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Wyniki wyszukiwania dla: Born-Oppenheimer approximation
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Born–Oppenheimer potential energy curves of NaK from the optimised atomic basis sets
PublikacjaThe article presents adiabatic potential energy curves of the ground and excited electronic states for the diatomic NaK molecule. The calculations were made using the ab initio computational methods to include electron correlation. The studied molecule was calculated as the effective two-electron problem, in which only the valence electrons of the molecule are explicitly taken into account. The remaining electrons with atomic nuclei...
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Potential energy surfaces of the low-lying electronic states of the Li+LiCs system
PublikacjaAb initio quantum chemistry calculations are performed for the mixed alkali triatomic system. Global minima of the ground and first excited doublet states of the trimer are found and Born-Oppenheimer potential energy surfaces of the Li atom interacting with the LiCs molecule were calculated for these states. The lithium atom is placed at various distances and bond angles from the lithium-caesium dimer. Three-body nonadditive forces...
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Performance of extended Lagrangian schemes for molecular dynamics simulations with classical polarizable force fields and density functional theory
PublikacjaIterative energy minimization with the aim of achieving self-consistency is a common feature of Born-Oppenheimer molecular dynamics (BOMD) and classical molecular dynamics with polarizable force fields. In the former, the electronic degrees of freedom are optimized, while the latter often involves an iterative determination of induced point dipoles. The computational effort of the self-consistency procedure can be reduced by re-using...
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Low-energy positron collisions with water: elastic and rotationally inelastic scattering
PublikacjaDifferential, integral and momentum transfer cross sections for the vibrationally elastic and rotationally inelastic scattering of positrons from water at low collision energy (E ≤ 10 eV) are reported. Several models within the R-matrix method are used to compute the body-fixed T-matrices, while the scattering calculations are performed within the fixed-nuclei approximation corrected with the standard Born-closure formula. These...
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Semantic Driven Table Understanding in Born-Digital Documents
PublikacjaThis paper presents a new approach to table understanding, suitable for born-digital PDF documents. Advance beyond the current state of the art in table understanding is provided by the proposed reverse MVC method, which takes advantage of only partial logic structure loss (degradation) in born-digital PDF documents, as opposed to unrecoverable loss (deterioration) taking place in scan based PDF documents.
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Internationalization of Born Globals from Theoretical Perspective
PublikacjaThe paper discusses the evolution of theoretical approaches towards internationalisation process of firms, especially SMEs. It clarifies the definitions of born global (BG) firm, presents its characteristics and the specifics of its internationalisation process. The objective of this paper is to present internationalisation process of born global firm from theoretical perspective. The article starts with presentation of the oldest...
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International Startups from Poland: Born Global or Born Regional?
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Determinanty tempa internacjonalizacji przedsiębiorstw ze szczególnym uwzględnieniem born globals
PublikacjaCelem artykułu jest przedstawienie czynników internacjonalizacji przedsiębiorstw, przede wszystkim born globals. Przedstawione zostały teorie internacjonalizacji przedsiębiorstw i ich ewolucja. Szczególny nacisk położono na wczesną i szybką internacjonalizację przedsiębiorstw. W części empirycznej przedstawiono wyniki badań przeprowadzonych na próbie 355 polskich zinternacjonalizowanych przedsiębiorstw.
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Extraction of information from born-digital PDF documents for reproducible research
PublikacjaBorn-digital PDF electronic documents might reasonably be expected to preserve useful data units of their source originals that suffice to produce executable papers for reproducible research. Unfortunately, developers of authoring tools may adopt arbitrary PDF generation strategies, producing a plethora of internal data representations. Such common information units as text paragraphs, tables, function graphs and flow diagrams,...
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Approximation Strategies for Generalized Binary Search in Weighted Trees
PublikacjaWe consider the following generalization of the binary search problem. A search strategy is required to locate an unknown target node t in a given tree T. Upon querying a node v of the tree, the strategy receives as a reply an indication of the connected component of T\{v} containing the target t. The cost of querying each node is given by a known non-negative weight function, and the considered objective is to minimize the total...
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An Approximation of the Zero Error Capacity by a Greedy Algorithm
PublikacjaWe present a greedy algorithm that determines a lower bound on the zero error capacity. The algorithm has many new advantages, e.g., it does not store a whole product graph in a computer memory and it uses the so-called distributions in all dimensions to get a better approximation of the zero error capacity. We also show an additional application of our algorithm.
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An Approximation of the Zero Error Capacity by a Greedy Algorithm.
PublikacjaWe present a greedy algorithm that determines a lower bound on the zero error capacity. The algorithm has many new advantages, e.g., it does not store a whole product graph in a computer memory and it uses the so-called distributions in all dimensions to get a better approximation of the zero error capacity. We also show an additional application of our algorithm.
