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Application of a stochastic compartmental model to approach the spread of environmental events with climatic bias
PublikacjaWildfires have significant impacts on both environment and economy, so understanding their behaviour is crucial for the planning and allocation of firefighting resources. Since forest fire management is of great concern, there has been an increasing demand for computationally efficient and accurate prediction models. In order to address this challenge, this work proposes applying a parameterised stochastic model to study the propagation...
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Analysis of ring cracks in ceramic rolling elements using the boundary element method
PublikacjaCeramic materials have been increasingly used in bearing technology for over a dozen years. This is due to the characteristic properties of ceramic materials such as: high hardness, corrosion resistance, the possibility of use in aggressive chemical environments, as well as due to the lower specific weight compared to steel materials. However, the use of ceramic materials is connected with many limitations. The main disadvantages...
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A higher order transversely deformable shell-type spectral finite element for dynamic analysis of isotropic structures
PublikacjaThis paper deals with certain aspects related to the dynamic behaviour of isotropic shell-like structures analysed by the use of a higher order transversely deformable shell-type spectral finite element newly formulated and the approach known as the Time-domain Spectral Finite Element Method (TD-SFEM). Although recently this spectral approach is reported in the literature as a very powerful numerical tool used to solve various...
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Generalized Taylor formula and shell structures for the analysis of the interaction between geosythetics and engineering structures of transportation lines
PublikacjaThe analysis of the interaction between geosynthetics and engineering structures (e.g. railroad bed, soil foundation, pipeline) assumes that the geosynthetic form elastic membranes or shell laid on different types of foundations. The mathematical description of that problems in continuous domain employs Laplace operator Δ or d’Alembert operator □. In this paper we demonstrate the analysis based on generalize Taylor formula, and...
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A Note on Reduced Strain Gradient Elasticity
PublikacjaWe discuss the particular class of strain-gradient elastic material models which we called the reduced or degenerated strain-gradient elasticity. For this class the strain energy density depends on functions which have different differential properties in different spatial directions. As an example of such media we consider the continual models of pantographic beam lattices and smectic and columnar liquid crystals.
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Multipath Complex Root Tracing
PublikacjaThe problem of multipath root tracing is being addressed in this communication. The self-adaptive complex root tracing algorithm, which was previously utilized for the investigation of various propagation and radiation problems, is analyzed here for the cases when the traced characteristic bifurcates. A procedure of multiroute detection is proposed and demonstrated on the coaxially loaded cylindrical waveguide example.
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Integrable zero-range potentials in a plane
PublikacjaWe examine general statements in the Wronskian representation of Darboux transformations for plane zero-range potentials. Such expressions naturally contain scattering problem solution. We also apply Abel theorem to Wronskians for differential equations and link it to chain equations for Darboux transforms to fix conditions for further development of the underlying distribution concept. Moutard transformations give a convenient...
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Selected problems of sensitivity and reliability of a jack-up platform
PublikacjaThe paper deals with sensitivity and reliability applications to numerical studies of an off-shore platform model. Structural parameters and sea conditions are referred to the Baltic jack-up drilling platform. The study aims at the influence of particular basic variables on static and dynamic response as well as the probability of failure due to water waves and wind loads. The paper presents the sensitivity approach to a generalized...
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Study of prototype multi-pole non-salient field winding for high speed brushless synchronous generator
PublikacjaIn this paper a non-salient field winding for a brushless synchronous generator working with high speed in an autonomous energy generation system (e.g. airplane power grid) has been presented. A conception of a six-pole cylindrical-rotor with distributed field winding has been proposed. Comparison study of salient and prototype non-salient field winding has been carried out. Chosen simulation and measurement results of the generator...
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Interactive Application for Visualization of the Basic Phenomena in RF and Microwave Devices
PublikacjaAn interactive computer application visualizing the basic phenomena in RF and microwave devices is presented. Such kind of educational package can be a very helpful tool for the students as well as for the teachers (of electronics and related fields). This paper is focused on three exemplary problems only and involves: movement of electric charge, filtering of electromagnetic waves and interference phenomena in antenna arrays. The...
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Theoretical and experimental study on scattering of low-energy electrons by dimethyl and diethyl ethers
PublikacjaWe report a joint theoretical and experimental investigation on low-energy electron scattering by dimethyl and diethyl ethers. The experimental elastic differential cross sections were measured at impact energies from 1 eV up to 30 eV and scattering angle range of 10◦ to 130◦. Theoretical elastic differential, integral and momentum-transfer cross sections are calculated at impact energies up to 30 eV, employing the Schwinger multichannel...
