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Search results for: FINITE DIFFERENCE METHODS
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Evaluation of Path Based Methods for Conceptual Representation of the Text
PublicationTypical text clustering methods use the bag of words (BoW) representation to describe content of documents. However, this method is known to have several limitations. Employing Wikipedia as the lexical knowledge base has shown an improvement of the text representation for data-mining purposes. Promising extensions of that trend employ hierarchical organization of Wikipedia category system. In this paper we propose three path-based...
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Closed Form Constraint Equations Used to Express Frictionless Slip of Multibody Systems Attached to Finite Elements—Application to a Contact between a Double Pendulum and a Beam
PublicationThis paper focuses on the numerical modeling of the dynamics of mechanical systems. Robots that can inspect high-voltage lines inspired this research. Their control systems must anticipate potential grab positions appropriately. We intend to formulate equations dedicated to the numerical description of the robot/cable contact. The investigated problem is not straightforward, since parts of the modeled systems are numerically inhomogeneous....
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Study of data scheduling methods in the WiMAX Mobile metropolitan area networks
PublicationThe paper discusses basic assumptions of the WiMAX Mobile system. It also presents and analyses the results of simulation tests run for selected data scheduling methods and subcarrier allocation. Based on the test results, the authors have prepared a comparative analysis of two popular data scheduling methods, i.e. WRR and PF, and their own method CDFQ which uses information about the current channel situation for the queuing processes...
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Modeling of the finite amplitude plane wave propagation in non-dissipative medium
PublicationPraca prezentuje wyniki analizy teoretycznej zagadnienia propagacji fali płaskiej o skończonej amplitudzie w ośrodku wodnym bez dyssypacji. Przedstawiono model matematyczny i przykładowe wyniki obliczeń numerycznych. Model matematyczny zbudowano w oparciu o jednowymiarowe równania mechaniki płynów. Do rozwiązania zagadnienia zastosowano metodę różnic skończonych. Analizowano zmiany ciśnienia i zmiany widma. Badano zbieżność i dokładność...
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Ground-State Entanglement Properties of Helium Atom in a Finite Spherical Cavity
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Wave propagation modelling in 1D structures using spectral finite elements
PublicationW artykule omówiono modele propagacji fal wzdłużnych i poprzecznych w prętach oparte na dwóch sformułowaniach (w dziedzinie częstości i w dziedzinie czasu) metody elemntów spektralnych. Porównano otrzymane wyniki z wynikami eksperymentu.
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Geometrically nonlinear finite element simulation of smart piezolaminated plates and shells
PublicationW pracy zaproponowano powłokowy element skończony pozwalający na uwzględnienie efektu piezoelektrycznego. Element został wykorzystany w podejściu Lagrange'a, które wymaga starannego dobrania definicji wielkości mechanicznych i elektrycznych. Zależności przemieszczenie-odkształcenie zbudowano na bazie teorii małych odkształceń i umiarkowanych obrotów. Założono liniowy rozkład pól odkształceń i pola elektrycznego po grubości powłoki....
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Analysis of unsteady pipe flow using the modified finite element method
PublicationW pracy przedstawiono rozwiązanie równania przepływu nieustalonego zmodyfikowaną metodą elementów skończonych. Podejście to prowadzi do 6-punktowego schematu niejawnego z dwoma parametrami wagowymi. Analiza dokładności wykonana metodą równania zmodyfikowanego wykazała, że zaproponowany schemat zapewnia wyższą dokładność rozwiązania niż inne schematy. Porównanie wyników obliczeń z wynikami eksperymentu fizycznego wskazuje, że ich...
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Modal energy identification of large stucture idealised by the finite element method
PublicationPrzedstawiono metodę określania energii drgań układów dyskretnych otrzyma-nych w wyniku modelowania metodą elementów skończonych wybranych fragmentów konstrukcji samochodów. W odróżnieniu od poprzednio stosowanych podejść, ro-zważa się całkowite energie mechaniczne odpowiadające poszczególnym posta-ciom drgań własnych. Całkowitą energię mechaniczną oblicza się na podstawie parametrów modelu modalnego. Energię mechaniczną można...
