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EN
Robotic Roller Forming (RRF) is a novel process using an articulated robotic manipulator that can bend Ultra-High Strength materials into thin-walled profiles. For high strength or difficult-to-form sheet materials, a laser can be employed to synchronously heat and soften the local material during RRF. The aim of RRF is to establish itself as a highly flexible process for rapid prototyping as well as for small batch production. However, in finished parts formed with different materials, a new defect that shapes the profile like that of a hook was observed. To overcome this defect and to improve the adaptability of the process, a new analytical model is suggested for the automatic calculation of the tool center point based on the given process parameters. The model was compared to the previous state, where the hook defect was noticeably reduced. Additionally, the control of the bend radius was studied, and the resulting bend radius diverged from the target radius by 0.04 mm (2.45%). Further, when examining the reproducibility, the same bend angles could be achieved as in previous experiments using the constant laser power density. Finally, the development of the bend allowance was studied in various experiments. The analytical model for RRF is a promising method for calculating tool placement and controlling the bend radius in a freeform environment.
EN
As we have known, permanent magnet synchronous motors (PMSMs) have garnered widespread interest across various industrial applications thanks to their advantages such as high efficiency, reliable performance, simple structure, and adaptability to various shapes and sizes. Due to characteristics of the high torque and low speed, the PMSMs make particularly well-suited for traction applications such as trucks, ship propulsion, mining, and more. In this context, a combination of the analytical method and finite element method (FEM) is proposed for designing and simulating a six-phase surface-mounted PMSM. Firstly, a model of the six-phase PMSM is analytically design to make required/main dimensions. The FEM is then applied to analyse and verify electromagnetic parameters such as of the current waveform, back electromagnetic force (EMF), magnetic flux density in the air gap, flux linkage, torque, cogging torque, torque ripple and harmonic components. Via the obtained results, the research will give a contribution of valuable insights for optimizing the design, performance and reliability for this motor in diverse industrial applications.
EN
This study investigates the problems of eccentricity and backlash using an analytical spur gear model with 26 degrees of freedom (DOF). Previous studies have only investigated the case of eccentricity with a parallel shift of the axis of rotation of the gear relative to its geometric axis of symmetry. This study presents a novel method for determining the radius of eccentricity and its angular position at any distance from the bearing support, in which the axis of rotation and the geometric axis of symmetry of the gear are non-parallel. The effect of gear motion in the line of action (LOA) and off-line of action (OLOA) directions on backlash is precisely determined, despite the fact that most studies usually ignore gear displacement along the OLOA direction. Numerical simulations are performed to determine the effect of eccentricity on backlash, and their results confirm that the proposed method for determining the radius of eccentricity for any eccentricity type is correct. A gear slice model is used for dynamic analysis. Results show that the type of eccentricity has a significant effect on the gear dynamics and that eccentricity analyses have to include other cases than merely eccentricity with parallel axes of gears.
4
Content available SPAD timing jitter modeling using Fourier series
EN
In this paper, a simple analytical model for the Gaussian’s peak response part of the timing jitter of single photon avalanche diodes (SPADs) is proposed using Fourier series in the multiplication time calculation. The multiplication time characterizes avalanche multiplication process speed in which low multiplication time suggests a swifter response time and a higher avalanche speed. This paper presents an analytical solution which results in a more accurate multiplication time. The model is verified for SPADs implemented in 0.15 and 0.18 μm standard CMOS process, and the accuracy of the proposed analytical method in full-width at half-maximum (FWHM) calculation is improved by 25% and 5% with respect to the numerical model, respectively.
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.
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.
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.
8
Content available remote An Enhancement of Reinforcement Learning by Scheduling with Learning Effects
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.
9
Content available remote Dyspersja hydrodynamiczna w procesie wypierania gazów w rdzeniach skalnych
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.
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.
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.
EN
The influence of the design parameters (width of the conductor, thickness of the copper foil and gap between the conductors) of the printed circuit board and the characteristics of the technological process of its production: stages of exposure and etching, on the output of defectfree products is considered. According to the results of the study, analytical dependences were obtained, which make it possible to determine the minimum width of the conductor depending on the thickness of the copper foil and etching factor. There is the model proposed that links the probability of manufacturing a defect-free printed circuit board with the parameters considered. The developed model can be extended with other design parameters and models of technological stages.
