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Search results for: stochastic dynamics
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Weakly nonlinear dynamics of short acoustic waves in exponentially stratified gas
PublicationRozpatruje się dynamika krótkich (w porównywaniu z charakterystyczną skalą zmiany gęstości gazu atmosferycznego) fal akustycznych. Wyprowadzone nowe równanie ewolucyjne, które uwzględnia dyspersję i nieliniowy charakter propagacji tych fal. Porównuje sie liniowa i nieliniowa dynamika. Ilustracje propagacji, numeryczne wyliczione na podstawie nowych wzorów, są przedstawione. Indexed and abstracted (from vol. 32(1) 2007) in Science...
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Effect of Nanohydroxyapatite on Silk Fibroin–Chitosan Interactions—Molecular Dynamics Study
PublicationFibroin–chitosan composites, especially those containing nanohydroxyapatite, show potential for bone tissue regeneration. The physicochemical properties of these biocomposites depend on the compatibility between their components. In this study, the intermolecular interactions of fibroin and chitosan were analyzed using a molecular dynamics approach. Two types of systems were investigated: one containing acetic acid and the other...
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Interaction of amphotericin B with phospholipids in the model membrane - molecular dynamics study.
PublicationAmfoterycyna B jest antybiotykiem używanym w leczeniu układowych infekcji grzybowych. Jej mechanizm działania polega na tworzeniu kanałów wewnątrz błon lipidowych. W przedstawianej pracy publikowane są wyniki symulacji przeprowadzonej dynamiką molekularną monomerycznej i dimerycznej formy antybiotyku wewnątrz błony lipidowej zbudowanej z cząsteczek DMPC. Wyniki te wskazują, że powinowactwo cząsteczek amfoterycyny wewnątrz dimeru...
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SimMechanics package - some effective tool for pedagogical exercises in multibody dynamics.
PublicationW pracy skoncentrowano się na poszukiwaniach narzędzia przydatnego w procesie nauczania dynamiki układów wielomasowch. Proces ten, z natury dwuetapowy, wymaga aby klasyczne wykłady dla studentów poszerzyć o ćwiczenia komputerowe, pozwalające na samodzielne modelowanie wybranych układów. Wymaga to zastosowania oprogramowania łatwego do nauki i wykorzystania, w tym pozwalającego na szybkie modelowanie prostych mechanizmów i umożliwiającego...
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Investigation of influence of space mopdes interaction on nonlinear dynamics of sound beams
PublicationOperatory rzutu na mody są zdefiniowane w dynamice płynów trójwymiarowych. Zostały wyprowadzone równania ewolucyjne. Rezultaty obliczeń numerycznych przedstawione.
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A Molecular dynamics study of the influence of chemical reduction on the structure of amorphous germania
PublicationPraca poświęcona jest badaniom struktury blisko- i średniozasięgowej redukowanego amorficznego tlenku germanu o składzie 1Ge 1GeO2 za pomocą symulacji dynamiczno-molekularnych. Symulacje MD realizowano w zespole mikrokanonicznym (NVE), z wykorzystaniem dwuciałowego potencjału oddziaływania miedzyatomowego Borna-Mayera-Hugginsa. Wyraźnie widoczna tendencja do aglomeracji neutralnych atomów Ge została porównana z tendencją do aglomeracji...
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The Dynamics of Party System in India: A Comparative Study of National and Regional Parties
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The structure of Pb-PbO-SiO2 glass via molecular dynamics simulation
PublicationPraca poświęcona jest badaniom struktury blisko i średniozasięgowej częściowo zredukowanego szkła ołowiowo-krzemianowego o stechiometrii 1Pb1PbO1SiO2 uzyskanego na drodze symulacji dynamiczno-molekularnych. Otrzymane rezultaty porównamy z danymi otrzymanymi dla szkła niemodyfikowanego (2PbO1SiO2) i całkowicie zredukowanego (2Pb1SiO2).
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The structure of porous and spontaneously densified amorphous PbSiO3: a Molecular Dynamics study.
