Ograniczanie wyników
Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 1467

Liczba wyników na stronie
first rewind previous Strona / 74 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  modeling
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 74 next fast forward last
EN
Seakeeping capabilities represent a crucial aspect of marine hydrodynamics research. Calculating the movements, amplitudes, and accelerations of the ships offers valuable support for assessing and forecasting their safety and security parameters while the ships are in use. While experimental data on ship movements in consistent wave patterns are considered reliable, they also come with high impacting costs. This research is particularly designed to estimate the seakeeping performance by assessing the hydrodynamic response of a 192-meter-long container ship vessel in both regular and irregular waves. The present computational study is focused on predicting the six degrees of freedom responses for a ship at zero speed for different heading angles. Using the panel method within Maxsurf Motions software, RAOs for all degrees of freedom are obtained. In irregular sea simulations, the ITTC spectrum is employed.
EN
In railway signaling, operational scenarios are integral to the system modeling process, serving to outline expected use cases and define the behavior of the system, subsystems, and actors within the railway environment. Operational scenarios are a primary source of requirements for developing the train control system and its subsystems. Additionally, the design of operational scenarios can offer invaluable insights for arranging trackside assets and may influence the creation of instructions and operational procedures for railway staff. This article highlights the advantages of defining operational scenarios in the early stages of implementing train control systems based on the European Train Control System application level 2 for high-speed lines. The process of defining and modeling operational scenarios is illustrated by analyzing a selected, representative scenario.
EN
A three-dimensional modeling approach is proposed to examine the dynamic interaction response of two foundations subjected to obliquely incident harmonic seismic waves (P, shear vertical, and shear horizontal waves). The two foundations are positioned on the surface of a uniform viscoelastic soil layer, underlain by a substratum. The dynamic response of the rigid foundations is determined by solving the wave equations, taking the soil–foundation interaction into account. The mathematical method employed is based on integral equations in the frequency domain, utilizing Green's function formalism presented by Kausel and Peek in 1982 for a multi layered soil. The solution is obtained using the frequency domain boundary element method, with Green's functions derived through the thin layer method. By discretizing the soil–foundation interface into quadrilateral constant elements, these equations are transformed into algebraic form, simplifying the force–displacement relationship within the discretized domain into a system of linear equations. This approach was applied to assess the impact of soil–structure interaction on the seismic response of two foundations, using the interaction coefficients proposed by Dobry and Gazetas in 1988. The results are presented in terms of displacement, rotation, and torsion at the center of the two massless surface foundations.
PL
Projektowanie i modelowanie sieci wodociągowych to skomplikowany proces wymagający uwzględnienia aspektów technicznych, ekonomicznych i środowiskowych. Współczesne technologie informatyczne i narzędzia symulacyjne znacząco usprawniły ten proces. Modelowanie sieci wodociągowych obejmuje projektowanie nowych odcinków, diagnostykę istniejących systemów, analizę sytuacji kryzysowych, kontrolę wydajności oraz optymalizację zarządzania. Niniejsza praca omawia nowoczesne technologie wspomagające projektowanie sieci oraz analizuje wybór oprogramowania do modelowania na podstawie analizy wielokryterialnej. Badanie to pozwala na lepsze dopasowanie narzędzi do specyficznych potrzeb branży wodociągowej.
EN
The design and modeling of water supply networks is a complex process that requires consideration of technical, economic, and environmental aspects. Modern information technologies and simulation tools have significantly improved this process. Water network modeling includes designing new sections, diagnosing existing systems, analyzing crisis situations performance control, and management optimization This study discusses modern technologies that support network design and analyzes the selection of modeling software based on multi-criteria analysis This research enables better adaptation of tools to the specific needs of the water supply industry.
PL
Przedstawiono wyniki badań dotyczące zastosowania mezoporowatego sita molekularnego MCM-41 jako adsorbentu dla leku o działaniu miejscowo znieczulającym. Przeprowadzono modelowanie procesu adsorpcji z zastosowaniem wielu modeli matematycznych (m. in. Freundlicha, Langmuira, Dubinina i Astachowa oraz Sipsa). Wartości parametrów równań oszacowano metodą dopasowania nieliniowego. Spośród modeli trójparametrowych izoterma Sipsa najlepiej opisywała proces adsorpcji lidokainy na krzemionce MCM-41, zaś spośród dwuparametrowych była to izoterma Freundlicha. Wykazano (model Dubinina i Astachowa) fizyczny charakter interakcji lidokainy z powierzchnią krzemionki MCM-41.
