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Wyszukujesz frazę "numerical experiments" wg kryterium: Temat


Wyświetlanie 1-13 z 13
Tytuł:
About special properties of the hidden structure of triangular numbers for immediate factorization
Autorzy:
Samojluk, Artur
Powiązania:
https://bibliotekanauki.pl/articles/2133934.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
factorization algorithm
RSA
cryptography
numerical experiments
triangular numbers
number theory
Opis:
The factorization problem belongs to a group of problems important in the security of information systems and cryptography. The article describes a new number factorization algorithm designed based on numerical experiments. We present an extension of number factorization using triangular numbers features. The described algorithm can be used to increase the security of key generation for the RSA algorithm.
Źródło:
Technical Sciences / University of Warmia and Mazury in Olsztyn; 2022, 25(1); 35--57
1505-4675
2083-4527
Pojawia się w:
Technical Sciences / University of Warmia and Mazury in Olsztyn
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and characterization of a novel knee articulation mechanism
Autorzy:
Olinski, M.
Gronowicz, A.
Handke, A.
Ceccarelli, M.
Powiązania:
https://bibliotekanauki.pl/articles/265067.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
staw kolanowy
optymalizacja
eksperymenty numeryczne
knee joint
3 DOF linkage
synthesis
optimization
numerical experiments
Opis:
The paper is focused on designing a novel controllable and adjustable mechanism for reproducing human knee joint’s complex motion by taking into account the flexion/extension movement in the sagittal plane, in combination with roll and slide. Main requirements for a knee rehabilitation supporting device are specified by researching the knee’s anatomy and already existing mechanisms. A three degree of freedom (3 DOF) system (four-bar like linkage with controlled variable lengths of rockers) is synthesised to perform the reference path of instantaneous centre of rotation (ICR). Finally, a preliminary design of the adaptive mechanism is elaborated and a numerical model is built in Adams. Numerical results are derived from simulations that are presented to evaluate the accuracy of the reproduced movement and the mechanism’s capabilities.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 3; 611-622
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Equivalent diagrams of fractional order elements
Autorzy:
Różowicz, Sebastian
Włodarczyk, Maciej
Zawadzki, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/27324011.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
fractional order derivative
Laplace transform for fractional order systems
CFE method
circuit synthesis
numerical experiments
Opis:
This paper presents equivalent impedance and operator admittance systems for fractional order elements. Presented models of fractional order elements of the type: sαL,sub>α and 1/sαCsub>α, (0 α 1) were obtained using the Laplace transform based on the expansion of the factor sign to an infinite fraction with varying degrees of accuracy – the continued fraction expansion method (CFE). Then circuit synthesis methods were applied. As a result, equivalent circuit diagrams of fractional order elements were obtained. The obtained equivalent schemes consist both of classical RLC elements, as well as active elements built based on operational amplifiers. Numerical experiments were conducted for the constructed models, presenting responses to selected input signals.
Źródło:
Archives of Control Sciences; 2023, 33, 4; 801--827
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pulsed Focused Nonlinear Acoustic Fields from Clinically Relevant Therapeutic Sources in Layered Media: Experimental Data and Numerical Prediction Results
Autorzy:
Kujawska, T.