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Modelling of the finite amplitude waves interaction problem inside truncated cone.
PublicationModel matematyczny zjawiska oddziaływania fal o dużej amplitudzie dla przetwornika kołowego zbudowanego w oparciu o równanie KZK. Rozwiązania zagadnienia poszukiwano wewnątrz stożka ściętego. Do rozwiązania zagadnienia zastosowano metodę różnic skończonych. Podano przykładowe wyniki badań numerycznych.
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Review of constitutive models for technical woven fabrics in finite element analysis
PublicationArtykuł opisuje typy modeli konstytutywnych stosowanych do opisu zachowania się tkanin technicznych w analizie MES. Proponowany jest także warstwowy model sieci gęstej.
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Assessment of rod behavior theories used in spectral finite element modeling
PublicationW pracy przedstawiono teorie prętów i przedstawiono ich przydatnośc w analizie propagacji fal sprężystych z wykorzystaniem metody spektralnych elementów skończonych.
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Quantum-correlation breaking channels, broadcasting scenarios, and finite Markov chains
PublicationOne of the classical results concerning quantum channels is the characterization of entanglementbreakingchannels [M. Horodecki et al., Rev. Math. Phys 15, 629 (2003)]. We address the questionwhether there exists a similar characterization on the level of quantum correlations which may gobeyond entanglement. The answer is fully affirmative in the case of breaking quantum correlationsdown to the, so called, QC (Quantum-Classical)...
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An Enhanced Reduced Basis Method for Wideband Finite Element Method Simulations
PublicationIn this paper, we present a novel strategy for selecting expansion points in the reduced basis method. A single computation of the error estimator is used to select a few expansion points in the multi-parameter space simultaneously. The number of selected points is determined adaptively, based on the accuracy of the current reduced model. The reliability and efficiency of this proposed approach are illustrated by numerical tests...
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Analysis of the Impact Resistance of Toecaps by the Finite Element Method: Preliminary Studies
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Finite element modeling of shear localization in granular bodies in hypoplasticity with enhancements
PublicationW pracy omówiono wyniki numeryczne lokalizacji okształceń stycznych w materiałach granulowanych. Obliczenia wykonano stosując prawo hipoplastyczne z rozszerzeniami w ramach mechaniki ośrodka gradientowego, nielokalnego i mikropolarnego. Obliczenia przeprowadzono dla różnych problemów brzegowych z uwzględnieniem lokalizacji. Wyniki analiz porównano z doświadczeniami.
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Comparison of various speech time-scale modificartion methods
PublicationThe objective of this work is to investigate the influence of the different time-scale modification (TSM) methods on the quality of the speech stretched up using the designed non-uniform real-time speech time-scale modification algorithm (NU-RTSM). The algorithm provides a combination of the typical TSM algorithm with the vowels, consonants, stutter, transients and silence detectors. Based on the information about the content and...
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Use of electrochemical methods to examine different surface preparation methods for organic coatings on steel
PublicationObróbka strumieniowo - ścierna jest jedną z powszechnie stosowanych metod przygotowania powierzchni. Wśród nowoczesnych metod coraz większe zainteresowanie wzbudza przygotowanie powierzchni wodą pod wysokim ciśnieniem (z ang. waterjetting). W porównaniu z konwencjonalnymi metodami ''waterjetting'' jest nowoczesną oraz przyjazną środowisku metodą. W literaturze brakuje informacji na temat skuteczności owej metody do zastosowań...
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Comparison of Two Methods for the Determination of Selected Pesticides in Honey and Honeybee Samples
PublicationDeveloped and validated analytical methods for the determination of a wide spectrum of pesticide residues in honey and honeybee samples after the modification of QuEChERS extraction in combination with gas chromatography–tandem quadrupole mass spectrometry (GC-MS/MS) and liquid chromatography–tandem quadrupole mass spectrometry (LC-MS/MS) were discussed and compared. The developed methods were evaluated regarding the utilized equipment...