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The Point Estimate Method in a Reticulated Shell Reliability Analysis
PublikacjaThe objective of this paper is to present an application of the point estimate method (PEM) to determine the probabilistic moments for engineering structures. Reliability analysis is illustrated by two examples: an estimation of the critical force in linear elastic buckling analysis and a reticulated shell limit load determinations. Calculations were also made using Monte Carlo method. It has been shown the practical usefulness...
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Distortional buckling of thin-walled columns of closed quadratic cross-section
PublikacjaThe elastic stability of axially compressed column related to the cross-section distortion is investigated. Two kinds of closed quadratic cross-sections are taken into consideration with internal walls and without it. The governing differential equation is derived with aid of the principle of stationary total potential energy. The critical loads for the simply supported columns are found in an analytical form and compared with...
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Modeling of Composite Shells in 6-Parameter Nonlinear Theory with Drilling Degree of Freedom
PublikacjaWithin the framework of a 6-parameter nonlinear shell theory, with strain measures of Cosserat type, constitutive relations are proposed for thin elastic composite shells. The material law is expressed in terms of five engineering constants of classical anisotropic continuum plus an additional parameter accounting for drilling stiffness. The theory allows for unlimited displacements and rotations. A number of examples are presented...
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New Indoor Positioning Algorithm for Distance Measurements
PublikacjaIn the paper a new indoor positioning algorithm is presented. This algorithm takes into account selected features of radio wave propagation in indoor environment. This results in improvement in accuracy of calculated position estimates. A comparative analysis of this new algorithm with Chan and Foy algorithms was made and described in the paper. This comparative analysis was made with utilization of real radio distance measurements.
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Characterization of corrosion in reinforced concrete beams using destructive and non-destructive tests
PublikacjaThe paper presents both non-destructive and destructive experimental tests on steel-reinforced concrete beams subjected to electrochemical corrosion. To examine the condition and behavior of the specimens, destructive tests were carried out, i.e., a three-point bending together with a modulated ultrasonic wave test. In addition, a series of non-destructive experiments were conducted, such as the potential measurement method, low-frequency...
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A method of selecting light sources from night satellite scenes
PublikacjaSatellite images carries a lot of data. Very sophisticated methods of analyses may reveal very complicated nature of the observed objects. In case of night images, lights play the role of information sources. In this paper we would like to present results of the research aimed to describe light sources from satellite night images by providing description of their luminosity. The authors point source imaging data from the satellite...
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Efficient uncertainty quantification using sequential sampling-based neural networks
PublikacjaUncertainty quantification (UQ) of an engineered system involves the identification of uncertainties, modeling of the uncertainties, and the forward propagation of the uncertainties through a system analysis model. In this work, a novel surrogate-based forward propagation algorithm for UQ is proposed. The proposed algorithm is a new and unique extension of the recent efficient global optimization using neural network (NN)-based...
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A study on transverse shear correction for laminated sandwich panels
PublikacjaThe paper presents a study on an application of the First Order Shear Deformation Theory in a linear static analysis of elastic sandwich panels. A special attention has been given to the issue of the transverse shear correction. Two benchmark examples of sandwich plate problems with known reference solutions have been selected for a comparative analysis performed with own Finite Element codes. Interesting results allowed for drawing...
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On the Bending of Multilayered Plates Considering Surface Viscoelasticity
PublikacjaWe discuss the bending resistance of multilayered plates taking into account surface/interfacial viscoelasticity. Within the linear surface viscoelasticity we introduce the surface/interfacial stresses linearly dependent on the history of surface strains. In order to underline the surface viscoelasticity contribution to the bending response we restrict ourselves to the elastic behaviour in the bulk. Using the correspondence principle...
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High Resolution Sea Ice Floe Size and Shape Data from Knox Coast, East Antarctica
PublikacjaThis dataset contains floe size distribution data from a very high resolution (pixel size: 0.3 m) optical satellite image of sea ice, acquired on 16 Feb. 2019 off the Knox Coast (East Antarctica). The image shows relatively small ice floes produced by wave-induced breakup of landfast ice between Mill Island and Bowman Island. The ice floes are characterised by a narrow size distribution and angular, polygonal shapes, typical...