Powiązania:
https://bibliotekanauki.pl/articles/176699.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
therapeutic ultrasound
circular focused transducers
pulsed nonlinear acoustic pressure beams
layered media
numerical modeling and experiments
Opis:
In many therapeutic applications of a pulsed focused ultrasound with various intensities the finite- amplitude acoustic waves propagate in water before penetrating into tissues and their local heating. Water is used as the matching, cooling and harmonics generating medium. In order to design ultrasonic probes for various therapeutic applications based on the local tissue heating induced in selected organs as well as to plan ultrasonic regimes of treatment a knowledge of pressure variations in pulsed focused nonlinear acoustic beams produced in layered media is necessary. The main objective of this work was to verify experimentally the applicability of the recently developed numerical model based on the Time- Averaged Wave Envelope (TAWE) approach (Wójcik et al., 2006) as an effective research tool for predicting the pulsed focused nonlinear fields produced in two-layer media comprising of water and tested materials (with attenuation arbitrarily dependent on frequency) by clinically relevant axially-symmetric therapeutic sources. First, the model was verified in water as a reference medium with known linear and nonlinear acoustic properties. The measurements in water were carried out at a 25.C temperature using a 2.25 MHz circular focused (f/3.0) transducer with an effective diameter of 29 mm. The measurement results obtained for 8-cycle tone bursts with three different initial pressure amplitudes varied between 37 kPa and 113 kPa were compared with the numerical predictions obtained for the source boundary condition parameters determined experimentally. The comparison of the experimental results with those simulated numerically has shown that the model based on the TAWE approach predicts well both the spatial-peak and spatial-spectral pressure variations in the pulsed focused nonlinear beams produced by the transducer used in water for all excitation levels complying with the condition corresponding to weak or moderate source-pressure levels. Quantitative analysis of the simulated nonlinear beams from circular transducers with ka ť 1 allowed to show that the axial distance at which sudden accretion of the 2nd or higher harmonics amplitude appears is specific for this transducer regardless of the excitation level providing weak to moderate nonlinear fields. For the transducer used, the axial distance at which the 2nd harmonics amplitude suddenly begins to grow was found to be equal to 60 mm. Then, the model was verified experimentally for two-layer parallel media comprising of a 60-mm water layer and a 60-mm layer of 1.3-butanediol (99%, Sigma-Aldrich Chemie GmbH, Steinheim, Germany). This medium was selected because of its tissue-mimicking acoustic properties and known nonlinearity parameter B/A. The measurements of both, the peak- and harmonic-pressure variations in the pulsed nonlinear acoustic beams produced in two-layer media (water/1.3-butanediol) were performed for the same source boundary conditions as in water. The measurement results were compared with those simulated numerically. The good agreement between the measured data and numerical calculations has shown that the model based on the TAWE approach is well suited to predict both the peak and harmonic pressure variations in the pulsed focused nonlinear sound beams produced in layered media by clinically relevant therapeutic sources. Finally, the pulsed focused nonlinear fields from the transducer used in two-layer media: water/castor oil, water/silicone oil (Dow Corning Ltd., Coventry, UK), water/human brain and water/pig liver were predicted for various values of the nonlinearity parameter of tested media.
Źródło:
Archives of Acoustics; 2012, 37, 3; 269-278
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Laboratory and numerical experiments into efficient management of VDR filter plants
Autorzy:
Zielina, M.
Dąbrowski, W.
Mackie, R. I.
Powiązania:
https://bibliotekanauki.pl/articles/206922.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
filters
environmental engineering
waste management
deep bed filtration
efficient management
numerical experiments
phenomenological modeling
mathematical model
theoretical modelling
filtry
inżynieria środowiska
gospodarowanie odpadami
filtracja wgłębna
sterowanie efektywne
eksperymenty numeryczne
modelowanie fenomenologiczne
model matematyczny
modelowanie teoretyczne
Opis:
runs are achieved when the highest flow through the most recently backwashed filter and the highest available head loss coincide. This rule has previously been published by Dąbrowski, who used a simplified mathematical model of VDR filters developed by Di Bernardo. However, until now no experimental verification of this optimisation approach has been presented. A series of tests were carried out on a laboratory VDR filter plant, using a suspension collected from an industrial sedimentation tank and using alum as a coagulant. The results of the experiments were compared with computations carried out according to a combined unit bed element (UBE)-phenomenological model of deep bed filtration adapted to VDR operation by Mackie and Zhao. It was confirmed that the longest filtration runs did indeed correspond to the pairs of the highest H and q1/qavr. The UBE-phenomenological model of deep bed filtration gave results of computations quite close to experimental results and improved the accuracy of calculations based on the theoretical model by Di Bernardo.
Źródło:
Environment Protection Engineering; 2015, 41, 3; 101-120
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling and Experimental Testing of Hybrid Joints Made of: Aluminium Adherends, Adhesive Layers and Rivets for Aerospace Applications
Autorzy:
Sadowski, T.
Golewski, P.