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Contextualizing a Knowledge Base by Approximation – A Case Study
PublikacjaModular knowledge bases give their users opportunity to store and access knowledge at different levels of generality. In this paper we present how to organize a modular knowledge bases organized into contexts in which a user can express their knowledge in much simplified way, yet without losing its precision. The work is centered around the notion of approximation - i.e. reducing the arity of predicates used. The presentation is...
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Proximal primal–dual best approximation algorithm with memory
PublikacjaWe propose a new modified primal–dual proximal best approximation method for solving convex not necessarily differentiable optimization problems. The novelty of the method relies on introducing memory by taking into account iterates computed in previous steps in the formulas defining current iterate. To this end we consider projections onto intersections of halfspaces generated on the basis of the current as well as the previous...
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On the approximation of the UWB dipole elliptical arms with stepped-edge polygon
PublikacjaA simple method of approximation of the ellipticalpatch with stepped-edge polygon is proposed as an introductionto wider studies over the planar ultrawideband (UWB) antennas.The general idea is to replace the elliptical patch with an equivalentpolygonal patch, with minimum loss in the performance. Theprinciples of the proposed method are presented in this letter, aswell as the results of performed numerical studies and its experimentalverification....
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Generalized Gradient Equivariant Multivalued Maps, Approximation and Degree
PublikacjaConsider the Euclidean space Rn with the orthogonal action of a compact Lie group G. We prove that a locally Lipschitz G-invariant mapping f from Rn to R can be uniformly approximated by G-invariant smooth mappings g in such a way that the gradient of g is a graph approximation of Clarke’s generalized gradient of f . This result enables a proper development of equivariant gradient degree theory for a class of set-valued gradient...
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A 27/26-approximation algorithm for the chromatic sum coloring of bipartitegraphs
PublikacjaWe consider the CHROMATIC SUM PROBLEM on bipartite graphs which appears to be much harder than the classical CHROMATIC NUMBER PROBLEM. We prove that the CHROMATIC SUM PROBLEM is NP-complete on planar bipartite graphs with Delta less than or equal to 5, but polynomial on bipartite graphs with Delta less than or equal to 3, for which we construct an O(n(2))-time algorithm. Hence, we tighten the borderline of intractability for this...
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Entropy of water calculated from harmonic approximation: estimation of the accuracy of method
PublikacjaSome molecular dynamics simulations were performed for liquid TIP4P and SPC water at a constant density (1.00 g/cm(3)) and within the temperature range of 5-90 degrees C. By using harmonic approximation, both the entropy of water S-H and the specific heat c(v) were calculated, and the results were compared to literature data. It was found that harmonic approximation overestimates absolute entropy of TIP4P water by 5.6 J/mol K (similar...
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Cavity-expansion approximation for projectile impact and penetration into sand
PublikacjaA one-dimensional problem of a spherical cavity expanding at a constant velocity from zero initial radius in an infinite granular medium, which has the first-kind self-similar solution, is considered. We are solving this dynamic spherical cavity-expansion problem to model rigid spheres penetrating into a granular media. Elastic–plastic deformation of the granular media is described in a barotropic approximation, using the high-pressure...
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Approximation algorithms for job scheduling with block-type conflict graphs
PublikacjaThe problem of scheduling jobs on parallel machines (identical, uniform, or unrelated), under incompatibility relation modeled as a block graph, under the makespan optimality criterion, is considered in this paper. No two jobs that are in the relation (equivalently in the same block) may be scheduled on the same machine in this model. The presented model stems from a well-established line of research combining scheduling theory...
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Stability by linear approximation for time scale dynamical systems
PublikacjaWe study systems on time scales that are generalizations of classical differential or difference equations and appear in numerical methods. In this paper we consider linear systems and their small nonlinear perturbations. In terms of time scales and of eigenvalues of matrices we formulate conditions, sufficient for stability by linear approximation. For non-periodic time scales we use techniques of central upper Lyapunov exponents...
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Errors of a Linear Current Approximation in High-Speed PMSM Drives
PublikacjaCurrent sampling techniques and predictive algorithms used in the digital control of electric drives rely on a simple mathematical model that assumes linear current changes upon constant supplying voltages. This paper identifies rotor movement as a factor that makes this assumption invalid when the rotor covers an angular distance of a few tens of degrees during the control interval duration. The errors of the linear current approximation...
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Approaches to experiment based friction modeling: polynomial approximation versus ann approximation
PublikacjaBadano warunki (poziom wymuszeń), przy których następowało wzbudzenie drgań mechanicznych przy tarciu ślizgowym konforemnego skojarzenia próbek wykonanych z Al2O3 (płaskie czoło tulei obracającej się względem swojej osi - powierzchnia płaska). Uzyskane dane eksperymentalne wykorzystano następnie do zbudowania modeli - stosując aproksymację wielomianami albo sztuczną siecią neuronową (ANN).
