Wyniki wyszukiwania - BazTech

1

Ocena dokładności estymacji charakterystyki odbiciowej matrycy RMA na podstawie modelu Tanga

Hatka Paweł, Lenarska Karolina, Kliks Adrian

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2025

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nr 4

145--148

PL

Jednym z intensywnie rozwijanych obszarów telekomunikacji bezprzewodowej ostatnich lat jest praktyczne zastosowanie rekonfigurowalnych macierzy antenowych (RMA). W pracy przedstawiono wyniki prac eksperymentalnych, których celem była weryfikacja dokładności teoretycznego modelu Tanga opisującego zachowanie sygnału w momencie odbicia od powierzchni RMA. Badania przeprowadzono w laboratorium będącym przykładem typowego pomieszczenia biurowego.

EN

One of the intensively developed areas of wireless telecommunications in recent years is the practical application of reconfigurable intelligent surfaces (RIS). The paper presents the results of experimental work aimed at verifying the accuracy of the theoretical Tang model describing the behavior of the signal at the moment of reflection from the RIS. The research was carried in a laboratory being an example of a typical office space.

2

Optymalizacja bezszczotkowego silnika pądu stałego do napędów pojazdów elektrycznych

Knypiński Łukasz, Kasprzak Kacper, Idziak Paweł

Przegląd Elektrotechniczny

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2025

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R. 101, nr 10

63--68

PL

W artykule przedstawiono algorytm wspomagający proces projektowania bezszczotkowych silników prądu stałego (BLDC) z zewnętrznym wirnikiem. Opracowano uniwersalny model silnika BLDC. W procedurze optymalizacyjnej zastosowano algorytm optymalizacji wielorybów. Opracowano autorskie oprogramowanie składające się z dwóch modułów: procedury optymalizacyjnej oraz modelu projektowanego silnika. Projektowany silnik opisano przy wykorzystaniu pięciu zmiennych decyzyjnych. Rozpatrywano dwa zadania optymalizacyjne. Przedstawiono i omówiono wybrane wyniki obliczeń optymalizacyjnych.

EN

The paper presents optimization algorithm for support designing process of a brushless DC (BLDC) motor with an outer-rotor for an electric bike. The universal model of the BLDC motor was developed. To optimization, the whale optimization algorithm was employed. Two module optimization script combine optimization procedure with model of designed BLDC motor. The designed motor was described by five design variables. Two optimization problems are solved. Selected optimization results was selected and discussed.

3

Ocena istniejących konstrukcji budowlanych według nowej normy Eurokod 1990-2

Halicka Anna

Przegląd Budowlany

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2025

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R. 96, nr 4

44--51

PL

W pracy przedstawiono reguły postępowania przy ocenie istniejących konstrukcji budowlanych zawarte w nowej normie Eurokod 1990-2. Przedstawiono normowy algorytm postępowania. Omówiono metody ilościowe oceny bezpieczeństwa konstrukcji – probabilistyczną, półprobabilityczną (metodę współczynników częściowych) ocenę ryzyka, a także metodę oceny jakościowej. Omawiając metodę współczynników częściowych dodano informacje dotyczące konstrukcji z betonu podane w nowelizacji Eurokodu 1992-1.

EN

The paper presents the rules of for the assessment of existing building structures included in the new Eurocode 1990-2 standard. A standard procedure algorithm is presented. Quantitative methods for assessing the safety of structures are discussed – probabilistic, semi-probable (partial coefficient method) risk assessment, as well as the qualitative assessment method. When discussing the partial coefficient method, information regarding concrete structures given in the Eurocode 1992-1 amendment was added.

4

Model and analysis of rope winch operation in underground rail transport

Krauze Krzysztof, Mucha Kamil, Wydro Tomasz, Klempka Ryszard

Archives of Mining Sciences

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2025

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Vol. 70, no. 3

377--386

EN

The primary means of rail transport in inclined workings up to 45° are typically single- or double-drum rope winches. These winches are part of a transport system consisting of the winch itself, a rope with a diameter d and length Ll, a track system, and a return drum with a rope tensioning mechanism. A fundamental challenge in employing winches in a given working is accounting for their operational conditions, which include the route length Lu, its inclination αu, and the value of the hauled mass (weight) Gm, given a specified load transport velocity vpł. These factors influence the drive load parameters, such as the winding rope force FC, unwinding rope force FS, and drive motor power Np. Manufacturers of these devices provide their structural (Lumax), kinematic (vpj), and energy-related (Np) parameters. However, it is the responsibility of the prospective user to assess the suitability of a specific winch for the conditions present in their transport excavation. To address this need, an analytical model, algorithm, and computer program have been developed to dynamically determine the required parameters while considering the winch’s operating conditions.