Powiązania:
https://bibliotekanauki.pl/articles/356712.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hybrid joints
numerical modelling
experiments
Opis:
The contemporary demands in different branches of engineering require application of new multi-component materials and structural systems. Appropriately chosen joining technology can offer significant enhancement of structural system performance in terms of effectiveness, reliability, safety and other design criteria. The modern applications of complex joints are of great technological interest as they permit to combine and to enhance the individual effects of each kind of joint. This is of great importance for modern applications in different branches of engineering: aerospace, mechanical and civil. Therefore in this paper we will focus on the analysis of mechanical response of adhesive joint of aluminium strips reinforced by rivets. The aim of the paper is to investigate experimentally the mechanical behaviour of adhesive joint of aluminium strips reinforced by rivets for industrial applications in aerospace. The considered joint was subjected to uniaxial loading. The tests in this paper were performed for: • classical adhesive joint in order to investigate material parameters for numerical modelling of the hybrid joint • hybrid joining of the structural elements in order to investigate the reinforcement effect. The experiments with application of digital image ARAMIS system allowed for on-line monitoring of the deformation process of the considered joining elements. The particular distributions of displacement fields at the joint surface were estimated for any stage of loading process. Numerical modelling was performed for experimentally investigated specimens. The materials parameters, necessary for calculation, were estimated from experiments. FEA modelling was done with the help of ABAQUS code.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1577-1583
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The bootstrap method as a tool to improve the design of experiments
Autorzy:
Dwornicka, Renata
Radek, Norbert
Pietraszek, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/88607.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
bootstrap
statistics
design of experiments
numerical simulation
statystyka
projektowanie eksperymentów
symulacje numeryczne
Opis:
The paper considers the use of the bootstrap method to improve the determination of confidence intervals identified by the DOE (design of experiment) procedure. Two different approaches have been used: one that is appropriate for factorial designs and the other one relevant to the methodology of the response surface. Both approaches were tested on the real experiment datasets and compared with the results obtained from the classical statistical expressions based on well known asymptotic formulas derived from the distribution.
Źródło:
System Safety : Human - Technical Facility - Environment; 2019, 1, 1; 724-729
2657-5450
Pojawia się w:
System Safety : Human - Technical Facility - Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The smoothed bootstrap fine-tuning
Autorzy:
Dwornicka, Renata
Goroshko, Andrii
Pietraszek, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/88564.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
smoothed bootstrap
statistic
design of experiments
numerical simulation
projektowanie eksperymentów
statystyka
symulacja numeryczna
Opis:
The bootstrap method is a well-known method to gather a full probability distribution from the dataset of a small sample. The simple bootstrap i.e. resampling from the raw dataset often leads to a significant irregularities in a shape of resulting empirical distribution due to the discontinuity of a support. The remedy for these irregularities is the smoothed bootstrap: a small random shift of source points before each resampling. This shift is controlled by specifically selected distributions. The key issue is such parameter settings of these distributions to achieve the desired characteristics of the empirical distribution. This paper describes an example of this procedure.
Źródło:
System Safety : Human - Technical Facility - Environment; 2019, 1, 1; 716-723
2657-5450
Pojawia się w:
System Safety : Human - Technical Facility - Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Jak nie porównywać wyników badań bioelektromagnetycznych
How to not compare results in bioelectromagnetic studies
Autorzy:
Długosz, T.
Powiązania:
https://bibliotekanauki.pl/articles/131978.pdf
Data publikacji:
2017
Wydawca:
Wrocławska Wyższa Szkoła Informatyki Stosowanej Horyzont
Tematy:
badania bioelektromagnetyczne
metody numeryczne
pole elektromagnetyczne
dokładność badań
układy ekspozycyjne
bioelectromagnetic studies
electromagnetic field
accuracy of experiments
exposure systems
numerical methods
Opis:
Artykuł poświęcony jest problemom związanym z porównywaniem wyników badań bioelektromagnetycznych. Można zauważyć, że badania poświęcone wpływom pola elektromagnetycznego, zwłaszcza na obiekty biologiczne, dają niejednoznaczne wyniki, które ciężko porównać między różnymi ośrodkami naukowymi. Wiele błędów wynika z technicznych aspektów tego typu eksperymentów. W pracy przedstawiono wybrane z nich. W badaniach nie wykorzystywano obiektów biologicznych, a jedynie ich numeryczne modele.
