Wyniki wyszukiwania - BazTech

1

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.

2

Simulation based study of ground mobile robots for inspection and control of the bridge assembly process

Rea Pierluigi, Ottaviano Erika, Figuli Lucia

Technologia i Automatyzacja Montażu

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2024

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nr 1

30--36

EN

Nowadays, the inspection of bridges poses a significant challenge for safeguarding critical infrastructures. Recent advancements have seen the integration of robots to replace human personnel in hazardous tasks. These robots, whether operating autonomously or through tele-operation, play a crucial role in monitoring structures and infrastructure, ensuring secure access to areas such as manholes on decks and box girder bridges. Specifically designed for environments deemed dangerous, difficult, or inaccessible to humans, ground mobile robots equipped with appropriate sensors are increasingly deployed for inspection purposes. This paper addresses simulation tests conducted by a hybrid mobile robot. Its compact design and maneuverability enable it to navigate through obstacles, making it suitable for inspecting railway or highway bridge decks as well as confined spaces within box girder bridges. The study includes a survey of existing bridges highlighting key issues to be addressed and presents simulation results for the hybrid rover. Automatic and robotic systems can play an important role for the control during the bridge assembling process increasing the reliability of the structure and improving its operational properties and security.

PL

Obecnie inspekcje mostów stanowią istotne wyzwanie dla ochrony infrastruktury krytycznej. Najnowsze osiągnięcia umożliwiły integrację robotów w celu zastąpienia personelu ludzkiego przy wykonywaniu niebezpiecznych zadań. Roboty te, działające autonomicznie lub w trybie teleoperacji, odgrywają kluczową rolę w monitorowaniu konstrukcji i infrastruktury, zapewniając bezpieczny dostęp do takich obszarów, jak włazy na pokładach i mosty z dźwigarami skrzynkowymi. Zaprojektowane specjalnie dla środowisk uznawanych za niebezpieczne, trudne lub niedostępne dla człowieka, naziemne roboty mobilne wyposażone w odpowiednie czujniki są coraz częściej wykorzystywane do celów inspekcyjnych. W artykule omówiono badania symulacyjne prowadzone przez hybrydowego robota mobilnego. Jego zwarta konstrukcja i zwrotność umożliwiają mu pokonywanie przeszkód, dzięki czemu nadaje się do inspekcji pomostów kolejowych lub autostradowych, a także ograniczonych przestrzeni w mostach z dźwigarami skrzynkowymi. Badanie obejmuje przegląd istniejących mostów, podkreślając kluczowe problemy, którymi należy się zająć, i przedstawia wyniki symulacji dla łazika hybrydowego. Systemy automatyczne i zrobotyzowane mogą odegrać ważną rolę w sterowaniu procesem montażu mostu, zwiększając niezawodność konstrukcji oraz poprawiając jej właściwości eksploatacyjne i bezpieczeństwo.

3

Optimizing the simulation of conveyor systems through digital shadow integration to increase assembly process efficiency

Husár Jozef, Hrehova Stella, Trojanowski Piotr, Brillinger Markus

Technologia i Automatyzacja Montażu

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2024

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nr 1

16--22

EN

In today's highly competitive industrial environment, continuous improvement of efficiency and optimization of processes is crucial. This paper presents an approach to the optimization of conveyor systems that uses the concept of a digital shadow. A digital shadow, as an exact digital replica of a physical conveyor system, enables detailed simulation and analysis of real operational data, providing a basis for in-depth analysis and identification of areas for improvement. The aim of this approach is not only to improve the understanding of the dynamics and performance of existing conveyor systems, but also to increase the overall efficiency through predictive simulations and optimization algorithms. In this work, we demonstrate how the integration of a digital shadow into the simulation process can contribute to a better reaction to changes in the production environment, to the reduction of downtime and to the optimization of production flows. Our methodology combines data collection / analysis, and enables the creation of accurate and flexible models of conveyor systems. These models are then used in simulations that help identify optimal settings for different production scenarios and predict potential problems before they occur. The results of applying our approach on a test laboratory line show a significant improvement in efficiency and a reduction in operating costs. This study provides important insights and practical guidelines for engineers and production managers focused on the use of digital shadow to increase the efficiency of conveyor systems. It also contributes to the development of intelligent production technologies in the era of Industry 4.0.

