applicanda; 1982, 10, 19
1730-2668
2299-4009
Pojawia się w:
Mathematica Applicanda
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The application of the arima model in forecasting the passenger traffic on the example of border crossings between the subcarpathian province and Ukraine
Autorzy:
Dejniak, D.
Powiązania:
https://bibliotekanauki.pl/articles/94741.pdf
Data publikacji:
2018
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
passenger border traffic
ARIMA models
time series analysis
Opis:
Accession of Poland to the European Union meant that its eastern border became the external frontier of the Community. The next step in the European integration was joining the Schengen Zone by Poland. Polish citizens may freely travel throughout the Schengen Zone and the state was obliged to tighten its eastern border. Under these circumstances conducting research on passenger traffic has become a vital issue, with particular focus on the eastern frontier. In the article an attempt is made at examining the possibility of forecasting passenger traffic on the example of border crossing points between the Subcarpathian Province and Ukraine using the ARIMA models. Confirmation of these possibilities seems to be crucial as the number of people crossing the border is characterized by high variability and sensitivity to the political situation. The study is based on the information provided by the Polish Border Guard. The conducted time series analysis is of a multi-purpose character. It may be used to support decision making processes of investment, organizational, as well as socio-political nature.
Źródło:
Information Systems in Management; 2018, 7, 3; 155-170
2084-5537
2544-1728
Pojawia się w:
Information Systems in Management
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extreme value distributions in the analysis of traffic time on the Świnoujście–Szczecin fairway
Autorzy:
Kasyk, L.
Powiązania:
https://bibliotekanauki.pl/articles/135336.pdf
Data publikacji:
2016
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
traffic time
fairway
generalized extreme value distributions
Frechet distribution
crossing time
simulated models
Opis:
The present article addresses the issue of crossing time on the fairway, modeling in restricted areas, where vessel traffic flow is disturbed. Data of movement time on the Świnoujście–Szczecin fairway was grouped according to ship type. The probability distributions describing the crossing time of different ship groups were analyzed. Using the Pearson chi-square goodness-of-fit and Cramer–von Mises tests it has been shown that the best distributions describing traffic time of all ship groups are the generalized extreme value distributions.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2016, 47 (119); 80-84
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Aspects of Using Markov Models in Research of Exchange Rate Volatility
Teoretyczne aspekty wykorzystania modeli Markowa do badania zmienności kursu walutowego
Autorzy:
Włodarczyk, Aneta
Szmigiel, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/904704.pdf
Data publikacji:
2005
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
Markov models
time series
exchange rate volatility
calendar anomalies
Opis:
During modeling of short-run exchange rate fluctuations, there is usually a need for taking into consideration some random-type conditions, i.e. it is necessary to abandon the fundamental exchange rate theories in favor of probabilistic modeling. Among stochastic models, of special interest are Markov models. The main advantages of Markov models include a relative simplicity of construction, easy inferences, well-known estimation methods and especially consistence of properties of these models with the observed properties of many real phenomena. Application of switching models is based on a general assumption that the examined time series can be presented as sequences of random variables of a known type of conditional distribution in all regimes. Known from literature propositions concerning the modeling of exchange rate with the use of switching models did not provide sufficiently good forecasts of the future exchange rate levels because of, among others, low frequency of data used for the construction of the model (quarterly or monthly data). The authors are going to continue the examination of the PLN exchange rate fluctuation with the use of Markov models that was started in this paper. The next stage of their work will be connected with conducting empirical research concerning the occurrence of calendar anomalies in the Polish currency market. For this purpose, a new method based on the Markov chains theory will be applied, which offers a new perspective to this problem. Testing o f the calendar time hypothesis has been considered so far mostly in the aspect of comparison of daily expected values and variances of exchange rate return rates. Then, on the basis of the da ta concerning exchange rates for high measurement frequency, a Ma rkov switching model will be constructed and used for description of the PLN depreciation and appreciation period.
Prawidłowe oszacowanie kierunku zmian kursu wymiany może zmniejszyć ryzyko inwestycji w walutę lub może pozwolić na osiągnięcie większych dochodów z tej inwestycji. W opracowaniu tym autorzy przedstawiają propozycję zastosowania modeli Markowa do wykrycia i opisania prawidłowości rządzących procesem zmienności kursu walutowego. W pierwszej części została wykorzystana teoria łańcuchów Markowa do badania anomalii kalendarzowych występujących n a rynku walutowym związanych z efektem weekendowym lub efektem stycznia. W artykule przedstawiona została również metoda o parta na teorii łańcuchów Markowa, k tó ra może posłużyć d o zbadania wzajemnych powiązań pomiędzy zmiennością wolumenu obrotu oraz zmiennością cen dla terminowych kontraktów walutowych. W drugiej części zostaną przedstawione zagadnienia związane z budową i estymacją parametrów przełącznikowych modeli Markowa. W oparciu o modele przełącznikowe można prognozować zmiany kursu walutowego. Praca ma charakter teoretyczny. Badania empiryczne zostaną przeprowadzone w późniejszym terminie.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2005, 194
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł

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