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Text-mining Similarity Approximation Operators for Opinion Mining in BI tools
PublikacjaThe concept of the Text-mining Similarity Approximation Operators for Opinion Mining as extensions to Natural Language Interface Database is defined. The new operators: “keywords of” dimension; subsetting operator “about C is q”; aggregation operator “by similar C” are proposed. These operators are based on the Latent Semantic Analysis and Social Network Analysis
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Constant-Factor Approximation Algorithm for Binary Search in Trees with Monotonic Query Times
PublikacjaWe consider a generalization of binary search in linear orders to the domain of weighted trees. The goal is to design an adaptive search strategy whose aim is to locate an unknown target vertex of a given tree. Each query to a vertex v incurs a non-negative cost ω(v) (that can be interpreted as the duration of the query) and returns a feedback that either v is the target or the edge incident to v is given that is on the path towards...
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The Method of a Two-Level Text-Meaning Similarity Approximation of the Customers’ Opinions
PublikacjaThe method of two-level text-meaning similarity approximation, consisting in the implementation of the classification of the stages of text opinions of customers and identifying their rank quality level was developed. Proposed and proved the significance of major hypotheses, put as the basis of the developed methodology, notably about the significance of suggestions about the existence of analogies between mathematical bases of...
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Familiness and Born Globals: Rapid Internationalisation among Polish Family Firms
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An Efficient Noisy Binary Search in Graphs via Median Approximation
PublikacjaConsider a generalization of the classical binary search problem in linearly sorted data to the graph-theoretic setting. The goal is to design an adaptive query algorithm, called a strategy, that identifies an initially unknown target vertex in a graph by asking queries. Each query is conducted as follows: the strategy selects a vertex q and receives a reply v: if q is the target, then =, and if q is not the target, then v is a...
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Approximation of the non-linear roll damping
PublikacjaArtykuł omawia, jak otrzymać oszacowanie nieliniowego momentu tłumiącehgo kołysania boczne okretu za pomocą zapisu przebiegu kołysań swobodnych modelu okrętu. Udowadnia, że 1) moment tłumiący w kategoriach aproksymacji jest nieanalityczną funkcją nieparzystą prędkosci kołysań, 2) standardowa metoda, oparta na stosunku dwóch kolejnych amplitud, ma ograniczone zastosowanie, do niezbyt dużych amplitud kołysań. Zaproponowano nową metodą...
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Approximation of Fractional Order Dynamic Systems Using Elman, GRU and LSTM Neural Networks
PublikacjaIn the paper, authors explore the possibility of using the recurrent neural networks (RNN) - Elman, GRU and LSTM - for an approximation of the solution of the fractional-orders differential equations. The RNN network parameters are estimated via optimisation with the second order L-BFGS algorithm. It is done based on data from four systems: simple first and second fractional order LTI systems, a system of fractional-order point...
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Approximation of extremal solutions for functional differential equations
PublikacjaDyskutowane są równania różniczkowe funkcyjne z liniowym warunkiem brzegowym. Podano warunki dostateczne dla istnienia ciągów monotonicznych, aproksymujących rozwiązania ekstremalne badanych zagadnień.
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Approximation of Covariance Function with Application to Stochastic Mechanics.
PublikacjaW pracy przedstawiono koncepcję rozwinięć kanonicznych dla funkcji losowych oraz możliwość ich zastosowania w stochastycznej mechanice gruntów. Rozpatrzono rozkład widmowy, rozwinięcia Karhunena-Loevego oraz rozwinięcia ortogonalne zmodyfikowanymi wielomianami Hermite'a. Przeprowadzono analizę błędów dla zagadnienia warstwy gruntu o losowych parametrach sprężystych, uzyskano analityczne rozwiązanie systemu stochastycznego.
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Nonquadratic quality indices in estimation, approximation and control
PublikacjaZaproponowano wykorzystanie niekwadratowych miar jakości w zagadnieniach estymacji parametrów modeli, aproksymacji funkcji okresowych oraz syntezy układów sterowania. Rozważono funkcje celu w postaci ważonych sum lub całek wartości bezwzględnej błędu predykcji. Ponieważ tego typu wskaźniki jakości są w swoich ekstremach nieróżniczkowalne, zadanie minimalizacji funkcji celu rozwiązano stosując iteracyjny algorytm kolejnych przybliżeń....
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Approximation task decomposition for artificial neural network.
PublikacjaW pracy przedstawiono wpływ dekompozycji zadania na czasochłonność projektowania oraz dokładność i szybkość obliczeń sztucznej sieci neuronowej wykorzystanej do rozwiązania rzeczywistego problemu technicznego, którego matematyczny model był znany. Celem obliczeń prowadzonych przez sieć neuronową było określenie wartości współczynnika przepływu m na podstawie znajomości wartości: przewodności dźwiękowej C i średnicy przewodu d (a...