PL

W dzisiejszym wysoce konkurencyjnym środowisku przemysłowym kluczowe znaczenie ma ciągła poprawa wydajności i optymalizacja procesów. W artykule przedstawiono podejście do optymalizacji systemów przenośnikowych wykorzystujące koncepcję cyfrowego cienia. Cyfrowy cień, jako dokładna cyfrowa replika fizycznego systemu przenośników, umożliwia szczegółową symulację i analizę rzeczywistych danych eksploatacyjnych, dając podstawę do dogłębnej analizy i identyfikacji obszarów wymagających poprawy. Celem tego podejścia jest nie tylko lepsze zrozumienie dynamiki i wydajności istniejących systemów przenośników, ale także zwiększenie ogólnej wydajności poprzez symulacje predykcyjne i algorytmy optymalizacyjne. W tej pracy pokazujemy, jak włączenie cienia cyfrowego do procesu symulacji może przyczynić się do lepszej reakcji na zmiany w środowisku produkcyjnym, ograniczenia przestojów i optymalizacji przepływów produkcyjnych. Nasza metodologia łączy zbieranie/analizę danych oraz umożliwia tworzenie dokładnych i elastycznych modeli systemów przenośnikowych. Modele te są następnie wykorzystywane w symulacjach, które pomagają zidentyfikować optymalne ustawienia dla różnych scenariuszy produkcji i przewidzieć potencjalne problemy, zanim one wystąpią. Wyniki zastosowania naszego podejścia na linii laboratorium badawczego wskazują na znaczną poprawę wydajności i redukcję kosztów operacyjnych. Niniejsze badanie dostarcza ważnych spostrzeżeń i praktycznych wskazówek dla inżynierów i kierowników produkcji skupiających się na wykorzystaniu cyfrowego cienia w celu zwiększenia wydajności systemów przenośników. Przyczynia się także do rozwoju inteligentnych technologii produkcyjnych w dobie Przemysłu 4.0.

4

Ocena jakości obserwacji skanera laserowego velodyne w oparciu o dane symulowane

Pałęcki Adam, Jóżków Grzegorz

Przegląd Geodezyjny

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2024

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R. 96, nr 6

1--3

PL

Tanie skanery z wieloma wiązkami laserowymi takie jak Velodyne, Ouster, Hesai często wykorzystywane są do budowy niedrogich systemów skaningu kinematycznego, w tym systemów plecakowych i bezzałogowych. Niski koszt skutkuje mniejszą jakością pozyskiwanych danych, a parametry dokładnościowe podawane przez producentów często odbiegają od rzeczywistych. Z tego powodu problem oceny dokładności danych pozyskanych za pomocą takich skanerów jest ciągle podnoszony przez naukowców. Metody przez nich stosowane mają na celu ocenę dokładności położenia punktów skaningu i opierają się głownie na punktach i powierzchniach referencyjnych. Należy jednak zaznaczyć, że na dokładność położenia tych punktów wpływ mają różne czynniki, w tym te wynikające z błędów instrumentalnych, wynikające z charakteru mierzonego obiektu, a także danych z innych sensorów (np. dane o trajektorii stosowane w skaningu mobilnym). W tym artykule proponujemy metodę, która pozwala na ocenę jakości obserwacji (odległości i kątów), których błędy wynikają głównie z pierwszego z wymienionych czynników, czyli instrumentu. Metoda ta bazuje na porównaniu obserwacji rzeczywistych z teoretycznymi powstającymi poprzez symulację. Do symulacji rzeczywistych obserwacji stosowany jest wirtualny skaner Velodyne, który umieszczany jest w takiej samej pozycji i orientacji jak rzeczywisty. Obserwacje teoretyczne dla skanera wirtualnego tworzone są w oparciu o znany mechanizm działania skanera oraz dokładną i bardzo gęstą chmurę punktów naziemnego skaningu laserowego. Wykonane dla skanera Velodyne HDL-32E eksperymenty wykazały, że dokładność pomiaru odległości jest porównywalna z podawaną przez producenta, jednak inna dla różnych diod laserowych, a dokładność pomiaru kąta poziomego wynosi około 0,04°. Ponadto wykazano, że częstotliwość wirownia skanera, od której zależy wartość kąta poziomego jest różna od wartości nominalnej i nie jest stała w trakcie całego obrotu. Opracowana metoda symulacji obserwacji może być w przyszłości wykorzystana do kalibracji podobnych skanerów tego typu.