5

Analytical study of frictional interaction of elastic cleaning pig with pipeline wall

Stetsiuk S.M., Shatskyi I.P., Doroshenko Ya.V., Velychkovych A.S.

Archives of Materials Science and Engineering

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2024

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Vol. 129, nr 2

67--76

EN

Purpose: Cleaning pigs made of highly elastic materials are used to remove contaminants from industrial gas pipelines. To ensure the movement of the pig in normal operation and narrow sections of the pipeline, it is necessary to generate the required gas pressure in the pig space. The study aims to establish the analytical conditions for the movement of a deformable pig in a cylindrical channel without stopping. Design/methodology/approach: A one-dimensional quasi-static model has been developed to analyse the frictional interaction of a moving deformable rod with a cylindrical pipe wall under conditions of uniform radial tightness. The normal contact is assumed to be dense, with no interfacial gas flow along the pig. Findings: Based on the solution of the formulated contact problem, the influence of frontal resistance, tension, friction, modulus of elasticity of the material and geometric dimensions of the rod on its stress state and on the value of pressure behind the pig required for the pig to pass through the pipeline without stopping is investigated. It is shown that an increase in the value of each factor leads to an increase in the driving gas pressure in the space behind the pig. Research limitations/implications: In the future, developing the proposed approach for the analytical modelling of pig motion in a pipe with variable narrowing is advisable. Practical implications: Recommendations for the design of deformable pigs for efficient gas pipeline cleaning are given. Originality/value: In analytical form, the dependences of the driving pressure on the key geometric and mechanical parameters of the process were found.

6

Modeling of air velocity in a fluid transported through a pipeline

Dmytriv Vasyl, Dmytriv Ihor, Horodetskyy Ivan, Wilk Andrzej, Hyla Pawel

Archives of Engineering Knowledge

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2024

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T. 10, Nr 1

100-108

EN

The article considers the movement of liquid with an air bubbles along a finite pipeline. Taking into account the Stokes equation, the Newtonian frictional stress and the Reynolds equation, a differential equation for the change in the velocity of an air bubble in a pipeline that transports a liquid at a given velocity speed is derived. It is assumed that the pipeline has no connection with the atmosphere. The analytical solution of the differential equation of the air bubble velocity in the moving fluid of the pipeline using the exponential integral is given. A fluid with dynamic viscosity of  = 1.79 10-3, Pas and density of ρp = 1027.3, kg/m3 was used for modeling. The angle of inclination of the pipeline was 45 degrees, the velocity of the liquid flow in the pipeline was taken as 0.1, 1.0, 2.0 and 5.0 m/s. The total length of the pipeline was H = 2 m. The air bubble was taken in the form of a sphere with an initial radius of 1, 5, and 10 mm. Air was blown into the fluid flow. When an air bubble enters the pipeline, its initial velocity corresponds to the velocity of the fluid flow. The diameter of the air bubble has almost no effect on its velocity speed. Аналіз Analysis of the velocity simulation results shows that as the velocity of the fluid increases, the velocity of the air bubble increases. The nature of the change of the air bubble velocity depending on the fluid velocity shows that there is a condition when the fluid velocity and the air bubble velocity will be equal. As the fluid velocity increases, the bubble velocity difference between the air entry point and the air exit point decreases. The decrease in the velocity difference is caused by the pressure force on the surface of the air bubble, which is caused by the velocity of the fluid and the air bubble itself. As the dynamic viscosity of the fluid increases, the air bubble velocity decreases. The developed dependence describes the physical process of the flow of Newtonian fluids and gases in the pipeline.