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"Born Poland, Gone Global". The case of successful Polish ICT company - Aiton Caldwell
PublikacjaThis work examines the pathway to global markets of Polish ICT company Aiton Caldwell
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An Approximation Algorithm for Diagnostic Test Scheduling in Multicomputer Systems
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Stability by linear approximation for time scale dynamical systems
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An approximation algorithm for maximum P3-packing in subcubic graphs
PublikacjaW pracy podano algorytm 4/3-przyliżony dla trudnego obliczeniowo problemu umieszczania wierzchołkowo rozłącznych dwukrawędziowych ścieżek w grafach o stopniu maksymalnym 3 i stopniu minimalnym 2. Poprawiono tym samym wcześniejsze wyniki dla grafów kubicznych (A. Kelmans, D. Mubayi, Journal of Graph Theory 45, 2004).
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Band structure, Born effective charges, and lattice dynamics of CuInS2 from ab initio calculations
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Quadratic approximation of solutions for differential equations with nonlinear boundary conditions.
PublikacjaZastosowano metodę kwazilinearyzacji i sformułowano warunki dostateczne przy których iteracje monotoniczne są kwadratowo zbieżne do jedynego rozwiązania wymienionego w tytule zagadnienia różniczkowego. Uzyskane wyniki uogólniają niektóre wcześniej publikowane rezultaty gdy warunek brzegowy był liniowy.
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A Criterion for Conditional Instability by the First Approximation for Solutions of Differential Systems
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Approximation strategies for routing edge disjoint paths in complete graphs
PublikacjaPraca dotyczy problemu ścieżek krawędziowo rozłącznych w nieskierowanych grafach pełnych, dla którego podano nowe algorytmy przybliżone: 3.75-przybliżony (model off-line) i 6.47-przybliżony (model on-line). Stosując podobną metodologię, uzyskano algorytm 4.5-przybliżony (off-line) i 6-przybliżony (on-line) dla problemu routingu i kolorowania ścieżek w grafach pełnych.
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The optimisation of induction heating system based on multiquadric function approximation
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Piece-wise constant approximation method of identification of RTS noise
PublikacjaPrzedstawiono nową metodę wydzielania szumów RTS z całkowitych szumów przyrządów półprzewodnikowych. Metoda ta oparta jest na aproksymacji liniowo odcinkowej przebiegu szumowego.Przedstawiono wyniki zastosowania tej metody do wydzielenia dwupoziomowego szumu RTS z szumu przyrządu półprzewodnikowego.
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Numerical approximation of first order partial differential equations withdeviated variables.
PublikacjaKlasyczne rozwiązania nieliniowego zagadnienia Cauchy´ego określone na piramidzie Haara są aproksymowane za pomocą rozwiązań układów quasiliniowych równań różnicowych. Stabilność schematu różnicowego jest wykazana metodą porównawczą z zastosowaniem nieliniowych oszacowań typu Perrona dla danych funkcji. Podano przykłady numeryczne.
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Note on the Harmonic Approximation in the Treatment of Entanglement: N Cold Trapped Ions
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Separation of variables in molecular-dynamics simulations: A criterion to estimate the quality of the approximation
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Justification of quasi-stationary approximation in models of gene expression of a self-regulating protein
PublikacjaWe analyse a model of Hes1 gene transcription and protein synthesis with a negative feedback loop. The effect of multiple binding sites in the Hes1 promoter as well as the dimer formation process are taken into account. We consider three, possibly different, time scales connected with: (i) the process of binding to/dissolving from a binding site, (ii) formation and dissociation of dimers, (iii) production and degradation of Hes1...
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Approximation of internodal conductivities in numericalsimulation of one-dimensional infiltration, drainage, and capillaryrise in unsaturated soils
PublikacjaW rozwiązaniu numerycznym jednowymiarowego równania przepływu nienasyconego wymagane jest oszacowanie średniej wartości przewodności hydraulicznej między sąsiednimi węzłami. W artykule zaproponowano nową metodę uśredniania która, w odróżnieniu od metod dotychczas proponowanych, charakteryzuje się dużą dokładnością i szerokim zakresem stosowalności. Nowa metoda oparta jest na analizie przybliżonego profilu potencjału hydraulicznego...
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approximation of photonic crystal fibres with large air holes by the step index fibre model
PublikacjaAn equivalent step index fibre with a silica core and air cladding is used to model photonic crystal fibres with large air holes. We model this fibre for linear polarisation (we focus on the lowest few transverse modes of the electromagnetic field). The equivalent step index radius is obtained by equating the lowest two eigenvalues of the model to those calculated numerically for the photonic crystal fibres. The step index parameters...
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Application of the Least Squares Method to the approximation of equally spaced samples in frequency measurement approach
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ORF Approximation in Numerical Analysis of Fractional Point Kinetics and Heat Exchange Model of Nuclear Reactor
PublikacjaThis paper presents results concerning numerical solutions of the fractional point kinetics (FPK) and heat exchange (HE) model for a nuclear reactor. The model consists of a nonlinear system of fractional and ordinary differential equations. Two methods to solve the model are compared. The first one applies Oustaloup Recursive Filter (ORF) and the second one applies Refined Oustaloup Recursive Filter (RORF). Simulation tests have...