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Testing the impact of simplifications adopted in models describing wave loads on ship
PublikacjaThe wave-ship system in naval architecture is generally assumed to be a linear one. This allows for the computation of a transfer function of ship response to waves including wave loads on ship. The transfer function and the wave spectral density function enable the development of the stochastic process of wave loads on ship, corresponding to the irregular wave generating that loads. If the mathematical models of wave load transfer...
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Testing the impact of simplifications adopted in models describing wave loads on ship
PublikacjaThe wave-ship system in naval architecture is generally assumed to be a linear one. This allows for the computation of a transfer function of ship response to waves including wave loads on ship. The transfer function and the wave spectral density function enable the development of the stochastic process of wave loads on ship, corresponding to the irregular wave generating that loads. If the mathematical models of wave load transfer...
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Numerical modeling of sound intensity distributions around acoustic transducer
PublikacjaThe aim of this research study is to measure, simulate and compare sound intensity distribution generated by the acoustic transducers of the loudspeaker. The comparison of the gathered data allows for validating the numerical model of the acoustic radiation. An accurate model of a sound source is necessary in mathematical modeling of the sound field distribution near the scattering obstacles. An example of such obstacle is a human...
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SIMULATION OF PROCEED® SURGICAL MESH APPLIED TO VENTRAL HERNIA REPAIR
PublikacjaIn the present research, Proceed® implant is considered. The system is subjected to short-time dynamic pressure load, similar to post-operative cough naturally occurring in human abdomen. The model refers to a clinical case of 5cm of hernia operated by Proceed implant fixed by 15 joints every 3cm around the orifice. The simulations of the implanted mesh are performed by means of the Finite Element Method. The implant is modelled...
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Mechanical Behavior of Bi-Layer and Dispersion Coatings Composed of Several Nanostructures on Ti13Nb13Zr Alloy
PublikacjaTitanium implants are commonly used because of several advantages, but their surface modification is necessary to enhance bioactivity. Recently, their surface coatings were developed to induce local antibacterial properties. The aim of this research was to investigate and compare me-chanical properties of three coatings: multi-wall carbon nanotubes (MWCNTs), bi-layer composed of an inner MWCNTs layer and an outer TiO2 layer, and...
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Using Minimum Actuators to Control Shape and Stress of a Double Layer Spherical Model Under Gravity and Lateral Loadings
PublikacjaSpherical domes are picturesque structures built in developed countries to attract tourists. Due to horizontal and vertical overloading, the structures’ attractive shapes may be disturbed, and some members' stress may exceed the elastic level. In this paper, the shape and stress of a deformed double-layer spherical numerical model due to simultaneous lateral and vertical loadings are controlled, meanwhile, the number of actuators...
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Analiza konstrukcji nawierzchni asfaltowych oparta o teorię lepkosprężystości
PublikacjaPrzedmiotem artykułu jest analiza przykładowej konstrukcji nawierzchni drogowej podatnej w oparciu o liniową teorię lepkosprężystości. Do symulacji pracy warstw asfaltowych wykorzystano model Burgersa, a obliczenia wykonano przy użyciu programu VEROAD (Visco-Elastic RoadAnalysis Delft). Autor poddaje analizie odkształcenia na spodzie warstw asfaltowych oraz ich deformacje odwracalne i trwałe, a także bada wpływ temperatury.
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Can we really solve an arch stability problem?
PublikacjaWe bring attention to the problem of solving nonlinear boundary-value problems for elastic structures such as arches and shells. Here we discuss a classical problem of a shear-deformable arch postbuckling. Considering a postbuckling behaviour of a circular arch we discuss the possibility to find numerically a solution for highly nonlinear regimes. The main attention is paid to the problem of determination of all solutions. The...
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Mechanical properties of Precontraint 1202 S2 based on uniaxial tensile and creep tests
PublikacjaThe purpose of the paper is the estimation of the polyvinyl chloride – polyester-coated fabric (Precontraint 1202 S2) mechanical properties under uniaxial tensile tests as well as short- and long-time creep tests. The uniaxial tests are the basis of non-linear elastic description while the creep tests are used for the evaluation of the stiffness parameters in time and for the identification of the standard viscoelastic model. The...
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A Monte Carlo Strategy to simulate Positrons and Positronium in biological Materials
PublikacjaWe present an algorithm for Monte Carlo simulations of positron tracks in biological materials. The algorithm takes into account the cross-section data for elastic and inelastic collisions between positrons and molecules and processes like direct annihilation, ionization and positronium formation. In the case of positronium formation, the algorithm considers the interactions of positronium with molecules. The algorithm can be used...