PublicationW pracy zaproponowano nową metodę numerycznego otrzymywania strukturporowatych metodą dynamiki molekularnej. Metoda polega na rozpoczęciu symulacji z ładunkami ekranowanymi i stopniowym zwiększaniu ich do pełnych ładunków jonowych. Metodę zastosowano do układu PbSiO3.
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Dynamics of mechanical model of implant-tissue system in ventral hernia repair
PublicationThe paper deals with a finite element modelling of implants in the problem of ventral hernia repair. The synthetic mesh implanted in the abdomen during surgery is here modelled as a membrane structure. Thesystem undergoes the internal abdominal pressure that occurs during the postoperative cough, the load identified in the literature as the main cause of the connection failure and hernia recurrence. The model can be used to estimate...
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Structure and Molecular Dynamics in Renewable Polyamides from Dideoxy-Diamino Isohexide
PublicationThe chemical structure, the conformation, andthe flexibility of the polymer chain fragments present in thepolyamides synthesized from 2,5-diamino-2,5-dideoxy-1,4;3,6-dianhydrosorbitol, 1,4-diaminobutane, and either sebacic orbrassylic acid have been studied by liquid-state 2D NMRspectroscopy viz. correlation spectra (COSY) and heteronuclearmultiple-bond correlation spectra (gHMBC), by 13Ccross-polarization/magic-angle spinning...
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A Comprehensive Review: Applications of the Kozeny–Carman Model in Engineering with Permeability Dynamics
PublicationIn this review article, we investigate the dynamic nature of the Kozeny–Carman Model concerning permeability and its application in engineering contexts. Providing insights into the changing dynamics of permeability within mining, petroleum, and geotechnical engineering, among other engineering applications. While some are complex and require additional modifcations to be applicable, others are simple and still function in specifc...
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A NUMERICAL STUDY ON THE DYNAMICS OF DENGUE DISEASE MODEL WITH FRACTIONAL PIECEWISE DERIVATIVE
PublicationThe aim of this paper is to study the dynamics of Dengue disease model using a novel piecewise derivative approach in the sense of singular and non-singular kernels. The singular kernel operator is in the sense of Caputo, whereas the non-singular kernel operator is the Atangana–Baleanu Caputo operator. The existence and uniqueness of a solution with piecewise derivative are examined for the aforementioned problem. The suggested...
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Hydration of N-Hydroxyurea from Ab Initio Molecular Dynamics Simulations
PublicationN-Hydroxyurea (HU) is an important chemotherapeutic agent used as a first-line treatment in conditions such as sickle cell disease and β-thalassemia, among others. To date, its properties as a hydrated molecule in the blood plasma or cytoplasm are dramatically understudied, although they may be crucial to the binding of HU to the radical catalytic site of ribonucleotide reductase, its molecular target. The purpose of this work...
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Analysis of dynamics of a map-based neuron model via Lorenz maps
PublicationModeling nerve cells can facilitate formulating hypotheses about their real behavior and improve understanding of their functioning. In this paper, we study a discrete neuron model introduced by Courbage et al. [Chaos 17, 043109 (2007)], where the originally piecewise linear function defining voltage dynamics is replaced by a cubic polynomial, with an additional parameter responsible for varying the slope. Showing that on a large...
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Studies of the Interaction Dynamics in Albumin-Chondroitin Sulfate Systems by Recurrence Method
PublicationThe physicochemical basis of lubrication of articular cartilage is still not fully understood. However, the synergy between components of the synovial fluid can be a crucial factor that could explain this phenomenon. This work presents a nonlinear data analysis technique named the recurrence method, applied to the system involving two components of synovial fluid: albumin and chondroitin sulfate (CS) immersed in a water environment....
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Studies of Nonlinear Sound Dynamics in Fluids Based on the Caloric Equation of State
PublicationThe sound speed and parameters of nonlinearity B/A, C/A in a fluid are expressed in terms of coefficients in the Taylor series expansion of an excess internal energy, in powers of excess pressure and density. That allows to conclude about features of the sound propagation in fluids, the internal energy of which is known as a function of pressure and density. The sound speed and parameters of nonlinearity in the mixture consisting...