7

Recent developments in pullout behaviors and tensile properties of ultra-high-performance concrete reinforced with steel fiber

Wu Hansong, Zang Zhishu, Deng Shiyi, Shen Aiqin, Cai Yanxia, Ren Guiping, Pan Hongmei

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e216, 2023

EN

Ultra-high-performance concrete (UHPC) has gained significant attention as a construction material owing to its exceptional mechanical properties and durability. Steel fibers are widely utilized as a reinforcement material for UHPC. Achieving excellent bond and tensile performances is considered to be a predominant issue for the utilization of steel fiber reinforcement. This comprehensive review presents recent research progress on the bond and tensile properties of steel-fiber-reinforced UHPC. First, an overview of the experimental methods for evaluating pullout and tensile performance is provided. Subsequently, the factors influencing these properties are discussed in detail. The review then comprehensively examines several analytical models for steel-fiber-reinforced UHPC, ranging from traditional approaches to innovative methods such as artificial neural network models, genetic algorithms, deep learning methods, inverse analysis, and micromechanical damage models. Furthermore, the correlations between pullout behavior, tensile performance, and flexural strength are explored in detail. Finally, the review addresses essential considerations and summarizes various modification techniques for improving the pullout and tensile performances, including physical and chemical methods of modifying the steel fiber surface and UHPC matrix. This review serves as a valuable reference for researchers and engineers in relevant fields, promoting further research and application of steel fiber-reinforced UHPC.

8

Classifying Speech Acts in Political Communication: A Transformer-based Approach with Weak Supervision and Active Learning

Schmidt Klaus, Niekler Andreas, Kantner Cathleen, Burghardt Manuel

Annals of Computer Science and Information Systems

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2023

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Vol. 35

739--748

EN

We present a study on the automatic classification of speech acts in the domain of political communication, based on J. R. Searle's classification of illocutionary acts. Our research involves creating a dataset using the US State of the Union corpus and the UN General Debate corpus (UNGD) as data sources. To overcome limited labeled data, we employ a combination of weak supervision and active learning techniques for dataset creation and model training. Through various experiments, we investigate the influence of external and internal factors on speech act classification. In addition, we discuss the potential for further analysis of speech act usage, using the trained model on the UNGD corpus. The findings demonstrate the effectiveness of Transformer-based models for automatic speech act classification, highlight the benefits of weak supervision and active learning for dataset creation and model training, and underscore the potential for large-scale statistical analysis of speech act usage in the domain of political communication.

9

Analysis of the Impact of Data Augmentation on the Performance of Deep Learning Models in Multispectral Food Authenticity Identification

Zhang Yaru, Yilmaz Arif, Popa Mirela, Brewster Christopher

Annals of Computer Science and Information Systems

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2023

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Vol. 35

823--832

EN

Food authenticity is a significant concern in the meat industry, demanding effective detection methods. This study explores the use of multispectral imaging (MSI) and deep learning for meat adulteration detection. We evaluate different deep learning models using transfer learning and preprocessing techniques in a multi-level adulteration classification task. In addition, we propose a novel approach called one-band mixed augmentation for band selection in MSI data, which outperforms traditional reflectance-based feature selection and enhances model robustness. Furthermore, employing the nine-crop approach for dataset augmentation improved the accuracy from 0.63 to 0.74 for DenseNet201 model without transfer learning. This research contributes to advancing food safety assessment practices and provides insights into the application of deep learning for preventing food adulteration. The proposed one-band mixed augmentation approach offers a novel strategy for handling band selection challenges in MSI data analysis.

10

An Enhancement of Reinforcement Learning by Scheduling with Learning Effects

Rudek Radosław

Annals of Computer Science and Information Systems

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2023

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Vol. 35

689--697

EN

This paper present results, which reveal that approaches obtained for scheduling problems with learning effects can be successfully used to improve the quality of machine learning methods. It is illustrated by modelling some aspects of Q-learning agents as scheduling problems with the learning effect, and constructing sequencing and dispatching algorithms, which take into account the existence of learning. Their application to determine the sequence of tasks processed by Q-learning agents can visibly speed up their convergence to an optimal strategy. Furthermore, we show that a dispatch of tasks according to the longest processing time algorithm for parallel computing can be replaced by a more efficient procedure, if agents can learn. The numerical analysis reveals that our approach is efficient, robust and only marginally dependents on a learning model and an accurate approximation of task processing times.