EN

Inexpensive scanners with multiple laser beams such as Velodyne, Ouster, Hesai are often used to build low-cost kinematic scanning systems, including backpack and unmanned systems. Low costs result in lower quality of the acquired data. In addition, the accuracy parameters provided by manufacturers are often different from the actual ones. For this reason, the problem of assessing the accuracy of data obtained using such scanners is investigated by scientists. The methods used for this purpose aim at assessing the accuracy of the position of scanning points and use mainly reference points and surfaces. However, that the accuracy of the location of these points is influenced by various factors, including those resulting from instrumental errors, from the nature of the measured object, as well as data from other sensors (e.g. trajectory data used in mobile scanning). In this article, we propose a method that allows for the assessment of the quality of observations (distances and angles) which errors result mainly from the first of the mentioned factors, i.e. the instrument. Proposed method bases on the comparison of real observations with theoretical ones created through simulation. To simulate real observations, a virtual Velodyne scanner is used, which is placed in the same position and orientation as the real one. Theoretical observations for the virtual scanner are created based on the known mechanism of scanner operation and an accurate and very dense terrestrial laser scanning point cloud. Experiments executed for the Velodyne HDL-32E scanner proved that the accuracy of distance measurement is comparable to that provided by the manufacturer, but different for different laser diodes, while the accuracy of horizontal angle measurement is equal to about 0.04°. Moreover, it was shown that the scanner's rotation frequency, which determines the value of the horizontal angle, is different from the nominal value and is not constant during the entire rotation. The developed observation simulation method can be used in the future to calibrate similar scanners of this type.

5

The reloading of a ship in a maritime container terminal as a queuing problem of interacting processes

Bartosiewicz Aleksandra, Kucharski Adam

Operations Research and Decisions

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2024

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Vol. 34, No. 1

17--33

EN

In this work, we propose a multi-server queuing system for modeling the processes that occur in a maritime container terminal. In our study, the main operations that take place at the quay and in the yard are first disaggregated into several elementary activities. Then we propose the step-by-step calculation of the times of each operation that influences both the unloading and the loading of a container. Next, we analyze the vessel cycle time while separately investigating the STS (ship to shore) crane cycle time, the RTG (rubber tyred gantry) cycle time, as well as the IMV (internal movement vehicle) transfer time. Finally, we apply two process-driven simulation experiments to the system analysis. The paper demonstrates the proposed model’s effectiveness with data from the BCT Gdynia container terminal. We show that, among others, even with properly planned work of STS cranes and RTGs, there is still a high probability that the quay will become a bottleneck of the described processes.