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The accuracy of alternative stock valuation methods – the case of the Warsaw Stock Exchange
PublicationThe main aim of this article is to examine the accuracy of different methods of share valuation used by Polish analysts in reports prepared in order to issue recommendations for companies listed on the Warsaw Stock Exchange. In the literature on the subject, the view which prevails is that the more sophisticated methods, i.e. those taking into account the discounting process, are characterised by higher valuation accuracy. However,...
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Standards Conformity Framework in comparison with contemporary methods supporting standards application
PublicationAchieving and assessing conformity with standards and compliance with various sets of requirements generates significant costs for contemporary economies. Great deal of this is spent on fulfilment of safety and security requirements. However, standards application is not supported sufficiently by the tools available on the market. Therefore, Standards Conformity Framework (SCF) containing methods and tools which provide support...
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Galerkin Finite Element Process for Entropy Production and Thermal Evaluation of Third-Grade Fluid Flow: A Thermal Case Study
Publication: A fluid’s moving class improves its heat transmission capability, as well as its rigidity, owing to multivariate molecule suspension. In this way, nanofluids are superior to common fluids. In this study, we evaluated the features of ease and heat transfer. Furthermore, we investigated permeable media, heat source, variable heat conductivity, and warm irradiation results. A mathematical technique known as the Galerkin finite element...
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Comparison of Classification Methods for EEG Signals of Real and Imaginary Motion
PublicationThe classification of EEG signals provides an important element of brain-computer interface (BCI) applications, underlying an efficient interaction between a human and a computer application. The BCI applications can be especially useful for people with disabilities. Numerous experiments aim at recognition of motion intent of left or right hand being useful for locked-in-state or paralyzed subjects in controlling computer applications....
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Enriching the Context: Methods of Improving the Non-contextual Assessment of Sentence Credibility
PublicationThis paper presents several methods of automatic context enrichment of sentences that need to be evaluated, tagged or fact-checked by human judges. We have created a corpus of medical Web articles. Sentences from this corpus have been fact-checked by medical experts in two modes: contextually (reading the entire article and evaluating sentence by sentence) and without context (evaluating sentences from all articles in random order)....
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Survey on fuzzy logic methods in control systems of electromechanical plants
PublicationРассмотрены алгоритмы управления электромеханическими системами с использованием теории нечеткой логики, приводятся основные положения их синтеза, рассматриваются методы анализа их устойчивости на основе нечетких функций Ляпунова. Эти алгоритмы чаще всего реализуются в виде различных регуляторов, применение которых целесообразно в системах, математическая модель которых не известна, не детерминирована или является строго нелинейной,...
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Global and regional economic inequality: Methods of measurement and evidences
PublicationThe lack of countries’ statistical income data, comparable across countries and years, seems to be the main reason of controversial conjectures concerning global inequality and its evolution over time. In the databases, which purport to collect income data on a worldwide scale, only some summary statistics (quantile income shares, means, Gini indices) are presented. Therefore, the development of efficient methods of extracting...
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Aiming at methods’ wider adoption: Applicability determinants and metrics
PublicationNumerous computer science methods and techniques have been proposed by the scientific community. However, depending on the domain, only their minor fraction has met wider adoption. This paper brings attention to the concept of applicability - the notion that is well acknowledged in the scientific field but have not been analysed with respect to determinants, metrics and systematisation. The primary objective of the study was to...
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AN OVERVIEW OF HEAT TRANSFER ENHANCEMENT BASED UPON NANOPARTICLES INFLUENCED BY INDUCED MAGNETIC FIELD WITH SLIP CONDITION VIA FINITE ELEMENT STRATEGY
PublicationThe mathematical model of heat generation and dissipation during thermal energy transmission employing nanoparticles in a Newtonian medium is investigated. Dimensionless boundary layer equations with correlations for titanium dioxide, copper oxide, and aluminium oxide are solved by the finite element method. Parameters are varied to analyze their impact on the flow fields. Various numerical experiments are performed consecutively...