EN
Exptl. data of lidocaine adsorption on mesoporous silica MCM-41 were modeled using several adsorption models, including Freundlich, Langmuir, Jovanovich, Dubinin-Astakhov, Redlich-Peterson, and Sips. The parameters of math. models were assessed using non-linear fitting anal. Among the three-parameter models, the Sips isotherm best described the process of lidocaine adsorption on MCM-41 silica, while among two-parameter models, it was the Freundlich isotherm. The lidocaine-mesoporous silica interactions were shown to have the phys. nature (Dubinin-Astakhov model).
PL
W artykule przedstawiono zasady tworzenia modeli trójfazowych odbiorników nieliniowych w języku Modelica oraz biblioteki pozwalające na modelowanie elementów systemu energetycznego. Zaproponowano sposób modelowania współpracy trójfazowego odbiornika nieliniowego z systemem energetycznym. Zaprezentowano wyniki badań symulacyjnych pozwalających na analizę wpływu pieca łukowego na system energetyczny dla różnych faz wytopu.
EN
The article presents the principles of creating models of three-phase nonlinear loads in the Modelica language and libraries that allow modeling of power system components. A method of modeling the interaction of a three-phase nonlinear load with a power system is proposed. The results of simulation studies allowing analysis of the impact of the arc furnace on the power system for different phases of melting are presented.
EN
This paper reports on development tests of the maximum load characteristics of medium voltage (MV) fuse links. The ABB motor fuse type CMF (Circuit Motor Fuse) rated at 12kV/200A was dismounted for testing of its link temperature while heating up with a rated current of 200 A. The tests were conducted for a link dismounted from a fuse and for the link mounted in a porcelain casing. The fuse casing containing the link had two options: filled with sand or left empty. While heating up, the temperature was measured on the fuse link in all cases. The tests were aimed at analyzing the impact of the environment on heat transfer from the fuse link to the environment. The tests were motivated by the adverse correlation between the overheating of the fuse links and the process of the fuse aging, which is a primary cause of their failures. The results reported so far are limited to examining the temperature at the fuse fittings and in the center of the porcelain casing. The research reported in this paper contributes to a better understanding of the behavior of the fuse links depending on the surrounding environment to which the heat is dissipated from the fuse links. A Finite Element Method (FEM) model was developed and qualitatively validated against the testing results. The model is suitable for allowing qualitative assessment of the fuse heating in an environment with limited heat exchange.
PL
W artykule przedstawiono badania rozwojowe charakterystyk maksymalnego obciążenia wkładek bezpiecznikowych średniego napięcia (SN). Bezpiecznik silnikowy ABB typu CMF (Circuit Motor Fuse) o napięciu 12kV/200A został zdemontowany w celu sprawdzenia temperatury jego topika podczas nagrzewania prądem znamionowym 200 A. Badania przeprowadzono dla topika zdemontowanego z bezpiecznika oraz dla osadzonego w porcelanowej obudowie. Badania wykonano dla dwóch układów: bezpiecznik wypełniony piaskiem lub pusty. Podczas nagrzewania we wszystkich przypadkach mierzono temperaturę na wkładce bezpiecznikowej jak i topiku. Badania miały na celu analizę wpływu otoczenia na przenikanie ciepła z wkładki topikowej do otoczenia. Motywacją do przeprowadzenia badań była negatywna korelacja pomiędzy przegrzaniem wkładek bezpiecznikowych a procesem starzenia się bezpieczników, który jest pierwotną przyczyną ich awarii. Dotychczasowe wyniki ograniczają się do badania temperatury na obudowach bezpieczników i w środku porcelanowej obudowy. Badania przedstawione w tym artykule przyczyniają się do lepszego zrozumienia zachowania wkładek topikowych w zależności od otaczającego środowiska, do którego odprowadzane jest ciepło z wkładek topikowych. Opracowano model metody elementów skończonych (MES), który poddano walidacji jakościowej w oparciu o wyniki testów. Model umożliwia jakościową ocenę nagrzewania się bezpiecznika w środowisku o ograniczonej wymianie ciepła.