6

Optimising the management of arriving baggage at a Kuwait Airways passenger terminal using mathematical programming and simulation

Abdullah Ahmad A., Al-Sultan Ahmad T., Alsaber Ahmad

Operations Research and Decisions

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2024

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Vol. 34, No. 1

1--16

EN

Handling luggage systems is a critical component of a passenger terminal’s operations. The proposed study attempts to find the optimal solution for a manually operated terminal concerning the luggage offloading process from arrival flights carried by a limited number of ground handling agents. Handling agents start the offloading process from the aircraft to the cargo luggage containers carried by a cargo car that will take the containers’ trolleys to the cargo area to offload them into the reserved luggage belt carousel. This study aims to improve airport service quality by minimizing the baggage handling process time for arrival flights which leads to minimizing passenger waiting time in the baggage claim area. We proposed both a deterministic and stochastic approach. The integer programming method is provided to minimize the total number of flights assigned to the belt carousel under the realistic constraint of minimizing the luggage load on each belt carousel. Simulation tools were used so that the offloading process could be modeled to study the effects of various parameters such as the number of ground handling agents for different flights with different amounts of luggage.

7

Control of chaos in the burke-shaw system of fractal-fractional order in the sense of Caputo-Fabrizio

Saber Sayed

Journal of Applied Mathematics and Computational Mechanics

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2024

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Vol. 23, nr 1

83-96

EN

For the Burke-Shaw system, we propose a fractal-fractional order in the sense of the Caputo-Fabrizio derivative. The proposed system is solved by utilizing the fractal-fractional derivative operator with an exponential decay kernel. Time-fractional Caputo-Fabrizio fractal fractional derivatives are applied to the Burke-Shaw-type nonlinear chaotic systems.Based on fixed point theory, it has been demonstrated that a fractal-fractional-order model under the Caputo-Fabrizio operator exists and is unique. Using a numerical power series method, we solve the fractional Burke-Shaw model. Using Newton’s interpolation polynomial, we solve the equation numerically by implementing a novel numerical scheme based on an efficient polynomial.

8

Validation research of pressure decay test method for internal leakage detection of hydraulic cylinder

Li Weijie, Qian Xinbo, Chen Xinyuan, Li Feihong, Lu Yan

Eksploatacja i Niezawodność

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2024

|

Vol. 26, no. 2

art. no. 184039

EN

Leakage test is one of the acceptance tests to ensure hydraulic cylinder reliability. Under the consideration of economic and technical maturity conditions, the existing internal leakage detection methods may be difficult to achieve rapid screening. After research, the pressure decay test method is a common method of quickly testing hydraulic cylinders for internal leakage in the manufacturing industry. However, the validity of the pressure decay test method has not been theoretically verified, limiting the versatility of the method. This paper will theoretically validate the effectiveness of the pressure decay test method and provide important theoretical support for its use as a general rapid screening method for internal leakage, thereby improving the reliability and safety of hydraulic systems. Both simulation and experimental results show that there is a linear relationship between the pressure decay rate and the internal leakage rate. Especially for working pressures greater than 16 MPa, the pressure factor has an insignificant impact on the application of this method.

9

The influence of the hydropneumaticaccumulator on the dynamic and noise of the hydrostatic drive operation

Stosiak Michał, Karpenko Mykola

Eksploatacja i Niezawodność

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2024

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Vol. 26, no. 2

art. no. 186169

EN

The article presents the possibility of influencing the hydrostatic drive's dynamics and noise using a hydropneumatics accumulator. The possibility of limiting the maximum dynamic load during the start-up period of a drive equipped with an accumulator and controlled by a slide distributor is presented in the article. The influence of the accumulator on the sound pressure level and its relationship with the maximum dynamic values of the working fluid pressure in the hydraulic system is also described. Experimental studies of the dynamics and acoustics of laboratory hydrostatic systems were performed. A dynamic model of a hydrostatic drive equipped with an accumulator was developed, which was used to perform simulation tests illustrating the impact of the accumulator capacity on the system's dynamics. Acoustic tests were carried out for a system with a linear hydrostatic drive simulator.