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Computational fluid dynamics simulation of heat transfer from densely packed gold nanoparticles to isotropic media
PublikacjaThis work aims to determine and compare heat generation and propagation of densely packed gold nanoparticles (Au NPs) induced by a resonant laser beam (532 nm) according to the Mie theory. The heat flux propagation is transferred into the materials, which here are: silica glass; soda-lime-silica glass; borosilicate glass; polymethyl methacrylate (PMMA); polycarbonate (PC); and polydimetylosiloxane (PDMS). This analysis aims to...
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Integrated Application of GPR and Ultrasonic Testing in the Diagnostics of a Historical Floor
PublikacjaThe paper presents the results of integrated ground penetrating radar (GPR) and ultrasonic testing (UT) measurements conducted on a historical floor in St. Nicholas’ Church, Gdańsk, Poland. The described inspection was the first stage of the technical state assessment of the building. The aim of the study was the detection of underfloor air gaps, which were observed in a few trial pits. The condition of the ground under the floor...
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Non-Destructive Assessment of Masonry Pillars using Ultrasonic Tomography
PublikacjaIn this paper, a condition assessment of masonry pillars is presented. Non-destructive tests were performed on an intact pillar as well as three pillars with internal inclusions in the form of a hole, a steel bar grouted by gypsum mortar, and a steel bar grouted by cement mortar. The inspection utilized ultrasonic stress waves and the reconstruction of the velocity distribution was performed by means of computed tomography. The...
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Chosen Analysis Results Of The Prototype Multicell Piezoelectric Motor
PublikacjaThis paper presents the design, modeling and tests of the prototype multicell piezoelectric motor (MPM). A new concept of the electromechanical structure of the considered prototype is based on three rotating-mode actuators. The electromechanical structure of each actuator has been considered as an independent one - referred to as a “single cell” (single actuator). Combined three resonant actuators generate three traveling waves...
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On the Nonlinea Distortions of Sound and its Coupling with Other Modes in a Gasesous Plasma with Finite Electric Conductivity in a Magnetic Field
PublikacjaNonlinear phenomena of the planar and quasi-planar magnetoacoustic waves are considered. We focus on deriving of equations which govern nonlinear excitation of the non-wave motions by the intense sound in initially static gaseous plasma. The plasma is treated as an ideal gas with finite electrical conductivity permeated by a magnetic field orthogonal to the trajectories of gas particles. This introduces dispersion of a flow. Magnetoacoustic...
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Using Wearable Electronics to Estimate Usefulness of Heart Rate Variability for Bathing Person Identif Cation
PublikacjaIn this paper the possibility of person identification based on biosignal is investigated. The work focus on the analysis of the changes in intervals between successive R-waves of electrocardiogram (ECG) recorded by wearable electronics in form of a necklaces. The main idea behind this project is to find efficient tool which may prevent sudden consciousness loss episodes or even sudden death episodes related to rapid temperature...
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New concept and analysis of the multicell piezoelectric motor
PublikacjaThis work presents the design, modeling and tests of the prototype multicell piezoelectric motor (MPM). A new concept of the electromechanical structure of the considered prototype is based on three rotating-mode actuators. The electromechanical structure of each actuator has been considered as an independent one - referred to as a ”single cell” (single actuator). Combined three resonant actuators generate three traveling waves...
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Influence of Giant Reed (Arundo Donax L.) Culms Processing Procedure on Physicochemical, Rheological, and Thermomechanical Properties of Polyethylene Composites
PublikacjaGiant reed (Arundo donax L.) is a plant species with a high growth rate and low requirements, which makes it particularly interesting for the production of different bioproducts, including natural fibers. This work assesses the use of fibers obtained from reed culms as reinforcement for a high-density polyethylene (HDPE) matrix. Two different lignocellulosic materials were used: i) shredded culms and ii) fibers obtained by culms...
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On Nonlinear Bending Study of a Piezo-Flexomagnetic Nanobeam Based on an Analytical-Numerical Solution
PublikacjaAmong various magneto-elastic phenomena, flexomagnetic (FM) coupling can be defined as a dependence between strain gradient and magnetic polarization and, contrariwise, elastic strain and magnetic field gradient. This feature is a higher-order one than piezomagnetic, which is the magnetic response to strain. At the nanoscale, where large strain gradients are expected, the FM effect is significant and could be even dominant. In...