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Chemoinformatics Methods for Studying Biomolecules
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Miniaturized methods of sample preparation
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Internet payment methods in Poland
PublicationIn this chapter authors intended to describe wide range of aspects of the Internet payment systems. At the beginning there is briefly shown their evolution and features required for the effective payment system. Data on the popularity of different payment systems in Internet transactions links this section with description of the current state of payment systems available in Poland.
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Teaching simulation methods in a university
PublicationZmiany, jakie zachodzą we współczesnym środowisku gospodarczym wymagają od menedżerów stosowania narzędzi umożliwiających identyfikację pojawiających się szans i zagrożeń oraz wspomagających procesy podejmowania decyzji. Symulacje komputerowe było stosowane przez firmy już w latach pięćdziesiątych w celu rozwiązywania problemów z zakresu zwiększenia wydajności, obniżki kosztów czy też zwiększenia dochodowości . Współcześnie modelowanie...
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Correction methods in impedance spectroscopy
PublicationW pracy przedstawiono trzy grupy metod, ktÓre mogą być zastosowane do korekcji danych pomiarowych uzyskanych za pomoca spektroskopii impedancyjnej.
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Methods of Cyclist Training in Europe
PublicationThe following study aims to address the issue of cyclist training methodologies. Recent European bicycle accident statistics reveal a troubling upward trend. A potential solution to mitigate such incidents involves providing cyclists with comprehensive training encompassing traffic regulations and interactions with fellow road users. We conducted a comparative analysis of the cycling education approaches and cyclist training systems...
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Shipyard Crane Modeling Methods
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Accurate Lightweight Calibration Methods for Mobile Low-Cost Particulate Matter Sensors
PublicationMonitoring air pollution is a critical step towards improving public health, particularly when it comes to identifying the primary air pollutants that can have an impact on human health. Among these pollutants, particulate matter (PM) with a diameter of up to 2.5 μ m (or PM2.5) is of particular concern, making it important to continuously and accurately monitor pollution related to PM. The emergence of mobile low-cost PM sensors...
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Requirements, modifications and methods of mechanical testing of bone cement – literature review
PublicationThe Aim of the paper is to show the basic requirements for the bone cement, its modifications in terms of physical, mechanical and biological properties and testing methods. This publication is intended to be a source of systematized basic knowledge regarding the modified bone cement.
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Testing Stability of Digital Filters Using Optimization Methods with Phase Analysis
PublicationIn this paper, novel methods for the evaluation of digital-filter stability are investigated. The methods are based on phase analysis of a complex function in the characteristic equation of a digital filter. It allows for evaluating stability when a characteristic equation is not based on a polynomial. The operation of these methods relies on sampling the unit circle on the complex plane and extracting the phase quadrant of a function...
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Sea bottom structure investigation by means of acoustic methods
PublicationThe main aim of the paper is the result of experimental investigations of the seabed in the Gulf of Gdańsk arried out using parametric echosounder as a main measuring tool. Examination of the surface's upper layer of the seabed, especially is acoustic properties, reflecting most often transsmision and reflection properties of the incident elastic wave, could be a valuable material for determination of the stratification, and the...
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Brief Literature Review and Classification System of Reliability Methods for Evaluating the Stability of Earth Slopes
PublicationThe issue of slope stability is one of the most important and yet most difficult geotechnical problems. Assessing slope stability is particularly difficult because of the many uncertainties involved in the process. To take these uncertainties into account, probabilistic methods are used, and the reliability approach is adopted. There are many methods for reliability assessment of earth slope stability. However, there is no system...
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General concept of reduction process for big data obtained by interferometric methods
PublicationInterferometric sonar systems apply the phase content of the sonar signal to measure the angle of a wave front returned from the seafloor or from a target. It collect a big data – datasets that are so large or complex that traditional data processing application software is inadequate to deal with them. The recording a large number of data is associated with the difficulty of their efficient use. So data have to be reduced. The main...