EN
The article analyses the cargo handling process at Warsaw Chopin Airport, focusing on assessing the existing infrastructure, the means of transport used, and technical solutions. The possibility of automating logistics processes by implementing autonomous AGV (Automated Guided Vehicles) robots is presented. Computer simulations in the FlexSim program are used to analyze three alternative automation concepts, considering the technical parameters of AGV robots and transport devices. The Belinger comparative method is used to assess the effectiveness of new solutions compared to traditional cargo handling methods. The article aims to assess the feasibility of implementing autonomous AGV robots at Warsaw Chopin Airport, indicating the benefits, challenges, and impact on the efficiency and quality of cargo handling concerning the criterion of cargo handling time.
PL
W artykule przeanalizowano proces obsługi ładunków cargo na Lotnisku Chopina w Warszawie koncentrując się na ocenie stanu istniejącej infrastruktury wykorzystywanych środków transportowych oraz rozwiązań technicznych. Przedstawiono możliwość automatyzacji procesów logistycznych poprzez wdrożenie autonomicznych robotów AGV (Automated Guided Vehicles). Zastosowano symulacje komputerowe w programie FlexSim do analizy trzech alternatywnych koncepcji automatyzacji uwzględniając parametry techniczne robotów AGV oraz zaproponowanych urządzeń transportowych. Metoda porównawcza Belingera została zastosowana do oceny efektywności nowych rozwiązań względem tradycyjnych metod obsługi cargo. Artykuł ma na celu ocenę zasadności wdrożenia autonomicznych robotów AGV na Lotnisku Chopina w Warszawie, wskazując na korzyści, wyzwania oraz ich wpływ na efektywność i jakość obsługi ładunków w odniesieniu do kryterium czasu obsługi ładunków cargo.
EN
Soil analysis plays a crucial role in precision agriculture, where alternatives or complementary methods to traditional laboratory analysis are needed to reduce costs and processing times. This study evaluated models from different devices for estimating soil organic carbon (SOC) using visible near-infrared (Vis-NIR) spectral data and examined the predictive performance of these models across diverse soil types and land uses. A total of 266 soil samples were collected at various depths from two dehesa farms. Soil reflectance spectra were measured using a LabSpec 5000 spectrophotometer with a contact probe and a Muglight accessory. SOC concentration was determined using the Walkley & Black method. Model prediction accuracy was assessed through metrics including the coefficient of determination (R2), residual predictive deviation (RPD), root mean squared error (RMSE), and range error ratio (RER). Cross-validation demonstrated strong predictive accuracy for SOC, with R2 and RPD values exceeding 0.95 and 4.54, respectively, and RER values surpassing 20. Although external validation metrics were more conservative, they still showed excellent RPD indices above 3.12, with no significant difference between devices. Both the Muglight and contact probe yielded low RMSE values (0.222 vs. 0.244) and high R2 values (0.90 vs. 0.89). These findings indicate that both devices can reliably predict SOC, with the contact probe offering the added advantage of faster spectrum recording compared to the Muglight.
PL
BIM (ang. Building Information Modeling) to proces umożliwiający tworzenie cyfrowego bliźniaka obiektu budowlanego. Proces ten polega na ekstrakcji danych i informacji w cyfrowym modelu 3D, który ma na celu najdokładniej odwzorować rzeczywistość. Zwykle na etapie projektowania model BIM jest wykorzystywany do przeprowadzania różnorodnych analiz, symulacji budowy, a dla już istniejących budynków zaplanowania remontów czy bieżącej konserwacji. Ogólna koncepcja BIM zakłada, że wirtualny model towarzyszy fizycznemu obiektowi budowlanemu przez cały cykl jego życia i na ile to możliwe, powinien wiernie odwzorowywać rzeczywisty stan obiektu. Z tej perspektywy zaprezentowano wybrane dobre praktyki w modelowaniu i zarządzaniu obiektem budowlanym. W badaniach wykorzystano modele i standardy pochodzące od kilku przedsiębiorstw, pracujących na różnym stopniu dojrzałości BIM.