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Nonlinear Modeling in Time Domain Numerical Analysis of Stringed Instrument Dynamics
PublicationMusical instruments are very various in terms of sound quality with their timbre shaped by materials and geometry. Materials' impact is commonly treated as dominant one by musicians, while it is unclear whether it is true or not. The research proposed in the study focuses on determining influence of both these factors on sound quality based on their impact on harmonic composition. Numerical approach has been chosen to allowed independent...
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Identification of Kinematic Excitation Function by the Modal Coordinates Estimation of the System's Dynamics
PublicationThe paper presents a method of the kinematic excitation courses’ identification in excitation points, based on the car road test acceleration at different measurement points. For the purpose of the laboratory fatigue life investigation of contemporary complex structures (e.g. cars bodies) and components of these structures (i.e. cars roofs), only a few first vibration modes are usually taken into account. During real life tests...
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Local dynamics of fluids and dielectrics as the foundation of signal-carrying wave properties
PublicationThis paper develops an original approach to fundamental problems of classical linear acoustics and electromagnetics, proving a crucial role of doubly-dynamic local properties of a propagation medium in supporting wave-like fields able to carry information signals. The proof is composed of two steps concerning, subsequently, fluid acoustics and dielectric electromagnetics. The first step consists in complementing a common, practically...
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Network Approach to Increments of RR-intervals for Visualization of Dynamics of Cardiac Regulation
PublicationThe transition network for RR -increments is pre- sented in a directed and weighted graph, with vertices represent- ing RR -increments and edges corresponding to the order in a sequence of increments. The adjacency matrix and the transition matrix of this network provide a graphical tool which could be useful in the assessment of cardiac regulation. As an example, the method is applied in detecting differences between diurnal activity...
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Uncertainty Quantification in Experimental Structural Dynamics Identification of Composite Material Structures
PublicationComposite materials are widely used in manufacture of aerospace and wind energy structural components. These load carrying structures are subjected to dynamic time-varying loading conditions. Robust structural dynamics identification procedure impose tight constraints on the quality of modal models estimates obtained from vibration experiments. Modal testing results are influenced by numerous factors introducing uncertainty to...
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Ultrashort Opposite Directed Pulses Dynamics with Kerr Effect and Polarization Account
PublicationWe present the application of projection operator methods to solving the problem of the propagation and interaction of short optical pulses of different polarizations and directions in a nonlinear dispersive medium. We restrict ourselves by the caseof one-dimensional theory, taking into account material dispersion and Kerr nonlinearity. The construction of operators is delivered in two variants: for the Cauchy problem and for the...
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Molecular dynamics simulations of the growth of poly (chloro-para-xylylene) films.
PublicationParylene C, poly(chloro-para-xylylene) is the most widely used member of the parylene family due to its excellent chemical and physical properties. In this work we analyzed the formation of the parylene C film using molecular mechanics and molecular dynamics methods. A five unit chain is necessary to create a stable hydrophobic cluster and to adhere to a covered surface. Two scenarios were deemed to take place. The obtained results...
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A review of emotion recognition methods based on keystroke dynamics and mouse movements
PublicationThe paper describes the approach based on using standard input devices, such as keyboard and mouse, as sources of data for the recognition of users’ emotional states. A number of systems applying this idea have been presented focusing on three categories of research problems, i.e. collecting and labeling training data, extracting features and training classifiers of emotions. Moreover the advantages and examples of combining standard...
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Quantum corrections to 4 model solutions and applications to Heisenberg chain dynamics
PublicationThe 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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Periodic Properties of 1D FE Discrete Models in High Frequency Dynamics
PublicationFinite element discrete models of various engineering 1D structures may be considered as structures of certain periodic characteristics. The source of this periodicity comes from the discontinuity of stress/strain field between the elements. This behaviour remains unnoticeable, when low frequency dynamics of these structures is investigated. At high frequency regimes, however, its influence may be strong enough to dominate calculated...