11

Dyspersja hydrodynamiczna w procesie wypierania gazów w rdzeniach skalnych

Blicharski Jacek, Stopa Jerzy

Przemysł Chemiczny

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2022

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T. 101, nr 1

50--54

PL

Przedstawiono wyniki badań laboratoryjnych wypierania azotu metanem w rdzeniach skalnych. Zaprezentowano model matematyczny eksperymentu oraz wyznaczono wartości współczynników dyfuzji molekularnej i dyspersji mechanicznej. Zaobserwowano zależność współczynnika dyspersji mechanicznej od ciśnienia w zakresie ciśnień 1-6 bar.

EN

Expts. of N2 displacement with MeH in rock cores were carried out on the laboratory test stand. The math. model of the expt. was presented and the coeff. of mol. diffusion and mech. dispersion were detd. The dependence of the mech. dispersion coeff. on the pressure in the range of 1-6 bar was obsd.

12

The influences of source intensity and meteorological factors on sulfur dioxide and nitrogen oxides based on the path analysis mode

Guo Chen-Lin, Zhang Jing, Zhou Qian Shuang, Ma Yong

Environment Protection Engineering

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2022

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Vol. 48, nr 4

51--65

EN

With rapid economic development and industrialization, air pollution is becoming a critical global issue affecting health. Sulfur dioxide and nitrogen oxides are the major contributors to acid rain and the key indicators for evaluating atmospheric pollution. And source intensity and meteorological factors are the main ways to influence the concentrations of sulfur dioxide and nitrogen oxides. Thus, to investigate the specific effects of source intensity, temperature, humidity, wind speed and atmospheric pressure on SO2 and NOx, the path analysis method was used for the model. The results showed that Source intensity significantly affects the concentrations of SO2and NO2. For both NO2 and SO2, the source intensity accounted for around 40%. Meteorological factors have very limited effects on the concentrations of SO2and NO2. The effects of the meteorological factors on air pollutants are specific as differences in material properties. Humidity significantly affects the concentration of SO2while temperature, humidity and wind speed have significantly affected the concentration of NO2.

13

Rule-based approximation of black-box classifiers for tabular data to generate global and local explanations

Maszczyk Cezary, Kozielski Michal, Sikora Marek

Annals of Computer Science and Information Systems

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2022

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Vol. 30

89--92

EN

The need to understand the decision bases of artificial intelligence methods is becoming widespread. One method to obtain explanations of machine learning models and their decisions is the approximation of a complex model treated as a black box by an interpretable rule-based model. Such an approach allows detailed and understandable explanations to be generated from the elementary conditions contained in the rule premises. However, there is a lack of research on the evaluation of such an approximation and the influence of the parameters of the rule-based approximator. In this work, a rule-based approximation of complex classifier for tabular data is evaluated. Moreover, it was investigated how selected measures of rule quality affect the approximation. The obtained results show what quality of approximation can be expected and indicate which measure of rule quality is worth using in such application.

14

Intuitionistic fuzzy model of the Hungarian algorithm for the salesman problem and software analysis of a shipping company example

Traneva Velichka, Mavrov Deyan, Tranev Stoyan

Annals of Computer Science and Information Systems

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2022

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Vol. 30

383--386

EN

Here we propose for the first time a temporal intuitionistic fuzzy extension of the Hungarian method for solving the Travelling Salesman Problem (TIFHA-TSP) based on intuitionistic fuzzy logic and index matrices theories. The time for passing a given route between the settlements depends on different factors. The expert approach is used to determine the intuitionistic fuzzy time values for passing the routes between the settlements. The rating coefficients of the experts take the times into account. We are also developing an application for the algorithm's provision to use it on a real case of TIFHA-TSP.