EN
BIM (Building Information Modeling) is the process by which the idea of a digital twin of an existing or planned building can be approached. The process involves the extraction of data and information in a 3D digital model that aims to reflect reality as closely as possible. Typically, at the design stage, the BIM model is used to perform various analyses, simulate construction, and for existing buildings to plan renovations or ongoing maintenance. The general concept of BIM is that a virtual model accompanies a building object throughout its life cycle and, as far as possible, should faithfully represent the actual state of the object. From this perspective, the paper presents selected best practices in the modeling and management of a building facility. The research uses models and standards from selected companies working at different levels of BIM maturity.
EN
Data analysis and model building are important elements of enterprise management, especially in mining, where the risk of conducting business is high. The article presents the procedure of building an econometric model that presents the realized level of net coal extraction. The procedure of model construction was carried out using one of the data selection methods, namely the graph method. Although the process of selecting variables for the model is correct, it is not sufficient for the correctness of the model itself. The example given shows what problems may arise and answers the question of whether modeling alone is a sufficient process to describe the analyzed phenomenon.
PL
Analiza danych i budowanie modeli są ważnym elementem zarządzania przedsiębiorstwem, szczególnie wydobywczym, gdzie ryzyko prowadzenia działalności jest duże. W artykule przeprowadzono procedurę budowy modelu ekonometrycznego przedstawiającego zrealizowany poziom wydobycia węgla netto. Przeprowadzono procedurę konstrukcji modelu z wykorzystaniem jednej z metod selekcji danych, a mianowicie metody grafowej. Pomimo, że proces doboru zmiennych do modelu jest prawidłowy, to jednak niewystarczający dla poprawności samego modelu. Przytoczony przykład pokazuje jakie problemy mogą się pojawić oraz odpowiada na pytanie czy samo modelowanie jest wystarczającym procesem do opisu analizowanego zjawiska.
EN
The article is devoted to modern software systems (SS) and improving their quality using machine learning methods, including the Integrated Gradients (IG) method. Key problems and limitation of IG use in real operating conditions of the SS, such as complexity of systems, correlation of variables and computing efficiency are considered. Ways to improve IG, including adaptive integration, spatial smoothing and use of weight factors, are proposed. Experimental results are described that confirm the effectiveness of the proposed modifications to improve the quality of the SS. Adaptive integration has achieved the best results (MAE 0.11), adaptability and interpretation.
PL
Artykuł poświęcony jest nowoczesnym systemom oprogramowania (SO) i poprawie ich jakości z wykorzystaniem metod uczenia maszynowego, w tym metody Zintegrowanych Gradientów (ZG). Rozważono kluczowe problemy i ograniczenia stosowania ZG w rzeczywistych warunkach działania SO, takie jak złożoność systemów, korelacja zmiennych i wydajność obliczeniowa. Zaproponowano sposoby ulepszenia ZG, w tym integrację adaptacyjną, wygładzanie przestrzenne i wykorzystanie współczynników wagowych. Opisano wyniki eksperymentalne, które potwierdzają skuteczność proponowanych modyfikacji w celu poprawy jakości SO. Integracja adaptacyjna osiągnęła najlepsze wyniki (MAE 0,11), zdolność adaptacji i interpretacji.
EN
To solve the constraints that are commonly faced in risk assessment, research on the modeling of the dispersion and distribution of pollutants in the environment are emerging, and software is being developed. This paper presents a tool that is based on the Eulerian approach coupled with Weibull’s law and the wind rose approach (called DRIMERA). This physically detailed modeling-based software can accurately predict pesticide drift under different weather conditions and calculate aerially applied pesticide concentrations in the environment at a threshold of p = 0.05; the values of the coefficient of determination r² vary between 0.6331 and 0.9876. This support thus helps facilitate the wider use and adaptation of atmospheric models.