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Description of the thermodynamic properties of BiH 5 and BiH 6 superconductors beyond the mean-field approximation
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ORF Approximation in Numerical Analysis of Fractional Point Kinetics and Heat Exchange Model of Nuclear Reactor
PublikacjaThis paper presents results concerning numerical solutions of the fractional point kinetics (FPK) and heat exchange (HE) model for a nuclear reactor. The model consists of a nonlinear system of fractional and ordinary differential equations. Two methods to solve the model are compared. The first one applies Oustaloup Recursive Filter (ORF) and the second one applies Refined Oustaloup Recursive Filter (RORF). Simulation tests have...
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Anomalous diffraction approximation to the light scattering coefficient spectra of marine particles with power-law size distribution
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Thermally stimulated currents in amorphous solids at mixed carrier recombination, Part I: Non-equilibrium approximation
PublikacjaPodano opis teoretyczny prądów termicznie stymulowanych dla przypadku mieszanej rekombinacji nośników ładunku, przy założeniu początkowego zapełnienia głębokich stanów pułapkowych oraz silnie nierównowagowego rozkładu nośników w aktywnych pułapkach. Otrzymane wyrażenia zweryfikowano za pomocą obliczeń numerycznych dla przypadku wykładniczego rozkładu pułapek.
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Continuum wave functions for estimating the electric dipole moment: Calculation based on a multiconfiguration Dirac-Hartree-Fock approximation
PublikacjaThe multiconfiguration Dirac-Hartree-Fock method is employed to calculate the continuum electron wave functions, which are then used to estimate their contribution to the atomic electric dipole moment (EDM) of 129Xe. The EDM arises from (P,T)-odd electron-nucleon tensor-pseudotensor and pseudoscalar-scalar interactions, the nuclear Schiff moment, the interaction of the electron electric dipole moment with nuclear magnetic moments,...
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Approximation of Message Inter-Arrival and Inter-Departure Time Distributions in IMS/NGN Architecture Using Phase-Type Distributions
PublikacjaCurrently it is assumed that requirements of the information society for delivering multimedia services will be satisfied by the Next Generation Network (NGN) architecture, which includes elements of the IP Multimedia Subsystem (IMS) solution. In order to guarantee Quality of Service (QoS), NGN has to be appropriately designed and dimensioned. Therefore, proper traffic models should be proposed and applied. This requires determination...
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Werkzeugübergreifende Konsistenzsicherung von Artefakten bei der Entwicklung softwarebasierter Systeme im Automobil
PublikacjaDie Entwicklung von eingebetteten Systemen im Auto mobilbereich zeichnet sich zunehmend durch steigende Komplexität der zu entwickelnden Fahrzeugfunktionen aus. Die Handhabung dieser Kompl exität wird über entsprechend mächtige Werkzeuge, welche die verschi edenen Aktivitäten des Softwareentwicklungsprozesses unterstützen, angestr ebt. Als eine Schwachstelle erweist sich dabei, dass die eingesetzten Werkzeugk etten im Automobilbereich...
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Power grid frequency measurement in LabVIEW environment using the least mean squares method to signal phase approximation in the presence of noise
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Smooth orthogonal projections on sphere.
PublikacjaWe construct a decomposition of the identity operator on the sphere S^d as a sum of smooth orthogonal projections subordinate to an open cover of S^d. We give applications of our main result in the study of function spaces and Parseval frames on the sphere.
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Specyfika modernizowanych obiektów zabytkowych.
PublikacjaOmówienie wpływu wyników badań archeologicznych na zakres prac modernizacyjnych oraz na wybór docelowego użytkowania Hali Targowej w Gdańsku i Merkat del Born w Walencji w Hiszpanii.
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Mathematical analysis of a generalised p53-Mdm2 protein gene expression model
PublikacjaWe propose the generalisation of the p53-Mdm2 protein gene expression model introduced by Monk (2003). We investigate the stability of a unique positive steady state and formulate conditions which guarantee the occurrence of the Hopf bifurcation. We show that oscillatory behaviour can be caused not only by time lag in protein transcription process, but also can be present in the model without time delay. Moreover, we investigate...
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PROPERTIES OF ONE DIMENSIONAL OPEN-CHANNEL STEADY FLOW EQUATIONS
PublikacjaIn this paper properties of discrete forms of one dimensional steady gradually varied flow equations are discussed. Such forms of flow equations are obtained as a result of approximation of their differential forms, which is required to solve them numerically. For such purpose explicit or implicit numerical approximation schemes for ordinary differential equations can be applied. It turns out that dependently on the chosen approximation...
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Impact of Low Switching-to-Fundamental Frequency Ratio on Predictive Current Control of PMSM: A simulation study
PublikacjaPredictive current control algorithms for permanent magnet synchronous (PMSM) drives rely on an assumption that within short intervals motor currents can be approximated with linear functions. This approximation may result either from discretizing the motor model or from simplifications applied to the continuous-time model. As the linear current approximation has been recognized as inaccurate in case when the drive operates with...