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The Role of Molecular Structure in Monte Carlo Simulations of the Secondary Electron Yield and Backscattering Coefficient from Methacrylic Acid
PublikacjaIn this paper, we show the influence of the chemical structure of four different conformers on the secondary electron emission and backscattering of an electron beam from a gel of methacrylic acid. The conformers have different permanent dipole moments, which determines the cross sections for elastic collisions with electrons. The cross sections are used in Monte Carlo simulations of an electron beam, which enters the gel of methacrylic...
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Acoustic Streaming Induced by Periodic and Aperiodic Sound in a Bubbly Liquid
PublikacjaThe vortex ow which follows intense sound propagating in a bubbly liquid, is considered. The reasons for acoustic streaming are both nonlinearity and dispersion. That makes streaming especial as compared with that in a Newtonian uid. Conclusions concern the vortex ow induced in a half-space by initially harmonic or impulse Gaussian beam. The vortex ow recalls a turbulent ow with increasing in time number of small-scale vortices...
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Estimation of the uncertainty of the AC/AC transducer output voltage
PublikacjaThe paper presents a methodology for estimating uncertainty of voltage transducers processing function, on the example of CYVS411D07 voltage transducers. The analysis was conducted using the method based on the GUM Guide propagation of uncertainty law and the determination of the coverage factor based on the effective number of degrees of freedom (t-Student distribution). The paper also presents example evaluation results of measured...
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Application of the distributed transfer function method and the rigid finite element method for modelling of 2-D and 3-D systems
PublikacjaIn the paper application of the Distributed Transfer Function Method and the Rigid Finite Element Method for modelling of 2-D and 3-D systems is presented. In this method an elastic body is divided into 1-D distributed parameter elements (strips or prisms). The whole body (divided into strips or prism) is described by a set of coupled partial differential equations. Solving this equations in the state space form it is possible...
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Geometrically nonlinear FEM analysis of 6-parameter resultant shell theory based on 2-D Cosserat constitutive model
PublikacjaWe develop the elastic constitutive law for the resultant statically and kinematically exact, nonlinear, 6-parameter shell theory. The Cosserat plane stress equations are integrated through-the- thickness under assumption of the Reissner-Mindlin kinematics. The resulting constitutive equations for stress resultant and couple resultants are expressed in terms of two micropolar constants: the micropolar modulus Gc and the micropolar...
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Laminated plates and shells - first ply failure analysis within 6-parameter shell theory
PublikacjaThis work describes Tsai-Wu and Hashin criteria modifications, dictated by nonlinear 6-parameter shell theory with asymmetric strain measures and drilling rotation. The material law is based on standard orthotropic elastic constants for a non-polar continuum, under plane state of stress. First ply failure loads of cylindrical panel subjected to pressure and flat compressed plate are estimated by means of Finite Element Analysis....
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Similarity Measures for Face Images: An Experimental Study
PublikacjaThis work describes experiments aimed at finding a straightforward but effective way of comparing face images.We discuss properties of the basic concepts, such as the Euclidean, cosine and correlation metrics, test the simplest version of elastic templates, and compare these solutions with distances based on texture descriptors (Local Ternary Patterns). The influence of selected image processing methods (e.g. bilateral ltering)...
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Monte-Carlo Modeling of Optical Sensors for Postoperative Free Flap Monitoring
PublikacjaThis work aims to develop a numerical tissue model and implement software to simulate photon propagation using the Monte Carlo method to determine design guidelines for a physical measurement system. C++ was used for the simulation program, and Python as a programming environment to create an interface that allows the user to customize individual simulation elements, allowing for increased accuracy and flexibility when simulating...
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Numerical modeling of quantum dynamical processes
PublikacjaIn this dissertation I present a high-precision (15, 18 or 33 decimal places) C++ implementation of quantum dynamics time propagation algorithms for both time-independent and time-dependent Hamiltonian with an inhomogeneous source term. Moreover I present an extension of both algorithms for time propagation to handle arbitrary number of coupled electronic levels. I have performed a careful validation of these implementations comparing...
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Monte-Carlo Modeling of Optical Sensors for Postoperative Free Flap Monitoring
PublikacjaThis work aims to develop a numerical tissue model and implement software to simulate photon propagation using the Monte Carlo method to determine design guidelines for a physical measurement system. C++ was used for the simulation program, and Python as a programming environment to create an interface that allows the user to customize individual simulation elements, allowing for increased accuracy and flexibility when simulating...