PL
Artykuł przedstawia 65 wybranych referatów spośród zaprezentowanych podczas paryskiej Sesji CIGRE 2024 w ramach Komitetu Studiów D1 „Materiały i nowoczesne techniki badawcze”. Tematyka referatów obejmowała trzy obszary wiodące: 1. Badania i diagnostyka urządzeń elektroenergetycznych; 2. Materiały do zastosowań elektrotechnicznych i modelowania; 3. Materiały wspierające transformację energetyczną. Komitet Studiów D1 koordynuje międzynarodową współpracę w obszarze materiałów i technik diagnostycznych urządzeń elektroenergetyki, przyczyniając się do rozwoju nowych technologii i produktów oraz stwarzając warunki dla opracowywania zaleceń związanych z projektowaniem, produkcją i eksploatacją tych urządzeń.
EN
The article provides an overview of selected papers from among 65 works presented during the Paris CIGRE 2024 Session under Study Committee D1: Materials and Emerging Test Techniques. The topics of the papers focused on three leading areas: 1. Testing, monitoring and diagnostics; 2. Materials for electrotechnical purposes and modelling; 3. Materials to enable the energy transition. Study Committee D1 promotes international collaboration in the field of materials and diagnostic techniques for power equipment, contributing to the development of new technologies and products and creating a foundation for formulating recommendations regarding the design, production, and operation of such equipment.
EN
The integration of satellite data in rainfall-runoff simulation is of paramount importance in regions where data are limited and not easily available. The data used in this study, concerning the daily precipitation and daily runoff during the period extending from 2007 to 2015, were measured and recorded in situ. This study aims primarily to optimize the performance of the modeling carried out, using data from various satellite sources in order to complete the missing data, and consequently to predict the liquid flow in the Beni Bahdel watershed, in the northwestern region of Algeria, by applying the long short-term memory (LSTM) learning model. It is important to know that the optimization of rainfall-runoff modeling is based on the use of satellite data relating to evapotranspiration, mean temperatures, minimum and maximum temperatures, net radiation, wind speed, and relative humidity. These data come from the NOAA CPC, ERA, ERA5_AG, ERA5-Land, GLDAS, CFSR and MERRA2 satellites. In addition, two statistical indicators were calculated to perform this optimization that is based on the LSTM approach that integrates remote sensing data, the coefficient of determination (R2), and the Nash-Sutcliffe efficiency (NSE). Thus, a performance difference of about 0.30 was observed, for the NSE and R2 coefficients, between the CFSR temperature data (NSE of 0.61and R2 of 0.61) and the maximum and minimum temperature data from the ERA5-LAND and ERA5 satellite sources (0.92 for NSE and 0.93 for R²), for the validation period. This significant difference suggests that the use of the minimum and maximum temperature data from the ERA5-LAND source allows achieving a rainfall-runoff modeling wih optimal performance. Indeed, the findings showed that quite high performances were achieved for the calibration period (0.93 for NSE and 0.95 for R2) and for the validation period (0.92 for NSE and 0.93 for R2).
EN
This paper studies the use of the Laplace transform as a key tool for solving fractional differential equations which involve non-integer derivatives and are used to model various physical phenomena such as viscoelastic materials and control systems Fractional differential equations pose significant challenges due to the complexity of fractional derivatives and integral terms making classical solution methods inefficient The methodology in the paper relies on the Laplace transform to convert fractional equations shifting to a frequency domain to the temporal domain simplifying the handling of these complex equations This approach enables precise and efficient solutions and transforms complex equations into more manageable forms The study also explores practical applications such as solving equations related to viscoelastic materials which exhibit dynamic behavior governed by fractional equations This contributes to a deeper understanding of these materials and their mathematical modeling The paper concludes that the Laplace transform offers a robust framework for solving a wide range of fractional differential equations more efficiently with significant benefits in mathematical modeling and analysis Additionally the study highlights the importance of integrating digital methods with the Laplace transform for solving complex boundary problems thereby enhancing practical applications in fields like applied mathematics and engineering.