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Improved magnitude estimation of complex numbers using alpha max and beta min algorithm
PublikacjaThe paper presents an improved algorithm for calculating the magnitude of complex numbers. This problem, which is a special case of square rooting, occurs for example, in FFT processors and complex FIR filters. The proposed method of magnitude calculation makes use of the modified alpha max and beta min algorithm. The improved version of the algorithm allows to control the maximum magnitude approximation error by using an adequate...
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Quantum corrections to phi^4 model solutions and applications to Heisenberg chain dynamics
PublikacjaThe Heisenberg spin chain is considered in φ^4 model approximation. Quantum corrections to classical solutions of the one-dimensional φ^4 model within the correspondent physics are evaluated with account of rest d−1 dimensions of a d-dimensional theory. A quantization of the model is considered in terms of spacetime functional integral. The generalized zeta-function formalism is used to renormalize and evaluate the functional integral...
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Quantum corrections to 4 model solutions and applications to Heisenberg chain dynamics
PublikacjaThe Heisenberg spin chain is considered in φ^4 model approximation. Quantum corrections to classical solutions of the one-dimensional φ^4 model within the correspondent physics are valuated with account of rest d − 1 dimensions of a d-dimensional theory. A quantization of the model is considered in terms of space- time functional integral. The generalized zeta-function formalism is used to renormalize and evaluate the functional...
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Gdańsk: a City of Solidarity and Freedom
PublikacjaOnly a few cities can claim that they have changed Europe and indeed the World. Gdańsk is privileged to be one of them. It is not a “caprice of history” that the Solidarity movement which, in the end, got the iron curtain torn, was born in this particular place. It is a logical consequence of ten centuries of the collective wisdom of the people that built Gdańsk and the region of Pomerania. The tragic assassination of the Mayor...
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FPGA realization of an improved alpha max plus beta min algorithm
PublikacjaThe generalized improved version of the alpha max plus beta min square-rooting algorithm and its realization in the Field Programmable Gate Array (FPGA) are presented. The algorithm computes the square root to calculate the approximate magnitude of a complex sample. It is especially useful for pipelined calculations in the DSP. In case of four approximation regions it is possible to reduce the peak error form 3.95% to 0.33%. This...
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Sensitivity analysis of critical loads of I-columns
PublikacjaThe first order variation of critical buckling load of thin-walled columns with bisymmetric open cross-section due to some variations of the design variables such as: cross-section dimensions, or material characteristics is derived. The influence of the residual welding stresses is taken into account. In the numerical examples dealing with I-column the functions describing the effect of the variation of the dimensions of the flange...
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Polypyrrole based gas sensor for ammonia detection
PublikacjaThe nature of polypyrrole response to toxic gases does not allow using the sensor in a conventional way. The main aim of this study is to acquire the information about the concentration using different approaches: a linear approximation, a non-linear approximation and a tangent method. In this paper a two-steps procedure for sensor response measurements has been utilized. Polypyrrole films were electrochemically synthesized on...
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Foreign Entry Modes of High-tech Firms in Poland
PublikacjaThe main objective of the article is to present the role and importance of foreign entry modes in internationalization process and their key determinants. Research methods: A quantitative research design was used. A survey was conducted on the sample of 263 firms operating in...
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Global Surrogate Modeling by Neural Network-Based Model Uncertainty
PublikacjaThis work proposes a novel adaptive global surrogate modeling algorithm which uses two neural networks, one for prediction and the other for the model uncertainty. Specifically, the algorithm proceeds in cycles and adaptively enhances the neural network-based surrogate model by selecting the next sampling points guided by an auxiliary neural network approximation of the spatial error. The proposed algorithm is tested numerically...
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Neural Approximators for Variable-Order Fractional Calculus Operators (VO-FC)
PublikacjaThe paper presents research on the approximation of variable-order fractional operators by recurrent neural networks. The research focuses on two basic variable-order fractional operators, i.e., integrator and differentiator. The study includes variations of the order of each fractional operator. The recurrent neural network architecture based on GRU (Gated Recurrent Unit) cells functioned as a neural approximation for selected...
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Rothe’s method for physiologically structured models with diffusion
PublikacjaWe consider structured population models with diffusion and dynamic boundary conditions. The respective approximation, called Rothe’s method, produces positive and exponentially bounded solutions. Its solutions converge to the exact solution of the original PDE.
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Computational methods for calculation of binding free energy for ligand-receptor complexes
PublikacjaAccurate description of the molecular complexes energetic influence is required for understanding of many biological functions carried out by proteins. Therefore, estimation of binding free energy for ligand-receptor complexes is of highest importance for structure-based ligand design and drug discovery approaches.Experimental methods of determination of difference in Gibbs'es free energy have many limitations. Thus, computational...
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Multiresolution analysis and adaptive estimation on a sphere using stereographic wavelets
PublikacjaWe construct an adaptive estimator of a density function on d dimensional unit sphere Sd (d ≥ 2), using a new type of spherical frames. The frames, or as we call them, stereografic wavelets are obtained by transforming a wavelet system, namely Daubechies, using some stereographic operators. We prove that our estimator achieves an optimal rate of convergence on some Besov type class of functions by adapting to unknown smoothness....
