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Simulation analysis of artificial neural network and XGBoost algorithms in time series forecasting

Sroka Łukasz

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2024

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z. 195

561--575

EN

Purpose: The aim of the article was to prepare a simulation analysis of artificial neural network and XGBoost algorithm with determining which of the method was characterized by a lower level of forecast errors for time series predictions. Design/methodology/approach: The objective of the article was reached by applying, a simulation study on a sample of 1000 artificially generated time series. The analyzed XGBoost algorithm and the artificial neural network ANN model were intended to prepare forecasts for five periods ahead. These forecasts were compared with the actual implementations of the time series and proposed forecast error measures. Findings: It is possible to use simulated time series to check which of the presented algorithms were characterized by a lower forecast error. The study showed that applying of the artificial neural networks ANN to forecast future observations generated a lower level of MAPE, MAE and RMSE errors than in the case of the XGBoost algorithm. It was found that both methods generate a lower level of forecast error for time series characterized by a high level of mean value, standard deviation and variance, and levels of kurtosis and skewness close to 0. Practical implications: The research results can be used by both investors and enterprises to better adjust their business decisions to changing market prices by using a model with a lower forecast bias. Originality/value: The original contribution of this article is a comprehensive comparison of forecasts generated by the XGBoost and ANN algorithm, along with determining for which types of time series of the algorithms forecast future values with less error. Moreover, due to the use of simulated artificial time series, it was possible to test each algorithm for various market conditions.

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Przeciwzapalne napromienianie płuc chorych na COVID-19

Sroka Łukasz, Gądek Adam, Dolla Łukasz, Radwan Michał, Rutkowski Tomasz, Ślosarek Krzysztof

Inżynier i Fizyk Medyczny

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2021

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Vol. 10, nr 2

93--96

PL

W pracy przedstawiono metodę napromieniania płuc pacjentów chorych na COVID-19. Wszelkie badania obrazowe, wymagane do zrealizowania radioterapii, są wykonywane na akceleratorze liniowym. Zastosowany plan leczenia jest planem 2D, natomiast rozkład dawki 3D otrzymuje się w oparciu o badanie tomografii stożkowej CBCT (Cone Beam Computed Tomography) wykonywane po napromienieniu pacjenta. Po tym badaniu pacjent może opuścić szpital. Celem takiego sposobu napromienienia jest skrócenie czasu pobytu pacjenta w placówce oraz ograniczenie jego kontaktu z personelem do niezbędnego minimum. W czasie napromienienia pacjenta mierzona jest mapa fluencji. Cały proces jest wykonywany z zachowaniem wszystkich procedur QA oraz zasad ochrony epidemiologicznej. Całość leczenia jest dokumentowana w postaci elektronicznej, jak i papierowej, generowanej na podstawie planu 3D.

EN

The paper presents a method of lung irradiation in COVID-19 patients. All imaging tests required for radiotherapy are performed on a linear accelerator. The treatment plan used is a 2D plan, while the 3D dose distribution is based on the Cone Beam Computed Tomography (CBCT) scan performed after the patient’s irradiation. After this examination, the patient can leave the hospital. The purpose of this method of irradiation is to shorten the patient’s stay in the facility and to limit his contact with the staff to the necessary minimum. During the irradiation of the patient, the fluency map is measured. The entire process is carried out in compliance with all QA procedures and the principles of epidemiological protection. The entire treatment is documented in electronic and paper form, generated on the basis of a 3D plan.

3

Porównanie weryfikacji dozymetrii portalowej EPID i RadCalc dla planów leczenia prostaty metodą VMAT

Gądek Adam, Plaza Dominika, Sroka Łukasz, Reudelsdorf-Ullmann Marta, Ślosarek Krzysztof

Inżynier i Fizyk Medyczny

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2021

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Vol. 10, nr 6

447--449

PL

Celem badania jest ocena przydatności wybranych metod weryfikacji planów leczenia jako wymagany element procesu zachowania jakości w radioterapii. Wykonano plany leczenia dla dziesięciu pacjentów leczonych techniką VMAT o maksymalnym potencjale przyspieszającym 6 MV. Następnie przeprowadzono weryfikację dozymetryczną na akceleratorze za pomocą portalu EPID i porównano z wynikami obliczeń niezależnego oprogramowania RadCalc. Porównując wyniki weryfikacji otrzymane przez dwie niezależne metody, stwierdzono, iż dla tej lokalizacji leczenia możliwe jest ich zamienne używanie.

EN

The aim of the study is to assess the suitability of selected methods of treatment plan verification as a required element of the quality maintenance process in radiotherapy. Treatment plans were made for ten patients treated with VMAT with a maximum potential accelerator of 6MV. Then, dosimetric verification was carried out on the accelerator using the EPID portal and the results from the calculations of the independent RadCalc software were compared. By comparing the results of the verification obtained by two independent methods, it was found that for this treatment location they could be used interchangeably.