10

Investigating Vibration Transmission in Cargo Containers During Heavy-Duty Off-Road Transport

Vilau Radu, Voicu Daniela, Stoica Ramona-Monica, Ciobotaru Ticusor, Rykała Magdalena, Rykała Łukasz

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 4

312--328

EN

This article focuses on the investigation and analysis of vibrations transmitted to cargo during off-road transportation, with particular emphasis on the impact of vehicle and road surface interactions. The primary objective of the research is to quantify and characterize the amplitudes of vibrations generated by the interaction between heavy-duty truck tires and rough terrain, and their subsequent transmission to cargo containers. To achieve this, a virtual model of a tactical transportation truck was created using TruckSim software. Two characteristic off-road tracks were simulated, based on driving conditions typically experienced by heavy-duty vehicles in demanding logistical scenarios. The experimental validation of the virtual model was conducted using a heavy-duty truck outfitted with a 20 ft (6096 mm) cargo container. The results of the work include recorded acceleration data, suspension behavior, and the maximum driving speed at which the vehicle remained stable on both tracks. Moreover, the work is a direct response to the needs of the automotive industry and the military.

11

Autonomous Mobile Robots in Automotive Remanufacturing: A Case Study for Intra-Logistics Support

Pizoń Jakub, Wójcik Łukasz, Gola Arkadiusz, Kański Łukasz, Nielsen Izabela Ewa

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 1

213--230

EN

The article focuses on the role of modern logistics 4.0 technologies and lean management in optimizing ancillary processes in intralogistics. The literature review presents critical aspects of intralogistics, including using autonomous mobile robots (AMR) and the challenges associated with their successful implementation. The article also discusses the concepts of Industry 4.0 and Industry 5.0. highlighting the importance of synergies between workers and advanced technologies. In optimizing logistics processes, the authors emphasize the importance of lean management and tools such as 5S and Kaizen. The authors analyze the research gap related to the organization of auxiliary processes, intralogistics, and the introduction of modern technologies. The lack of good practices and strategies for implementing new technologies for ancillary processes makes this a critical issue for managers and production engineers. The article provides practical strategies that can be implemented in companies. It is a valuable resource for managers seeking to manage intralogistics and effectively improve support processes in manufacturing plants. In summary, the article provides a comprehensive look at modern approaches to optimizing support processes in internal logistics. It highlights the importance of integrating modern logistics technologies with lean management principles, which can increase companies' efficiency and competitiveness.

12

Numerical investigations on the dynamic behaviour of a 2-DOF airfoil with application in energy harvesting system

Haniszewski Tomasz, Gąska Damian, Margielewicz Jerzy, Opasiak Tadeusz

Zeszyty Naukowe. Transport / Politechnika Śląska

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2023

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z. 118

77--91

EN

This article presents the basic airfoil model with two degrees of freedom - the semi-rigid model, where its forced vibrations were considered, and the exciting force is the aerodynamic force, including its periodic changes, that is, gusts. Since the phenomenological model under study has a coupled form, its versions after decoupling are presented, which has an impact on the results of the final research. The airfoil model presented in this way was shown from the application side in the system of a simple energy harvester based on a deformable beam with piezoelectric elements. The result of the simulation tests is a preliminary analysis of the possibility of using the airfoil as a vibration generator for the energy harvesting system. Along with the application of the mechanical part, a numerical simulation of the electrical part was also implemented, related to the transformation of the voltage generated by piezoelectric elements into a constant voltage signal with a connected receiver with power consumption similar to the Atmega microcontroller with battery charging.

13

Testing algorithms for quick rescheduling flow shop problems with FlexSim based simulation and R engine