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Gas sensors based on conducting polymers-recent developments
PublikacjaThis work discusses sensing performance dependence of PEDOT polymer and its composites on the counter ions used in the polymerization process. The sensors based on PEDOT-RGO composite show reversible response to NO2, while on PEDOT/LiClO4 irreversible. As a result, PEDOT-RGO could be used as a typical gas sensor, while sensor based PEDOT/LiClO4 could be used as an integrating gas sensor, also known as an accumulating gas sensor....
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Aproksymacja przebiegu trasy kolejowej na przykładzie krzywoliniowego odcinka połączenia Somonino-Gdańsk Osowa
PublikacjaW artykule zaprezentowano wyniki wyznaczenia współrzędnych przebiegu trasy kolejowej metodami aproksymacji wielomianowej i interpolacji krzywą kubiczną w oparciu o pomiary czasu rzeczywistego GPS zrealizowane z wykorzystanie polskiej aktywnej sieci geodezyjnej ASG-EUPOS. Rozważania teoretyczne poparte zostały praktycznym przykładem aplikacyjnym opartym o zrealizowane pomiary inwentaryzacyjne zmodernizowanego odcinka toru kolejowego...
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Application of regularized Savitzky–Golay filters to identification of time-varying systems
PublikacjaSavitzky–Golay (SG) filtering is a classical signal smoothing technique based on the local least squares approximation of the analyzed signal by a linear combination of known functions of time (originally — powers of time, which corresponds to polynomial approximation). It is shown that the regularized version of the SG algorithm can be successfully applied to identification of time-varying finite impulse response (FIR) systems....
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Shared processor scheduling of multiprocessor jobs
PublikacjaWe study a problem of shared processor scheduling of multiprocessor weighted jobs. Each job can be executed on its private processor and simultaneously on possibly many processors shared by all jobs. This simultaneous execution reduces their completion times due to the processing time overlap. Each of the m shared processors may charge a different fee but otherwise the processors are identical. The goal is to maximize the total...
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Scheduling on Uniform and Unrelated Machines with Bipartite Incompatibility Graphs
PublikacjaThe problem of scheduling jobs on parallel machines under an incompatibility relation is considered in this paper. In this model, a binary relation between jobs is given and no two jobs that are in the relation can be scheduled on the same machine. We consider job scheduling under the incompatibility relation modeled by a bipartite graph, under the makespan optimality criterion, on uniform and unrelated machines. Unrelated machines...
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Connected early-career experiences of equality in academia during the pandemic and beyond: Our liminal journey
PublikacjaIn this paper, we draw on our subjective experiences as two female early-career academics during the global COVID-19 pandemic. While we acknowledge that the pandemic had negative implications for many female scholars due to compulsory telework or increased family responsibilities, we also want to shed light on the empowering experiences shaped by collegial support that became an important part of our pandemic story. We build on...
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Multi-objective design of miniaturized impedance transformers by domain segmentation
PublikacjaFast multi-objective design optimization of compact microstrip impedance transformers is discussed. Our approach exploits approximation models constructed using sampled coarse- mesh EM simulation data in a partitioned design space and response correction techniques for design refinement. Demonstra
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Combined spline wavelet decomposition for 3d seafloor imaging from multibeam sonar echoes
PublikacjaThe paper proposes combined spline-wavelet approach to the raw echoes seaflor imaging from Multibeam Sonar System (MBSS) records. Wavelet representation is closely related to image representation, due to its unique approximations properties. Splines have the best approximation properties among all known wavelets of a given order, so they are best suited for approximating of smooth seafloor surface. Additionaly, wavelet bases have...
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Method of lines for physiologically structured models with diffusion
PublikacjaWe deal with a size-structured model with diffusion. Partial differential equations are approximated by a large system of ordinary differential equations. Due to a maximum principle for this approximation method its solutions preserve positivity and boundedness. We formulate theorems on stability of the method of lines and provide suitable numerical experiments.
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Cost-efficient multi-objective design optimization of antennas in highly-dimensional parameter spaces
PublikacjaMulti-objective optimization of antenna structures in highly-dimensional parameter spaces is investigated. For expedited design, variable-fidelity EM simulations and domain patching algorithm are utilized. The results obtained for a monopole antenna with 13 geometry parameters are compared with surrogate-assisted optimization involving response surface approximation modeling.
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Pareto Ranking Bisection Algorithm for EM-Driven Multi-Objective Design of Antennas in Highly-Dimensional Parameter Spaces
PublikacjaA deterministic technique for fast surrogate-assisted multi-objective design optimization of antennas in highly-dimensional parameters spaces has been discussed. In this two-stage approach, the initial approximation of the Pareto set representing the best compromise between conflicting objectives is obtained using a bisection algorithm which finds new Pareto-optimal designs by dividing the line segments interconnecting previously...