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Mathematical Modeling of Ice Dynamics as a Decision Support Tool in River Engineering
PublicationThe prediction of winter flooding is a complicated task since it is affected by many meteorological and hydraulic factors. Typically, information on river ice conditions is based on historical observations, which are usually incomplete. Recently, data have been supplemented by information extracted from satellite images. All the above mentioned factors provide a good background of the characteristics of ice processes, but are not...
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Experimental and Numerical Study on Dynamics of Two Footbridges with Different Shapes of Girders
PublicationThe paper presents the experimental and numerical results of the dynamic system identification and verification of the behavior of two footbridges in Poland. The experimental part of the study involved vibration testing under different scenarios of human-induced load, impulse load, and excitations induced by vibration exciter. Based on the results obtained, the identification of dynamic parameters of the footbridges was performed...
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Adaptive dynamic control allocation for over-actuated dynamic positioning system based on backstepping method in case of thruster faults
PublicationThe objective of the research considered in this paper is dynamic positioning of a nonlinear over-actuated marine vessel in the presence of limited information about thruster forces. First, the adaptive backstepping method is used to estimate the input matrix which will compensate partial loss of actuator effectiveness in the presence of actuator dynamics. Then, the adaptive commanded virtual forces and moment are allocated into...
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Contribution of dynamic vehicle loads to pavement failure
PublicationPavement surfaces are not ideally even, which causes dynamic loads of vehicle axles. Distribution of dynamic loads of a given axle is similar to normal distribution and can be described by static load and dynamic load coefficient. The dynamic load coefficient depends on road profile, vehicle speed, properties of suspensions and static load of axle. While for a given road section road profile remains constant, vehicle speed and...
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Economic benefits of dynamic charging of electric buses
PublicationDiesel engines buses are still the most used type of buses. Electric buses provide promising green alternatives and a lot of advantages, but their main disadvantages are limited travel range and long charging time. This article is a presentation of innovative solution for charging of electric busses - Dynamic Charging (IMC). The modern IMC system in Solingen was presented. At the end of the article, a proposal was made to introduce...
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Analysis of the dynamic influences on the Lowland Gate in Gdańsk
PublicationThe Lowland Gate has been built in 1626. It is one of the best-preserved historical buildings in Gdansk. The structure is still of the city's infrastructural importance as through it goes a road connecting two districts. The Gate is now so neglected that it is hard to appreciate its value. The main purpose of the investigation carried out was to determine the harmfulness of the traffic on the structure as well as the reasons of...
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Polish experience of dynamic tests for bored piles
PublicationPrzedstawiono zastosowanie badań dynamicznych, DLT, do oceny nośności wierconych pali wielkośrednicowych.Na podstawie badań terenowych, dla dwóch obiektów mostowych, wykonano badania dynamiczne (DLT) oraz korelacyjne badania statyczne (ASPLT). Określono pełną krzywą osiadania. Uzyskano dobrą zgodność krzywych obciążenie - osiadanie dla zakresu obciążeń roboczych.
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A novel dynamic noise maps visualization tool
PublicationW referacie przedstawiono aplikację realizujacą wizualizację dynamicznych map akustycznych zintegrowaną z multimedialnym systemem monitoringu hałasu. Moduł ten został oparty na nowym podejściu do wykreślania dynamicznych map, w referacie przedstawiono porównanie wyników uzyskanych metodami tradycyjnymi i zaproponowaną metodą. Słowa kluczowe: dynamiczne mapy, wizualizacja, monitoring, hałas, system GIS
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Simulation model for evaluation of QOS dynamic routing
PublicationCurrent informational networks use a large variety of technologies to support data exchange. Most of them are focused on IP protocol and include mechanisms which by definition should supply demanded QoS. One of those mechanisms is efficient path calculation - routing. Traffic offered to the network can change very rapidly in short term. Routing should support such traffic changes and all the time calculate valid paths in terms...
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Test Stand for Metamaterials Dynamic Properties Examination
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The dynamic thermal properties of aerogel-incorporated concretes
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Dynamic effects during emptying of large silos.