Janke Piotr

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2023

|

z. 168

163--175

EN

Purpose: The aim of this paper is to present a combination of advanced algorithms for finding optimal solutions together with their tests for a permutation flow-shop problem with the possibilities offered by a simulation environment. Four time-constrained algorithms are tested and compared for a specific problem. Design/methodology/approach: Four time-constrained algorithms are tested and compared for a specific problem. The results of the work realisation of the algorithms are transferred to a simulation environment. The entire solution proposed in the work is composed as a parallel environment to the real implementation of the production process. Findings: The genetic algorithm generated the best solution in the same specified short time. By implementing the adopted approach, the correct cooperation of the FlexSim simulation environment with the R language engine was obtained. Research limitations/implications: The genetic algorithm generated the best solution in the same specified short time. By implementing the approach, a correct interaction between the FlexSim simulation environment and the R language engine was achieved. Practical implications: The solution proposed in this paper can be used as an environment to test solutions proposed in production. Simulation methods in the areas of logistics and production have for years attracted the interest of the scientific community and the wider industry. Combining the achievements of science in solving computationally complex problems with increasingly sophisticated algorithms, including artificial intelligence algorithms, with simulation methods that allow a detailed overview of the consequences of changes made seems promising. Originality/value: The original concept of cooperation between the R environment and the FlexSim simulation software for a specific problem was presented.

14

Ochrona odgromowa stacji transformatorowej dla pływającej elektrowni fotowoltaicznej

Sobolewski Konrad

Wiadomości Elektrotechniczne

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2023

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R. 91, nr 11

16--22

PL

Artykuł poświęcono ogólnej charakterystyce ochrony odgromowej pływającej elektrowni fotowoltaicznej wraz ze stacją transformatorową. Przedstawione zostało zagrożenie piorunowe dla poszczególnych struktur obiektu, a następnie dokonano analizy możliwych do zastosowania wariantów ochrony przed działaniem pioruna. Odniesiono się zarówno do: zwodów, przewodów odprowadzających, jak i systemu uziemiającego. Temu ostatniemu, jako elementowi najbardziej różnicującemu sposób wykonania pływającej elektrowni, poświęcono dodatkową analizę modelowo-symulacyjną obejmującą różne sposoby wykonania oraz wpływ zmian środowiskowych na skuteczność jego działania. Całość zamyka podsumowanie oraz wnioski.

EN

This article is devoted to the general characteristics of lightning protection of a floating photovoltaic power plant with a transformer station. The lightning hazard for individual structures of the facility was presented, and then the possible variants of lightning protection were analysed. Reference was made to the air terminals, the discharge wires and the grounding system. The last one was the subject of an additional model and simulation analysis covering various forms of execution and the impact of environmental changes on the effectiveness of its operation as the element that provides the most differentiation of a floating power plant construction method. The paper ends with a summary and conclusions.

15

Analyzing Safe Epidemic Distancing in Public Transport Buses: A Simulation Study on Passenger Flow

Chema Wongelawit, Burdzik Rafał, Celiński Ireneusz, Dębicka Ewa

Transport Samochodowy

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2023

|

z. 2

3--7

EN

During the COVID-19 pandemic, public transport played a crucial role in maintaining essential services while ensuring the safety of both passengers and staff. As the world gradually resumes operations, the impact of the pandemic is expected to persist for some time. Existing studies focus on virus transmission in vehicles, with limited knowledge about post-pandemic passenger flow, safety, and satisfaction. This paper presents a model of passenger movement in public transport, considering factors like boarding times, movement within stops, and the impact of crowding and delays. To reduce transmission at bus stops, we developed a simulation-based passenger flow model using PTV Vissim. The program was used to simulate passenger exchange scenarios, using data collected from real data. The goal was to create a model that minimizes the risk of infection. By understanding passenger flow and interactions with the public transport system, effective measures can be implemented to mitigate the spread of COVID-19 and other infectious diseases.