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On the Structure of Time in Computational Semantics of a Variable-Step Solver for Hybrid Behavior Analysis
PublikacjaHybrid dynamic systems combine continuous and discrete behavior. Often, computational approaches are employed to derive behaviors that approximate the analytic solution. An important part of this is the approximation of differential equation behavior by numerical integration. The accuracy and computational efficiency of the integration usually depend on the complexity of the method and its implicated approximation errors, especially...
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Laboratory Determination of Burger's Model Parameters for Visco-elastic Analysis of Road Pavement Materials
PublikacjaBurger's Model is one of those models that describes performance of asphalt mixtures. Its parameters can be used in road construction analysis based on visco-elastic properties in wide variety of temperatures using dedicated programs (e.g. Veroad) or in Finite Element Method (FEM). Parameters of Burger's Model can be used for example in prediction of low temperature cracking in low winter temperatures or permanent deformation...
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A Simplified Method of Trend Removal to Determine Noise Observed During a Supercapacitor’s Discharging
PublikacjaIn this paper, new method of trend removal is proposed. This is a simplified method based on Empirical Mode Decomposition (EMD). The method was applied for voltage time series observed during supercapacitor discharging process. It assured the determination of an additive noise component after subtracting the identified trend component. We analyzed voltage time series observed between the terminals of the supercapacitor when discharged...
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Oriented Gaussian beams for high-accuracy computation with accuracy control of X-ray propagation through a multi-lens system
PublikacjaA highly accurate method for calculating X-ray propagation is developed. Within this approach, the propagating wave is represented as a superposition of oriented Gaussian beams. The direction of wave propagation in each Gaussian beam agrees with the local direction of propagation of the X-ray wavefront. When calculating the propagation of X-ray waves through lenses, the thin lens approximation is applied. In this approximation,...
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Fundamentals of Physics-Based Surrogate Modeling
PublikacjaChapter 1 was focused on data-driven (or approximation-based) modeling methods. The second major class of surrogates are physics-based models outlined in this chapter. Although they are not as popular, their importance is growing because of the challenges related to construction and handling of approximation surrogates for many real-world problems. The high cost of evaluating computational models, nonlinearity of system responses,...
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Exploiting multi-interface networks: Connectivity and Cheapest Paths
PublikacjaLet G = (V,E) be a graph which models a set of wireless devices (nodes V) that can communicate by means of multiple radio interfaces, according to proximity and common interfaces (edges E). The problem of switching on (activating) the minimum cost set of interfaces at the nodes in order to guarantee the coverage of G was recently studied. A connection is covered (activated) when the endpoints of the corresponding edge share at...
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Design Space Reduction for Expedited Multi-Objective Design Optimization of Antennas in Highly-Dimensional Spaces
PublikacjaA surrogate-based technique for efficient multi-objective antenna optimization is discussed. Our approach exploits response surface approximation (RSA) model constructed from low-fidelity antenna model data (here, obtained through coarse-discretization electromagnetic simulations). The RSA model enables fast determination of the best available trade-offs between conflicting design goals. The cost of RSA model construction for multi-parameter...
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Reduced-Cost Constrained Modeling of Microwave and Antenna Components: Recent Advances
PublikacjaElectromagnetic (EM) simulation models are ubiquitous in the design of microwave and antenna components. EM analysis is reliable but CPU intensive. In particular, multiple simulations entailed by parametric optimization or uncertainty quantification may considerably slow down the design processes. In order to address this problem, it is possible to employ fast metamodels. Here, the popular solution approaches are approximation...
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Pressure effects on the electronic structure and superconductivity of (TaNb)0.67(HfZrTi)0.33 high entropy alloy
PublikacjaEffects of pressure on the electronic structure, electron-phonon interaction, and superconductivity of the high entropy alloy ( TaNb ) 0.67 ( HfZrTi ) 0.33 are studied in the pressure range 0–100 GPa. The electronic structure is calculated using the Korringa-Kohn-Rostoker method with the coherent potential approximation. Effects of pressure on the lattice dynamics are simulated using the Debye-Grüneisen model and the Grüneisen...
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On Bayesian Tracking and Prediction of Radar Cross Section
PublikacjaWe consider the problem of Bayesian tracking of radar cross section. The adopted observation model employs the gamma family, which covers all Swerling cases in a unified framework. State dynamics are modeled using a nonstationary autoregressive gamma process. The principal component of the proposed solution is a nontrivial gamma approximation, applied during the time update recursion. The superior performance of the proposed approach...
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Residue-Pole Methods for Variability Analysis of S-parameters of Microwave Devices with 3D FEM and Mesh Deformation
PublikacjaThis paper presents a new approach for variability analysis of microwave devices with a high dimension of uncertain parameters. The proposed technique is based on modeling an approximation of system by its poles and residues using several modeling methods, including ordinary kriging, Adaptive Polynomial Chaos (APCE), and Support Vector Machine Regression (SVM). The computational cost is compared with the traditional Monte-Carlo...