PublicationPublikacja obejmuje zagadnienie rezonansowych efektów dynamicznych występujących podczas opróżniania silosów zawierających materiały sypkie
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Dynamic Perfect hashing with finite-state automata
PublicationMinimalna doskonała funkcja mieszająca dostarcza odwzorowania zbioru n niepowtarzalnych słów w zwarty zakres n liczb całkowitych. Gdy jest realizowane za pomocą automatów skończonych, odwzorowanie wynika z porządku słów (zwykle alfabetycznego) w zbiorze. Dodanie nowych słów zmieniłoby porządek słów rozpoznawanych przez automat, zmieniając całe odwzorowanie i czyniąc je bezużytecznym w wielu dziedzinach. Dlatego nazywamy je statycznym....
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Vibration surveillance of dynamic systems and production processes
PublicationPraca dotyczy poszukiwania sposobów minimalizacji poziomu drgań podczas pracy maszyn i urządzeń wykonujących określone procesy robocze. Do modelowania dyskretnego wykorzystano metodę elementów skończonych. Rozważano dynamikę niestacjonarnego dyskretnego układu sterowanego, którego zachowanie opisano we współrzędnych uogólnionych, jak również - układu hybrydowego. Ten ostatni uzyskano dzięki wyodrębnieniu z całości podukładu stacjonarnego,...
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Data processing methods for dynamic medical thermography.
PublicationArtykuł przedstawia zastosowanie nowej metody syntezy obrazów w termografii dla potrzeb opisu ilościowego właściwości termicznych tkanek. Opis taki umożliwia różnicowanie przypadków medycznych. Metodę zastosowania dla licznych pomiarów fantomowych i in vitro w eksperymentach na zwierzętach (świnia domowa). Przedstawiono i omówiono rezultaty prac.
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Fading modelling in dynamic off-body channels
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A Surveillance Of Dynamic Processes in Selected Mechatronic Systems
PublicationThe paper concerns development of original method of optimal control at energy performance index and its application to dynamic processes surveillance of some mechatronic systems. The latter concerns chatter vibration surveillance during highspeed slender milling of rigid details, as well as motion control of two-wheeled mobile platform. Results of on-line computer simulations and real performance on the target objects reflect...
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Dynamic Positioning System with Vectorial Backstepping Controller
PublicationThe problem of synthesis a dynamic positioning system for low frequency model of surface vessel was considered in this paper. The recursive vectorial backstepping control design was used to keep a fixed position and heading in presence of wave disturbances. The passive observer was introduced to smooth the measurements and to estimate the velocities needed for the control algorithm. Some parameters of observer were optimized off-line...
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An Evaluation Engine for Dynamic Ranking of Cloud Providers
PublicationThe paper focuses on creation of an effective dynamic ranking service for IaaS, PaaS and SaaS cloud providers. It considers building a quality model for this purpose along with definition of quality measure- ment procedures. The paper discusses several techniques known from already existing price comparison engines that could be modified and adopted for comparison of cloud providers. A technique for filtering measured data is proposed,...
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Fading Modelling in Dynamic Off-Body Channels
PublicationThis paper presents an off-body fading channel model for Body Area Networks (BANs) in indoor environments. The proposed model, which is based on both simulations and measurements in a realistic environment, consists of three components: mean path loss, body shadowing, and multipath fading. Seven scenarios in an indoor environment (a medium-size room with furniture, mostly consisting of wooden tables and chairs) have been measured:...
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The influence of carbon dioxide on dynamic thermography results
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Implementation of Active Dynamic Thermography in medical diagnostics
PublicationW pracy przedstawiono wyniki badań wdrożeniowych Aktywnej Termografii Dynamicznej w diagnostyce wybranych chorób.
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Dynamic Research of Masonry Vault in a Technical Scale
PublicationThe paper presents preliminary results of dynamic tests of the masonry barrel vault in a technical scale. Experimental studies are intended to identify material properties of homogenized masonry vaults under dynamic loads. The aim of the work is to create numerical models to analyse vault’s dynamic response to dynamic loads in a simplest and accurate way. The process of building the vault in a technical scale is presented in the...