PL

Podczas pandemii COVID-19 transport publiczny odegrał kluczową rolę w utrzymaniu podstawowych usług, zapewniając jednocześnie bezpieczeństwo zarówno pasażerów, jak i personelu. W miarę jak świat stopniowo wznawia działalność, oczekuje się, że skutki pandemii utrzymają się przez jakiś czas. Istniejące badania koncentrują się na przenoszeniu wirusów w pojazdach, przy ograniczonej wiedzy na temat przepływu pasażerów, bezpieczeństwa i satysfakcji po pandemii. W artykule przedstawiono model poruszania się pasażerów w transporcie publicznym, biorąc pod uwagę takie czynniki, jak czas wejścia do pojazdu, ruch w obrębie przystanków oraz wpływ zatłoczenia i opóźnień. Aby ograniczyć przekazywanie zakażeń na przystankach autobusowych, opracowaliśmy model przepływu pasażerów oparty na symulacji przy użyciu PTV Vissim. W programie przeprowadzono symulację scenariuszy wymiany pasażerów, wykorzystując dane zebrane z danych rzeczywistych. Celem było stworzenie modelu, który minimalizuje ryzyko infekcji. Rozumiejąc przepływ pasażerów i interakcje z systemem transportu publicznego, można wdrożyć skuteczne środki ograniczające rozprzestrzenianie się Covid-19 i innych chorób zakaźnych.

16

Verification of a train on railway track simulation and optimization system

Mańka Adam, Kisielewski Piotr, Konieczny Jarosław, Labisz Krzysztof, Ćwiek Janusz

Transport Problems

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2023

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T. 18, z. 3

137--150

EN

This article presents a Train on Railway Track simulation model and program developed by the authors. The model implements the module for multiple-criteria optimization with a set of proposed objective functions allowing reductions in train passing time, total costs, energy consumption, and adverse environmental impacts. The Train on Railway Track simulator has been developed to allow both the simulation itself and the ride optimization. The main achievement is the development of an algorithm that simulates the passage of a train over 500 km, the duration of which did not exceed two minutes. We present an analysis of the impact of model changes on the duration of the simulation and the accuracy of the results obtained. This allows the use of these achievements in simulations carried out for the railway, automotive, or aviation industries as well. Changes in the classical approach to optimization proposed by the authors made it possible to obtain results directly by solving classical systems of equations. The change in the approach to the optimization and system algorithm has reduced the operating time of the optimization system from thousands of simulations to a single simulation with an additional optimization process that takes several minutes to calculate. This article is a continuation of the description of the work performed, and basic information about the developed simulation model and software functionality is included in a separate publication [13].

17

Changes in the perception of telematics technology by road transport companies: an empirical analysis in 2020-21

Zalewski Wojciech, Osińska Magdalena, Żurek Mirosława

Transport Problems

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2023

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T. 18, z. 1

5--17

EN

We present a novel study concerning the attitudes of road transport enterprises towards a broad application of telematics in operational management in road transportation. The study aims to assess telematics application in road transport and its changes over time while showing the factors most likely to determine the systems’ use. Unobserved categories defined in the technology acceptance model (TAM) are adjusted to measure perceived usefulness, perceived ease of use, and attitudes toward using telematics systems by road transport managers. The study is based on 323 transport enterprises analyzed in two waves in 2020 and 2021. The use of two different time points is motivated by an observed increase in the digitalization of transport documents caused by the COVID-19 pandemic. The empirical findings support the TAM’s usefulness in evaluating IT in transport business management. The findings also reveal that the significantly increased telematics use in 2020 was observed while it was endured. The results are checked for robustness and used for simulations. The study compares managers’ behaviors over time and simulates the effect of individual (observed) variables on unobserved TAM categories.

18

Model of the random phase of signal E6 of the Galileo Satellite Navigation System

Džunda M., Čikovský S., Melniková L.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2023

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Vol. 17 No. 1

61--68

EN

The aim of this paper was to describe the random phase of the E6 signal, the Galileo satellite navigation system. Based on the available information, mathematical models of the measurement signals of the Galileo system were created. The frequencies of individual signals were determined and their structure visualized. A block diagram of the generation of individual signals is also shown. The main contribution of the paper is the creation of a random phase model of the E6 signal from the Galileo system. In accordance with the technical data of the Galileo system, the parameters of the random phase model were determined. The simulation results confirmed that the frequency instability of the continuous signal E6 n received from the satellite is a stationary process. The short-term stability of the frequency ranges from 10-13 to 10-14. The simulation results confirmed that the Doppler effect significantly affects the random phase of the E6 signal. This phenomenon can affect the results of navigation measurements using the E6 signal. The modeling and simulation results of the random phase of the E6 signal presented in the paper can be used to evaluate the immunity of the Galileo navigation system to interference.