The paper is devoted to the problem of difficulty in results comparision of bioelectromeganetic experiments. It may be noticed that many studies which are devoted to biological effects of electromagnetic field exposure on biological objects can not be compared to each other. There may be many reasons responisble for that state. Certainly one of them are different sources of uncertainty resulting from the technical aspects of this type of research. One such source is influence of exposure system on tested object.
Źródło:
Biuletyn Naukowy Wrocławskiej Wyższej Szkoły Informatyki Stosowanej. Informatyka; 2017, 7, 2; 13-16
2082-9892
Pojawia się w:
Biuletyn Naukowy Wrocławskiej Wyższej Szkoły Informatyki Stosowanej. Informatyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quality improvement of a safety valve with the use of numerical and experimental studies
Autorzy:
Filo, Grzegorz
Domagała, Mariusz
Lempa, Paweł
Fabiś-Domagała, Joanna
Kwiatkowski, Dominik
Momeni, Hassan
Powiązania:
https://bibliotekanauki.pl/articles/104055.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
hydraulic system protection
safety valve
relief valve
numerical modelling
test bench experiments
układ hydrauliczny
zawór bezpieczeństwa
zawór nadmiarowy
modelowanie numeryczne
testy eksperymentalne
Opis:
This article presents results of numerical modelling, simulation and test bench experiments of a hydraulic direct-acting relief valve was used as a safety valve. The analyzed safety valve was placed in a system consisting of a fixed-speed pump, a control valve, a hydraulic cylinder as an actuator and a second pressure valve in the load line used as a payload generator for the cylinder. In the first step mathematical model of the system was formulated in the form of a system of ordinary differential equations. Next, simulation model was created in Matlab/Simulink. Simulations were carried out for different values of the actuator payload. The obtained results include time series of pressure, flow rate and displacement of the actuator piston. In order to confirm simulation results, a test bench was built and series of experiments were carried out. High compliance of simulation and laboratory results was obtained. It was confirmed that the proposed solution with the relief valve used as a safety valve fulfills its task of protecting the hydraulic system from excessive pressure increase.
Źródło:
Quality Production Improvement - QPI; 2019, 1, 1; 378-385
2657-8603
Pojawia się w:
Quality Production Improvement - QPI
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of fluid flow inside the flow control valve
Autorzy:
Domagała, Mariusz
Momeni, Hassan
Fabis-Domagała, Joanna
Krawczyk, Mariusz
Filo, Grzegorz
Bikass, Saeed
Powiązania:
https://bibliotekanauki.pl/articles/104138.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
hydraulic system protection
safety valve
relief valve
numerical modelling
test bench experiments
układ hydrauliczny
zawór bezpieczeństwa
zawór nadmiarowy
modelowanie numeryczne
eksperyment badawczy
Opis:
Hydraulic valves are widely used in many branches and they are still developed and improved. Due to the problem with verification of flow phenomena which appears during valves operation numerical simulations methods are tools which allows to improved valves design. This paper presents numerical simulation of fluid flow inside flow control valve.
Źródło:
Quality Production Improvement - QPI; 2019, 1, 1; 394-399
2657-8603
Pojawia się w:
Quality Production Improvement - QPI
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Failure mechanism and supporting measures for large deformation of soft rock roadway in Baluba copper mine
Mechanizm pękania skał i kroki zapobiegawcze podejmowane w celu przeciwdziałania odkształceniom chodnika prowadzonego w skałach miękkich w kopalni miedzi Baluba
Autorzy:
Wu, A.
Chen, S.
Wang, Y.
Chen, X.