15

Wizualne odwzorowanie nowoczesnych fasad szklanych. Część 1

Jakica Nebojsa, Kragh Mikkel, Besse Gregoire

Świat Szkła

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2021

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R. 26, nr 4

45--48

16

Analytical Models for Optimal Design of a Trapezoidal Composite Channel Cross-Section

Pourbakhshian Somayyeh, Pouraminian Majid

Civil and Environmental Engineering Reports

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2021

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Vol. 31, no. 1

118--138

EN

In this paper, several analytical models are presented for the optimal design of a trapezoidal composite channel cross-section. The objective function is the cost function per unit length of the channel, which includes the excavation and lining costs. To define the system, design variables including channel depth, channel width, side slopes, freeboard, and roughness coefficients were used. The constraints include Manning’s equation, flow velocity, Froude number, and water surface width. The Simultaneous Perturbation Stochastic Approximation (SPSA) algorithm was used to solve the optimization problem. The results are presented in three parts; in the first part, the optimal values of the design variables and the objective function are presented in different discharges. In the second part, the relationship between cost and design variables in different discharges is presented in the form of conceptual and analytical models and mathematical functions. Finally, in the third part, the changes in the design variables and cost function are presented as a graph based on the discharge variations. Results indicate that the cost increases with increasing water depth, left side slope, equivalent roughness coefficient, and freeboard.

17

Analytical models tracing deformation of wood-framed walls during vertical transport

Malesza Jarosław, Miedziałowski Czesław

Archives of Civil Engineering

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2021

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Vol. 67, nr 1

131--146

EN

Vertical transport of wall-panels is a part of the prefabrication process of wood-framed buildings. The total dead weight of a wall is suspended on several lifting slings, pointwise clasping the top plate of the wall. This indicates, that all the weight of a wall is cumulated in sheathing-to-framing fasteners, usually staples. This article presents experimental investigations and analytical models evaluated for the description of light wood-framed walls in the process of lifting. Three different models cover the analytical approach: a model of a simple beam on elastic supports (BSS), a model of assembled beams (ACBS), three-dimensional (3D) spatial FE model of the wall (WFEM). Board-to-beam joint material parameters are determined on the base of experimental results. These connections are converted into two variants in the form of spring elements for 2D analysis, and beam elements for 3D analysis. The numerical results exhibit that the proposed models may correctly represent behavior of a real wall in lifting, applying elastic materials parameters.

PL

Transport pionowy tarcz ściennych jest częścią procesu prefabrykacji szkieletowych budynków drewnianych. Cały ciężar ściany spoczywa wówczas na kilku zawiesiach zaplecionych wokół górnej belki ściany. Oznacza to, iż obciążenie to kumuluje się w łącznikach (zszywkach) łączących górną belkę z poszyciem ściany. W artykule opisano badania doświadczalne oraz zaproponowano modele obliczeniowe ścian poddanych odkształceniom w procesie podnoszenia. W badaniach szczególną uwagę zwrócono na miejsca zaczepienia zawiesi i ich wpływ na pracę statyczną elementów konstrukcji. Dodatkowym efektem badań był wpływ wad materiałowych na zachowanie się konstrukcji. Badania eksperymentalne prowadzono do zniszczenia, które dla tarcz bez otworów i bez widocznych wad materiałowych obserwowano przy obciążeniu około P=50kN, natomiast w przypadku tarczy z wadami materiałowymi obciążenie niszczące osiągnęło wartość P=34kN. Dzięki badaniom uzyskano obraz deformacji górnego rygla oraz łączników poszycia i konstrukcji drewnianej w szczególności w obszarze bezpośrednich oddziaływań sił pochodzących od zawiesi. W artykule zaproponowano trzy modele obliczeniowe do oceny deformacji ścian: model belki na sprężystych podporach (BSS), model belek złożonych z połączeniami w postaci sprężyn (ACBS) i przestrzenny model MES (WFEM). W modelach belkowych połączenia opisano za pomocą elementów sprężynowych, a w modelu 3D za pomocą elementów belkowych. Parametry materiałowe użyte w opisie połączeń określono na podstawie badań złączy na zszywki. Analizy teoretyczne wykazała bardzo dobrą zbieżność modeli teoretycznych z badaniami doświadczalnymi w zakresie obciążeń P od około 8kN do 20kN. Ten zakres obciążeń określono na podstawie rzeczywistych obciążeń wynikających z ciężarów podnoszonych elementów, ponadto wielkości tych obciążeń wynikają z liniowo-sprężystej fazy pracy łącznika w połączeniu płyty poszycia z konstrukcją. Obciążenia powyżej P=20,00 kN wykazują w analizach modelowych większą sztywność niż to wynika z rezultatów badań doświadczalnych tarcz. Zaproponowany nowy, złożony model belkowy (ACBS) z dużą dokładnością odwzorowuje rzeczywistą pracę konstrukcji ścian na obciążenia ciężarem własnym w procesie podnoszenia. Może być zastosowany do ścian o różnej długości i konfiguracji otworów. Model ten w łatwy sposób może służyć ocenie wytężenia łączników, a w szczególności określeniu takiego rozstawu zawiesi, w którym zagwarantowane jest bezpieczne przenoszenie ściany. Jako kryterium bezpieczeństwa można, w zależności od wymagań, przyjąć: dopuszczalną nośność, dopuszczalną deformację lub dopuszczalną podatność łącznika.