19

Thermal Operating Window in Selective Laser Melting Processes

Kozak Jerzy, Zakrzewski Tomasz, Witt Marta, Dębowska-Wąsak Martyna

Transactions on Aerospace Research

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2023

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Nr 4 (273)

18--32

EN

Selective laser melting (SLM) is one of the most effective methods of additive manufacturing (AM). It is used to manufacture products with very complex geometries using a wide range of materials. Practical process conditions are limited by the occurrence of undesirable melting instabilities that degrade the surface quality and lead to product defects. These disadvantages are related to the thermal limitations of the SLM process. The lower thermal limit is due to the need to completely melt the powder layer and partially remelt the underlying layer again to ensure proper bonding between the layers. Exceeding the upper thermal limit in the molten metal pool may cause extensive evaporation, boiling and ejection of molten metal droplets outside the melting area. The article presents an approach and methodology that enable the determination of thermal limits and the operating window of SLM/selective laser sintering (SLS) processes in a relatively simple way. The studies have been performed using various settings of SLM process parameters. The usefulness of the preliminary determination of thermal limitations and approximate prediction of operating window of SLM has been confirmed experimentally and by more accurate computer simulation.

20

Modeling and simulation of the furniture manufacturing and assembly process in the Arena simulation software

Kolny Damian, Kaczmar-Kolny Ewa, Dulina Ľuboslav

Technologia i Automatyzacja Montażu

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2023

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nr 1

13--22

EN

The article describes issues related to creating discrete simulation models for the implementation of the furniture manufacturing and assembly process in a furniture company. The methodology of the manufacturing system analysis was presented, which is aimed to support the appropriate approach to the construction of simulation models. The scope of the work includes the technological identification of the furniture manufacturing and assembly process in real production conditions, on the basis of which the appropriate simulation model was built. The course of the process was analyzed in the Arena software on the basis of a computer simulation based on reports. As a result of the simulation of the manufacturing process with the use of information from report of usage, an area for improvement was located. The re-analysis of the material flow made it possible to propose a change in the input parameters for the simulation model in the indicated area. The results of the second simulation show significant changes in the effective use of workstations and increase in the efficiency of the production line. In practice, it can be the basis for introducing simulated changes in the production system.

PL

W artykule opisano zagadnienia związane z tworzeniem dyskretnych modeli symulacyjnych dla realizacji procesu wytwarzania i montażu mebli w przedsiębiorstwie branży meblarskiej. Przedstawiono metodykę analizy systemu wytwarzania, która ma za zadanie wspierać właściwe podejście dla budowy modeli symulacyjnych. Zakresem praca obejmuje identyfikację technologiczną procesu wytwarzania i montażu mebli w rzeczywistych warunkach produkcyjnych, w oparciu o którą zbudowano właściwy model symulacyjny na przykładzie procesu wytwarzania w rzeczywistych warunkach produkcyjnych. Analizę przebiegu procesu na podstawie symulacji komputerowej w oparciu o raporty przeprowadzono w oprogramowaniu Arena. W wyniku przeprowadzonej symulacji procesu wytwarzania z wykorzystaniem informacji z raportu obciążeń stanowiskowych zlokalizowano obszar do doskonalenia. Powtórna analiza przepływu materiałowego pozwoliła zaproponować zmianę parametrów wejściowych dla modelu symulacyjnego we wskazanym obszarze. Wyniki drugiej symulacji wskazują istotne zmiany w zakresie efektywnego wykorzystania stanowisk pracy oraz zwiększenia wydajności linii produkcyjnej. W praktyce może to stanowić podstawę do wprowadzenia symulowanych zmian w omawianym systemie produkcyjnym.