PL
W pracy dokonano oceny wpływu parametrów konstrukcyjnych płytki drukowanej (szerokości ścieżki, grubości folii miedzianej i szczeliny między ścieżkami) oraz charakterystyki procesu technologicznego jej wytwarzania: etapy naświetlania i trawienia, na wytwarzanie płytek PCB wolnych od wad. W ramach badań uzyskano zależności analityczne, które pozwalają określić minimalną szerokość ścieżki w zależności od grubości folii miedzianej oraz tzw. współczynnika trawienia. Zaproponowano model łączący prawdopodobieństwo wyprodukowania płytki drukowanej wolnej od defektów z rozważanymi w pracy parametrami. Opracowany model można rozszerzyć o inne parametry projektowe oraz modele etapów technologicznych podczas wytwarzania PCB.
EN
In the article, the analytical dependences of modelling the cell cross-sectional area between two adjacent blades of a rotary blade pump and capacity for a pump with fixed and rotating stators are given, and analytical dependences are derived to model the power necessary to overcome the friction forces of the blades. The forces acting on the radially placed blade of a rotary pump with a fixed stator (non-rotating or stationary) and a rotating stator are analyzed. Design and technological parameters that influence the pump capacity and power are taken into account. The power required for the movement of the pump blade without taking into account the compression of the air has the opposite character of the change as to the pump capacity The capacity of a rotary pump with a rotating stator is three times higher than that of a stationary stator. The rotary pump with a rotating stator, with six radially spaced blades, consumes 0.854 [kW] less power to overcome the blade friction of 1313 kW The results of modelling of the pump work are given.
EN
When gears change their distance along the off-line of action (OLOA) direction, this affects the distance between the working surfaces of the meshing teeth along the line of action (LOA). This effect is usually neglected in studies. To include this effect precise equations are derived for spur gears. The analysis is carried out for the general case of spur gears with shifted profiles frequently used in the industry. The influence of OLOA gear displacement on LOA direction is also a function of gears parameters. An analysis is conducted, and the impact of parameters such as module, pressure angle, gear ratio, and the number of teeth is determined. As an example, a simulation of a 12 DOF analytical model is presented. The movement of gears along OLOA is caused by a frictional force that can be high during tooth degradation e.g. scuffing. Results show that when the movement of gears along the OLOA direction is significant, its influence on the distance between the mating teeth should not be neglected.
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.
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.
17
Content available Modeling of Complex Non-Full-Availability Systems
EN
This article presents an analytical model of complex non-full-availability telecommunications systems. The high degree of accuracy of the model is demonstrated by a comparison with the results of simulation experiments. Due to the introduction of an availability parameter, this model may be used in the future for analyzing real systems, such as, for example, cloud computing infrastructure. This will be possible provided that the function combining the physical structure of the system and the availability parameter is specified. This problem will be addressed in our future work and will constitute the next stage of research undertaken by the authors.
18
Content available Management of technological process optimisation
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.
EN
This article proposes an analytical model of a system with priorities servicing a mixture of different elastic traffic streams. The model presented in the article was developed as the extension of earlier works published by the authors. It utilizes the concept of equivalent bandwidth and then, following bandwidth discretization, uses the dependencies introduced on the basis of the assumptions adopted for the generalized Kaufman-Roberts formula and for the model of a full-availability group with traffic compression. The article presents a possibility of using the proposed model to model the radio interface in a multi-service mobile network and provides an example of the above with the interface of an LTE network. Since the proposed model is an approximate one, the results of the calculations are compared with the results of simulations. A comparison of the results confirms an acceptable level of accuracy of the model. The model can be successfully used in the analysis and design of links and nodes of telecommunication and computer networks.
EN
The paper presents the implementation of the modified strains development model (MSDM) for the two-way restrained self-stressed members such as expansive concrete-filled steel tubes and expansive concrete plane elements with arbitrary orthogonal reinforcement. The analytical approach allows defining the restrained strains and stresses in any 2D restraint conditions by following the iterative procedures and accounting for the elastic-plastic behaviour of expansive concrete at an early age. The consistency of the proposed method was confirmed by assessing the experimental results of the two series of the expansive concrete-filled steel tubes and three series of the expansive concrete plane members with mesh reinforcement in the centre of gravity.
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