Powiązania:
https://bibliotekanauki.pl/articles/219772.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chodnik prowadzony w skałach miękkich
analiza teoretyczna
symulacje numeryczne
eksperymenty w terenie
parametry podpór stropu
soft rock roadway
theoretical analysis
numerical simulation
field experiments
support parameters
Opis:
To solve the problem of large deformation soft rock roadway with complicated stress condition in Baluba copper mine, the characteristics of roadway deformation and failure modes are analyzed deeply on the basis of geological survey. Combined with the theoretical analysis and numerical simulation, the new reinforcement technology with floor mudsill and grouting anchor cable is proposed. Moreover, the three dimension numerical simulation model is established by the software FLAC-3D, the support parameter is optimized by it. The results show that the optical array pitch of the U-steel shelf arch is 0.8 m, and the optical array pitch of the grouting anchor cable is 2.4 m. At last, the field experiments are done all over the soft rock roadway. Engineering practice shows that the deformation of soft rock roadway in Baluba copper mine is effectively controlled by adopting the new reinforcement technology, which can provide certain references for similar engineering.
W celu rozwiązania problemu powstawania znacznych odkształceń chodnika biegnącego w skale miękkiej w skomplikowanym układzie naprężeń, przeprowadzono dogłębną analizę warunków odkształceń i pękania skał w oparciu o badania geologiczne. W oparciu o rozważania teoretyczne i symulacje numeryczne, zaproponowano nową technologię wzmocnienia progu spągowego z iłowców z linami kotwiącymi osadzonymi w zaprawie. Na podstawie trójwymiarowego modelu do symulacji numerycznych opracowanego z wykorzystaniem oprogramowania FLAC-3D dokonano optymalizacji parametrów podpór. Wyniki pokazują, że optymalne rozmieszczenie stalowych podpór wykonanych z profili w kształcie U wyniesie 0.8 m, zaś optymalny rozstaw mocowań lin wynosi 2.4 m. W końcowym etapie przeprowadzono eksperymenty terenowe na całej długości chodnika. Praktyka inżynierska wskazuje, że odkształcenia chodników prowadzonych w skałach miękkich w kopalni Baluba mogą być skutecznie kontrolowane poprzez zastosowanie nowej metody wzmocnienia, która stanowić może podstawę dla opracowywania skutecznych technik wzmacniania stropu w chodnikach prowadzonych w podobnych warunkach geologicznych.
Źródło:
Archives of Mining Sciences; 2018, 63, 2; 449-464
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Landslide stability analysis with the use of the design of experiments method – case study of souk ahras, Algeria
Autorzy:
Charef, Nouar
Mezhoudi, Issam
Boumezbeur, Abderrahmane
Harrat, Nabil
Powiązania:
https://bibliotekanauki.pl/articles/2201668.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie
Tematy:
landslide
Souk-Ahras region
numerical modeling
safety factor
geotechnical parameters
design of experiments DoE
response surface methodology
RSM
osuwisko
region Souk-Ahras
modelowanie numeryczne
współczynnik bezpieczeństwa
parametry geotechniczne
Opis:
In the northeast of Algeria, Souk Ahras area is known for the severity and spread of landslides, especially in Mechroha and Zaarouria municipalities. Stability analysis of landslides in these areas depends on the calculations of safety factor according to several parameters (physical, mechanical, geological…). The aim of this study is to investigate the parameters affecting the safety factor using the design of experiments (DOE) method, central composite design (CCD) and response surfaces methodology (RSM). These methods use parameter modeling and optimization to discuss a solution of landslide hazard by developing models of safety factor (Fs) considered as response. The other parameters adopted as input independent factors are geotechnical physical and mechanical parameters such as: the dry and wet unit weight (γd, γh), the water content (w), the plasticity and liquidity limits and the plasticity index (WL, WP, IP), the percentage of fine elements Ff (%) < 0.08 mm), the cohesion C and the internal friction angle (Phi). Obtained results show high correlations with a regression coefficient R2 of 0.88 and 0.93 in the two cases study and the predicted factor of safety model fit best to those obtained in the analytical and numerical modeling procedure. The final model is applicable to give reliable results on the safety factor of landslides.
Źródło:
Geomatics, Landmanagement and Landscape; 2022, 4; 137--150
2300-1496
Pojawia się w:
Geomatics, Landmanagement and Landscape
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-13 z 13

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