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Searching of the buried objects into the sea bottom by means of nonlinear acouctic methods
PublicationThe main goal of this paper is to introduce the methodology of preparing the area for investigations that will be carried out at the sea. As the first step there is recognition of the basic method both in the theory as well as experimental investigation. There were taken into account the nonlinear methods. These ones are very promising methods that have very interesting features, very convenient for examinations of the seabed structure....
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Reconstruction Methods for 3D Underwater Objects Using Point Cloud Data
PublicationExisting methods for visualizing underwater objects in three dimensions are usually based on displaying the imaged objects either as unorganised point sets or in the form of edges connecting the points in a trivial way. To allow the researcher to recognise more details and characteristic features of an investigated object, the visualization quality may be improved by transforming the unordered point clouds into higher order structures....
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Analytical methods for exhaustive characterization of Brassica plants and dietary products based on them
PublicationGlucosinolates (GLs), and particularly two classes of their degradation products - isothiocyanates (ITC) and indoles - released upon myrosinase catalyzed hydrolysis, belong to the most promising chemopreventive dietary components. Despite their wide use in plant research, studies on chemopreventive mechanisms and industrial utilization in the production of e.g. dietary supplements, the methods of reliable characterization of myrosinase-GLs...
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Use of numerical methods in the analysis of traction energy systems—an overview of the practical examples
PublicationA characteristic feature of trolleybus transport is the random nature of traffic caused by congestion. It predestinates statistical and numerical methods for the analysis of trolleybus energy system. There are presented 3 methods of trolleybus traction system analysis: simulation of supply system based on Monte Carlo method, analysis of energy recovery potential based on statistical data analysis and benchmark of trolleybus supply...
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Experimental verification and comparison of mode shape-based damage detection methods
PublicationThis paper presents experimental verification and comparison of damage detection methods based on changes in mode shapes such as: mode shape curvature (MSC), modal assurance criterion (MAC), strain energy (SE), modified Laplacian operator (MLO), generalized fractal dimension (GFD) and Wavelet Transform (WT).
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Calculation methods of interaction of electromagnetic waves with objects of complex geometries
PublicationModeling of the electromagnetic interaction with different homogeneous or inhomo-geneous objects is a fundamental and important problem. It is relatively easy to solve Maxwellequations analytically when the scattering object is spherical or cylindrical, for example. How-ever, when it loses these properties all that is left for us is to useapproximation models, to ac-quire the solution we need. Modeling of complex, non-spherical,...
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Comparison of GC–MS and MEKC methods for caffeine determination in preworkout supplements
PublicationIn this study, GC–MS- and MEKC-based methods for determination of caffeine (CAF) in preworkout supplements were developed and validated. The proposed protocols utilized minimal sample preparation (simple dilution and syringe filtration). The developed methods achieved satisfactory validation parameters, i.e. good linearity (R2 0.9988 and R2 0.9985 for GC–MS- and MEKC-based method, respectively), satisfactory intraand interaccuracy...
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Optimizing Construction Engineering Management Using Metaheuristic Methods and Bayesian Networks
PublicationThe construction of buildings invariably involves time and costs, and disruptions impact ongoing construction projects. Crisis situations in management strategies, structural confusion, and finan-cial miscalculations often arise due to misguided decision-making. This article proposes a method that combines the learning of Bayesian Networks and heuristic techniques to optimize deci-sion-making processes in construction scheduling....
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A BRIEF REVIEW AND COMPARISON OF SELECTED EXPERIMENTAL METHODS FOR MEASURING NATURAL FREQUENCIES OF CIRCULAR SAW BLADES
PublicationDifferent methods for the empirical determination of the natural frequencies of circular saw blades are presented. Stationary methods, such as the harmonic and impulse tests, are discussed and the results of related comparison are given. The comparison of the methods revealed their degree of practical usefulness and their accuracy in determining natural frequencies. A combination of specific methods is proposed, which should allow...