18

Management of technological process optimisation

Lypchuk Vasyl, Dmytriv Vasyl

Engineering Management in Production and Services

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2020

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Vol. 12, no. 3

103--115

EN

The research aims to characterise the optimisation of a technological process depending on the main time parameters for production. The optimisation does not require to correct technical parameters of a system, but rather the organisational and managerial factors of the technological process. The workload is taken as an evaluation criterion, which factors in the probability distribution of time characteristics of computer process operations. Time characteristics that represent the performance of an operation influence the workloads of an operator and equipment, determining the productivity of the technological process. Analytical models were developed for the operational control of a production line efficiency considering the probability–statistical parameters pertaining to the performance of operations and technological equipment peculiarities. The article presents research results, which characterise the dependence of a production line efficiency on the type of equipment, and the duration of preparatory and final operations considering their probability. Under an optimal workload of the operator, the duration of the complete program changes linearly, regardless of the time required for the performance of operations by a computer without the involvement of the operator, and depending on the type of equipment. A managerial decision can be optimal under the condition that the factor of technological process efficiency (K_TP) tends to max. The developed method of analytical determination can be used to calculate the workload of both an operator and technological equipment. The calculations of the duration of a production line operation resulted in the methodology for the consideration of probability characteristics pertaining to the time distribution of the period required to perform operations, which influences the unequal efficiency of the production line. The probabilistic character of time distribution related to intervals of performed operations serves as a parameter in the management of technological process optimisation, which can be achieved using simulators of technological processes optimised in terms of their efficiency.

19

BIM w budownictwie – parametryczne modele w prefabrykacji

Salamak Marek, Grzesiak Szymon

Materiały Budowlane

|

2019

|

nr 9

26--29

20

Analytical dynamic model of coefficient of friction of air pipeline under pressure

Dmytriv Vasyl, Dmytriv Ihor, Horodetskyy Ivan, Dmytriv Taras

Diagnostyka

|

2019

|

Vol. 20, No. 4

89--94

EN

To transport of the air in the pipeline, an analytical model is developed that takes into account the gas velocity, its kinematic and dynamic characteristics - density, viscosity depending on the pressure in a given space of the pipeline. The analytical model makes it possible to calculate the coefficient of friction of gas transportation in the pipeline at intervals of the absolute pressure from 220 to 2 kPa and M < 1 Mach numbers, depending on the diameter and length of the pipeline and physical and technological characteristics of the gas. The K1* aspect ratio is proposed, which characterizes in time the ratio of the dynamic force of movement of gas to the static pressure related to the diameter of the pipeline. The coefficient of air friction was modeled according to the vacuum pressure as a parameter of density and air flow. Air flow was taken from 1.917·10-3 m 3/s to 44.5·10-3 m 3/s respectively, diameters from 0.030 to 0.070 m and Mach number was M = 0.005-0.13. At the vacuum and excess pressures with increasing of Reynolds number and decreasing of Mach number the gas friction coefficient increased linearly. According to the simulation results as the pressure loss and the diameter of the pipeline are increased the friction coefficient increased as well. Analogically, at the vacuum metric pressure when the pressure loss and the diameter of the pipeline are increased the friction coefficient increased. At the pipeline internal diameters of 22, 30, 36 mm accordingly for pressure losses from 2 to 14 kPa the coefficient of air friction varies from 0.006 to 54.527 respectively.