EN
Forecasting relative humidity is a critical for addressing the challenges of climate change. It facilitates comprehension of climatic mechanisms and the anticipation of extreme weather events, while also contributing to strengthening societal resilience and protection. Indeed, elevated levels of humidity have been demonstrated to exacerbate heat waves, leading to a marked increase in both the perceived temperature and the associated health risks. Conversely, low humidity promotes conditions conducive to droughts and wildfires. Moreover, relative humidity plays a key role in the water cycle, influencing precipitation, evaporation, and cloud formation. Understanding these mechanisms is essential for anticipating floods, droughts, and water shortages. In this study, mathematical models were developed to predict relative humidity in the Fez, Morocco, using multilayer perceptron (MLP) neural networks, radial basis function (RBF) neural networks, and multiple linear regression (MLR). The dataset used in this study includes daily values of eight meteorological parameters, including temperature at 2m, shortwave Radiation, diffuse shortwave radiation, precipitation total, evapotranspiration, vapor pressure deficit and wind speed and relative humidity as the output. The data spans 38 years, from January 1985 to December 2022, and includes 13879 observation days.. To evaluate the predictive performance of these models, we analyzed their architectures, learning algorithms, correlation coefficients, and mean squared errors. The results indicate that the MLP model attains the highest predictive accuracy, with a correlation coefficient of 0.9809 and a mean squared error MSE of 0.0099, outperforming the RBF model (correlation of 0.9603) and the MLR model (correlation of 0.9023), the best performing model used a Tansig activation function in the hidden layer, a Purelin function in the output layer and the Levenberg-Marquardt learning algorithm with a MLP configuration [7-15-1]. The findings of this study offer a valuable contribution to the field of water resource management in the region. They demonstrate the efficacy of artificial neural network models in enhancing moisture forecasting, thereby providing a solid foundation for future research in climate modelling.
EN
It has proven to be a difficult task to design and provide an ankle-foot orthosis (AFO) that enables the client to walk securely and comfortably without bearing weight through the lower leg and foot skeletal parts. Although it is widely acknowledged that the patella tendon weightbearing (PTB) ankle-loot orthosis only partially unweights the lower tibia, ankle, and foot, it is nevertheless frequently prescribed for this purpose. In this work, two ankle foot orthoses of the AFO PTB type of Calf-Corset were manufactured using a vacuum molding technique based on two kinds of materials as composite material reinforcement. The first AFO material was based on 8 layers of Perlon, while the second was based on 8 layers of fiberglass. A tensile and a fatigue test had been used to investigate the mechanical properties of the AFOs' material. The findings revealed that the yield strength (Ϭy) is 42.897 MPa, the tensile strength (Ϭult) for Perlon is 42.993 MPa, and the elongation at break is 1.138 mm, whereas fiber glass has a tensile strength (Ϭult), yield strength (Ϭy), and elongation at break of 224 MPa, 170 MPa, and 2.17 mm, respectively. Additionally, the gait cycle and the collected data on distributed pressure are measured using force plates and F-socket devices. The patellar tendon-bearing model was constructed using the SolidWorks software tool. In addition, for the fiber glass and Perlon PTB orthosis models, the total deformation, safety factor of fatigue, and Von-Mises stress were calculated using the FEM (ANSYS). The safety factor of fatigue values for the material PTBO with 8 layers of fiber glass was 2.2895, and for 8 layers of Perlon, it was 0.083515.
EN
Purpose: The aim of this publication is to present the application of workflow modelling and patterns of activities in production company. Design/methodology/approach: Critical analysis of the literature. Analysis of international literature from major databases and Polish literature related to the topic under study. Findings: Workflow modelling involves transforming the actual work process into its schematic representation. The transformation process itself must be based on reliable and structured data, on the basis of which the stages of the work process are recorded at a specific level of detail. And examining employee patterns of activities in workflow systems is a key step in improving the safety and efficiency of work processes. Thanks to continuous monitoring of working conditions, it is possible to quickly respond to threats and eliminate non-compliance. This approach not only reduces occupational risks, but also increases the efficiency of the production process. Originality/value: Most research on workflow modelling is applied to information systems. What is new in this article is that the author discusses workflow modelling in production company. In addition, the workflow system has been expanded to include patterns of activities using Motion Capture.
EN
The article presents model of the Radio–communications Platform supporting Inland Navigation. The model of integrated satellite, analog and digital radio – communications systems has been presented. Individual blocks included in the module architecture has been developed. A communication model which integrates the Galileo system with Inland-AIS for the purpose of obtaining a reliable position in limited waters has been presented. The functional requirements of the Galileo Satellite System for integration with Inland-AIS in restricted areas was characterized. The integration of satellite systems was analysed in order to improve the compatibility of Communication Systems.
first rewind previous Strona / 74 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.